Analysis of the China Study

The China Study is one of the most famous and comprehensive studies of human diets ever undertaken. Proponents of this study often use it to vindicate pro-vegetarian or vegan views. So here is my analysis of the study. It’s a little dry, but hopefully imformative.

The China Study was an epidemiological study, one of the largest of its kind.It was conducted by four professors representing well known institutions and a number of their colleagues. They were Dr. Chen Junshi of the Chiense Academy of Preventive Medicine, Professor T. Colin Campbell of Cornell University, Professor Richard Peto of the University of Oxford, and Dr. Li Junyao of the Chinese Academy of Medical Sciences (http://webarchive.human.cornell.edu/chinaproject/).

The funding came from two American nonprofit organizations, the US National Cancer Institute and the American Institute for Cancer Research, as well as from The Imperial Cancer Research fund of England (http://webarchive.human.cornell.edu/chinaproject/).

Was the study biased? The variety and quality of institutions from which the scholars came should create an appropriate setting for a bias-free study. Also, because there was no profit motive—the only motive being to prevent cancer—the funding should not have contributed to bias in the results.

Methodology

The China Study took place with the goal of learning about the dietary causes of cancer. The study looked at sixty five randomly chosen counties of China, predominately rural. The differences in climate, lifestyle, urbanization, socioeconomics, etc. among the different counties provided adequate groups to test various controls and variables. County mortality rates and causes of death were surveyed from 1973 to 1975 and from 1986 to 1988. In 1983 and 1989, detailed surveys of biochemistry profiles, diet, and lifestyle were undertaken. Within each location, individuals from 50-60 households were surveyed. Blood and urine sample analyses, three day dietary surveys, lifestyle questionnaires, and county geographic characteristics were noted in the study. Blood samples were pooled among males and females within counties, preventing complete individualization of results, but individual samples were also saved. Household food consumption was measured by subtracting the weight of the food at the end of the three days from the weight at the beginning. Some of this information was resurveyed in 1993 (http://www.ctsu.ox.ac.uk/~china/monograph/).

This methodology was of utility in gathering a wild amount of facts, and I don’t want to diminish the value in this. But in my view there were a couple of problematic elements in the methodology. Generally speaking, the survey is limited in that unlike other surveys of traditional diets, the China Study only surveyed one ethnic group. This precludes any use of the ideas behind biochemical individuality. Not everyone will respond to the same diet in the same way. Also, by reducing all food values to their macro and micro nutrient values, the quality of the food is not accounted for. The idea that macronutrients can be good or bad for us seems silly, if the carbohydrate could be either organic broccoli or pure sugar. Additionally, because of the pooled blood samples, outliers cannot be accounted for and may sway results significantly. Finally, there was no accounting for exposure to toxic chemicals, which in my view should be of primary concern in a cancer study.

Results and Conclusions

Altogether, the China Study yielded an impressive amount of data. It was found that the Chinese consume 30% more total calories, yet have significantly lower rates of obesity. The Chinese had healthier levels of certain beneficial minerals including iron. Plant protein consumption was colerated with lower levels of both total and LDL cholesterol, with positive implications for heart health. Only 10% of protein came from animal foods; the rest came from plant sources. Chinese consumption of fat (14% of total calories) was much lower than American consumption (36%). Calcium intake in China were lower, but so were osteoporosis incidences. Liver cancer was found to be much more common in China, mainly due to hepatitis, and higher cholesterol levels were also correlated with the cancer. Stomach cancer were found to be much more common in China, perhaps because of H. Pylori infections, and plant consumption was negatively correlated with the cancer. High dietary fat intake and elevated estrogen and testosterone levels were correlated with breast cancer. Compared to the US, China was found to have significantly higher consumption of fiber, starches, plant protein, and vitamin C (http://webarchive.human.cornell.edu/chinaproject/).

The data concluded undeniably that the Chinese people were subsisting comparatively very healthfully on a diet comparatively very low in animal protein. The researches thus concluded that Americans would do well to eat less animal protein in their diet. To use a quote, “The major comprehensive dietary factor responsible for disease rates of pre-industrialized societies changing to those of post-industrialized societies is the decision to consume much larger quantities of animal based foods” (http://webarchive.human.cornell.edu/chinaproject/results.html).

To me, that seems like a problematic assertion to focus on. While the researchers also concluded that degenerative diseases concentrated in urban areas, the need to live in a rural environment did not emerge as a recommendation. While animal protein is an important part of the results, it is by no means the sum of all of the results of the study. Numerous lifestyle factors were surveyed, but none of them seem to come through in the results. Clearly, people in rural China were living more active lives. Also, some analysts point out the negative correlation in the study between fat consumption intake and cancer and the fact that in one measure carbohydrates were more closely correlated with cancer than animal protein (http://www.cholesterol-and-health.com/China-Study.html).  Campbell seems to ignore these results. Taken together with my methodology criticisms above—namely regarding the lack of variable ethnic groups and the lack of discourse on the quality of the food—the detracting elements of the China Study make it hard to whole heartedly endorse.

