The China Study 4 – The Chinese

This is a continuation of my series discussing the book The China Study by Dr. Campbell.  I’m doing this because I often want to refer to the results in this important book, but there’s nowhere to point on the internet.  I am hoping that this “quick” rundown of what the book tells us will shake people up enough to get them to read it and find out more.  Or at the very least, think twice about “Milk – it does a body good!”  I originally checked The China Study out of the library, but then bought my own copy because I wanted to refer to it so often.

Last time Dr. Campbell had found that cancer in rats and mice seems to be promoted by a variety of animal-based nutrients and stalled by plant-based nutrients.  But he wanted to see if this was true in people.  It is considered unethical to experiment on people and try to give them cancer, so instead he assembled a team to begin an epidemiological study, which studies people “in their natural habitat,” eating what they eat, and getting whatever diseases that ensue.

I won’t go into why they went to China in particular – it had to do with an enormous cancer study that had occurred there just before this.  But I do need to point out why China made such a good study.  Most studies of this sort were looking at Westerners, and so researchers were comparing the effect of meaty diets to very meaty diets.  In China, people’s diets on average were much more plant-centered.  For example, the average animal protein consumed in China was 0.8% of calories, vs. 10-11% of calories in the U.S – a twelvefold difference!  And yet there was still enough variation in China, both in diet and diseases, to make correlations, but this time between people eating a plant-based diet and a very plant-based diet.

I believe this was one of the largest studies ever conducted.  The original cancer study, which they built on, included 880 million people in 2,400 counties.  Dr. Campbell’s team gathered data from 6,500 individuals in 65 counties on 367 variables.  Every person submitted a questionnaire, blood, and urine, researchers measured what they ate for 3 days, and food samples were taken in the towns.  When they were done they had “8,000 statistically significant associations between lifestyle, diet and disease variables” [p.73].

One of the first things they did was to see what diseases tended to go together.  They found certain diseases were found in more affluent areas: cancer, diabetes, and coronary heart disease.  The diseases found in poorer areas were: pneumonia, intestinal obstruction, peptic ulcer, digestive disease, pulmonary tuberculosis, and many others.  If a county had a high rate of breast cancer, for example, it would also have a high rate of coronary heart disease, but not a high rate of pneumonia.  This wasn’t a new idea, but the China Study for the first time correlated these diseases with diet.

The vast majority of people in Western countries die of diseases of affluence, so they are often called Western diseases.  The China Study revealed that one of the strongest predictors of Western diseases was blood cholesterol.  Dr. Campbell explains that dietary cholesterol is what is in the animal-based food we eat – that’s what’s on the nutritional labels.  When you get a blood test, they are not measuring dietary cholesterol (any more than they could measure calories consumed) – they are measuring blood cholesterol that your liver has produced.  Even though they’re chemically identical, they don’t measure the same thing.  Dietary fats and cholesterol that you eat don’t necessarily turn into your body fat and cholesterol.  The synthesis of blood cholesterol “is extremely complex, involving hundreds of different chemical reactions and dozens of nutrients” [p.78].

As blood cholesterol levels in rural China rose (from person to person), the incidence of Western diseases also increased.  This occurred even though Chinese blood cholesterol levels (127 mg/dl) were much lower than in the U.S. (215 mg/DL).  As blood cholesterol decreased from 170 to 90, twelve different kinds of cancer decreased, with either 95+% or 99+% statistical significances (that means there is a <5% or <1% chance the results were chance).   Most Americans know that high blood cholesterol impacts your heart, but it also clearly impacts chances of cancer.

Most Americans are confused about how to lower their blood cholesterol.  I mean, we think we know, but we are missing something.  Ask your doctor how to lower your cholesterol through diet.  You already know what he/she will say, don’t you?  Cut your dietary cholesterol and saturated fat.  Those are important, but did you know that there are two other things you can do which are actually more important?  In both human [*] and animal studies [endnote 1 & *], these two secret tips are more closely correlated with lowering blood cholesterol than the two everybody knows.  They are, in order of importance: eat less animal-based protein, and eat more plant-based foods.   This is so surprising that I want to restate it:  Eating less animal protein and eating more plants are both more important in lowering your blood cholesterol than eating less dietary cholesterol or saturated fat.  You may argue that people eating fewer animal products are necessarily eating less fat and cholesterol, but you would be forgetting about low-fat animal products, exactly the items being pushed on us as a healthy alternative.

So where are we?  We have direct lab animal evidence that animal protein strongly promotes cancer, via several different mechanisms.  We have epidemiological evidence that high blood cholesterol is strongly associated with cancer.  We have human and animal studies showing that animal protein is strongly associated with high blood cholesterol.  And I am not anywhere near done yet.  But already, what do you think of someone like Jean Carper or the American Cancer Society telling you to cut the fat and cholesterol out of your beef, chicken, clams, cheese, eggs, milk, and sour cream?  I want to mention that I looked over some of the recipes at Jean Carper’s site, and many of them are vegan, but at least half feature heavy doses of animal protein.  Out of 34 recipes I found at the ACS site (including here), five had no animal products, and none of those were entrees.

One of the main points Dr. Campbell makes is that most nutritional research centers on particular micro-nutrients, for example the effect of selenium on breast cancer rates.  He says he prefers to study a broad array of nutrients in the same study, because nutrients work together in our bodies to create health or disease.  He studies dietary patterns.  He readily concedes that the China Study results do not constitute absolute scientific proof, but it certainly gives enough information to make some practical decisions.  As a result of this study, Dr. Campbell went from scoffing at vegetarians to giving up most meat and dairy products.  He lost 45 pounds, his cholesterol dropped, and he is more physically fit.

Next, Dr. Campbell looks at more studies done by other scientists, one disease at a time.

Endnote 1: Carroll, K.K. 1983. Dietary proteins and amino acids—their effects on cholesterol metabolism, in Gibney, M.J., and D. Kritchevshy, eds. Animal and vegetable proteins in lipid metabolism and atherosclerosis. New York: Liss, 9-17