The China Study

First, my thanks to May for recommending this book!

The China Study is the second book that I have read and commented upon on The Marginal Virtues that was written by more than one author. The first was The Rebel Sell, the authors of which were Canadian philosophers. The China Study is probably the most technically complex work which I have read for the blog, and the credentials of its authors the most professional, although, as the example of The Rebel Sell shows, they are hardly the only professionals whose work I have written about. (By 'professional' I mean someone with an accredited profession, not whether the authors were paid for their work, which would be true with respect to very nearly every book I have written about.) Ernest Becker wrote The Denial of Death in relation to his profession; and so with Robert Farrar Capon, Rob Brendle, Brian Rosebury, and Paul Scott Wilson.

The edition from which I shall be quoting was published by BenBella Books in 2006. My copy is of the paperback edition, in case the pagination of this edition differs from that of the hardcover.

In a blog of this nature, it is impossible to follow closely the argument of a book like The China Study in one marginal commentary, so my post won't be as comprehensive as the study purports to be, and I won't be able to provide enough detail to assess the book's conclusions in a satisfactory fashion. Fortunately, the doctors Campbell state their case from the beginning, and use most of the book to support it.

A brief editorial note: I have referred to the authors variously in the plural and in the singular (since the book takes place entirely from Dr Campbell père's perspective). So you'll see 'the Campbells', 'Campbell', 'the doctors Campbell', 'Dr Campbell', &c.

One thing which helps alleviate the dry style (although I have not found the book to be boring) is the occasional quip by Dr Campbell. In a work of this nature his purpose isn't to do a stand-up routine, but every once in a while he has a good line.

The first one I noticed came while Campbell discusses what proteins do and how the sources of protein have been ranked by medical science. Given the widely held view that animal-based proteins are the best source of protein (although it is the purpose of The China Study to show that this is not so), you can probably guess from where we might get the best 'mix' of protein needed to sustain human life:
Can you guess what food we might eat to most efficiently provide the building blocks for our replacement proteins? The answer is human flesh. Its protein has just the right amount of the needed amino acids. But while our fellow men and women are not for dinner, we do get the next "best" protein by eating other animals. [p. 30] Well, that explains why Soylent Green is people. But, as Campbell's work purports to show, a diet heavy in animal-based protein results in obesity, heart disease, and all kinds of other nasty diseases of affluence. So Hannibal Lecter wouldn't be a suave, energetic dude but a fat old fart dying of coronary disease in an old-age home (if he even makes it that far). Campbell's expression of humour here is very dry; I had a hard time deciding whether or not he was playing it straight. In either case, The China Study rules out cannibalism as just another diet heavy in animal protein and so the source of many health problems.
Another quip is a remark Dr Campbell makes while assessing fad diets promoted by authors he calls 'snake oil salesmen' (among whom the most prominent is Dr Atkins, he of the notorious 'Atkins Diet'; Campbell points out that Dr Atkins himself was 'obese' and has 'heart disease and high blood pressure', while asking us to ponder whether a diet is really healthy when, in order to do well, one has to 'take over thirty vitamin pills a day'; p. 97):
I have heard one doctor call high-protein, high-fat, low-carbohydrate diets "make-yourself-sick" diets, and I think that's an appropriate moniker. You can also lose weight by undergoing chemotherapy or starting a heroin addiction, but I wouldn't recommend those, either. [p. 97] Sadly, I bet a number of people whose professional lives depend on being ultra-thin rely on heroin to keep their weight down. The line isn't exactly a zinger by itself, but you can sense the ironic tone of the passage. The point Dr Campbell is making is that the kinds of diets he is arguing against in this section of the book (pp. 95-7), like 'undergoing chemotherapy or starting a heroin addiction', are more trouble than they're worth. Incidentally, there's a Canadian connection to Campbell's remarks about Atkins's health problems: the source he cites in his notes (note 57, p. 377) is a February 2004 article from the Ottawa Citizen! Meanwhile, drug pushers everywhere rejoice in the fact that they can now promote heroin as a 'weight loss supplement'.
Another great moment is during a discussion of carcinogens. It is important to note that while Campbell père et fils emphasise the 'environmental' factors underlying cancers, heart disease, and other 'Western diseases' (or 'diseases of affluence'), they almost always are thereby referring to what I would describe as 'dietary' factors. For most people, 'environment' would be thought to refer to, well, pretty much anything other than what they eat - which, the good doctors Campbell would want to insist, is to miss the point.

Anyway, to return to Campbell's discussion of carcinogens, it turns out (file it under the plus ça change category) that there was a cancer scare regarding chemicals known as nitrites, preservatives used in meat such as hot dogs and bacon (whence their pink colour). 'In 1970,' Campbell reports, 'the journal Nature reported that the nitrite we consume may be reacting in our bodies to form nitrosamines.' These are considered carcinogens because they are ' "anticipated to be human carcinogens" ' based on data from experiments on rats. Two groups of rats were dosed with a particular nitrosamine, NSAR, one group receiving a lower dosage, the other a higher. The rats given the higher dosage all died of cancer. Because rats (and other rodents such as mice) respond to cancer-causing agents much like humans do, it is reasonable, based on the results from such studies (provided that more than one such study is conducted to confirm the results), to conclude that if a chemical results in a higher incidence of cancer in rats, it is likely to do the same in humans.

