Emissions GR Nuclear

Would sir like a caesium salad with his steak?

Guest Post by Geoff RussellGeoff is a mathematician and computer programmer and is a member of Animal Liberation SA. His recently published book is CSIRO Perfidy. To see a list of other BNC posts by Geoff, click here.


A recent Nature column raised the prospect that the legacy of radiation leaks at Fukushima Daiichi nuclear power plant would be decades of caesium-137 contamination around the plant. After reading this opening, I expected a hysterical beat up similar to that which prompted my last BNC piece. I was wrong. The author is the editor of a substantial book on the aftermath of the Chernobyl disaster and his Nature column ended with a clear and hopeful message summed up in a concluding anecdote about an elderly couple living near a heavily contaminated lake in Belarus. They were growing their own food and eating highly radioactive fish and doing just fine. They were survivors rather than victims. They had aligned their perception of risk with the numbers. The alternative is like the smoker who is terrified of air travel.

The rest of this piece is devoted to doing some risk perception re-alignment but I need to begin with a covering paragraph.

Nothing in this piece should be taken to imply that nuclear reactors should be allowed to become cheap and nasty because we can live with the consequences. Modern reactors with passive safety features are extremely safe and should reduce in price with appropriate modular mass production techniques. There is no need for corner cutting.

There will be two parts to this post. The first part is about the similarities and differences in the way radiation and food shred your DNA and the second describes the practical consequences with a little case study of Japan.

Part I: What exactly does radiation do to your cells?

Caesium-137 (Cs-137) has recently hit the headlines like some kind of scarlet pimpernel. Caesium here, caesium there, where will caesium next appear. Road blocks on Japanese roads now forcibly protect the public against caesium here and caesium there. It causes cancer. So do sake, bacon and steak, but I don’t notice road blocks on Tokyo bars or McDonalds.

Here’s a picture of what Cs-137 radiation does to your DNA. These come from a recent paper comparing damage from a range of sources and this particular picture is of damage caused by Cs-137.

The right hand image looks a little like a comet. Hence the name comet assay. First some cells were exposed to radiation and then they were chemically busted open to expose the DNA material from the cell nucleus. DNA is normally in coiled braids and when the braids are unbroken, they stay globbed up in a ball like the image on the left. On the right, busted strands of DNA are streaming out of the glob. It’s a bloody mess. The cell in this image was hit with 10 Grays. The unit used in most Fukushima publicity has been Sieverts. For the moment, just think of a Gray as another name for a Sievert. So 10 Grays is 10 Sieverts or 10,000 milli-Sieverts. A person receiving a full body dose of just half this amount would have a 50/50 chance of being dead within a couple of months.

What’s the difference between a full body 10 Gray dose and a cell being hit by 10 Grays? Don’t worry about it … just accept that this cell nucleus took a monster hit. Imagine blasting a water melon with a shotgun but instead of a shot cartridge with 200 pellets, you are using something with 100,000 really tiny pellets. That’s about what happened to this cell nucleus … the 100,000 is an approximately correct number, I didn’t just make it up!

Just to be clear. If the cell hadn’t been busted open by curious researchers, but was in a living person, the DNA would be still in the nucleus and cellular machinery would be either re-stiching the DNA strands or calling it quits and telling itself to suicide … cell death.

What, for comparison, does “low dose” radiation look like? Definitions vary, but small doses are like putting a few tiny pellets into that melon with perhaps a single pellet hitting the cell nucleus. You’d never see the damage with a comet assay. Over the course of a year background radiation and naturally occuring isotopes in your body do this, on average, once to every single cell in your body.

Comet assays are relatively crude but pretty simple and very widely used. The top images were made using a form of the test that gives particularly clear images. The degree of damage is judged by the length of the tail … long tail, more damage. Typically, an image would have hundreds of blobs and the degree of comet-ness of each would be categorised and counted according to standard protocols. A lucky researcher might have some image recognition software for the job. Otherwise tedium is ensured.

Here’s another pair of comet assays.

The scaling isn’t quite the same, and the method is a little different, but I think you get the picture. In this pair, both images have a tail, but one is much longer than the other. Remember, long tail … more damage. The image on the right looks like a massive radiation dose. It definitely doesn’t look like “low dose” with one or at most a few pellet tracks through the cell nucleus. This is massive damage.

What were these cells hit with and how much? Was it caesium here or caesium there? Or perhaps something from an exotic isotope of strontium, iodine, plutonium or americium?

None of the above … this damage was caused by milk. Yes, cow’s milk.

Not actually whole milk, just the milk protein casein. These particular cells are from the colon of a rat, but human cells would look no different. The left cell is from a rat fed a diet with 15 percent protein and the right is from a rat fed 25 percent protein. For people, a diet of 15 percent protein is fairly normal in a place like Australia, and at least double the amount required. At the recommended amount, there would be even less DNA damage. 25 percent is the amount that the National Health and Medical Research Council says you should stay below … which is rather less than the 31 percent of the CSIRO Total Wellbeing Diet. And yes, … rats were harmed in the production of both images.

It’s pretty simple really … more protein equals longer tail equals more DNA damage. All proteins will do this, but not all to the same degree. Red meat produces more and even longer comets than either casein or chicken but I couldn’t find a red meat research paper with pictures so I’ve used a casein picture. Most papers don’t have any pictures, just the DNA damage scores.

Is this DNA damage dangerous? Might it lead to cancer? The CSIRO certainly seems to thing so, along with everybody else working in cancer research. These particular images are from tests on a form of corn starch which the CSIRO has patents on. They want patent protection so they can charge a premium price to sell the starch to people to reduce the DNA damage done by the foods that the CSIRO tell people to eat as part of their famous high red meat, high protein diet. I’m not sure how the marketing will work, but advertising packets of starch to reduce red meat DNA damage probably won’t lock in high levels of CSIRO research funding from Meat and Livestock Australia.

Food damage, radiation damage …

Just two months after the massive release in April 1986 of radiation during the reactor explosion at Chernobyl, Russian scientists made rapid estimates of the probable extent of consequences to determine public health requirements. They needed to calculate if the affected regions need more hospitals, doctors, nurses and so on. The 1986 knowledge base was built on four decades studying survivors of the atomic bombs in Japan, together with patients receiving diagnostic radiation therapies. They identified thyroid cancer as a special case and estimated that (see para 90ff in 2008 summary ):

The increased incidence of cancers due to radiation exposure would not be significant from the point of view of organizing health care, although some effects on some population groups at specific periods of time might be detected using epidemiological methods;

They also predicted:

Psychological trauma caused by the accident would affect millions of people.

Such a laid back estimation of the medical outcomes will seem astonishing to people like myself brought up on anti-nuclear propaganda. My point in displaying the comet assays was to try and graphically demonstrate that cigarettes, foods, alcohol and radiation are surprisingly similar in their impacts and that modest radiation doses are merely bit-players next to cancer’s true super stars.

Consider the numbers. A 500 milli-Sievert dose of radiation isn’t a modest dose, it is a large dose. It is about double the reported average dose of the helicopter pilots who flew over the stricken Chernobyl reactor dropping stuff to cover the reactor core. Is this the kind of dose that would see people slough their skin and muscles and bleed out internally as hopefully infamously claimed by Crikey journalist Guy Rundle? What is the probability you would get cancer over the next couple of decades? According to Mayo Clinic experts, if you expose 250 people to a dose like this then, on average, one will get cancer during their lifetime as a result. In a world cancer frontrunner like Australia, about 80 of the 250 will get cancer anyway. It isn’t even clear that the single cancer from the radiation would be over and above the 80. This is possible if the person got leukemia, which has a short latency period. Otherwise the radiation damage might just mean that instead of getting cancer at 60, a person gets it 2 months earlier.

Why is radiation such a wimp?

Warning: this section is a little speculative … based on evidence, but with a speculative leap above and beyond!

Part of the reason that radiation is a relative wimp in the cancer stakes, is its randomness and and lack of accomplices. DNA damage is normally repaired. It’s what cells do. If the damage can’t be fixed, then the cell gets put in the garbage. Thrown out. Even when the damage isn’t fixed, or disposed of, it doesn’t go on to become a cancer without plenty of help. Radiation alone doesn’t cause cancer, it needs mates. People with a rare condition called Laron’s syndrome have a deficiency in a protein receptor required to assist a damaged cell along the pathway to becoming fully cancerous. So, far, nobody with this condition has been found with cancer … among all 230 known cases. These people, like the rest of us, get plenty of DNA damage but no cancer. By comparison, when people eat red meat, a cocktail of other chemical changes are induced some of which are required for DNA damage to become cancerous. Most of the time the DNA damage is still fixed, but if not, some of the help needed to turn mere damage into cancer is on-hand.

Australian Nobel Laureate Elizabeth Blackburn has been working with preventative health medical experts to show what happens to the pattern of genetic activation in cells when people change their diet and lifestyle. This is the beginning of an explanation of why some people get cancer remissions when adopting vegan diets and more exercise. Here and here are a couple of early results. Diet and exercise can make huge changes in the pattern of gene expressions in every cell in your body. In the figure below (from the second linked paper) you can see huge changes in which genes are on and off as a result of diet and lifestyle (stretching and exercise) changes. Some genes thought to promote cancer are turned off and others though to suppress cancer are turned on.

Radiation, as a cancer cause, is on its own. Just a random damage. It might hit a cell where other cancer growth conditions are satisfied … or not.

Now let’s switch focus from cell damage to people. In particular the people of Japan.

Part II: Cs-137 in your soil, or red meat on your plate, which is more dangerous?

