The China study—what it means: an interview with T. Colin Campbell, Ph.D
Q. Could you tell us about the China Study and the China Project?
A. The title of my book is The China Study, but only one chapter is focused on the China Project itself. The rest of the book integrates and puts into context the China Study findings–both the records of the research and the research my students did before and after the project.
The China Project was a joint undertaking between Cornell University, the University of Oxford in England, and two Chinese government science academies. That project was run in the early 1980’s, and it continued into the early 1990’s. It was designed to see why a dozen different cancers tended to be concentrated geographically in certain areas and not in others.
In the 1970’s, the Chinese government observed an intense concentration of these diseases in some places and not in others. So we went there to do a study on why these cancers were localized.
We organized a survey of some 65 counties around China, or two villages in every county. We went to each of those villages and made lots of measurements. We took blood, urine, and food samples and administered questionnaires about diet and lifestyle. We also brought food samples back to analyze. We went into these people’s homes and studied what they ate for three days.
We then spent the next several years analyzing those samples for a large array of different nutrient factors, toxin factors, and viruses. We collected all that information and assembled it as one large document, published in 1990.
That body of information was the most comprehensive ever collected. The reason it was comprehensive was, in part, was that I wanted to see what kind of dietary patterns were most related to disease occurrence. At that point, we were given information on cancer, heart diseases, other diseases, and dietary patterns.
That was an intentional objective of the study. I was quite concerned then, but I am even more concerned now that we focus too much on what individual nutrients do. To me, that is not nutrition; it is pharmacology, or drug therapy. Diseases do not occur that way; they do not occur as a result of a single change or a single nutrient. They occur as a result of multiple factors working together to produce an effect in the form of food.
This is a very important point. Our focus has been on individual nutrients, and we have created a multibillion-dollar nutrient supplement industry in the hope that it can solve problems, but it is not working.
Q. Is there a large nutrient supplement industry in China?
A. No. There wasn’t at the time; in the last half-dozen years, it is really spreading a lot, especially with Western companies coming in.
When I talk about nutritional supplements, I’m talking about individual nutrients, like vitamin C. In contrast, the Chinese have used herbal supplements for many decades, even centuries. I have always considered herbal supplements to be different from nutritional supplements; herbal supplements usually have an extract of a plant. They contain many things that work together. Sometimes herbs will even be mixed for different uses.
People often confuse these different ideas. Herbal supplements have been tested in practice and in reality for centuries and millennia; they also make a lot more biological sense. You want to take extracts of things that are present in foods. You want to reduce it down to a liquid, a syrup, or a pill. I do want to make that distinction.
Q. What does the typical Chinese diet consist of?
A. Across the country, in many areas the diet is almost entirely plantbased, coupled with a grain or two. The Chinese use rice a lot-polished rice, actually. It is rather odd, but they have used it for a long time. Polished or semi-polished rice is not in their best interest, but the Chinese have used this type. “Polished” is my term, but that’s not what they call it. It would probably be on par with what we call “processed.”
In other areas of China, people use a lot of corn, almost in place of rice. In some places up north, wheat, millet, or sorghum is used. The Chinese people continue to use rice all throughout China, but in some places it has been replaced. In addition, they use vegetables quite generously and, occasionally, fruit.
Q. Has the Chinese diet changed in the last 20 or 30 years?
A. Yes, definitely. It tends to change along with the acquisition of wealth and capital. These changes have been most marked along the urban areas. In the major cities these days, the first and second causes of death are heart disease and cancer. In other words, the Chinese have become just like us. It didn’t take them long to do, either, after they changed their diet.
For example, they started using more fat, more animal foods, and more processed foods. They seem to think that becoming Western is a sign of progress, but I do not agree, at least not in terms of food and health. So we expected changes to occur, and they are occurring rapidly.
Q. Do they use monosodium glutamate in China?
A. Yes, they have used a lot of monosodium glutamate (MSG) over the years. We did not specifically measure that ingredient, but yes, they do. Usage varies a lot over the country.
Q. Do the Chinese have data showing that MSG is not harmful?
A. I am not aware of any particular studies that show benefits of MSG.
They like that taste.