But wait! Before you reach into your freezer to throw out those hot dogs (actually, the Campbells would advise you to do so anyway, just on different grounds), Campbell provides this gem which provides a context not usually considered when we panic over carcinogens:
How much NSAR did the rats get? Both groups of rats were given an incredible amount. Let me translate the "low" dose by giving you a little scenario. Let's say you go over to your friend's house to eat every meal. This friend is sick of you and wants to give you throat cancer by exposing you to NSAR. So he gives you the equivalent of the "low" level given to the rats. You go to his house, and your friend offers you a bologna sandwich that has a whole pound of bologna on it! You eat it. He offers you another, and another, and another.... You'll have to eat 270,000 bologna sandwiches before your friend lets you leave. You better like bologna, because your friend is going to have to feed you this way every day for over thirty years! If he does this, you will have had about as much exposure to NSAR (per body weight) as the rats in the "low"-dose group. [p. 45; cf. pp. 44-5] That's a lot of bologna. This absurd scenario (which is what is so funny about it - imagine eating 270,000 bologna sandwiches a day, each being a pound of bologna, for over thirty years!) really helped drive home a point that the Campbells make, which their research has demonstrated, which is that it is not so much the chemicals identified as carcinogens that are the problem - in order to get verifiable experimental results researchers have to dose rats with proportionately enormous amounts of would-be carcinogens, amounts that you'd never find in products for human consumption and which no one would actually consume over a lifetime - but the way in which those carcinogens interact with cellular enzymes, an interaction that is made easier by animal-based protein. In other words, the real problem with your hot dog with nitrites is not the nitrites, but the hot dog.
As increasing numbers of Americans fall victim to chronic diseases, we hope that our hospitals and doctors will do all that they can to help us. Unfortunately, both the newspapers and the courts are filled with stories and cases that tell us that inadequate care has become the norm.
One of the most well-regarded voices representing the medical community, the Journal of the American Medical Association (JAMA) included a recent article by Barbara Starfield, M.D., stating that physician error, medication error and adverse effects from drugs or surgery kill 225,400 people per year... . That makes our health care system the third leading cause of death in the United States, behind only cancer and heart disease... . [p. 15] Campbell is definitely not trying to be funny here, but this is a statement about which one has to laugh, or else one will cry. Starfield's article was published in 2000 (in JAMA 284), and I suspect that the number of Americans who die every year from (in effect) going to the hospital has only increased in the past dozen years, despite, no doubt, endless calls for increased 'accountability' and 'efficiency'. What's more, Campbell writes, '[t]he... largest category of deaths in this group are the hospitalized patients who die from the "noxious, unintended and undesired effect of a drug," which occurs at normal doses.' [p. 16; emphasis mine] In other words (as Campbell more or less says himself), over one hundred thousand Americans die every year from taking their medication exactly the way they're supposed to. This is cruelly ironic, and it is doubly so when you consider that (to use the heading of the following section) American hospitals are an 'expensive grave'; Campbell reports (pp. 17-9) that in 1997 the health care system in the US cost 1 trillion dollars. (And whatever you may think of 'Obamacare', it is sure to raise the overall cost of the health care system to incredible heights.) One chart shows that health care spending in the US went from just under 6% of the GDP in 1960 to about 14% in 1997. In 1997 (Campbell notes, providing a chart), no country spent as much on health care per capita than the US did ($3912 USD per capita, compared to $2364 per capita by Germany, and, in third place, Canada at $2175 per capita). And what has all that money bought? As of 2000, according to the World Health Organization, it bought the United States the thirty-seventh best health care system in the world. Right.
Proteins and Cancer
The first major section of The China Study goes over the results of years of research by Dr Campbell and many associates and students, all of which demonstrates the connection between rates of cancer and from where we get our protein.