Personal Reflections

What I gather from the China Study is that Americans need to reconsider the way we choose to lead our modernized, urbanized lifestyles and the way we choose to eat so much processed food and to be sedentary. Indeed, many of us will not do well on the meat and fat heavy Western diet, and I don’t mean to say that the diet described in the China Study is not a very healthful one for many people. It certainly is. To me, this study is one more survey of a traditional society thriving on a traditional diet, fitting in suitably with the works of Weston A. Price and others.

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5 responses to “Analysis of the China Study

  1. Hi, I think you need to re-read the book; I am sorry, but you missed a lot.

    The actual China Study was only one chapter in the book. The author covered a lot more ground than that one massive study.

    You talked a bit about macronutrients; the author went to great lengths to say that foods should not be broken down into their constituent parts. He argued at great length against scientific reductionism – thinking of foods in terms of macronutrients or individual chemicals. He repeated the conclusion that humans are best served on a “whole foods, plant-based diet” many times throughout the book. You basically said that he did the opposite, which is not true. He does talk about macronutrients, but in the context of the whole food.

    Please note that he also took care to account for rural and non-rural Chinese. He did not repeat that as much, so it can be easy to forget, but he did report that differences in health were noted between rural Chinese and city-dwelling Chinese who ate higher concentrations of animal foods.

    But again, the China study part of “The China Study” book was not the entire book.

    Also, your comment about biochemical individuality requiring different diets is unsubstantiated and has no significant basis in science (this is the “blood type” diets). Besides, it does not make any sense; no other animal species in the world is so differentiated that some members must eat one thing while other members must eat a completely different thing. If they did, they would be considered separate species. Thus, the author is right to ignore it, because the blood-type idea is simply a new fad diet.

    Finally, I would advise ignoring the Weston A. Price Foundation (WAPF) completely. They are a very small, pro-meat lobby group that is very vocal (and some would say, violent). If you look closely, a large percentage of their “references” and quotes are referencing themselves and their own members. They don’t reference much science in from non-members because they have trouble finding any science to back up their claims. When they do quote outside sources, either they mis-quote the source or they use a study that has serious known flaws or omissions (eg: feeding tons of vegetables to people drinking milk in a study in order to counter-act the bone-breaking effect of the milk (a cause of osteoporosis) and then claiming the calcium in milk helped their bones while saying almost nothing about the vegetables). Then, if you read their literature, you may notice that they use a lot of ad hominems to get around their deficiencies of persuasion. They also have members that spend a lot of time attacking people they don’t like in public, often using ad hominems and/or foul-language. T. Colin Campbell, one of the authors of The China Study, is one such person that is persistently attacked. For example, in the amazon.com reviews section for The China Study, almost every single positive review or comment (of which there are many hundreds) has been attacked by a small group of individuals who identify themselves with the WAPF. Many of these attacks were so bad, that amazon.com actually deleted them (normally unhelpful comments are just hidden, and you click a button to see them). At one point, one of the WAPF commentors said he didn’t care if amazon deleted his comments since he saved them and would re-post as they are deleted.

    That said, many of these WAPF members quote a book written by Weston A. Price – Nutrition and Physical Degeneration – so often one wonders if it is a bible for them. They say it describes the ideal diet for all human beings. For those who don’t know, Weston A. Price was a dentist living in the early 1900’s. He traveled the world to study teeth and he wrote a book about. I went ahead and read this book. He does not conclude what the WAPF members say. Basically, he said that sugar and processed foods, like white bread, would rot your teeth. He also commented on what he observed in his travels regarding the diets and behaviors of the people he visited. This is interesting in a historical context, but other than the comment on teeth, it is not scientific. I don’t have time to go into all of it, but briefly: he was not a researcher (like the author of The China Study, who has a 40+ year career researching nutrition), he was not conducting a scientific study, he did not measure anything but simply reported observations, and his observations don’t account for survivor bias (the people who died young were not counted). This could go on, but suffice it to say that Mr. Price did some great work for dentistry, but his observations don’t compare to even the most basic scientific study. And this is essentially the Weston A. Price Foundation bible.

    The China Study obviously cannot answer every question – no one can. But it is rather amazing in what the author has accomplished, and what he is able to tell us. I, for one, am grateful that he wrote this book, since what he taught me has quite literally saved my life.

  2. By the way, I hope that didn’t sound condescending or insulting; if it did, that certainly was not my intent.

    Thanks,
    JR

  3. goodfriendsam

    John, I appreciate your thoughtful and in depth comment. I don’t wish to get into a serious debate about this, but I hope others can weigh in on our disagreement.

    Weston A. Price’s research, though largely based on pictures and anecdotal findings, did provide facts that document peoples thriving on a variety of different diets. Clearly, one size does not fit all. I used this as a reference only to discuss the scope of the China Study as a fundamental flaw. Studying the recommended diet with numerous groups of different ethnicities would have been better. Instead, we have one diet that worked for one ethnic group, and we are told that it will be great for everybody.