Even before the mechanisms started to be understood, medical scientists knew that diet and other lifestyle factors caused most cancers. When people migrate and adopt the habits of a new country, their disease patterns follow suit. When in Rome, dine like a Roman, die like a Roman. It works the other way round as well and Japan is an excellent example. Over the past 60 years, the Japanese have adopted some of the diet and lifestyle habits of another culture. Consequently their disease patterns have changed. It takes a couple of decades for cancer rates to change, but they do. I’ll focus on bowel cancer primarily because its change in Japan has been well documented and its main causes are fairly well known.

Japanese bowel cancer rates

In the 1950s, just after World War II, Japan moved toward the diet of the victors. Consumption of milk, meat, eggs and fat climbed. The following graph is redrawn from a paper on bowel cancer in Japan. The y-axis is an index, not a quantity. It will look pretty weird to those without a technical background. Briefly, milk consumption went up 20-fold, which doesn’t say much because there wasn’t much milk in the traditional Japanese diet. More significant was an almost 10 fold increase in meat and a halving of rice and potatoes. Those who have been sold the advertising pseudo science on carbohydrates making you fat might like to reflect on the rising rates of obesity in Japan as elsewhere with rising protein intakes and falling consumption of carbohydrates. (Hint: scam)

Of all these possible dietary changes that might cause bowel cancer, the World Cancer Research Fund (WCRF) and American Institute for Cancer Research (AICR) have found convincing evidence of a causal relationship for just two foods: red and processed meat. There are other cancers that these foods might also cause, but the evidence on bowel cancer is quite solid. Epidemiologists rarely say X causes Y and when they do, without caveat, as in the case of red and processed meats, you’d better believe it.

Sure enough, a couple of decades later and Japan is seeing the payoff for its expansion in red and processed meat intake. The graph shows the rising wave of bowel cancer. It’s tempting to call it a tsunami, but it kills even more people each and every year than the horror of March 2011. There are about 43,000 deaths and just over 100,000 new cases of bowel cancer each year in Japan. Bowel cancer rates now match stomach cancer rates which is the traditional big cancer in Japan and thought to be a result of too much salty food.

Japan buys plenty of beef from Australia, but the per-capita beef consumption is still quite low with the most popular red meat in Japan being pig meat. Forget the advertising, from an epidemiological perspective, pig meat is just another red meat, except when it is treated with various additives and made into processed meat. I don’t have data on Japan, but am confident that, as in Australia, the difference in male and female bowel cancer rates mirror the significant differences in male and female red meat consumption. South Korea, also with a growing red meat intake shows the same pattern.

The traditional Japanese bowel cancer rate, down around 10 per 100,000 per year, is at a level still found in many parts of the world and there is little difference between male and female rates. This traditional rate is mainly down to a couple of genetic predispositions. The massive increase is down to red and processed meat, inactivity and obesity, in that order.

Leukemia compared with bowel cancer

Radiation as a carcinogen is well demonstrated above certain doses and the main cancers involved are thyroid and leukemia. The thousands of thyroid cancers around Chernobyl after the 1986 accident were prevented by simple measures in the rest of Europe, and should be preventable where ever contamination with iodine-131 occurs. Leukemia from caesium-137 is more intractable so that’s what I’ll focus on.

Currently in Japan, the age standardised rate of leukemia is about 4.3 per 100,000 people per year (averaged over both sexes). The age standardised rate for bowel cancer is about 7 times higher at 31 in 2008 (averaged over box sexes). Australia, is even higher with an average over both sexes of 39 with men up at 46 and women down at 32.

If the whole of Japan was blanketed in the kinds of levels of Cs-137 seen around Chernobyl and experienced a similar rise in leukemia levels, what would happen? Firstly, what actually happened after Chernobyl? A number of Chernobyl leukemia studies were reviewed in 2005. Those involving the general population are less clear cut than those involving clean up crews, sometimes called liquidators, who received much higher exposure. Let’s concentrate on those. One study of 168,000 Russian liquidators found a 77 percent increase in leukemia. How big is this? A recent Taiwanese study found a similar sized risk increase in leukemia associated with eating cured meat in young people under 20. Cancer researchers have only recently begun to look at dietary connections with leukemia because there isn’t any obvious mechanism to drive it. If this connection were eventually proven, would cured meats be banned? Would people lay down in front of meat delivery trucks to save their children the horrors of cured meat? Would local councils call themselves “Cured Meat Free” and block transport of cured meat on their roads? As a vegan, I’d certainly back such a move, but I doubt the anti-nuclear movement is consistently anti-cancer.

But, back to the liquidators. Not only did the liquidators have a higher exposure than ordinary people but the researchers included types of leukemia not thought to be caused by radiation. Another study found an increase of 150 percent in leukemia among a cohort of 71,870 liquidators with a radiation dose estimated at 150–300 mSv. How big a dose is this? It’s similar to the doses experienced by helicopter pilots flying over the Chernobyl reactor dropping material on the reactor core. A third study of Ukrainian cleanup crews found a doubling of leukemia. So, three studies of liquidators, three rates of leukemia increase … all well below a tripling of leukemia.

So, let’s suppose the whole of Japan was covered in caesium-137 to give everybody a dose similar to the helicopter crews flying over the Chernobyl reactor core. Let’s further suppose that there was subsequently a tripling of leukemia rates throughout the whole of Japan.

What are we up to? I’ve postulated a ridiculous worst case scenario over a ridiculously large area causing a rate of leukemia way above anything actually measured. The result would be that leukemia would rise to about 13 cases per 100,000 people per year. This is about half the rate of bowel cancer increase that has afflicted the country as a result of shifting from their traditional diet to one with more red and processed meat. It’s about a third of the male rate of bowel cancer.

Comet assays, as described above have been used to test DNA damage in lymphocytes of children from Chernobyl who have ingested low doses (up to 3 mSv) Cs-137. As expected, there was no difference in the DNA damage between these children and a matched control group. A 2002 review found no overall increase in childhood leukemia but left open the possibility of localised increases.

Oh, I almost forgot …

Food and lifestyle changes in Japan haven’t just caused a wave of bowel cancer far in excess of anything even remotely possible from a disaster far worse than Chernobyl. Those changes have also driven a similar rise in other cancers, particularly the most common cancer in women, breast cancer. Japanese women used to have about one seventh the rate of breast cancer of US or Australian women. I don’t have a nice chart for this, but the rate in Japan has risen to well over half that of the US. The age standardised incidence rate in Japan is now 42 per 100,000 women per year compared to 76 in the US and 85 in Australia. The cause(s) of this increase aren’t as easy to pin point as with bowel cancer. However, as with all cancers, getting taller is a marker. Increased protein, whether animal or vegetable made people taller in the middle of last century in western countries. The effect leveled off in about 1970 in the US, so as meat consumption continued to rise, people just spread out instead of up. On average cancer rates increase about 10 percent for each extra 5cm of height. Similarly, fatter and more inactive people get more cancer also.

In addition, high calcium diets are also considered by WCRF/AICR as a probable cause of prostate cancer, currently sitting at about 22 per 100,000 per year in Japan compared to 82 in the US and 104 in Australia. Australian dairy exports and marketing are Asian focused with Simon Crean, for example, very publicly salivating at the thought of selling Aussie milk to 1.5 billion Chinese.. About 75 percent of the world’s adults, including most Asians, don’t have the enzymes to break down lactose and get various gastrointestinal problems from drinking milk but can still usually eat yogurt and hard cheese where most of the lactose has been pre-digested by bacteria. If WCRF is right about high calcium diets, then, as with bowel cancer, the expansion of such diets will again cause far more cancer than anything that even the worst of nuclear power accidents might deliver.

Just a final note. Japan is still a relatively low-cancer country. Average red meat and dairy intake is still quite low. The rises I’ve discussed above (liver cancer is up also) have still only brought Japan’s age standardised all-cancer rate up to about 200 new cases of cancer per 100,000 per year compared to about 314 in Australia (360 for men and 274 for women). But attention to detail and perseverance should see them one day challenging us near the top of the table.

Reference: Most references are hyperlinked, but general background on radiation comes from the IARC site (monographs 75 and 78). Hopefully I haven’t misrepresented any of it!

By Barry Brook

Barry Brook is an ARC Laureate Fellow and Chair of Environmental Sustainability at the University of Tasmania. He researches global change, ecology and energy.

97 replies on “Would sir like a caesium salad with his steak?”

Enjoyed that post Geoff. Will be looking forward to part 2. Suggest you repeat the opening caveat. It’s important


Well Geoff, you can have my red meat and dairy when you prise it from my cold, dead hands but I’ve got to admit that when it comes to putting the risks of nuclear energy in perspective you are second to none.


Thanks for a very interesting presentation. Just one thing that chafed a little was your idea that Grays and Sieverts are equivalent.

When we are talking about physiological effects in humans the appropriate unit of measurement is the Sievert. A Gray is not equivalent to a Sievert for all types of ionizing radiation. If the radiation consists of alpha particles one Gray is 20 Sieverts.

If you want a unit that is truly equivalent to the Gray, I suggest the Rad (1 Gray = 100 Rads).

Likewise I Sievert = 100 Rem (Roentgen equivalent in man).


Must resist posting.. aahh.. cant resist.