One of Campbell's earliest experiments was to look at rates of liver cancer in children in the Philippines. It began when he started working on developing protein-based diets for children there to deal with malnourishment.
There was, however, a nagging problem with the tasty legumes. Considerable evidence had been emerging, first from England and later from MIT (the same lab that I had worked in) to show that peanuts often were contaminated with a fungus-produced toxin called aflatoxin (AF). It was an alarming problem because AF was being shown to cause liver cancer in rats. It was said to be the most potent chemical carcinogen ever discovered.
The first step of investigating AF was to gather some basic information. Who in the Philippines was consuming AF, and who was subject to liver cancer? ... We also adopted a second strategy by asking another question: how does AF actually affect liver cancer? ...
We began with a stepwise series of surveys. First, we wanted to know which foods contained the most AF. We learned that peanuts and corn were the foods most contaminated. All twenty-nine jars of peanut butter we had purchased in the local groceries, for example, were contaminated, with levels of AF as much as 300 times the amount judged to be acceptable in U.S. food. Whole peanuts were much less contaminated; none exceeded the AF amounts allowed in U.S. commodities. This disparity between peanut butter and whole peanuts originated at the peanut factory. The best peanuts, which filled "cocktail" jars, were hand selected from a moving conveyor belt, leaving the worst, moldiest nuts to be delivered to the end of the belt to make peanut butter.
Our second question concerned who was most susceptible to this AF contamination and its cancer-producing effects. We learned that it was children. They were the ones consuming the AF-laced peanut butter. ... As we gathered... information [about AF consumption] an interesting pattern emerged: the two areas of the country with the highest rates of liver cancer, the cities of Manila and Cebu, also were the same areas where the most AF was being consumed. Peanut butter was almost exclusively consumed in the Manila area, while corn was consumed in Cebu... . [At first glance, looks like AF's the bad guy; case closed.]
But, as it turned out, there was more to this story. It emerged from my making the acquaintance of a prominent doctor, Dr. Jose Caedo, who was an advisor to President Marcos. He told me that the liver cancer problem in the Philippines was quite serious. What was so devastating was that the disease was claiming the lives of children before the age of ten. Whereas in the West, this disease mostly strikes people only after forty years of age, Caedo told me that he had personally operated on children younger than four years of age for liver cancer!
That alone was incredible, but what he then told me was even more striking. Namely, the children who got liver cancer were from the best-fed families. [italics original] The families with the most money ate what we thought were the healthiest diets, the diets most like our own meaty American diets. They consumed more protein than anyone else in the country (high quality animal protein, at that), and yet they were the ones getting liver cancer! [ditto]
How could this be? Worldwide, liver cancer rates were highest in countries with the lowest average protein intake. It was therefore widely believed that this cancer was the result in a deficiency in protein. Further, the deficiency problem was a major reason we were workng in the Philippines: to increase the consumption of protein by as many malnourished children as possible. But now Dr. Caedo and his colleagues were telling me that the most protein-righ children had the highest rates of liver cancer. This seemed strange to me, at first, but over time my own information increasingly confirmed their observations. [pp. 34-6] Campbell père's work in the Philippines, then, was the genesis of his research into the link between sources of protein and cancer which culminated in the China Study. It says something about my childhood interests, as about societal interests as a whole at the time, that I'd never heard of the China Study until I purchased this book to write my marginal commentary on it, even though it took place during (so far as I can tell), the eighties and nineties. Actually, the name of the book is a bit of a misnomer, for although an entire chapter and an appendix are devoted to the China Study per se, that landmark study is not the work's primary focus. The China Study, moreover, was not simply a study of cancer rates and the like, but a snapshot of the life and health of Chinese peoples from mostly rural counties over a long period of time, and from the data it accrued a wide variety of inferrals could be made (as Dr Campbell puts it, the study showed more than eight thousand statistically significant associations between diet, lifestyle, and health [cf. p. 73]). But this is getting away from the point of this passage. The point is, what Campbell and his colleagues discovered based on the studies they did after learning who was getting liver cancer, was that the link between cancer and diet was not simply the presence or absence of carcinogens (in this case, of AF), but had more to do with the food being eaten.
Time to look at this link between protein and cancer rates a little more closely. I once mentioned The China Study and its conclusions at a dinner I hosted, and my brother, no slouch when it comes to research, wondered how there could be a link between protein consumption and illness. After all, presumably the body would treat proteins from different sources in similar ways. (I hope that I've summarised what he said accurately, after all, it was a while ago and I didn't write it down.)