    And that leads into biochemical individuality. Rather than blood type diets, I would ask you to read Dr. Roger Williams book, Biochemical Individuality (originally published in the 50s), or even look into metabolic typing. There is indeed a scientific basis to the fact that we are all different and metabolize different foods differently.

    Those two arguments are my main points against the China study.

    Take care
    Sam

  4. One more update, then I am off to other things.

    I wouldn’t say that Mr. Price’s observations were of groups of people thriving on different diets. They appear to be thriving because his observations do not account for survivor bias. That is, only the people that survived to middle age were accounted for; if 10 others died for every one that made it to 50, that would affect the results. Unfortunately, he did not report on that. What we do know, however, is that all animal bodies, humans included, can tolerate a lot of abuse for an extended period of time before noticably breaking. Look up what we feed cows in the U.S. if you would like a non-human example (hint: they are supposed to eat grass, but don’t anymore). There are some people that smoke and drink to excess their whole lives and die of old age; there aren’t many, but there are a few. If we only ever counted the ones that survived to old age, wouldn’t we conclude that smoking and drinking to excess is a perfectly healthy activity? That is survivor bias.

    “Clearly, one size does not fit all.”

    This is not true. “One size fits all” is true for every other species, and it is true for us as well. Of course, you will have tiny differences among members, and yes, you will have some odd-balls (like the old smoker). But in general, just about every human on the face of the earth can thrive on the same type of diet. For most people throughout history, this has been a high-starch, whole-food, plant-based diet. Here is what Dr. John McDougall has to say: “Similar observations correlating high carbohydrate consumption with good health can be made for people living in rural Mexico on corn and beans, Africa on millet and beans, Peru on potatoes, New Guinea on sweet potatoes, and in the Middle East on chickpeas and rice.” The common traits are a high-starch, low-fat, and plant-based. Billions of people both in the past and present thrive on these types of diets. On the other hand, the WAPF cannot point to a single large population that has thrived on animal-based foods. Instead, they can only point to small tribes and societies that subsist on some higher percentage of animal foods because they have no other choice in their environment. Then, when you look closely, you see that these tribes are not actually thriving, as is claimed. The Masai, for example, are, on average, dead in their 40’s. The Innuit made it to about their 60s (not sure if that is still true today; incidentally, the Innuit have the highest rate of osteoporosis in the world; they also found the remains of a young and old woman frozen 500 years ago – both suffered from osteoporosis). You can make some counter-arguments to these last points, and I could respond to them, but instead, I will leave that as an exercise to the reader since I don’t want to spend a lot of time debating this either. What are the counter-points to what I just said, and what are the counter-points to that? Take the research as far as it will go and read far and wide. What conclusions to you come up with?

    I briefly looked into metabolic typing. It strikes me as new-age mumbo-jumbo. Maybe I will read the book you mentioned, but frankly, I think there are stronger arguments for eating animals than that (still fundamentally flawed, but a stronger case nonetheless). I guess it doesn’t help that the creator of this diet was a dentist (what is it with these dentists?) who was convicted of practicing medicine without a license, and later became a successful marketer. It is hard to get interested enough to devote the time to researching a thing when its creator and champion is a salesman with no credentials. Sorry, but the scientists win this one.

    Keep researching. Don’t stop here. The China Study referenced a lot of other doctors and researchers who have spent decades in this field. Follow these references and read it all. The China Study is very important and very comprehensive, but it does not cover everything that is important to know about the subject. My suggestion for your next step: read the stuff put out by Dr. John McDougall, Dr. Neal Barnard, John Robbins, and Dr. Michael Greger. Then keep going.

  5. The China Study did not account for whether the animal products consumed were denatured or not. Price’s primary argument was that COOKED food caused the degeneration he saw, in addition to processed sugar/flour etc. So the China Study looks at meat consumption and fat consumption, but never considers what kind of fat was eaten, whether it was oxidized, or even what temperature the meat was cooked at, which is a huge variable. (incidentally, Chinese cooking usually uses high temperature for short time period) There is a measurable difference in carcinogens in meat cooked at 500 degrees in soy oil vs meat cooked at 200 degrees in ghee.
    The China Study also fails to look at what the animals were fed – was it mycotoxin-laced corn or soy, or was it grass-fed?
    And was it stored to avoid formation of mycotoxins, or was it cured? (hint, refridgerators in China weren’t common when the data was created.) We know cured meat contains mycotoxins.

    The recently published “Good Calories, Bad Calories” by Taubes is a definitive look at the history of the radical carb/low fat movement, which has only been around since the 80’s. Read it and discover how politics played a role in the RDA, and what the scientific studies actually say. Taubes spoke with more than 900 people who wrote the studies that define what a “healthy” diet is today, in a world where cancer and heart disease are rampant.

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