T. Colin Campbell's Response to Questions Raised About the Book, "The China Study. Startling Implications for Diet, Weight Loss and Long-Term Health"

October 1, 2006

Sales of our book, "The China Study…", co-authored by me and my son, Tom, has exceeded our expectations. With no formal public relations campaign, no recipes, no menus and many scientific references, we were cautioned by some in the publishing world not to expect a market of more than 5-15,000 copies sold. Instead, we sold more than 100,000 copies in about the first 18 months. We also are delighted with the 300 or so on-line reviews and e-mails that speak of very positive personal health benefits.

But, not all readers agree. A small number (5-10%) have not only disagreed, but have done so rather vigorously and vehemently. I have accepted with interest these commentaries, mostly assuming that our book must be having an impact.

I have not been inclined to respond to these relatively few critics. Yet, a few friends and colleagues have asked that I consider doing so, especially because a couple of the seemingly well-researched commentaries are being vigorously promoted far and wide. These include, for example, commentaries by Mr. Chris Masterjohn (Amazon and Barnes & Noble websites, July 4, 2005, and http://www.cholesterol-and-health.com/index.html) and an anonymous Mr. "JayY" (Amazon website, May 18, 2006, with numerous additional "comments" on many positive reviews on Amazon.com). So, here goes my rebuttal.

I have several concerns with these critiques. First, these writers do not understand the overarching theme of our book. They even misunderstand what scientific discovery is all about—at least the version of discovery that I have learned over the past half century. Second, these critics--at least for Masterjohn and his enthusiasts— are following an agenda which promotes a diet high in cholesterol, fat and animal protein, which is the mission of an organization to which Masterjohn belongs. Third, they question the misleading title of our book, and on this point, I agree (more later).

Although I would like to respond to each of their specific items, I believe that discussing these broader points will suffice. The strategy that we used in our book was designed to explain how I came to have a worldview of diet and health, both personally and professionally, that was almost diametrically opposed to what I had at the beginning of my 50-year research career.

In planning the strategy for our book to tell this story, we wondered: Do we simply summarize a bunch of studies favoring my new views and run the risk of selecting only the evidence that I liked? Or do we summarize, without judgment, both the pro and con evidence, only to leave the reader more confused? We chose neither. We decided to tell the story how I personally learned it and why I was willing to recommend it for my family, my friends and myself. In this way, the reader decides whether the message is as convincing as I found it, perhaps even worth trying.

Our book starts with a short recounting of my personal background and professional training that may have influenced my early thinking. Mainly, I was raised on a dairy farm, milking cows while believing in the great health value of the typical high fat, animal protein based American diet. On our farm, for example, we were paid more for high fat milk than for low fat milk. To the extent that I even thought about such things, I also believed that cow's milk was the nearest thing to Nature's most perfect food, being especially rich in protein and calcium. Eventually, it was on to my doctoral dissertation research at Cornell University when I investigated with my professors how to produce MORE not less animal protein, because of the widespread belief that so-called 'high quality' animal protein was the quintessential hallmark of good health.

I then began my formal research career investigating a very narrow topic, the dietary causes of primary liver cancer. Each of the experiments in this early research was quite focused and a variety of experimental designs was used. I certainly had no preconceived ideas where our research might be headed except, possibly, for my bias in favor of the typical American diet, high in fat and animal-based protein. Our research began with an anecdotal observation in children that coincided with an experimental animal study in India, then proceeded through a widening array of basic laboratory experiments and hypotheses, eventually to involve an unusually comprehensive human observational study in China.

As the years progressed, our research, which was handsomely funded for most of my career by the U.S. National Institutes of Health (NIH), was producing more than a few findings that did not agree with my training or with my preconceived hypotheses. At times, these findings were provocative and frustrating, however well our experiments may have been planned and executed. These experiments often turned up more questions than answers. Nonetheless, I was also being reminded that if a more comprehensive truth were emerging from these detailed, isolated and sometimes controversial experiments, this truth had to be consistent both with a variety of experimental study designs, with real life conditions and with a rational biological explanation, among other criteria.