What Campbell père and his colleagues and students found, though, was that something else was the case. Their discoveries, furthermore, allowed them to discover new connections between disease and diet. Let's look at cancer as an example.
Cancer proceeds through three stages: initiation, promotion and progression. ...
Chemicals that... [initiate cancer-prone cells] are called carcinogens. ... These carcinogens genetically transform, or mutate, normal cells into cancer-prone cells. A mutation involves permanent alteration of the genes of the cell, with damage to its DNA.
The entire initiation stage... can take place in a very short period of time, even minutes. It is the time required for the chemical carcinogen to be consumed, absorbed into the blood, transported into cells, changed into its active product, bonded to DNA and passed on to the daughter cells. ...
... The second growth stage is called promotion. ... This stage occurs over a far longer period of time than initiation, often many years for humans. It is when the newly-initiated cluster [of cancer-prone cells] multiplies and grows into larger and larger masses and a clinically visible tumor is formed.
But... the initial cancer cells will not grow and multiply unless the right conditions are met. ... This is one of the most profound features of promotion. Promotion is reversible, depending on whether the early cancer growth is given the right conditions in which to grow. [italics original] This is where certain dietary factors become so important. These dietary factors, called promoters, feed cancer growth. Other dietary factors, called anti-promoters, slow cancer growth. Cancer growth flourishes when there are more promoters than anti-promoters: when anti-promoters prevail cancer growth slows or stops. [p. 50] The final stage of cancer, progression, is when a 'clinically visible tumour' (or 'tumor' in American English) spreads or, worse, metastasizes. As we are about to see, in brief, what Campbell père et al. found was that it was surprisingly easy to identify certain promoters and anti-promoters of cancer.
At the time we started our research, we hypothesized that the protein we consume alters tumor growth by changing how aflatoxin is detoxified by the enzymes present in the liver.
We initially determined whether the amount of protein that we eat could change this activity. After a series of experiments..., the answer was clear. Enzyme activity could be easily modified simply by changing the level of protein intake.
Decreasing protein intake like that done in the original research [Campbell is referring to research done in India, which he first brings up on pp. 36-7]... not only greatly decreased enzyme activity, but did so very quickly. What does this mean? Decreasing enzyme activity via low-protein diets implied that less aflatoxin was being transformed into the dangerous aflatoxin metabolite that had the potential to bind and to mutate the DNA.
We decided to test this implication: did a low-protein diet actually decrease the binding of aflatoxin product to DNA, resulting in fewer adducts? An... experiment... showed that the lower the protein intake, the lower the amount of aflatoxin-DNA adducts.
We now had impressive evidence that low protein intake could markedly decrease enzyme activity and prevent carcinogen binding to DNA. ...
... [O]ne idea seemed to be clear: lower protein intake dramatically decreased tumor initiation. [pp. 52-3] The first major experimental discovery, then, was that, less protein consumed meant fewer carcinogens binding to DNA in cells. It should be noted that the experimental subjects - rats - being tested were exposed to amounts of aflatoxin (AF), in proportion to their body weight, far greater than the amount found in the peanut butter consumed by the Filipino children who came to be affected by liver cancer, or so it seems; in the book proper Campbell does not provide exact numbers in every case, but provides copious notes to various published research papers and studies. My quotations are unable to include the notes and accompanying charts. For best results, you'll have to get your hands on a copy of The China Study in order to see the data, notes, and charts for yourself.
A major section of Campbell's research on cancer has to do with observing cancer foci (tiny clusters of cancer cells which can be observed experimentally instead of having to wait for full-blown tumours to grow) and how these responded to varying doses of AF and high (20%) or low (5 or 10%) protein diets; I won't quote any of it at length here, but as you can imagine, Campbell et al. found that foci growth disappeared in test subjects on a 5% protein diet: 'There was no foci response, even when animals were given the maximum tolerated aflatoxin dose.' By contrast, on a 20% protein diet (close to the typical American, and probably Canadian diet), 'foci increased in number and size... as the aflatoxin dose was increased. The dose-response relationship was strong and clear.' [pp. 58-9] Campbell then records the next logical step in experimentation.
Controlling cancer through nutrition was, and still is, a radical idea. [As an aside, my dislike for the word 'radical' ranges, depending on the context in which it is used, from cordial to vehement. But it's Dr Campbell's book, so he can write what he wants.] But as if this weren't enough, one more issue would yield explosive information: did it make any difference what type of protein was used in these experiments? For all of these experiments, we were using casein, which makes up 87% of cow's milk protein. So the next logical question was whether plant protein, tested in the same way, has the same effect on cancer promotion as casein. The answer is an astonishing "NO." In these experiments, plant protein did not promote cancer growth, even at the higher levels of intake. ... Gluten, the protein of wheat, did not produce the same result as casein, even when fed at the same 20% level. [italics original]
We also examined whether soy protein had the same effect as casein on foci development. Rats fed 20% soy protein diets did not form early foci, just like the 20% wheat protein diets. [ditto] Suddenly protein, milk protein in this case, wasn't looking so good. We had discovered that low protein intake reduces cancer initiation and works in multiple synchronous ways. As if that weren't enough, we were finding that high protein intake, in excess of the amount needed for growth, promotes cancer for initiation. Like flipping a light switch on and off, we could control cancer promotion merely by changing levels of protein, regardless of initial carcinogen exposure. But the cancer-promoting factor in this case was cow's milk protein. It was difficult enough for my colleagues to accept the idea that protein might help cancer grow, but cow's milk protein? ...
Thus far we had relied on experiments where we measured only the early indicators of tumor development... . Now it was time to do... [a] study... where we would measure complete tumor formation. We organized a very large study of several hundred rats and examined tumor formation over their lifetimes using several different approaches.
The effects of protein feeding on tumor development were nothing less than spectacular. Rats generally live for about two years, thus the study was 100 weeks in length. All animals that were administered aflatoxin and fed the regular 20% levels of casein either were dead or near death from liver tumors at 100 weeks. All animals administered the same level of aflatoxin but fed the low 5% protein diet were alive, active and thrifty [if anyone knows what this means with respect to lab rats, let me know, because I'm stumped as to why anyone would call a rat 'thrifty'], with sleek hair coats at 100 weeks. This was a virtual 100 to 0 score, something almost never seen in research and almost identical to the original research in India. [pp. 59-61] A couple of notes on the text: Campbell provides some charts and it is interesting to see that a low-protein diet of 5% casein (cow's milk protein) was effective in keeping the development of cancer foci low. But the difference between animal-based protein and plant-based protein, as these studies demonstrated, is that a diet high in animal-based protein (more than 10%) leads to a higher likelihood of cancer, but a diet high in plant-based protein does not. The chapter continues with researchers switching diets over the course of the experiment; they switched from animal- to plant-based protein (or the other way around) in every level of protein intake, and discovered that in every case, diets with animal-based protein promoted cancer growth to a greater extent than their equivalent plant-based protein diets (although, as I have said, the low protein diet of casein was effective at hindering tumor growth). Campbell and his associates and students would go on to confirm these experimental findings in the population survey called the 'China Study'. That is, they were able to observe how the rates of cancer and other illnesses corresponded to actual human diets and exposure to carcinogens, instead of the measured diets and 'astronomically high' doses of carcinogens used in their experiments. At this point you won't be surprised to read that diets heavy in whole, plant-based foods were healthier (even when the subject ate more calories per meal than was found on the typical American plate at the time) than those with more meat. One of the implications I find interesting is that, granting for the purposes of argument that Campbell's et al's findings are true, a great deal of anti-cancer work is going about things the wrong way. Exposure to carcinogens is less dangerous if you eat the right diet, because it is the kind and amount of protein that you eat that is the crucial factor in determining your chances of getting cancer. I don't think this means that, say, a society of vegetarians could take up smoking, nude sunbathing without sunblock and drinking water from a river next to an industrial plant without thinking twice about it, but if what the Campbells write is true, you are less likely to get cancer (or other illnesses) from your other bad habits if you can at least change your diet. (It does suggest that some of the regulations introduced to protect our health are over-rated because they are going after the wrong target.) The other implication is that all those runs, walks, motorcycle rides, and other fundraising activities to fight cancer should be doing them to promote awareness of the link between cancer and protein consumption; in other words, should be done to promote a near-vegetarian diet. Now, I do not believe that vegetarianism is per se a moral position or lifestyle (that is an essay begging to be written), but the point that is at present implied, and, later, stated explicitly in The China Study is that vegetarianism is healthier than the 'all-American' beefy diet.
Diet and Disease
After establishing the link between meat protein and cancer, in chapter after chapter the doctors Campbell go on to show how excessive consumption of animal-based foods (with associated levels of animal protein) is linked to one illness after another. A brief selection of quotations should serve to highlight this point:
At the end of the [Korean War], a landmark scientific study was reported in the Journal of the American Medical Association. Military medical investigators had examined the hearts of 300 male soldiers killed in action in Korea. The soldiers, at an average age of twenty-two years, had never been diagnosed with heart problems. In dissecting those hearts, researchers found startling evidence of disease in an exceptional number of cases. Fully 77.3% of the hearts they examined had "gross evidence" of heart disease. (In this instance, "gross" means large.) [italics original]
That number, 77.3%, is startling. Coming at a time when our number one killer was still shrouded in mystery, the research clearly demonstrated that heart disease develops over an entire lifetime. Furthermore, almost everyone was susceptible! These soldiers were not couch-potato slouches; they were in top condition in the prime of their physical lives. Since that time, several other studies have confirmed that heart disease is pervasive in young Americans.
But what is heart disease? ... If you have plaque building up in your coronary arteries, you have some degree of heart disease. Of the autopsied soldiers in Korea, one out of twenty diseased men had so much plaque that 90% of an artery was blocked. ...