So here goes anyway.
There are health risks associated with going all out vegan as well.
Several animal proteins are key for brain development in foetuses and young children among other things. that being said. there is no reason why people should eat red meat at each and every meal.
Optimally there should be a big variety of food put on the table throughout the week imho.

this is not only probably the healthiest option, but also the one that opens up the greatest potential for making meals enjoyable instead of being just a body refuelling ritual.
And this is a key aspect of food. it’s more than just fuel for your body. it’s an ingrained aspect of our collective cultures and it is part of what makes us who we are.
Thus you will never convince people to lay off the meat entirely no matter how much evidence you got that says they should. the risk is quite simply considered acceptable by most. most people do indeed know that they are more likely to die in a car or bathroom accident than from bowel cancer in any case.
/end rant

you do have a knack for putting things in perspective. it’s rather obvious that the risks associated with food is generally seen as more than acceptable by large segments of the world population. And it does seem rather strange that a lot of the same people then find that the fractional comparative risk from radiation is not acceptable. I tend to chalk this down to people not knowing the relative risks these factors represents, and hence are unable to make a rational judgement call on it.
This is one of the things that i find the most challenging to get people to understand in a conversation. the food analogy is quite apt and it puts a nice byte sized perspective on things.
going to be using this one extensively in the coming months.


Antice: Find me evidence that any animal proteins are necessary for normal brain growth and development. I’m familiar with the claim, but have never seen evidence and there are many millions of soy formula infants with perfectly normal brains all over the world to serve as counter examples.

On the article itself, I don’t see food as an analogy, the correspondence is closer than that but the damage from foods will eventually be categorised and genetic interactions will be determined. I suspect radiation damage will always be random inside a cell … but the actual pathway of the radiation will mean damage at the multi-cellular level may not be modelled well as random.

Gallopingcamel. Yeah. I had a primer on units and isotopes in the draft but eventually cut it. Non-techos glaze over when multiple unit systems start appearing. Hopefully people swallowing alpha-emitters won’t be common! Apoptosis got cut also in favour of garbage! It’s tough to be jargon free and accurate … probably impossible … but thanks for supplying some details for people who have enough
background not to get spooked.



Varieties of Ionising Radiation:

Alpha Radiation (a-Radiation):

Alpha particles are emitted by atomic nuclei in the radioactive process known as alpha decay. They consist of two protons and two neutrons bound together by nuclear forces, and are therefore in fact helium nuclei travelling at high velocity. Alpha particles radiated by decaying radioactive atoms will soon attract electrons, becoming neutral helium atoms (all helium gas on earth has been produced by radioactive decay in this manner).

Alpha particles are highly ionising, but cannot penetrate materials very well. They are stopped by a peice of paper, or the surface of skin, and only penetrate a few centimetres through air, after which they have been slowed down to normal velocity for atmospheric gas and are inert helium atoms. Alpha radiation emitted by external sources is therefore quite easy to sheild against. Alpha radiation is much more dangerous if it is emitted internally. The chief hazards associated with alpha emitting materials come from injecting, inhaling or ingesting them.

Beta Radiation (b-Radiation):

Beta particles are either electrons or positrons (anti-electrons) emitted by atomic nuclei in the radioactive process known as beta decay. Beta particles have moderate penetrative power and can penetrate skin and flesh, but can usually be blocked by a few millimetres of aluminium sheet. They do not have the same ionising power as alpha particles, but their greater penetrative power must be accounted for when handling beta emitters.

Gamma Radiation (g-Radiation):

Gamma radiation is electromagnetic radiation emitted from atomic nuclei as a result of nuclear reactions taking place. Gamma radiation is less ionising than alpha or beta radiation, but has much greater penetrating power, generally needing thick shielding (usually consisting of lead or uranium) to protect people and equipment near a strong gamma source. While exposure to an external source of alpha or beta radiation can cause dangerous doses at or just beneath the skin in people, gamma radiation can penetrate the entire body.


Like gamma radiation, X-rays are electromagnetic waves. The difference between gamma and X-rays has traditionally been the shorter wavelength and higher energy of gamma rays compared to Xrays, but modern X-ray generators have entered territory previously assigned to gamma rays, and some astrophysical processes are now known to generate low-energy gamma rays. The older definitions had the cutoff point between gamma and X-rays at about 10^-11m wavelength. The current definition is connected with the origin of the radiation. Electromagnetic radiation emitted by atomic nuclei is considered gamma radiation, and high energy electromagnetic radiation emitted by electrons outside the nucleus is considered X-radiation.

X-rays can be dangerous in large doses. Most exposure comes from medical imaging sources in carefully controlled quantities.

Neutron Radiation:

Neutron radiation most commonly occurs in the context of nuclear fission. Neutrons are liberated when a heavy atomic nucleus splits into two lighter daughter products. This phenomenon is the foundation of both controlled nuclear power and of nuclear weapons.

Neutron radiation is highly penetrating, and is able to ionise atoms either by colliding directly with atomic nuclei and imparting enough velocity for them to become ionising particle radiation as well, or by the creation of radioactive neutron activation products which can subsequently emit their own ionising radiation. Shielding from neutron radiation generally involves materials containing large quantities of light elements like hydrogen, such as water, plastic or concrete. Using heavier elements does not reduce the energy of neutron radiation very much, but lighter atomic nuclei such as hydrogen will rapidly absorb most of a neutron’s energy.

Detecting and Measuring Radiation:

Units of Measurement:

The activity of a radioactive source can be measured using two different units, the curie (Ci) and the becquerel (Bq). One curie is approximately equal to the radioactivity of one gram of radium.

Becquerel (Bq):
1 Bq = 1 disintegration (decay of an unstable atomic nucleus) per second.

Curie (Ci):
1 Ci = 37 billion Bq = 37 billion disintegrations per second.

The radiation dosage recieved by a person or other living thing or object is measured using a variety of units. Doses of radiation are measured in gray (Gy), sievert (Sv) or roentgen (R). These units are derived within the SI system (the roentgen is an older unit redefined in SI terms and accepted as an SI unit). The rad (radiation absorbed dose) and the rem (roentgen equivalent man) are derived from CGS (centimetre-gram-second) units. As we shall see, conversion between the old and modern units is straightforward.

Gray (Gy):
1 gray = 1 Joule of radiation energy per kilogram of absorbing material.

1 rad = 100 ergs of radiation energy per gram of absorbing material.

1Gy = 100 rad.

Sievert (Sv):
The sievert is the SI unit for the dose equivalent, a measure of the biological effect of a given radiation dose. The dose equivalent in sieverts is obtained by measuring the radiation exposure in gray (Gy) and multiplying this value by two dimensionless constants, Q and N. Q corrects the dose according to the type of radiation in question. N is used to modify the result for the particular organ or kind of tissue exposed.

Roentgen (R):
1 roentgen is the amount of radiation required to liberate positive and negative charges of one electrostatic unit of charge (esu) in 1 cm^3 of dry air at standard temperature and pressure (STP). This corresponds to the generation of approximately 2.08×10^9 ion pairs. One rad is approximately equal to 1.07 roentgen. Conversly, one roentgen is approximately equivalent to 0.93 rad.

1 R = 2.58 x 10^-4 C kg^-1 (charge in coulombs per kilogram of material).

Rem (roentgen equivalent man/mammal):
The rem bears the same relation to the rad as the sievert to the gray, and is calculated with the same dimensionless constants.

1Sv = 100 rem.

Rep (Roentgen Equivalent Physical):
The rep is a unit of absorbed dose of ionising radiation equivalent to 93 ergs per gram. It is obselete and has been superseded by the rad.

CPM (Counts Per Minute) and DPM (Disintegrations per Minute):
Counts Per Minute is the number of atoms in a given quantity of radioactive material that are detected to have decayed in one minute. This is closely related to the unit Disintegrations Per Minute (DPM). DPM is a measure of radioactivity. It is the number of atoms in a given quantity of radioactive material that decay in one minute. One Bq = 60 DPM.
Counts per minute can be useful when detector efficiency is in question. For example, when a scintillator is designed to detect the 0.013 Mev photons from uranium 238 and one is measuring the 1.146 Mev photons from potassium 40, the units cannot be easily converted to roentgens. CPM is a more appropriate unit under such conditions.

Q values:
Selected quality factor values:
Photons, all energies : Q = 1
Electrons and muons, all energies : Q = 1
Protons and charged pions : Q = 2
Neutrons : Q is a continuous function of neutron energy
Alpha particles and other atomic nuclei : Q = 20

N values:
N values for selected organs and tissue:
Gonads: N = 0.08
Bone marrow, colon, lung, breast, stomach: N = 0.12
Bladder, brain, salivary glands, kidney, liver, muscles, oesophagus, pancreas, small intestine, spleen, thyroid, uterus: N = 0.05
Bone surface, skin: N = 0.01


More propaganda from the veganistas.

I’ve just finished dinner – a small portion of kangaroo along with the usual vegetables.Also on my third glass of red wine.After a day of hard physical work it does go down rather well.

Jeez,guess I’ll die someday. At 63,I can hardly wait.
At least I won’t have to read this crap while looking for something relevant to climate change or nuclear energy.


So, are you suggesting, the overhyped effects of radiation on humans is not relevant to nuclear energy? Didn’t you read the post?
Thanks Geoff, for another sane analysis of risk comparisons.


To elaborate on your analogy of the smoker that is afraid of air travel, if one wide-body airline crashed every day, it would still be safer to fly than smoke or drive, or eat red meat, but we wouldnt have a functioning airline industry after a very short time.
Similarly, the nuclear industry cannot tolerate too many reactor core meltdowns, the number of deaths due to radiation leaks would be irrelevant if we had say one core melt-down ever few years instead of ever few decades, even if this was with ten times the number of operating reactors(ie today’s probability of a core melt-down). Risk perception will never be rational!


Thanks Finrod, Ms Perps.