These considerations and observations of mine are important for understanding my criticisms of the commentaries of these writers. In effect, our research was conducted with an eye toward breadth, consistency, plausibility and, eventually, human health. It was not emphasizing the results of one experiment or one bit of data. In contrast, the critics are uncritically using highly selected detailed observations with no respect for context. They rely rather heavily, for example, on choosing selected but uncorrected correlations (associations of one variable with another) from the huge number (about 100,000 or so) that were published in the 894-page China Project monograph itself (Chen, J., Campbell, T. C., Li, J., and Peto, R. Diet, life-style and mortality in China. A study of the characteristics of 65 Chinese counties, pp. 894. Oxford, UK; Ithaca, NY; Beijing, PRC: Oxford University Press; Cornell University Press; People's Medical Publishing House, 1990). Moreover, they emphasize the results of this one project in China as if it were the whole story in the book. This is wrong, quite literally, dead wrong. They not only miss the connectedness of the observations in this study with other research presented in the book, but also they also are selecting and interpreting from this study individual unadjusted correlations out of context, perhaps to please their own biases. It is important to understand both the limitations and the interpretations of these correlations. In contrast to these critics, most readers seem to have understood that there is far more to our book than the China Project. Indeed, this project represents only one of eighteen chapters in the book.

As my own research experience so well illustrated for me, no one study can define an emerging whole truth, or worldview. When most researchers do experiments in an area as biologically complex as diet and health, they almost always focus on very specific hypotheses, investigating how single agents cause specific effects, often by so-called single mechanisms (I also followed such a path). But these kinds of experiments have limitations both in their design and in their underlying hypotheses. The combination of a limited design and a narrowly focused hypothesis for individual experiments can only give impressions of a larger truth, even though each experiment may be well done. It is only after doing varied experiments is it possible to begin constructing a network of evidence and articulating a larger truth.

At least, this is the way research SHOULD be done. Unfortunately, this often fails to take place. Instead, researchers get anxious and speculate beyond the results of a single experiment thus giving rise to the perception that a very broad truth has been discovered or is emerging. This especially happens when there are financial implications.

We tried in our book to avoid this problem by chronologically reporting on the main experiments during my career, along with the research of others, to elaborate a larger view that I thought was taking shape. We felt that this chronology of experiments respects readers, leaving them to decide whether they agree or disagree. It's about connecting the dots, so to speak.

It is quite easy to find a weakness or an aberrant observation in every single experiment. If executed and interpreted within the context of a larger worldview/hypothesis, each experiment gives direction as to what to do next, perhaps even suggesting a sharp turn in a new direction. If a larger truth is emerging, it seldom if ever depends on one experiment. Rather, it is a matter of accumulating evidence for a series of experiments, especially to see if the evidence is logically connected and consistent. In my research career, an unexpected trend was emerging not only from the results of our experiments, but also from the findings of others. Although this trend initially was quite provocative, it nonetheless was beginning to show promise for human health.

The China Project results are no exception to these limitations of single experiments. It was very large, unique and comprehensive but it was observational (i.e., not interventional), simply observing things as they were at a single point in time. It provided an exceptionally large number of hypothetical associations (shown as statistically assessed correlations) that may indicate but does not prove cause and effect relationships. These unanalyzed correlations are considered raw or crude. It is highly unusual to find such 'raw' data in a scientific report because, in part, untrained observers may misunderstand such raw data.

For the monograph, we were somewhat uncertain whether to publish such raw data but decided to do so for two principle reasons. First, we wanted to make these data available to other researchers, while hoping that data misuse would not be a significant problem. Second, because these data were collected in rural China at a time when data reliability might have been questioned, we chose to be as transparent as possible. We discussed data use and misuse on pp. 54-82 of the China Project monograph that curiously was overlooked by Masterjohn and Jay'Y'.

In brief, while fully understanding the pitfalls, the purpose of interpreting data of this kind is to extract from these crude correlations their true correlation counterparts, then interpret these counterparts within the context of information derived from other sources. In making these adjustments and interpretations, we want to consider, for example, 1) whether there is a sufficiently broad range of exposure for each of the variables comprising the associations (e.g., a true association of breast cancer with dietary fat consumption can only be detected if there is a sufficient range—above zero—for each of these variables), 2) whether there are confounding factors (e.g., high fat consumption might reflect high animal protein consumption, low dietary fiber consumption or even ownership of TVS), 3) whether the associations are biologically plausible (e.g., being consistent with existing clinical information, especially within this clinical project) and 4) whether these associations collectively reflect a consistent dietary pattern, among other considerations. In addition to these individual associations, we also had opportunities to evaluate aggregate associations, keeping the same caveats and considerations in mind.