Why hadn't these soldiers had a heart attack already? After all, only 10% of the artery was open. Hpw could that be enough? It turns out that if the plaque on the inner wall of the artery accumulates slowly, over several years, blood flow has time to adjust. ... If plaque accumulates over everal years there will be enough collateral development [growth of numerous small arteries to circumvent plaque-filled ones] that blood can still travel through the heart. However, too much plaque buildup can cause severe blood restriction, and debilitating chest pain, or angina, can result. [pp. 112-3] Heart attacks, the Campbells go on to write, occur in arteries where, ironically, there is less, not more plaque. Under certain circumstances, the 'cap' of plaque build-up in an artery can rupture, and the plaque flow into the bloodstream, whereupon the blood clots around the rupture, blocking the flow of blood through the artery. Because this happens so suddenly, the body does not have time to develop alternative passageways for the blood, and so you have a heart attack. But, as the example of angina shows, even if you don't ever have a heart attack in your life, if you are subjec to heart disease, you are likely going to suffer something. I am not a man in peak physical condition, I am about to leave the prime of my youth, and my diet is high in animal protein and low in plant-based whole foods. How much you want to bet my heart is in even worse shape than those soldiers who, at an average of twenty-two years of age, displayed 'gross evidence' of heart disease? Diet is a controlling factor in heart disease, as the Campbells go on to demonstrate, citing the work of other American medical luminaries, among them Dr Dean Ornish, whose work is also discussed in a handy little book called Change or Die, by Alan Deutschman. You will not be at all surrpised to learn that our diet, relatively high in fat and protein, is the cause of heart disease; while diets relativey low in fat and (animal) protein are the best preventative measures against heart disease.
[Once] I [Campbell père] was in my office at Cornell when I was told that a woman with a question regarding breast cancer was on the phone.
"I have a strong history of breast cancer in my family," the woman... said. "My mother and grandmother both died from the disease and my forty-five-year-old sister was recently diagnosed with it. Given this family problem, I can't help but be afraid for my nine-year-old daughter. She's going to start menstruating soon and I worry about her risks of getting breast cancer." Her fear was evident in her voice. "I've seen a lot of research showing that family history is important, and I'm afraid that it's inevitable that my daughter will get breast cancer. One of the options I've been thinking about is a mastectomy for my daughter, to remove both breasts. Do you have any advice?"
This woman was in an exceptionally difficult position. Does she let her daughter grow up into a deathtrap, or grow up without breasts? Although extreme, this question represents a variety of similar questions faced every day by thousands of women around the world.
... Understandably, women who are most afraid of this disease have a family history of breast cancer. Family history implies that genes do play a role in the development of breast cancer. But I hear too many people say, in effect, that "it's all in the family" and deny that they can do anything to help themselves. This fatalistic attitude removes a sense of personal responsibility for one's own health and profoundly limits available options.
It is true that if you have a family history of breast cancer, you are at an increased risk of getting the disease. However... the vast majority of breast cancer in American women is not due to family history or genes. But genetic fatalism continues to define the nation's mindset.
... I do not mean to diminish the importance of knowing all there is to know about these genes for the small minority of women who carry them [that is, the mutated versions which increase one's risk of getting breast cancer]. But we need to remind ourselves that these genes need to be "expressed" in order for them to participate in disease formation, and nutrition can affect this. We've already seen... how a diet high in animal-based protein has the potential to control genetic expression. [pp. 158, 161-2] Campbell goes on (pp. 163-8) to look at other aspects of breast cancer formation and treatment, and shows that they are problematic. For instance, screening for breast cancer doesn't necessarilly prolong your life; mostly it means you are aware you have breast cancer sooner than if you weren't screening. The other major factor cited in causing breast cancer, environment, is shown to have less causal correlation, and more incidental, than is usually thought. It is well known (at least among those engaging in breast cancer research), Campbell explains, that levels of estrogen in the body are the crucial factor in determining one's risk for breast cancer, and, quelle surprise, high-fat and protein diets increase the amount of estrogen in women. Higher levels of estrogen are also responsible for the markedly earlier age of menarche (one's first menstruation) in girls, and the later age of menopause (and worse effects thereof), so the societal problems surrounding those are, in the end, mostly due to diet. My emphasis here is on what might be called the other kind of 'genetic fallacy' (not the invalid form of logical argument but the appeal to genetics in order to foster fatalistic dependency). A funny expression of the appeal to genetics can be seen in the pilot episode of Modern Family, in which one character, Cameron, explains his weight gain (prompted, apparently, by his eventual parenthood; he and his partner Mitchell are adopting a baby) as the result of a 'natural nesting instinct' and says something to the effect of 'it's science, you can't fight it'. This is accompanied by what looks like security video footage of him going into the pantry to gorge on midnight snacks. I recently went to a presentation on genes and how information about our genetic structure can be used or misused, and the presenter, Dr Jean Jordan of Ottawa, discussed briefly how it is, in effect, impossible to say (under most circumstances) that a single gene 'causes' this or that disease. (Hopefully I am paraphrasing her statements more or less accurately.) The 'appeal to genetics' as a way of limiting options in treatment and prevention - in other words, as a way of promoting fatalism - is its own kind of fallacious argument. The woman who called Dr Campbell père in his office at Cornell, had she been aware of the link between nutrition/diet and breast cancer, would not have been caught (or so she believed) on the horns of the dilemma of letting 'her daughter grow up into a death-trap or grow up without breasts'. To mix metaphors, she could have cut the Gordian knot by putting her daughter (not to mention herself, since, with her family history, she would have been at a high risk to develop breast cancer) on a whole-foods, plant-based diet, and avoided the dilemma altogether.
In the case of Type 1 diabetes [an autoimmune disease], the immune system atacks the pancreas cells responsible for producing insulin. This devastating, incurable disease strikes children, creating a painful and difficult experience for young families. What most people don't know, though, is that there is strong evidence that this disease is linked to diet and, more specifically, to dairy products. The ability of cow's milk protein to initiate Type 1 diabetes is well documented. ...
... [The] process [by which Type 1 diabetes is initiated in infants] boils down to a truly remarkable statement: cow's milk may cause one of the most devastating diseases that can befall a child. [italics original; Campbell handily highlights key phrases with italics, does he not?] For obvious reasons, this is one of the most contentious issues in nutrition today.
... [One study] discovered something truly remarkable. Of... 142 diabetic children measured [for levels of antibodies formed against BSA, a cow's milk protein], every single one had antibody levels higher than 3.55. Of the seventy-nine normal children measured, every single one had antibody levels less than 3.55. [ditto]
There is absolutely no overlap between antibodies of healthy and diabetic children. All of the diabetic children had levels of cow's milk antibodies higher than those of all the non-diabetic children. This implies two things: children with more anitbodies consumed more cow's milk, and second, increased antibodies may cause Type 1 diabetes.
... Several studies have since investigated this effect of cow's milk and BSA antibody levels. All but one showed that cow's milk increases BSA antibodies in Type 1 diabetic children, although the responses were quite variable in their magnitude.
... Consider... the link between one aspect of environment, cow's milk consumption, and this disease. Cow's milk consumption by children zero to fourteen years of age in twelve countries shows an almost perfect correlation with Type 1 diabetes. The greater the consumption of cow's milk, the greater the prevalence of Type 1 diabetes. In Finland, Type 1 diabetes is thirty-six times more common than in Japan. Large amounts of cow's milk products are consumed in Finland but very little is consumed in Japan.
As we have seen with other [such] diseases... when people migrate from areas of the world where disease incidence is low to areas of the world where disease incidence is high, they quickly adopt the high incidence rates as they change their diet and lifestyle. This shows that even though individuals may have the necessary gene(s), the disease will occur only in response to certain dietary and/or environmental circumstances.
Disease trends over time show the same thing. The worlwide prevalence of Type 1 diabetes is increasing at an alarming rate of 3% per year. This increase is occurring for different populations even though there may be substantial differences in disease rates. This relatively rapid increase cannot be due to genetic susceptibility. The frequency of any one gene in a large population is relatively stable over time, unless there are changing environmental pressures that allow one group to reproduce more successfully than another group. For example, if all families with Type 1 diabetic relatives had a dozen babies and all the families without Type 1 diabetic relatives died off, then the gene or genes that may be responsible for Type 1 diabetes would become much more common in the population. This, of course, is not what is happening, and the fact that Type 1 diabetes is increasing 3% every year is very strong evidence that genes are not solely responsible for this disease. [pp. 187-91] Well, as this shows, you could say that milk doesn't really do a body good. Of course, except in the case of Type 1 diabetes, most of the autoimmune disorders and other diseases which Campbell shows correlate to consumption of cow's milk protein only begin to afflict people when they are older (so far as I know), which is one reason why the cow's milk/autoimmune correlation is not widely known. Campbell later addresses other, less salutary reasons why the correlation between cow's milk protein and autoimmune diseases are not well known. Later, on pp. 204-11, Campbell shows how consumption of cow's milk correlates with incidence of osteoperosis. His point is not that we don't need calcium, mind; it is that it can be had without the risk of osteoperosis (in older women) by eating the right kinds of veggies. Which means that Captain Vegetable is right. Oh so right.
Speculation Regarding the Impact of Evolution on Diet and Health
There is a lot more to The China Study than all this; possibly the most important section of the book deals with the problem of dissemination - that is, why, when there exists all these studies that demonstrate scientifically and empirically (think of Ornish's dietary programme) that a whole-foods, plant-based diet (and one in which, by implication, the consumption of meat and animal-based protein is curtailed almost the point of non-consumption) and all kinds of advocacy for such things, do people continue to eat boatloads of meat, and get sick, fat and cancerous? But I would like to look briefly at a different question, one which the Campbells do not address, probably on the good grounds that they are not necessarily competent to address the question and that it is probably impossible to address the question in any way other than speculative.