Podargus: I’m unapologetic about wanting people to
be vegan. The consequences of everybody being vegan are better than the current mess.
If, on the other hand, kangaroo eating became popular, then you’d have a problem. No more kangaroos or really, really, really expensive. So you have to be hoping people don’t live like you … now there’s something we can both agree on :)


Neil: core meltdowns could become common without killing the nuclear industry … provided there was no radiation release. But I take your point, risk perception isn’t rational. Then again, the Indians still travel by train despite fairly frequent accidents.

I’d like to see something like a Toshiba 4S deliberately melted down in the worst possible way under the full glare of media. If there was
no radiation release, it would be a very useful investment.


Geoff: thought you might want to take crack at a couple of alarmist pieces from usual suspects:

[from institute for policy studies, which put out Frances Moore Lappe’s fine work: but when it comes to nuclear, spread fear]

and then gundersen, following chris busby I guess, ginning up bodies:

seems to me these scare stories do real damage.


oh: here’s arnie’s solution to our energy problems.

It’s astonishing, the combination of FUD and fairy tales:

With the advent of smart grids and distributed transmission of electricity and power sources like a 2 megawatt windmill or a gas-powered “bloom box” fuel cell that generates electricity very efficiently, I think that by 2040 we’ll be a distributed energy network. New nukes are like the Maginot line of electricity. By building them, we’ll be trying to solve a problem that technology has already surpassed, the way the French built the Maginot line tried to prevent the Germans from invading. Instead, they just went around.”


-> “On average cancer rates increase about 10 percent for each extra 5cm of height. ”

Hell, that’s an extraordinary claim wich requires extraordinary evidence. Cancer statistics are full of junk science, I hope someone would come up with better than spurious causation or amend such an overblown claim.


Geoff, nice post, well written and well documented.

However, I still don’t get the point. Some level of radiation is less dangerous than other things. So what? It is still dangerous and should be avoided.

There are many things that are potentially in this world. Some are more dangerous than others, but this is no excuse for dismissing the less dangerous ones.

The perception of danger is notoriously irrational. Trying to fight back with rational reasoning is hopeless.

I like the analogy with the smoker that is afraid of air travel. However, explaining that flying is less dangerous than smoking won’t help much.

I think we need to understand the deep causes of the radiation fear and work on those.

One major difference between red meat (or other diets) and radiation lies in the (perception of) control and freedom: The Japanese are free to decide what they want to eat. They are not free to decide if the place where they live is contaminated with something bad.

The same comment applies to the smokers: they decide to smoke and pay the price for that. But up in a plane they have no control.


Using information directly from the recent Ontario Power Generation Environmental Impact Assessments, I get much more concerning results for radiation induced lethal cancer than what is discussed above. Ontario Power generation, in their environmental impact assessment documents for the NNP in Ontario uses the 2007 ICRP (ISBN 978-92-64-90153-8) coefficient for a SGB scenario of 5.5E-5 deaths due to cancer/mSv in assessing the death rate for exposure following a nuclear accident in Ontario. Using the OPG data and the example of exposing everyone in Japan to the helicopter pilot exposure of 150 mSv will mean over 1 million would die due to radiation induced cancer because of the exposure. Please note the example is not mine, but postulated above. This sounds much worse than the scenario described by Geoff. 5.5E-5 lethal cancers/mSv adds uo.


MsPerps on 2 may at 6.20 PM –

Yes,I did read the article and the basic thrust of it is correct,in my opinion.However,Mr Russell invariably sprinkles varying doses of vegan propaganda over the facts.He also adopts a proselytizing mode of writing.This doesn’t surprise me as extremist movements,like veganism and Animal Liberation are quasi religions or a substitute for religion for people of a certain personality type.

The basic message of the article is useful but the way it is presented virtually guarantees that many people will distracted from the real message and be turned off this site as a result. That is not a desireable outcome.

I have tried to make this point before (several times) but with no effect,apparently.In these circumstances I sometimes lose patience and use irony and bitter humour.It seems that neither you nor Mr Russell “got it”.

The bottom line is this – We can argue the rights and wrongs of radiation doses and the effects of diet till the cows or the radishes come home but that won’t have the slightest effect on the main issues of concern to this site. I presume those issues are climate change and the one practical and reliable way of mitigating it – replacing fossil fuels with nuclear energy.


Gregory: No, I meant please post links to my piece as comments on those sites. Better to have someone else blowing my trumpet than me.

Podargus: I have vegan mates who think that everybody being vegan will fix all the problems and nuclear mates who think nuclear power will solve all the problems. Both are wrong.
Have a read of James Hansen:

He’s very clear, fixing our energy problems won’t solve our climate problems … it is necessary but not sufficient. We also need massive reforestation which can’t happen while we have 1.4 billion cattle … among other things. But some people put their personal food preferences ahead of mitigating climate change. It’s that simple.


Steve: I based my estimate on actual data from the liquidator studies, which is I think reasonable. My hypothetical exposure was deliberately ridiculous. If I’d used some other method of calculating impact, I would have been forced to be less ridiculous and use a realistic area rather than “the whole of Japan”.
If the ICRP method gives a mortality figure way over what the liquidators are experiencing, then ICRP has a problem.

Jean Gasso: The height/cancer relation is just a fact. I’m sorry if I wasn’t clear that nobody thinks there is a causal relation. There will be one or more causes and i’d be putting protein as a candidate because it both makes you tall and shreds your DNA. If you read the WCRF report, there is a fuller discussion of possible underlying causes, but the matter is not decided by any means. This is no different from
the wealth/health association. Wealthier people are healthier, but it isn’t because of their bank account. Some studies “correct” for socioeconomic class when they shouldn’t because the correction may wipe out some of the effects they are examining.


Francois: I don’t think people are afraid of radiation primarily because it’s something they cannot control
–even in the event of a nuclear accident.

I think people are afraid of radiation because they don’t understand its real risks, which is to say they think it is orders of magnitude more dangerous than it really is (low level radiation).

So Geoff’s various analogies are important. I was anti nuclear and I was scared to death of radiation until I got educated. I’m no more or less rational than most.

If something is not all that dangerous (comparatively), and you cannot control it, the usual reaction is, well, I’m not going to worry too much about it since I can’t control it and it’s not that dangerous, etc. With nuclear accidents like Fukushima, you hear scare talk that only makes sense if nuclear power is a near apocalyptic danger.

Look at the Gundersen article I linked to above and count the words like “catastrophe,” etc. And the thing is, even if you bought (incorrectly) into the scare numbers of 200,000 premature deaths (always referred sensationally as 200,000 killed by radiation), over 50 years, that’s 4000/year, nothing compared to risks we take for granted–like smoking, eating red meat, etc.

It’s no accident that Gundersen does nothing like what Geoff does here: put the dangers into perspective. That’s the last thing the anti nukes want to do, especially someone like Gundersen who probably makes his livelihood from consulting for anti nuclear groups.


Geoff Russell,
Clearly you understand the niceties of dosimetry units and measurements. Please accept my apologies for doubting it!


Radiation-Related Cancer Risk at Low Doses Among Atomic Bomob Survivors
D.A. Pierce & D.L. Preston
consider two alternatives to LNT and find reasons to reject both. They do, however, suggest one linear rate for so-called high dose and a linear rate of pricisely half that for low dose.

The result then approximates the beginning portion of a sigmoidal (S-shaped) curve. While there are many possible functional forms which approximately fit the data as shown in Figure 1, at least one family of sigmoidal functions can be justified by a simple model based of the physics and biology. Fitting a sigmoidal function from that family to the data of Figure 1 would produce an approximately quadratically growing risk at very low doses.

In another paper, Frome(?) and others @ ORNL compute AIC values for several different models. At least 4 of the ones considered ought to be viewed ast indestinguishable from LNT. The same would be true for the sigmoidal function suggested in the prior paragraph.

I conclude that LNT, even at the 1/2 rate suggests by Pierce & Preston, is an over-estimate of the risk at very low doses.


Geoff Russell,I have read James Hansen and I don’t think that nuclear power will solve all our problems.However,by far the largest emitter of greenhouse gasses and other pollution in Australia is coal fired electricity generation.This is an eminently solvable problem with a big return on investment in a comparatively short time frame.

By contrast,if you think you can shut down the meat producing industry in Australia (not just cattle) in any sort of realistic time frame you are off with the pixies.While there is a certain political and social investment in fossil fuel use there is a massive investment in meat production and consumption.What you and your ilk want to do is not only destroy an industry but drastically change the dietary habits and preferences of a large majority of the population.No matter how desireable this might be it is not going to happen in the sort of time frame in which we are talking about re climate change.

As for reforestation,you are preaching to the choir in my case.I have worked and travelled in this wide brown land for most of my life.I know,first hand,the damage done by unsustainable grazing and agricultural practices,not just with cattle but also with sheep.We now also have major problems with feral animals as well,like goats, pigs,horses and camels.Unlike you,I am engaged in trying to do something, by direct means,about this problem.My engagement costs me money and time.
If this poor excuse for a government we have at present could be persuaded to invest in a program of remediation of degraded areas I doubt whether pastoral land owners would stand in the way in any significant fashion.What you,in your typically townie narrow minded atitude,have to realize,is that most country people love the land,otherwise they would not continue to tolerate the hardships of staying out there.Certainly there may be a need for education in certain aspects of conservation but there is no place for confrontation and condemnation.That is totally counter productive.The people you have wet dreams about tackling head on will not let you pass.

I have been environmentally conscious since my teens when it certainly was not fashionable – early 60s.I certainly don’t need Johnny-Come-Latelies like you teling me about environmental damage in Australia from whatever cause.

What I am suggesting,if you care to listen to reason,is to calm down on the rhetoric,address the important and readily addressable issues minus your particular bias.


