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The China Study Finding Number Six

Breast cancer is not just a function of fat intake. There is a complex biochemical network that determines risk of breast cancer and other cancers. Obsessing over one nutrient at a time is not likely to reap any special benefit. It is much more fruitful (and much more relaxing!) simply to eat the right types of whole, unrefined foods and let your body take care of the rest.

The comprehensiveness of the China Study is second to none. This does not mean it is the largest study ever done. The number of subjects studied in rural China, for example, was ?only? 6500 adults and their families. There have been many studies now that have examined far more than 100,000 adults, and are thus much larger. However, the number of variables measured in conjunction with each individual in rural China was unusually large. In contrast, many larger studies only record information on several dozen different variables at most. The Cornell, Oxford, and China researchers, on the other hand, examined and compared 367 variables, meaning that the complex network of food, health, and environment was studied in a most comprehensive way.

This is useful for understanding the interconnectedness of the evidence regarding breast cancer and diet. Famous studies from several decades ago had shown that countries with a higher per capita consumption of fat had higher rates of breast cancer. It was a very strong, nearly linear relationship. Many scientists then thought that fat intake alone was likely to be responsible for breast cancer. The China-Oxford-Cornell Diet and Health Project added far more to this debate, however, because of its inclusion of a much more comprehensive collection of dietary, lifestyle and disease characteristics.

Fat intake was significantly associated with breast cancer incidence in rural China, but several other risk factors and clinical markers also were associated. Risk factors for breast cancer include early age of menarche (age at first menstruation), high blood cholesterol, late menopause, and high exposure to female hormones. It turns out that higher dietary fat intake is linked to higher blood cholesterol levels, and both of these factors are associated with earlier age of menarche, later menopause, and higher production of female hormones. Furthermore, it is not only fat alone that may trigger these changes but, more importantly, it is animal foods in general.

Breast cancer is now accepted to be, in many cases, a function of lifetime exposure to female hormones; the higher the hormone exposure, the higher the breast cancer-risk. The China-Oxford-Cornell Diet and Health Project found that not only does fat potentially play a role in increasing female hormones over a lifetime, but so does animal protein and animal-based foods in general. The comprehensiveness of the study, attained by measuring many more variables than just fat intake and cancer risk, make this a very compelling finding. Biological associations almost never point in the same direction like this by chance. Further, these findings in rural China are especially compelling because of they apply to a range of dietary experience that is unusually low in animal-based foods.

This means that breast cancer risk, and very likely risk of other diseases, does not revolve around one nutrient, such as fat, or one risk factor, such as family history. There is a network of food chemicals, as found in Nutrient Rich Foods, and environmental factors that work together to create or undermine health. Adjusting one tiny link in the scheme of things, such as using margarine instead of butter, is unlikely to make a difference. Magic bullet chemicals rarely heal and single risk factors rarely explain complex diseases. Biochemical realities are far more complex.

Fortunately, however, this leads to an astonishingly simple message: a total dietary and lifestyle approach, one that favors a plant based diet and limits animal foods, is more powerful than any single pill or supplement you might take. This lifestyle affects the multitude of complex biochemical reactions in a positive way across the board, which is the closest thing to a magic bullet we?ll ever get.