The question I wish to ask, then, is why do we respond so well to a plant-based diet, and so poorly to an animal-based diet (as well as to diets high in refined products of plants)? For there are certainly signs that our bodies have evolved to eat meat more effectively - consider our incisors and canines and shorter intestines. It is highly probable - so probable as to be conclusive, in fact - that the appendix, for example, is a vestige of a larger digestive tract for the digestion of plants. If eating meat is so bad for us, as evidently appears to be the case, why have we been eating meat long enough that our bodies have begun to change to help us eat it more effectively?

A passage the Campbells write about migrant studies showing the importance of environment (how one's social milieu determines lifestyle and diet) in assessing the degree of risk for colorectal cancer may be said to represent, in an indirect way, what they might say about 'why' meat (in effect) is still so bad for us:
It seems that environmental factors, including diet, play the most important roles in colorectal cancer. Migrant studies have shown that as people move from a low-cancer risk area to a high-cancer risk area, they assume an increased risk within two generations. This suggests that diet and lifestyle are important causes of this cancer. Other studies have also found that rates of colorectal cancer change rapidly as a population's diet or lifestyle changes. These rapid changes in cancer rates within one population cannot possibly be explained by changes in inherited genes. In the context of human society, it takes thousands of years to get widespread, permanent changes in the inherited genes that are passed from one generation to the next. Clearly, something about environment or lifestyle is either preventing or enhancing the risk of getting colorectal cancer. [pp. 169-70] Just to comment briefly on this passage for its own sake, it is a telling blow against the view that genetic factors are a significant or primary cause of (in this case colorectal) cancer, or, to put it as the Campbells do, that one's genes absolutely determine the risk to which one is exposed for cancer.
I am moving into the realm of speculation here, but I think that the following may be tentatively advanced as an answer to why animal-based diets have such pervasively baleful effects on our health.