Clearly, Podargus does not like being preached to… he has given us all a sermon in reply.

Geoff, thank you for your article and for your clear responses… however…

Not everything bad can be traced back to eating meat, in the same way that not everything good can be traced to veganism or belief in fairies of an ability to count and to add up.

If you really want to discuss veganism, there are sites for it.

If you want to help people to get their heads around the intersection of mathematics with health statistics, then please, just once, surprise us by climbing down off the awful soap box of yours, get the chip off your shoulder and stay on topic.

Otherwise, you will continue to lose at least half of your audience purely because you have dressed up your message within a theme song.

Well done! So you are a vegan! Bully for you, even if I do suspect that, at some level or other, you must have reservations which present as an automatic, persistent and aggressive defence of your own behaviour. Now, please, let me and many others make our own choices and stop bashing us with the guilt trip, moralistic, one-eyed, unwavering, repetitive theme song.

Now, what was that about cancer and nuclear dose rates again? It seems to have been lost in transmission. The signal-to-noise ratio was too much for effective communication.


podargus: I’m not sure why you think coal is “an eminently solvable problem” but cattle is hard. As
an employer, cattle is tiny compared to coal and no
new technology is required to change diets … just a few cooking lessons. Are coal miners more likely to “go quietly” than cattle farmers and butchers?

Hansen has an interesting section in Storm of My Grandchildren relating his first attempts at talking
to politicians about methane and other non-CO2
forcers. They were very interested because this was
something quick and simple as opposed to
restructure the energy infrastructure. He backed
right off because he didn’t want them to think they didn’t have to tackle the hard problems.

You can bluster all you like, but when people wake up that the sh.t is hitting the fan, then the cattle industry will be quickly identified as “low hanging fruit”. Go and talk to
the many tens of thousands of ex bank staff if you want to see how quickly an industry can be axed when there is political will. Or ex-tobacco growers.

Cutting cattle’s huge health subsidies would be a start, probably by taxing various meats to pay for their various adverse health impacts … this approach has made huge inroads into smoking.

How many sheep in Australia in 1990? And now? The number has been slashed by over half in two decades and that was just market forces, which are cruel and brutal. I’d prefer kinder methods.


Thanks, John Bennetts.

Geoff Russell,I knew I was wasting my time in my last comment as far as you personally were concerned. You are the sort of person who is always right,regardless of the obvious facts.History contains many examples of this type.Usually they have contributed significantly to detrimental outcomes.


David B Bensen: This has a good discussion of LNT and alternatives and when they over/underestimate
risks … and is public access:

I didn’t take a position on LNT/Hormesis in the post because it wasn’t necessary and because I saw far too much cherry picking of studies in the literature I read on the issue.



In many ways, I represent the worst kind of landowner, and I understand that you have seen a few. I have used a management style called benign neglect in order to give my little 16 hectares a bit of breathing space. 24 years later, the weeds are in recession and the regrowth is absolutely huge, even after allowing for the odd bit of firewood I use for my cosmetic 5 or ten open fires each year.

By my reckoning, I am about 100 tonnes of carbon better off than when I moved in. In the near future I will add a couple of steers, the first stock in decades, as lawnmowers.

On topic, I am committed to climate change action. As a person, I now eat about one third of the meat that I used to, but without a side serve of guilt.

My carnivore neighbour fixed our fence by himself this weekend, unasked, at age 86. I must ask him whether he fears colon cancer.

Right on topic, when he and his wife told me that they do not use heating or cooling in their home, they explained that they choose not to use electricity or to burn timber. They use simpler methods, such as rugs. I dips my lid to these self-funded, fit, eco-aware and eco-active retirees.

There are many ways to lead a healthy life. Worrying excessively about nuclear threats is not one of them. Neither is worrying about dietary preference.

Ever wondered why we have canine teeth? If not for chewing meat, then why? Darwin was right.


@ Podargus

You are not refuting the problems associated with livestock (which Geoff has outlined on many occasions) in any way. Instead, you are basically saying “It’s too hard, so just shut up about it.”

This doesn’t make the problem go away, so I don’t see your point.


John Bennetts: Spot on about regrowth. I’ve seen all kinds of papers and reforestation projects and talk of stages and weeds and understories … etc. But whereever people vacate land, carbon accumulates. Dare I say it … even without weed and feral animal control.


Gregory> I think people are afraid of radiation because they don’t understand its real risks

I’d even say they are afraid of radiation simply because they don’t understand it (fear of the unknown). There are other reasons, starting with the fact that nuclear power is tightly associated with nuclear weapons.

For nuclear power to gain public acceptance, we need a massive education effort. This is going to take time, I’d say a whole generation to complete.


-> Gregory Meyerson : “
Jean: here’s one article.”

Thank you Gregory for the link.
The article’s numbers are about 3% increase in cancer rate per extra 5cm height, not 10%.

3% with +-15% uncertainties range belongs to the realm of irreproducible thought experiments. If it’s not spurrious stats, it has a strong smell of that.


François Manchon, on 3 May 2011 at 6:08 PM said:

There are other reasons, starting with the fact that nuclear power is tightly associated with nuclear weapons.

And it was in the interest of various powers that people fear nuclear weapons. What good is a weapon if no one fears it?


Tom Keen on 3 May at 5.32 PM.

Tom,I’ve already been accused of sermonizing once on this thread so I won’t tread there again.

I have tackled Mr Russells views on livestock in the past and I really consider it a waste of my time and the space on this blog to do so again.Mr Russell is in his ideological straitjacket and he will not be gainsaid so argument is useless with such people.

Certainly there are many environmental and ethical problems with the way livestock are run in Australia.These have been,are and will be tackled in the future but it is a long,hard road.There are so many economic and social factors in the picture.
Basically it is human behaviour which has to change and that is a slow process.By way of illustration,the campaign against smoking has been going on for about 30 years and we still have large numbers of smokers and tragically,more young people are taking up the “cool” habit.

Mr Russell,with his ideological blinkers on,thinks that the livestock industry is” low hanging fruit ” for the likes of Animal Liberation to pick off.That is nonsense and not worth a second thought.

What is of concern is the pronounced tendency of the ideologues to come up with crazy schemes and ideas to reduce carbon emissions.Some of them just won’t work,like BZE,some of them,like AL,cause more trouble than they could ever possibly be worth in terms of carbon pollution reduction.This ratbaggery is a distraction.

I say let’s concentrate on the main game which is reducing fossil fuel use.That is where the big gains are to be made.We don’t have the luxury of time to stuff around with side issues.


Geoff Russell, on 3 May 2011 at 4:58 PM — Thanks for the link. That is indeed a fine review.


While I agree with Geoff’s basic conclusions, I think his methods are very low-quality. In general I’ve found the pro-nuclear people to be more fact-based than anti-nuclear people. But this post doesn’t hold to high standards for objectivity and rationality.
So he gives us pictures of cells subjected to radiation and milk. Without any proof of what this implies about their carcinogenicity. He cites a paper about changes in blood factors from eating beef as evidence that beef promotes cancer – but it is not solid evidence. He talks about people getting cancer remissions with vegan diet and exercise – but of course, people also get cancer remissions after taking up smoking and charred barbeque.
It seems like propaganda. It might be true – there can be true propaganda and I more or less believe the same things, although without a sense of certainty, knowing they could turn out to be wrong or incomplete.
He is not a cancer expert or a medical person (so far as I know) so he’s overreaching in making general statements about how cancer works.
The same things could be argued for in a responsible way, by not giving his personal opinions since he is not an expert, and by quoting unbiased experts.
The American Cancer Society says 1/3 of cancers are linked to poor diet, not enough exercise, and being overweight – see The American Institute for Cancer Research may think more, see
Here are the American Cancer Society’s anti-cancer recommendations:
As you can see, this does not have a vegan slant, they give advice like, avoid cooking meat at high temperatures – grilling etc – because it generates carcinogenic heterocyclic amines. They discuss different types of cancers, some have a dietary contribution and some may not.
Neither of them recommend being vegetarian or vegan, only eating plenty of fruits and vegetables.
I’m pretty much vegan myself, so I don’t say this as a meateater.
Veganism can be quite healthy, the dieticians seem to agree on that. But, you have to be willing to take supplements. Jack Norris, a vegan dietician, maintains a webpage which has supplement recommendations for vegans. I was shocked to read that many vegans don’t take B12 and have high homocysteine levels as a result. I wonder if being a malnourished vegan raises any cancer risks.
People’s diet does have a big influence on their global warming contribution. Veganism is about the best, but if you eat animals, then small animals like chickens are better. They convert food into meat more efficiently. See
I don’t agree that it’s pointless to recommend veganism. It would make a huge difference if our standard diet were vegan or much more so. We are going to have to make huge changes in the future because of resource pressures, and becoming vegan, or vegan + poultry, would be a much better way of making the huge changes, than having wars over oil or mass starvation or a breakdown of social order.


Laura: The object of the post wasn’t to convince people that red meat causes bowel cancer. That has already been decided by real experts … the WCRF and AICR. I make no claims to being such
an expert. I’m just the messenger.

Have a look at the Cancer Councils recent position statement on Alcohol:

The 2007 WCRF/AICR report features heavily in their justification that alcohol causes cancer. They refer to that report placing alcohol in its “convincingly” demonstrated causal category. Clearly, the WCRF/AICR report is good enough for them to come out on alcohol. They say that the reason for making a new and stronger call for alcohol reductions now is new evidence that allows a higher estimate of cancer cases attributable to alcohol … 5070 new cases every year from a range of cancers. Rather less than the cases of bowel cancer due to red meat (see below).