Q. What are some of the problems with today’s Western diet?
A. We eat too many animal-based foods–far too much. We are basically a carnivore society. We also eat far too much processed food. To be more specific, those processed foods give us a lot of extra salt, sugar, and fat. So we add a lot of salt, sugar and fat to our bodies, junk foods, if you will.
We also drink too much sugar in caffeinated beverages. All that animal food, processed food, and sugary beverages add up to a huge problem.
Q. What is the relationship between fat and cancer?
A. For a while, it was thought that the societies that consumed the most fat got the most breast cancer per capita. A lot was made of that. For the last few decades, the public has been advised to cut down on fat in order to reduce cancer, heart disease, and other illnesses. This has proved to be bad advice.
People have decreased their fat intake, but they have not changed the ratio of animal to plant-based foods. That was the change that really had to be made.
My view is that we should be consuming a reasonably low-fat diet. There are two ways of doing that. We can continue to eat a lot of animal foods but take the fat out of them, like skim milk, for example. We can decrease our use of spreads and oils. The problem with this approach is that we would still be consuming a high ratio of animal-based foods. We continue to consume processed foods that have a lot of sugar in them. The fat reduction is almost erased by all the animal-based foods.
That view is highly reductionist. It is looking at the whole food–health relationship in respect to changing a single nutrient. When we start blaming one nutrient, we start doing bizarre things like adding one nutrient, taking out the fat alone, and ignoring all of the other changes that should be made. As a result, we still end up with poor health.
The changes that need to be made are more holistic and natural. We need to get serious about consuming a much higher level of fruits and grains.
Q. How is fiber intake related to cancer?
A. Fiber occurs only in plant-based materials, usually only in whole plants. Again, the term “fiber” describes hundreds, maybe thousands, of variations of that nutrient. If you polish the rice, you get rid of most of the bran layer. This step takes the sugar out of the plant. Fiber has been studied many different ways, and it has been noted that a high-fiber diet may result in a lower risk of cancer.
But again, that focus was just too narrow. It wasn’t as if the fiber alone prevented cancer. That idea translated into adding bran and other fiber to cereal grains, for example, which is kind of useless. This is just one more example of this focus on individual food fractions.
We know from studying fiber and its effects on various and sundry biological events that it has the potential to prevent some of these diseases.
But then again, in order to translate that information into something useful, we should be consuming high-fiber foods. That is one of the reasons that I emphasize consuming whole foods, which provide fiber in its myriad forms and minerals and vitamins along with it.
I think it has been a huge mistake in our public and professional understanding of nutrition to focus on individual nutrients. We have made many mistakes that have been very costly. It’s not good science to even talk that way.
When you consume the food, there are hundreds of thousands–maybe even millions–of chemical variants. They really work together to create the health or disease response. It is the integration of all this stuff that is the fascinating part of nutrition.
Q. Since we focus so much on single nutrients and ignore the overall picture, has the value of carbohydrates and proteins been misunderstood?
A. Yes, terribly misunderstood. I think some of that was intentional.
Some people use that type of information to make a statement.
When the original popularization of low-carbohydrate diets came in to view with people such as Dr. Robert Atkins and others, they were saying that carbohydrates were bad. They were just making a blanket, superficial statement. “Carbohydrates are bad, and therefore we should not consume them.” They even reduced the word carbohydrate to “carb,” which I find offensive; in any case, their intent was to make it a marketable term.
They said that high-carb diets are bad and that low-carb diets are bad. In the beginning they did not bother to distinguish between the different kinds of carbohydrates, and that confused the public. In reality, when people are consuming a high-plant-based diet, that is a “high-carb” diet, but that diet is associated with the best health. There is no question about it.
What the authors, in fact, were talking about were the simple carbohydrates like sugar, white starch, and white flour. Those kinds of carbohydrates are problematic, but that was never the intention.
The dietary recommendations over the past 20 to 30 years have been troublesome. I know this very well because I was on the expert panels that helped write those reports. When we said “consume low-fat diets,” we never meant that that these high-carbohydrate diets should contain a lot of white flour and sugar. That was never stated and never intended.
So in recent years, when people start talking about high-carb diets not working and being responsible for obesity, that was total nonsense.
Q. Do some people walk into a fast-food restaurant, order a triple cheeseburger, throw out the bun, and claim they are eating healthfully?