First, the observeable changes to our teeth and digestive system are cosmetic, as it were. The way in which our genetic structure encodes our cells so that they absorb and incorporate proteins from different sources is much more basic, more fundamental, to our functioning than what shape our teeth are or how long our guts are. (I could be way off base here.) It seems to me that the 'cosmetic' changes to our bodies merely affect how we digest certain things, while the way our bodies process and incorporate proteins from food are intrinsic to the digestive process per se. You might say that it is 'harder' for our bodies to evolve to digest animal-based foods more effectively (that is, resulting in fewer health problems) because the way we digest food is a complex organic system, less affected by relatively minor structural changes to our teeth and digestive tract than we might suppose.

Second, if we bring up the fact that nature provides many examples of animals that are carnivores, it must be pointed out that, in nature, even carnivorous animals eat far less meat per capita than humans do. What's more, some of them, like sharks, have had millions upon millions more years to evolve so that they don't suffer health problems from eating meat (so far as we know). But would you rather be a shark? Carnivorous mammals, for instance, probably consume more plant-based food than we observe (think of cats eating plants to aid in digestion), and, moreover, have a harder time catching prey to eat than we have driving to the supermarket to pick up a steak, so that they simply don't eat that much meat, compared to humans.

One begins to wonder, in light of the data provided by The China Study, whether much incidence of sickness in tamed animals has something to do with the fact that we feed them more animal-based protein than they would have ever had occasion to eat naturally. If I am not mistaken, cows, chickens, and other livestock raised as food often eat feed high in animal-based protein, while pet dogs and cats get loads of meat in dry and wet food in quantities that they simply would not consume in the wild. (Note that it does not follow from this that, for example, we should subject our carnivorous pets to a 'vegan' diet; but it may be said that it would be better for them if we left our pets to fend for themselves when it comes to finding animal-based food.)

Third, this draws attention to the fact that our consumption of meat is, in relative terms, incredibly greater than anything like what our ancestors, near and remote, human or pre-human, would have eaten, because they had to work harder to catch prey. Hunter-gatherer societies may (again I am speculating here) have only got once a week or so the quantity of meat we eat every day, or even only a portion of the amount of meat we eat daily. There is a reason a successful hunt was such a big deal: it didn't happen all that often. (In The Rebel Sell, the fact is pointed out that in hunter-gatherer societies more murders were committed per capita than in modern industrialised ones; this suggests that it was generally easier to hunt, so to speak, one's fellow man than to help him hunt for dinner.)

On evolutionary grounds, it may be supposed (although it may remain nothing more than unproven speculation), our bodies are unaccustomed to eating meat to the extent that we presently do. We aren't made to eat so much meat. Our bodies can handle small quantities of animal-based food without any problem (which is why the Campbells say that, so long as the vast majority of what we eat are plant-based whole foods, we don't have to worry about eating meat or food high in refined carbohydrates once in a while), but they simply don't have what it takes to digest and process meat in the quantity in which it is usually consumed in affluent societies.