As I stated in my post. The only FOODS given such
prominence by WCRF/AICR in its report are red and processed meat … both convincingly demonstrated to cause bowel cancer.

As to the issue of how much bowel cancer can be
attributed to red meat and how much can be avoided, the answers will depend on the country.
Australians eat, on average, about double the
red meat that people in the US eat (FAOstat) so
figures here will be much higher than the US.

In Australia, Professor Graham Giles of Cancer Council Australia has sent me
correspondence saying that the Population Attributable Fraction (PAF) of bowel cancer in Australia attributable to more than one red meat meal per week is 48% (about 6,000 cases of bowel cancer
per year). This is based on data from the biggest cohort in Australia.

As yet, Cancer Council Australia has been very low key about red and processed meat. There are a few weak statements on its web sites but nothing like
last week’s Alcohol position statement.

As for me and veganism. Most authors in nutrition journals don’t have to expose their dietary habits in their biographical details, but when I submitted to “Nutrition and Dietetics” a few years back, the fact that I was a member of an organisation which advocated a vegan diet was included by the editors in the Acknowledgements. Have you ever seen similar acknowledgement for members of the CSIRO, an organisation which not only advocates meat but make bucket loads of money consulting to the meat industry? There are two standards here.

So rather than being accused of “hiding” my animal liberation association, I asked Barry to put it at the top of each post. So now I don’t
get accused of hiding anything, just accused of letting that thing cloud my judgement.

Lastly, I didn’t demonstrate that the DNA damage due to food is more or less carcinogenic than radiation damage but pointed to the fact that CSIRO scientists are spruiking reductions in damage as significant for reducing cancer risk. Again, I’m just the messenger.


Excellent article, Geoff. Also appreciate the graceful way you’ve responded to the attacks. Podargus accusing you of being close-minded—priceless!


First, I want to thank Barry for inviting Geoff to write this excellent article. BNC continues it’s mission of putting out there science/fact based polemics over energy and climate change. This is enhanced by various guest columnists. I would love to see anti-nuke Jim Green come back again and pen something here, instead of the already-converted Green-Left miliue on that list.

I actually do appreciate Geoff’s veganism. While most vegan *activists* are the culinary equivalent of Al Quida, Geoff is no such…animal, but a calm, interesting and fact based writer. He got me to read Omnivore’s Dilemma and for that I’ll always be grateful.

I still enjoy my meat eating but try to source locally whenever possible and I can afford it. I’m supporting my local sushi industry in California by upping my intake of fish (they took a marketing hit, obviously, since Fukushima) :)

I for one don’t deny the cancer effects of high diary, high animal protein diets and the facts about the Japanese diet are well known. There is a lot of *other* mitigating issues, like the occupations Japanese have that have contributed to cancer rates and why, often, in much poorer, but far physically harder labor countries cancer rates are not as high as the sedentary Japanese. But I think Geoff’s points are well taken.

Keep up the good work!



Clearly reducing the impact of animals raised for food is no ‘low hanging fruit,’ it is a major issue that will need to be addressed sooner rather than later, not only for its role in AGW, but in the broader issue of carrying capacity which is sneaking up from behind. Arguing that this is a life-style issue is simply wrong.

However, that cuts both ways, and as I have written here before, arguing the issue on animal rights, and other moral/ethical grounds, instead of economic and public heath ones, simply obscures the real problems and does not address practical solutions.

Finding ways to supply the world’s growing population with sufficient affordable, and palatable sources of protein is an important subject, and should not get bogged down in what amounts to religious debate.


Thanks Josh, David.

DV82XL: I don’t recall arguing morals or animal rights on any BNC post.

Palatability is a solvable problem, after all, most people use plant based seasonings to improve the flavour of their meat … tomato sauce being an Australian BBQ icon. Do you have Gravox in Canada? It’s gravy to make meat taste meatier … except its vegan. Traditionally used on the now endangered Sunday roast. Most Gravox lines are vegan, I think one has milk powder.


@Geoff Russell, – I wasn’t accusing you of doing so Geoff, my remarks were more directed to some in the broader debate that do.

As I have mentioned before, I am more of the opinion that culturing insects as a feedstock for some meat substitute is the way to go. I have eaten a ground meat analog made from some type of earthworm that was indistinguishable from the real thing. I also love silkworm grubs done up with glee and garlic, and make a point of having a meal of them when I am in Thailand.


DV82XL: No worries. I have no opposition to arguing ethics, I just don’t see such arguments as consistent with BNC’s purpose. As for eating insects. It introduces an unnecessary layer so I doubt it will be as efficient as eating plants directly. People like NHMRC (our top medical body) would also be wanting proper nutritional research on insects. The fact that some people have been eating them for years (with a life expectancy of … short) doesn’t cut it as evidence of safety for anything aiming to be a serious part of the food supply.

How do prices of Thai insect foods compare with meats?


@Geoff Russell, Silkworm grubs are street food, not the sort of thing you find in upscale dining, however I have eaten them many times without trouble.

Note too that insects can convert matter unfit for human consumption in its raw form, and many insects contain abundant stores of lysine, an amino acid deficient in the diets of many people who depend heavily on cereals as a main source of food. Insects can be a good source of not only protein, but also vitamins, minerals, and fats. For example, crickets are high in calcium, and termites are rich in iron. One hundred grams of giant silkworm moth larvae provide 100 percent of the daily requirements for copper, zinc, iron, thiamin, and riboflavin.

Insects generally have a higher food conversion efficiency than more traditional meats, measured as efficiency of conversion of ingested food. While many insects can have an energy input to protein output ratio of around 4:1, traditional livestock has a ratio closer to 54:1. As well the spatial usage and water requirements are only a fraction of that required to produce the same mass of food with cattle farming.

Over 1,000 different types of insects are known to be eaten in 80% of the world’s nations. One way or the other they will form an important food source down the line.


Having given up eating red meat and dairy products quite a while ago I was comfortable with the dietary issues being discussed on this thread.

That was until Geoff mentioned that alcohol causes cancer. DV8XL, how could you let that go without comment? You are the one who extolled the virtues of Canadian rye above single malt scotch.

This illustrates what is wrong with the LNT theory of ionising radiation. While Geoff may be quite correct to state that alcohol raises the incidence of cancer in humans, such statements are misleading if one ignores the beneficial effects of alcohol.

There is ample evidence to suggest that moderate consumption of alcohol has benefits in relation to the incidence of heart disease that may outweigh the many known negative effects of alcohol,

Likewise people who write papers about the negative effects of radiation while ignoring the possible benefits are misleading the public.



You have eulogised insects as a source of animal protein before. I also recall having questioned your judgement on this matter.

Our family farms insects for a living and, until retirement, I lectured as a veterinarian on animal husbandry and animal nutrition. I therefore feel I have better than average qualifications to comment on this issue than most. However, it is OT.

I hold you in very high regard as one with expertise and good judgement in matters nuclear, but worry that you put your reputation and credibility at risk by spouting off on subjects about which you lack experience. It makes you sound like a renewables enthusiast! And where are the cites to back your claims?


@gallopingcamel, I like my Canadian rye, but I have no illusions of what the impact of drinking a fifth every day of it would do to my health. Yet, there is some evidence that a moderate intake of alcohol has benefits – or at least that’s what I keep telling my wife.

@ Douglas Wise – The information came from:

The Eat-A-Bug Cookbook. Gordon, David George (1998)<Berkely, California: Ten Speed Press. p. xiv. ISBN 0-898-159-776.

Ecological implications of minilivestock: potential of insects, rodents, frogs, and snails. Paoletti, M.G. (2005) Science Publishers. pp. 648. ISBN 9781578083398


“An exploration on greenhouse gas and ammonia production by insect species suitable for animal or human consumption”. Oonincx DG, van Itterbeeck J, Heetkamp MJ, van den Brand H, van Loon JJ, van Huis A (2010). PLoS ONE 5 (12): e14445. doi:10.1371/journal.pone.0014445. PMC 3012052. PMID 21206900

If, in your opinion, anything I have written was inaccurate, I would welcome corrections.

I have been interested in entomophagy for some time now, and have done some research into the matter, however I would yield to your greater experience in this matter.


Ugh! I’d rather be a vegan than eat insects – and I’d rather not be a vegan:-)
However, ask me again if I’m dying of starvation ;-)


gallopingcamel: have a look at latest Cancer Council Australia position statement …

I haven’t dug deeply enough to challenge the Cancer Council’s call on this, but the costs of Australia’s current binge drinking culture cause far, far, far more problems than “mere” cancer. This of course is quite a different issue from the technical issues of cancer causation.


Hey Geoff and anyone else:

I read the radiation study you cite. It argues pretty strongly for the correctness of LNT, but doesn’t confront the best arguments for alternative positions.

Reading this piece side by side with Luckey’s “atomic bomb health benefits” (somewhat tongue in cheek) essay published in Dose Response (2008) is disconcerting (the essays look at first glance virtually incommensurable). I’m rereading the Luckey to try and get a handle on where the agreements and disagreements lie.

at any rate, why, Geoff, do you view the essay you link as accurate, and others as cherry picking?

Just curious, since the link you cite cites very little evidence for its claims, treating the evidence it does cite as representative of the state of the science.


At the end of the day, there is little evidence that a vegetarian diet of any sort is healthier that what we evolved to be: omnivores. I say this in seeming contradiction to what I wrote above but it’s the details that count.

A Japanese/Aussie/American omnivorous diet is unhealthy. But it’s really hard to do control studies where things like industrial pollution, processed foods and so on are actually excluded.