These critics, who are mischievously posing as qualified scientists, have committed errors that expose either their ignorance of basic research principles and/or their passionate following of an unstated agenda. By superficially citing uncorrected crude correlations from the China Project monograph, they show a serious lack of understanding not only of the fundamentals of scientific research but also of the principles of statistics, epidemiology and nutrition. To make matters worse, they have selected correlations that reflect an alternative agenda or bias that has nothing to do with objective science.

It was this suspicion of bias that reminded me of an eerily similar commentary earlier written by Ms. Sally Fallon, President of a special interest group located in Washington, DC, known as the Weston A. Price Foundation (WAPF). Ms. Fallon's commentary was widely circulated in cyberspace several years before we published our book. Thus I began to wonder who was WAPF and especially who was Weston A. Price, now the adopted 'patron saint' of WAPF.

Price's main book was published in the late 1930s—at least this is the book that is most commonly cited by WAPF. I bought the book, carefully read it and learned that the WAPF staff and associates substantially exaggerate, in my opinion, the importance of Price's observations and the importance of his book. Price was a dental surgeon who visited more than a dozen indigenous populations around the world and became quite impressed with the overall good health of these geographically isolated people when compared with their kin who had become exposed to commerce from other lands. He seemed to regard these native peoples as the nearest link to our own past. With background in dentistry, Price assessed their health mainly by dental caries incidence and facial structures, supplementing his observations with many photographs. Although he made certain inferences about health in general, he published no reliable empirical data to support this view.

In brief, Weston Price's suggestion that dental caries was associated with the introduction of commerce (probably including processed and sweetened food products) was quite convincing, not unlike similar reports of others. He also speculated about an 'X' factor in milk fat, supposedly suggesting health benefits for cow's milk, but no follow-up findings on this 'X' factor consistent with human health have since been reported. In no way did Price publish reliable data in this book that could be used to evaluate the relationship of food with overall health. He did speculate, however, with some evidence, on the loss of nutritional value of food at that time (1920s-1930s) as a result of soil depletion and overuse. Excepting his observations on an association of dental caries incidence with processed food, Price's study, in my opinion, is of limited scientific value.

The WAPF enthusiasts nonetheless suggest that this was a major survey of the relationship of food with human health, perhaps being one of the most important. Either by statements or inferences, WAPF writers and enthusiasts then go on from Price's meager observations to aggressively claim health benefits for animal based foods, especially those associated with unprocessed, raw cow's milk produced by grass-fed animals.

It was the aggressiveness and supreme confidence of the WAPF people that was, for me, puzzling. Was this group scientifically experienced and qualified to be so certain of their views? They certainly wrote well and presented their arguments in a seemingly scientific manner—at least for the lay reader. I therefore became engaged in an email dialogue with Mr. Chris Masterjohn to learn about his background and his sources that seemed to be so closely aligned with WAPF interests.

I learned that Masterjohn was a 24 year old 'chapter leader' of WAPF in Massachusetts. He claimed that he was a former vegetarian who nearly lost his life (according to his account) because of his following the earlier advice of John Robbins. He said that he only knew 'former' not present vegetarians and was convinced that every vegetarian would eventually learn the error of their ways. Most importantly, he has had no first hand experience or training in experimental nutrition research and no professional peer reviewed publications. He has his own website that promotes consumption of high cholesterol high fat foods <http://www.cholesterol-and-health.com/index.html>. He also writes for the WAPF website <http://www.westonaprice.org/splash_2.htm>. I am impressed with his writing skills but not with the content of his argument. I also wonder, however, whether his writing skills have been honed and reviewed by his superior, Sally Fallon, who has training in English. (I recently saw, for example, a final Masterjohn draft report that was circulated to a large group of people for comment. In this report, he concludes that dairy is not an important source of dioxin, opposite that reported in a 10-year report by EPA, among others.)

The fact that the WAPF people and their enthusiasts are so hostile to our book, to me personally and to anyone reflecting similar views needs some elaboration. Masterjohn, for example, claims in his website that, in effect, I am primarily being subservient to the animal rights agenda and more specifically to the Physicians' Committee for Responsible Medicine (PCRM) who according to Masterjohn, are associated with PETA (People for the Ethical Treatment of Animals). (I have been for some years on the PCRM science advisory board and am pleased to continue doing so.) He assigns guilt by association for me by pointing out how the US Department of Justice has labeled PETA a domestic terrorist threat. JayY, who mysteriously remains anonymous, also repeats some of this same animal rights mantra on the Amazon.com website.