A. Yes, it’s funny. What they do is slip into a rather ketotic state and actually decrease their caloric intake for a while, and they feel nauseated. They do lose weight, and there’s no question about that, but the weight loss and lower cholesterol cannot be sustained. They are setting themselves up to cultivate a taste for that food that they will probably retain, then gradually, over time, consume more and more of it and get away from fruits and vegetables.
Q. How important is protein in a diet?
A. Protein is usually expressed in grams per kilogram of body weight. It has been worked out over the past few decades that we need about 0.8 grams of protein per kilogram of body weight. A 150-pound man would need about 56 grams of protein per day. That 0.8 g./kg, is about 10 percent of the total daily caloric intake that would go to protein. That is the Recommended Daily Allowance (RDA), and we have been living with that for a long time.
In reality, we need only about 0.6 g./kg, to serve our needs, but the recommendation was to get it up to 0.8 (equivalent to about 10 percent of total calories). Because of all this faddishness and the religiosity surrounding protein, people have always thought that they need more protein in their diet and that the more protein consumed, the better. They wanted primarily animal proteins, as well.
Instead of consuming the 10 percent of calories as protein, our society has been, on average, consuming 17 to 18 percent of total calories as protein. The range is from 11 to 25 percent. Much of that has been animal protein rather than plant protein.
So all this emphasis given to protein over the years has a been a serious problem because people want to consume more meat, more dairy, more eggs.
Q. Is there a relationship between protein and certain types of cancer?
A. Yes. If you look at protein intake–particularly animal protein–and look at the places with the highest intake of protein, you will see a higher incidence of heart disease, cancer, osteoporosis, and some other diseases. Having said that, I am referring to animal-based foods. Therefore, the more animal-based foods are consumed, the less plant-based foods are consumed. It turns out that it is a combination of too much animal food and too little plant food.
Protein has driven our decisions. We need to get protein, and very subtly it has driven us to change what we eat. This is a mistake. High intakes of animal-based products increase the risk of cancer, and we know how this can occur. We have been overconsuming animal-based foods.
Q. What was the Cancer Atlas in China?
A. From 1973 to 1975, the Chinese and measured how much cancer existed throughout their country. In approximately 2,400 counties of China, they learned that these cancers tended to concentrate in certain areas. They recorded information for about a dozen different cancers. At the same time, however, they evaluated other diseases, but only the cancer data were published in 1980-1981. The information was published as an atlas; a color-coded map indicated the types of cancer. It was a beautiful publication. You can see that, for some of these cancers, some rates were high and some were low. It was really remarkable.
Q. Did that tell you anything about types of cancer in relation to particular regional diets?
A. Cancer is a disease that begins with a so-called initiating event. It may be a chemical that starts it, or maybe a virus or radiation. But the disease begins with an event that alters the DNA [deoxyribonucleic acid] of the cell. If the DNA is not repaired and is passed on to the subsequent cell generations, those cells are considered to be initiated. That is not cancer, but they are primed to grow into cancer if we fertilize them with nutrients. This process can take many years, depending on what we are eating.
The question of whether or not the cancer appears as a tumor is usually a function of the kinds of nutrients we are consuming. It depends, to a great extent, on whether we are fertilizing or inhibiting those infant cancer cells.
Given that idea, the causes of cancer tend to divide into two clusters: initiators, which are the chemicals and the carcinogens, and the consumption of substances at inappropriate levels, such as too few antioxidants, too much animal protein, too much total fat, and so on.
When you ask about these cancer rates and nutrition in China, it turns out that most cancers have common causes. The common causes are the nutrients, but they have rather different initiators, as when the hepatitis C virus tends to program the liver to get cancer. Whether people do get cancer is a function of nutrition.
Lung cancers are initiated by certain chemicals from smoking or noxious agents that we breathe. In this case, we do or do not get cancer from the types of foods we eat, which in turn is the same type of food that has an effect on liver cancer.
With esophageal cancer, it may be the Epstein-Barr virus. With stomach cancer, it may be an organism called Helicobacter pylori or a nitrosamine.
These various cancers seem to have different initiators, but the growth factors tend to be similar. Antioxidants tend to suppress cancer growth. Anything that promotes oxidation seem to promote cancer growth. High animal protein and high animal fat intakes tend to increase cancer rates.
