In 2005, Colin Campbell, now Professor Emeritus at Cornell University, authored 鈥淭he China Study.鈥� The book became a best seller with its claim that the聽road to good health meanders through fields of vegetables and fruits with no animal in sight. A vegan diet, he claimed, is the answer to beating the diseases of western civilization, namely heart disease, cancer and diabetes. Campbell鈥檚 opinion is forged by one of the most extensive epidemiological studies ever carried out, a collaborative effort between Cornell and Oxford Universities and the Chinese government back in the 1980s.
China seemed to be an ideal place to study the relationship between diet and disease because of genetic uniformity but widespread differences by region in food consumption and disease patterns especially when it comes聽to cancer. Furthermore,聽residents tend to spend their lives in the same area and consume the same diet,聽unique to each region, throughout their lives. Whereas in North America cancer rates vary only about two-fold聽from highest incidence regions to the lowest, in China the variation can be as much as a hundred-fold. That was certainly deemed worthy of investigation.
Researchers randomly selected 50 families in 2 villages in each of 65 counties from whom blood and urine聽samples were obtained along with 3-day food diaries. The massive amount of data collected were analyzed and related to mortality rates that had been compiled about ten years earlier for about 4 dozen different kinds of cancers and other diseases. According to Dr. Campbell, the overall results could be summarized quite simply. The more animal protein consumed, the greater the toll of disease. From this he extrapolated to suggest that eating no animal protein at all is the ideal diet.
Campbell鈥檚 interpretation of the data has been accepted by some with quasi-religious fervor and roundly criticized by others. This is not surprising in the ambiguous world of nutrition where pet theories abound,聽and numerous experts claim to have solved the mystery of what constitutes the ideal diet. The problem is that they don鈥檛 agree on what that solution is. Low fat, low carb, vegan , carnivore and paleo all have their champions. Colin Campbell is firmly planted in the vegan camp, no meat or dairy cross his lips. That is not like any Chinese diet he studied. The Chinese do eat meat of all kinds, albeit not as much as North Americans. And there has been plenty of criticism from statisticians who claim that Campbell鈥檚 conclusions are in fact not supported by the data and that he has dredged the data to conform to a preconceived notion. He also makes no mention of the fact that China has the highest rate of stomach cancer in the world.
Arguments fly back and forth with each side flinging muddy statistics at the other. Campbell鈥檚 supporters point at a study carried out by Dr. Caldwell Esselstyn that showed regression in coronary disease among patients who adhered to a strict vegan diet that allows no oils of any kind or nuts or avocados. But the study involved only a handful of patients who were also treated with statins, so it was not a diet-only trial. It would have been more meaningful had there been a control group not treated with statins. 鈥淐hina Study鈥� advocates also bring up Dr. Dean Ornish鈥檚 reversing heart disease in his patients with an exclusively plant-based diet but there were also alterations in other life-style factors.
What are we to make of all this? There is enough evidence to suggest that in North America we eat too much meat and the dairy industry has convinced us that its products should be consumed at every meal, which is not supported by evidence. And there is certainly no evidence that nuts or avocados are harmful, in fact there is evidence to the contrary. There is consensus that ideally diet should be plant-based, but that does not mean total elimination of animal products. The benefits of a vegan or vegetarian diet may very well be due to specific beneficial components found in fruits and vegetables rather than detrimental effects of meat or dairy.
Professor Campbell has followed his regimen and is still active at 91 years of age. That鈥檚 something to chew on.