I find it puzzling that these critics want to make this point. Much of our earlier—and seminal—research was conducted on experimental animals. This was an activity that does not please the more vocal animal rights advocates, some of whom have pleaded with me to eliminate the animal research findings from my public lectures.

Then there is the anonymous and enigmatic 'JayY' who is vigorously submitting a Masterjohn/Fallon look-alike commentary to counter many of the positive reviews on Amazon.com. He says, "I've never sat on a government advisory panel, never attended even a single university lecture, and cannot yet boast of having the same volume of published literature as Campbell, but I'm smart enough to know most of the claims made in his book are utter rubbish." Oh, that all of us might be so fortunate! I can't help but wonder whether he is advocating the abolition of universities for, in his case, he became unusually intelligent without such training! Further on, he adds, "Within minutes of beginning his book, even the dullest reader will quickly realize that Campbell is on a zealous mission against animal protein, which he believes to be public health enemy number one." No, this is not my choice for public enemy number one. Rather, I am now wondering whether overzealous, arrogant but untrained critics are a more serious threat.

Masterjohn also strongly laments, both on the WAPF website and on his own website, the negative publicity long given to high cholesterol foods like eggs, butter and liver, and says that these are "super foods" that must be consumed. He claims that dietary cholesterol itself must be consumed and that the concept of good and bad blood cholesterol (HDL and LDL, respectively) is a myth. He then goes on to label the government's diet and health recommendations to lower dietary fat as "totalitarian". Strong views, strong language, lots of confidence, especially for someone with no nutrition research training or experience. When I asked him who supports WAPF, he told me that farmers, among others, were important contributors. Because factory farms now produce most of the food in the U.S., I would be more comfortable if I knew how much influence these 'farmer' conglomerates have on WAPF itself. I don't decry the industry promoting its product—honestly of course—but I question the blatant attempt of WAPF writers to convey seemingly objective opinion that favors the industry without making clear their serious lack of qualifications and conflicts of interest.

WAPF Founder Sally Fallon who has Bachelors and Masters degrees in English sums up her organization's views as follows, "Animal fats and cholesterol are not villains but vital factors in the diet, necessary for normal growth, proper function of the brain and nervous system, protection from disease and optimum energy levels." It is time to seriously question the scientific objectivity and professional qualifications of WAPF staffers and their writers. It also is time to question their excessive exaggeration of Weston A. Price's observations.

I would be remiss, however, not to mention two areas of agreement. First, WAPF have emphasized the questionable value of highly processed essentially plant based foods whose calories are mostly comprised of refined carbohydrate (e.g., sugar, white flour) and oils, both plant based. I concur with this view. Indeed this is the main reason that my son and I emphasize in the book "whole" plant based foods, not these plant food fragments. Second, some have been critical of our book title that incorrectly implies that the book's overall message mainly depends on the China Study itself (it is only one chapter in our book). This title was the choice of our publisher. His view was based on marketing considerations and certainly was not due to the fact that the entirety of the book is represented by the findings from the China Project.

In summary, our book and my views are not about one study, one or even a few nutrients, or about one or a few aberrant but unadjusted correlations in the study in China! Moreover, we made this point on p. 106 of our book, as follows:

Do I think the China Study findings constitute absolute scientific proof? Of course not. Does it provide enough information to inform some practical decision-making? Absolutely.

An impressive and informative web of information was emerging from this study. But does every potential strand (or association) in this mammoth study fit perfectively into this web of information? No. Although most statistically significant strands readily fit into the web, there were a few surprises. Most, but not all, have since been explained [by considering the adjustments discussed above].

My present views on diet and health are based on the consistency of the vast majority of evidence produced by a wide variety of studies. I see three types of evidence that has most influenced my present views. First, there is the research data from our own studies that are summarized in our book. Second, there is the evidence obtained by many other laboratories, a sample of which is summarized in our book. Third, there is, perhaps, the most important evidence of all, the clinical experiences of the practicing physicians who I had come to know, especially those of Drs. John McDougall, Caldwell Esselstyn, Jr., Terry Shintani, Joel Fuhrman and Alan Goldhamer. For me, these medical practitioners, entirely on their own initiative and knowledge, were advising, with impressive success, their patients with the same information that I had come to know from the scientific literature and laboratory. The proof is in the pudding, so to speak. The idea works!