Secondly, a really controlled diet, where, say, a breakfast consists over a week of 5 days of eating cereal with milk but no sugar and an egg or two, vs eggs almost everyday with bacon, is conducted over a true lifetime. Where meat is eaten once or twice a week vs 6 or 7 times a week. Again, over a lifetime.

I’d like to see within the same society [instead of measuring New Yorkers diet vs that of vegan Georgians in the Caucuses which is what I’ve seen so often] where such studies can really show the “LNT” for not being a vegan. ’nuff said on that.

Eating insects. I did the grub worm thing. Gross. Crickets, on the other hand, fried and drizzled with dry chili are quite good. If you’ve had an egg from a chicken that actually eats insects and then…eat the chicken, it is something to write home about. Absolutely and noticeably better than mass produced chickens and their eggs.



Dr. Michael Klaper, a vegan doctor, has been doing a vegan health study for many years. He concludes there are both advantages and disadvantages to vegan diets. See
I like this because I think he’s being objective and fair. He says lower risk of cardiovascular disease, type 2 diabetes, probably reduced risk of prostate and colorectal cancer, helps preserve kidney function, somewhat anti-inflammatory, fewer GI disorders, fewer cataracts.
The disadvantages come from the risks of nutrient deficiencies.
So if you want to promote veganism, it needs to go along with recommendations on how to do it healthily, which Dr. Klaper gives in the link.
Vegans have a reputation for being sickly, and every time someone posts about how much better they feel after going back to eating meat, it does damage to veganism. They might have had an easily preventable nutrient deficiency, but that truth isn’t heard.
Eating far less animal food would certainly help a lot with global warming and our energy use.


by the way one nutrient which Dr. Klaper doesn’t mention but is important for vegans to be aware of, is choline. Omnivores usually get plenty from eggs and meat, but vegans often don’t. Choline deficiency can cause things like neural tube defects in babies.


For statistical reasons the LNT cannot be falsified and so the precautionary principle is adopted by default. The reason being that an LNT model is the simplest, most conservative model that can be fit to currently existing evidence.

The problem with the LNT model is the same as the problem with any other environmental insult model. While at higher radiation doses, effects due to radiation are, like effects due to pretty much any other high-level environmental exposure, much more robust and reproducible, at lower radiation doses, the effects are weaker, and the scatter in the data is much greater. In other words, at low doses the signal-to-noise ratio is much lower due to a lot more noise and a lot less signal in the data. Moreover, the data are more difficult to collect, and variability from system to system, organism to organism, and cancer to cancer is likely to be much greater.

Thus for a regulator, as imperfect as it is, the LNT model is a reasonable approximation for purposes of policy-making because it is conservative and safe.

What is needed is a new paradigm for radiation exposure built from scratch, rather than current attempts to discredit LNT by validating the radiation hormesis model, which seems to be the thrust of the current efforts.

Because until better data can be gathered that clearly demonstrate the superiority of one model over another, for a regulator, the responsible and safe model to choose is the most conservative one that fits reasonably well. Basing public policy on a model that, if incorrect, has the potential to result in considerable harm in the form of increased radiation-induced disease prevalence is not wise policy at all, at least when the alternate model is not demonstrably wrong.

Yes, this is politics, not science, but in this case the former will always prevail. Change will only come when the scientific evidence is so overwhelming, that the precautionary principle need not apply.


Thanks DV:

as a point, the article Geoff links to claims that LNT is NOT THE MOST CONSERVATIVE POSITION (though it is the simplest).

The most conservative position would be based not on a linear relationship between dose and cancer incidence but a downwardly curving dose-response relationship, with RATE of incidence higher at lower doses (steeper curve) and then becoming less steep.

The physiological basis for this curve is rooted in the presence of “bystander effects.” The anti nuclear people would probably prefer this curve to LNT.

Anyway, nitpick aside, your description fits what I have read.

What is interesting is to note how those who lean one way or another describe the state of the science: that is to say there are disagreements about what the epidemiological evidence shows.

For example, Sanders says this:

“The LNT assumption is not supported by low LET data at acute doses <100 mSv or at
chronic dose rates <200 mSv year−1 "

The 2003 article (Sanders' book is 2010) says this:

"Above doses of 50–100 mSv (protracted exposure) or 10–50 mSv (acute exposure), direct epidemiological evidence from human populations demonstrates that exposure to ionizing radiation increases the risk of some cancers."

Pretty big difference in the description of the state of the science, no?


Actually, as I look at the two citations I posted on LNT, there is wiggle room. “LNT is not supported” may assume that LNT applies to all cancers. And then the 2003 piece says “some cancers,” leaving one to wonder about the others.

That said, the pro and anti LNT positions do largely conflict on the state of the evidence, mechanisms aside.


@Gregory Meyerson – Keep in mind I was referring to the politics, not the science per se.

The problem is that LNT cannot be falsified (or verified) due to the way it is stated, so arguing over it is a waste of time. What is needed is a solid mechanistic model that is not based of vague statistical foundations. The same is true of the radiation hormesis model, at the moment it too develops out of statistical evidence. While both sides can provide a plausible mechanism explaining what they think is happening on the cellular level, hard empirical proof is lacking.

The debate is becoming somewhat sterile at this point and something needs to be done to break the logjam. But guaranteed, no regulator is going to budge on the counter-evidence tabled to date against LNT.


I get it, DV.

part of the problem I have is that if both sides actually admitted what you state, at least there’d be some honesty.

Here is what the Hall et al essay concludes:

“In summary, given our current state of knowledge, the most reasonable assumption is that the cancer risks from low doses of x- or


DV82XL, on 6 May 2011 at 5:59 AM — A Bayesian would use a weighted average of all the models.


@David B. Benson – The problem is that first, there are different types of radiation, some known to be more dangerous than others and second there are many different types of cancer, some of which are known to be induced by radiation, others not, and still others with unknown responses to radiation. This is why broad analytical tools, like population stats, or Bayesian analytics will not yield trustworthy results.


I never thought I would see the day that the benefits of a Vegan lifestyle would be linked to support of nuclear energy. I am truly fulfilled, even though I remain addicted to dead cow meat.


Regarding LNT: DV82XL has summed it up pretty well. I’d only add that it isn’t enough to have a plausible biological mechanism for hormesis. Hormesis in a test tube, or even a rat isn’t hormesis in a person. You have to also have epidemiology and as DV8 points out, this is impossible … or at least very unlikely.

Regarding omnivores and vegans. The word omnivore doesn’t mean “eater of balanced diet”, quite the opposite. It means unspecialised eater. Homo’s didn’t die out because somebody removed their favourite plant or animal food source. We are remarkably capable of thriving on all kinds of absolutely unbalanced diets. If you look at The China Study (, they looked at rural diets in China in the early 80s. This was pre-globalisation and the people lived exclusively on what was produced in the area. 69 diets, and very different.
Some ate fish every day, others ate no fish, 6 ate no animal foods (and had no B12 supplements) other had high levels. The non-accident mortality was quite tightly bunched. People can be healthy over a reasonable life span on all kinds of diets. When you start thinking about minimising environmental impacts then there are vast differences between diets. When you talk about minimising particular diseases, there are differences, but not huge.


@Geoff Russell – Epidemiological studies are not impossible in this case, they just need to be designed such that they can be verified, (or falsified) which is what the current work being done cannot.

Necessarily this will mean paying attention to what cancers are being caused and by what sources of radiation, and not trying to lump the results together to make sweeping statements. It is this, I believe is at the root of the problem. With specifics in hand we will be able to make choices that better match what the real risks/benefits might be.

I also disagree that animal models cannot be used as human analogs, this has been done in the past and is a very good way of looking at the biology. At the very least this can help determine thresholds, which are obviously there.


This site, and the community that goes with it, has been undermining its own credibility since the beginning of the Fukushima incident. Why? Because you are effectively the opposite of the media hysteria. In the first week you said it cannot possibly get any worse than L4. Then you said it cannot possibly get as bad as Chernobyl. When it went L7 you lamented the million aspects that make this different from Chernobyl (irrelevant). Now we have radiation on the ground you are trivializing it, almost as if it was harmless and safe on humans.

This site has a lot of nuclear power supporters. I can tell you that being smartass about the “truth” is not going to help you. No more “it was a biblical event” excuses. If you are serious about your cause, you better wake up and smell the roses. The perception, not realities, of nuclear will decide whether it will have a future, so step down from your high horses and talk to the public eye to eye. No more “nobody has died yet, millions will die when coal burning continues”. Nobody cares.

In Japan, Fukushima governor Sato has told Tepco already that they can forget about ever operating the plant again. Other mayors and governors may follow. Japanese power company shareholders are already demanding that they exit nuclear because they don’t want the risk to their investment (money talks). Wake up.


@ Commenter:

Your cry of bitterness at the failure of the Fukushima accident to provoke the pro-nuclear community into abject surrender will be a source of great amusement.


Your rant here is totally Off-Topic (and thus breaks the commenting rules) and should be consigned to the Open Thread where any one and their dog can put in their twopence worth. Again – oh for the moderator.


@ Commenter

Fukushima or no fukushima, we still need to close down coal.

If we reject nuclear power what are our alternatives? Hydro? Not in Australia. What other zero emissions technology, or mix of technologies have proven able to replace a fossil fuel power station?

For my money GLOBAL warming (and thus by implication fossil fuels) is the bigger risk but I’d be interested to hear your perspective on this.


@ commenter. The only ones who don’t care about the massive fossil deathtoll are the traditional, predictable, yet fallacious ‘environmentalists’ and you sound just like one.

The shocking conclusion is that this group, which is small but vocal (and in no way representative of most of the public) does not care about human development, and has a high degree of morbid sarcasm. They don’t even really care about the environment, either. In stead, this group wants to drink lattes at Starbucks and live isolated in their fallacious worldviews.