Repeating Histories
Finally, to look at another issue which is raised incidentally, as it were, in The China Study, late in the work (in the chapter from which the title of this section takes its name) Campbell quotes from an old book, The Ethics of Diet: A Catena of Authorities Deprecatory of the Practice of Flesh-Eating, written by Howard Williams and published in 1883. Long before the advent of empirical science (in the way in which we recognise and practise it today), writers such as Plato identified the problems caused by excessive meat-eating. (In one Platonic dialogue Campbell quotes on pp. 344-5, Socrates says 'when dissoluteness and diseases abound in a city [due to the increased eating of meat], are not law courts and surgeries opened in abundance, and do not Law and Physic begin to hold their heads high[...]?' Campbell's point in quoting this is sharp. What, after all, are two of the largest (and growing) professions in North America today? Williams (and Campbell) might have quoted Genesis 1.29-30, too, in which God commands humankind and the rest of the animals as follows:
See, I have given you every plant yielding seed that is upon the face of all the earth, and every tree with seed in its fruit; you shall have them for food. And to every beast of the earth, and to every bird of the air, and to everything that creeps on the earth, everything that has the breath of life, I have given every green plant for food. [NRSV]
One possible interpretation of this part of the passage, told me by my OT prof (formerly) at Huron, Dr Gord Hamilton, is that God initially gave only plants to be used as food (later, after the Flood [Gen. 9.2-3], animals are given by God in into our hands in order to be used as food, one reason why it is important not to consider the earliest chapters of Genesis as historical in the strict sense). On the other hand, read Genesis, the Movie for a different take on interpreting the first chapter of Genesis.

The point I would take about diet from the opening chapter of Genesis is not so much that a vegetarian diet is 'proved' to be healthy by the Bible (although books and individuals advocating 'Biblical diets', most if not all of which are nonsense from a health perspective, abound), as that the account of God's creative act in Genesis reflects something which could be observed, as it was by Plato, without a medical degree (or even a scientific method such as we now are lucky to have), that is, that it is healthier to eat a plant-based diet ('every plant yielding seed... and every tree with seed in its fruit') than an animal-based one.

Moreover, given that the China Study, which provided the basis for this book, was a study of dietary practises observed in China since (presumably) time immemorial, it is not as though Campbell, and the many others to whom he refers in the work, are discovering something new. Rather, it is that their studies, research, and experiments methodically demonstrate something already observeable; namely, that plant-based, whole foods diets are healthier than high-fat, high-protein ones. If you like, the doctors Campbell, et al., provide a scientific imprimatur on dietary habits long-established as healthy. Given the climate of opinion, it is necessary and important that this sort of thing be validated as experimentally sound. While it is not as though the studies, research, and experiments have 'proved' something that was not known before, it is important to emphasise that they lend to the diet advocated by the doctors Campbell in The China Study the considerable authority of the scientific establishment, even if, as the Campbells are wont to admit, that establishment is, as it were, a 'kingdom divided against itself.'


  1. I have retained my suspicions of the conclusions of The China Study insofar as they assert that there is a difference in kind between nutrients derived from animal sources and those derived from other sources.

    (I should contrast that with your concluding remarks discussing how there is such a difference in degree in how humans in affluent societies consume meats compared to (most) other humans or even to non-human obligate carnivores.)

    From a viewpoint of first principles, if there is one solid conclusion from biochemistry, to the best of my understanding, it is that a molecule is a molecule is a molecule - which is why we can, say, consume synthesized ASA rather than drive willow trees to extinction by mining their bark for it. Likewise a protein is a protein is a protein - and at any rate they are broken down during digestion (see opening notes here) in the stomach: at the point of absorption into cells the source of dietary proteins or their amino acid constituents surely could not be discerned.

    In addition, there are several critiques of the methods and conclusions of The China Study and its related publications beyond any objection from biochemical principles.

    Science-Based Medicine has two articles specifically related to The China Study, here and here. The second article is, strictly speaking, a limited review of a more comprehensive criticism of The China Study published by one Denise Minger (who, like you or I is an amateur, although I suspect more well-versed in statistics). Her weblog includes an entire section dedicated to critical analysis of The China Study.

    While The China Study itself is not a professional scientific publication, I assume that it has references to several such publications, including some by the authors. At least some of the research involved has come under professional criticism in the scientific literature (for example, this letter in Cancer Research).

    Long story short: between adhering to the dietary recommendations of, say, Canada's Food Guide or those of The China Study, you can definitely put me square on the side of the Food Guide (although either way I am sure I would, regrettably, need to cut down on the amount of bacon I eat).

    1. The second link you provided, to Hall's review of Minger is the most helpful critique, I thought.

      The problem with writing these things without doing a lot of research (how much time am I really going to devote to this stuff anyway) is that you end up writing something and regretting it later - as I am with this post. At least with primary literary criticism (such as the kind I did on The Wednesday Letters, for instance), the text itself is your subject and you don't have to widen your gaze.

      I wonder at the comment about 'unbiased scientists' since I don't believe anyone can act or think without bias - there are by nature limitations on human perspective - and the conclusion should be amended to read 'not sufficient reason to recommend drastic reductions in animal protein intake' since dietary protein would come from plants.

      Still, there are certainly grounds to show that Campbell has far from clinched his argument, to put it mildly. (I am happy to say that at least in SBM reading the comments is sometimes rewarding, as opposed to never on some other sites, since I have gleaned a lot of information from the comments to the second article.)

      Broadly speaking, one of my chief personal frustrations is that there do not seem to be 'holistic' (in the strict sense of 'having to do with wholes') studies of anything that seem to do justice to their subject. Campbell's holism, in other words, appears to be the wrong sort. Perhaps there is no kind of holism but the wrong sort, although systems theory might be useful in this respect.

      Anyway, if I learn anything from this it is to always remember that you shouldn't believe your own press.

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