Q. What are some diseases of affluence?
A. Cancers, heart diseases, stroke, hypertension, heart disease, coronary heart disease, atherosclerosis, type 2 diabetes, insulin-resistance syndrome, and obesity. Obesity is classified as a disease, but I disagree with that. It does not have an independent cause or an independent solution, but it is considered to be a forerunner of heart disease and diabetes. It is a preliminary event for subsequent disease.
Q. What are some of the eight principles of eating right, as mentioned in your book?
A. Those eight principles came about after I sat down and thought about how we could tell this story in a way that has a solid foundation. These principles were goalposts, or guidelines. They could be used to sort out whether or not a new observation is meaningful.
They also elaborated on some ideas that people tend to be interested in; for example, nutrition trumps genes. Everything starts with genes, but whether someone gets a disease from bad genes is basically a function of nutrition. You might have bad genes, but you do not necessarily get a disease unless you fertilize the gene the right way.
Nutrition also essentially trumps chemical carcinogens. Unfortunately, this principle may be taken as that it is okay to consume noxious agents, but I do not mean that at all. I am saying that nutrition is so powerful that it can help to control the hazards of carcinogens. Another principle says that nutrients work together.
I find that these more global statements help people understand new discoveries, wherever they may be at the end of it. I know that every day in the media are reports of a new medicine. I can quickly discern how likely a drug is likely to work or whether it is legitimate by applying these principles.
Q. How do these principles differ from governmental nutrition guidelines?
A. There are two types of guidelines. One committee establishes the
minimum intake in the form of the RDA. The second body decides on the dietary guidelines. They basically take the information on individual nutrients and translate it to recommendations on food. They put it in a nice little picture called the “food pyramid.”
Those guidelines give us summary statements. They say that our diet needs these types of nutrients and that we can choose these types of food to get them. They do not resemble my principles; mine serve a different purpose. I fred my principles very useful.
Q. Have you faced any friction from government-based scientists or nutritionists?
A. Oh yes, for some years. I tend to think “outside the box.” Although I was totally within the box for the first 20 or 30 years of my career and receiving lots of money and doing lots of research, I was meeting resistance when I started talking about cow’s milk and casein as a carcinogen.
The Dark Side Of China
Although much can be learned from the low-fat, plant-based traditional Chinese diet, Communist China cannot be looked at as an exemplary model of health. Some horrific examples from China’s past show that the country’s rapid modernization and human rights violations are keeping the country from widespread acceptance as an example of a healthy, conscientious world power.
In Chairman Mao’s Cultural Revolution, peasants with little or nothing to eat were encouraged to rise up against their landlords, kill them then eat their bodies.
China’s well-known law that dictates the number of children per family has resulted in many aborted fetuses, which are often then consumed because they believe it will strengthen their immunity.
At this point in time, I just want to bring my information to the attention of others.
I have wondered why the public is so confused. Senator John Glenn invited me one time to present my views on that question. I concluded that the major reason that people are confused is because of the enormous amount of interference from the food and drug industry in academic research and policy development. The public is not aware. I think the public is going to be ill served until these facts are known.
Q. Do you think that most Americans could change their diets for the better?
A. That’s an interesting question. Although I sometimes become despondent with the state of affairs, I am very impressed as far as what nutrition can do, much more so than I ever was before. There is a story there just waiting to emerge, and although the audience is self-selected because they wanted to see me, I find that doctors now are somewhat more interested than they were before, maybe because their own industry is under attack. Economically, the doctors have problems, and people are beginning to search for answers.
I think that if the public were informed about what nutrition can do, a good lifestyle would make a huge difference in one’s life. At the least, we might extend our life span by about 10 years, so that when people get older, they do not have to suffer the consequences of various diseases. It is a tragedy that we place people into warehouses because they have Alzheimer’s disease. What kind of society puts its old people away? We have plenty of work to do in this area.
I think if people are just told the story in a good way, it’s not that difficult–that if we can prepare food in a tasty and convenient way, people will be fine.
Dr. Campbell is the Jacob Gould Schurman Professor Emeritus of Nutritional Biochemistry at Cornell University and also holds an honorary professorship at the Chinese Academy of Preventive Medicine. His principal scientific interest has been the effects of nutrition on long-term health, particularly on cancer prevention. He is a member of the National Academy of Sciences and is senior science adviser for the American Institute for Cancer Research.
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