The public at large realises that these traditional environmentalists have exaggerated the downsides of nuclear power and have been uncritical of their favored renewable energy solutions.

It turns out that renewable energy won’t cut it. Solar and wind are non-options due to their not-being-there-80%-of-the-time factor. They are essentially greenwashing fossil fuel grids – fossil fuel lock-ins. The only renewable worth doing at any scale large enough to matter is large hydroelectric, which not surprisingly the moronic traditional enviornmentalists also condemn.

Energy efficiency at best isn’t nearly enough and at worst does nothing at all.

Its nuclear or fossil. In this thing called real life, a term very difficult to comprehend for traditional environmentalists, there are choices which invariably have to be made. Nuclear or fossil. Take your pick.


@commenter: Many of us at BNC understand that perception frequently overrides reality in the nuclear debate … as in many other debates. We just don’t know what to do about it other than keep repeating the truth in various ways. For my part I’m trying to go outside BNC where possible, but the mainstream media aren’t generally all that receptive. Crikey has been publishing total rubbish on Fukushima, as has SBS TV. I considered going to the Press Council but previous dealings with them have left me quite confident that they aren’t up to dealing with complex issues.


> More significant was an almost 10 fold increase in meat and a halving of rice and potatoes.

Yes, but the use of meat in the Japanese diet is still low. The ten fold increase came off a very, very low base. The Japanese diet is still quite traditional and heavily focussed on noodles and rice with meat acting essentially as a condiment. (Think ramen, and the various forms of Udon). Even Japanese junk food is heavily focussed on rice etc in the shape of rice balls and so on.)

If you have any doubt just go to Tokyo and order a steak. You’ll be lucky to get change from $150.

As a mathematician Geoff, you need to get your facts right first(deleted unsupported personal accusation)


And your C-137 argument is rubbish. Basically what you’re saying is that the conventional understanding that:-

a.) there is a linear relationship between exposure and damage

b.) there is no “safe” minimum exposure

is wrong.

That’s a medical argument, not a mathematical one. And while it is entirely at odds with the accepted view you’re welcome to put it. To a peer reviewed journal.

Until you do that, your argument is worthless.


And while I’m on the subject, I think it would help if you could refer to original papers rather than just abstracts and “redrawn” versions of graphs.

The paper your Japanese food intake graph is taken from is here while the actual data for that graph is actually sourced from an earlier paper on diabetes which can be found here

It’s also worth noting that the majority of change occurred between 1950 and 1970 and things have been stable since. Since the Japanese have heavy restrictions on the importation of meat (and other foods) and still insist on producing all their own, I would wonder if 1950 isn’t itself a low base coming as it does just after the end of the war. A time when they were close to starvation.

In the meantime I’m a bit curious as to why you did nothing to that graph other than relabel the y-axis to the ambiguous term “Index” from the original “Ratio compared with values in 1950”

The original term is far more precise and clearly indicates that the Japanese consumption of traditional staples (rice, vegetables) has not fallen off much despite a 5 fold (not 10 fold as you assert) rise in meat consumption.

“Index” on the other hand could mean anything.


JM: Thanks for the comments, I’ll respond more fully later … you seem to think I hid the fact that red meat consumption in Japan is still quite low, I said explicitly that beef consumption was low but that pigmeat was the most popular. Sure, red meat consumption in Japan is low on average and it’s really expensive. The cancer rate will depend not on averages but on the number of people who eat it more than once a week. The shape of the distribution. I don’t have that data. All I know is that the average rose and the cancer rate followed and with the known causal relation, then that is enough.

Point taken about “index”. The graph was redrawn because I used it in my book and I replotted plenty of data rather than get publisher permission to use images. It’s annoying that you can quote somebody without needing permission, but you can’t use an image. On the web, people just illegally use images all the time, but I had to be more careful in the book. As far as I can see, nothing of relevance was changed during the redrawing … but I left of some
predicted data … not relevant. Ok, more later, must


JM: I just rechecked the original paper and the meat intake definitely rose 10 fold as I said, not 5 fold. My
redrawn graph isn’t ideal because R didn’t put a 1000 label on the Y axis. “Index” was a poor choice of label
on my part, but all the text talks as if its a ratio, which it
is. Okay?

I’m not sure what you mean by my Cs argument being rubbish. I don’t think I implied LNT is
false, only that it doesn’t much matter.
I’ve already linked to what I think is a good

Which says that there is a linear region in the
dose response curve and a “don’t know” region which will probably always be a don’t know region because the number of cases is tiny compared to those caused by other more potent causes of cancer.


Geoff, I’ll quote the authors from the original paper:

Food intake in Japan increased most for milk from 1950 to 2000, followed by meat, eggs, fat/oil and fruit, while those of rice and potatoes gradually decreased (Figure 2). Westernized food intake, especially milk, meat, eggs and fat/oil, was increased 5 times or more until 1970, and then maintained up to today or further slightly increased.

Milk increased 10x, red meat only 5x. This is not quite clear from your graph as you use a log vertical scale and the meat rise appears “close” to that of milk as opposed to being only half as much which is the actual value.

As for your statement regarding a “flat spot” let me again quote the authors of that particular paper (from the abstract):

Given that it is supported by experimentally grounded, quantifiable, biophysical arguments, a linear extrapolation of cancer risks from intermediate to very low doses currently appears to be the most appropriate methodology. This linearity assumption is not necessarily the most conservative approach, and it is likely that it will result in an underestimate of some radiation-induced cancer risks and an overestimate of others.

In other words, the conventional view that there is no minimum dose and that a linear assumption is the best we currently have. In fact, that it may not be conservative enough.

ie. quite the opposite of your view, which can only be regarded as radical and speaking as a mathematician rather than a medical professional, you’ve – in my opinion – no basis for a claim to authority.



We disagree on reading the original log figure … I see meat up closer to 10 … the “or more” part of the paper.

I just had a look on FAOSTAT … Japan red meat 1961 (earliest data on FAOSTAT) 4.1 kg/cap/yr (beef/sheep/pig). by 1980 it was 19.0 kg and by In 1990 up to 24.2 and 28.9 in 2007.

As for LNT … I’ve never claimed any authority and I don’t dispute LNT, it is one of a number of possibilities which are consistent with the data. What I would say, not as an authority is that if LNT is true it’s a biological anomaly. Nothing else that I know of works that way. As toxicologists are fond of saying … “the dose maketh the poison”.


One thing about risk perception:
Humans feel a lot safer when they think they are in control. When you drive: you think you are in control. You think you can control your diet.
However, how can you control exposure to radioactivity? How are you in control of the plane when flying?
Personally I actually experience this when sitting next to the driver instead of driving myself.


GlobalWarming: You can’t control your intake of toxic fumes from particle board glues either, but nobody seems concerned. How much control influences perception probably says more about individuals than about the flow of information that controls societal levels of concern or panic. I’m a terrible passenger also!

How many people refuse a CT scan because of radiation concerns? Probably far fewer than are extremely anxious over nuclear power. But some CT scans can deliver fairly hefty doses of radiation.


It seems to me it would be very hard to quantify cancer rates and its causes over the last 40 or more years. Statistics are only as good as the data. In my opinion, it would be very difficult to compare cancer rates to diets going back more than 20 years. It seems obvious that many people died of cancer in the past and it was never detected, so the cause of death was unknown or old age. So with today’s technology and record keeping, one would expect to see a higher cancer rates than in the past.

In fact, a male has a lifetime probability of getting cancer of 43%.

Also, from what I have read, genetics play a large role in one’s risks for cancer. Also, as we approach our later years, our bodies begin to break down and perhaps many people develop cancer just because the body is not able to repair its DNA. When I was a kid, no one talked about Alzheimer or Lewy Bodies or other types of dementia. My mother would only say grandfather was a little senile and that was it.

Today, different types of cancers and dementia are meticulously recorded in the United States. So, in my opinion, one cannot draw any conclusion from the increase of meat and milk products in Japan from a very low rate to 5 or 10 times that rate (which is still a very low rate).

I find Geoff’s article informative about radiation in food. From what I understand, it is the cooking of any meat (red meat, fish or poultry) at high heat is the problem and not the meat itself. Is cooking vegetables at high heat considered to be carcinogenic?

Also, I read eating bananas or Brazil nuts may me more carcinogenic than red meat.


Howard B: The US put a man on the moon in 1969 and they had a pretty good handle on recording cancer stats a long time before that, and not just in the US, but in the entire developed world. The International Classification of Diseases is now at
version 10 (1990), ICD9 was in 1965 and the first
version was back in about 1929. But the way prospective studies work means you don’t need as much historical data as you may think to determine causality. Here’s roughly how it works. Take a bunch of people and record everything they do … food, work, income, weight, etc, etc. then wait some time.
Usually 5 years would be minimum. Then compare the rates of bowel cancer in high meat eaters with low meat eaters and correct for confounders. The
correction is technically easy but choosing them is hard. Even over a short time span, the impact of
red meat shows up. And it isn’t just the method of
cooking. There are plenty of known carcinogens in fried chicken, but does it cause an increase in cancer in studies like these? No (or not enough to
be sure about). It’s the type of damage that matters far more than just the magnitude. It’s the heme iron that is the problem, not the cooking (… well the cooking may also be a problem, but it isn’t THE problem). eg., some people eat blood pudding in
some germanic countries. Do they get more bowel cancer? Yes. How many servings of blood pudding does it take to show up in one of these studies? About 1 per month. You don’t have to burn the pudding, it’s just the blood.


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