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Dietitians Review the China Study

09, July 2013 7:51 AM

I belong to a book club with registered dietitian nutritionists from the San Jose, California area. We recently gathered to discuss the China Study, by T. Colin Campbell. In spite of the fact that this book is almost 10 years old, it continues to be discussed among consumers and health professionals.

Here are a few of the main ideas from the book:

  • Chinese villages that consumed the least amount of animal protein had less cancer than the villages that consumed more animal protein.
  • Casein consumption (protein found in milk) promotes cancer in rats.
  • Nutrition must be considered holistically; “Nutrition represents the combined activities of countless food substances. The whole is greater than the sum of its parts.”
  • The How to Eat section of the book recommends a vegan eating pattern.

Our group strongly agreed with a few principles in the book: that eating more whole and unprocessed foods and plant-based foods like fruits, vegetables and beans will improve the health of most Americans. We also agreed that you can’t look at nutrients in isolation, that the overall pattern of food choices and diets over time are what matter.

However, we also observed many holes in Campbell’s arguments. Here are just a few:
  • The China Study is an observational study, in other words it only identifies relationships between different variables. It does not prove that a particular behavior or food choice causes a certain outcome. There are many other variables in the Chinese villages studied that could increase cancer risk that were overlooked—such as industrialization, exposure to chemicals, sugar and refined carbohydrate consumption. These could easily have been the culprits responsible for differences in cancer risk among groups.
  • Although individuals in the counties studied may have been vegan, whole counties did not follow vegan food patterns, so it is difficult to understand how Campbell came up with his conclusions that all animal products should be omitted.
  • Campbell’s experiments with casein were conducted with laboratory rats and mice. His hypothesis that casein behaves the same way in a whole food as when fed in isolation is flawed and violates his own philosophy to look at diets holistically. In milk, casein and whey are paired together. Newer studies suggest that calcium, milk and/or dairy consumption may actually reduce the risk of certain types of cancer, however experts do not agree on the mechanism of any effect.
  • Campbell is very selective in building his bibliography. A more comprehensive review of the literature reveals scientific research confirming the many health benefits that milk and milk products provide. For this reason the 2010 Dietary Guidelines for Americans recommends that Americans consume three servings of milk and milk products per day.

Finally, and perhaps one of the most significant flaws of the book, is that the recommendations are so extreme. Diets that remove entire food groups have the potential for unintended consequences of under-consuming essential nutrients. Bringing food choices into better alignment with the Dietary Guidelines is a preferred approach—specifically eating more under-consumed foods such as vegetables, fruits, low-fat dairy products, whole grains, beans, lean meats and fish while also reducing the consumption of refined grains, fats and sugars. These changes will go a long way toward promoting health.

While we found this book interesting, our club members are sticking with a more balanced approach to nutrition. Just as important, we equipped each other with talking points to use when someone—friend, neighbor, relative, client or colleague—asks questions about the China Study. It is important for consumers to understand the basis for Campbell’s flawed conclusions and the potential negative consequences of following diets that omit whole food groups.

Maureen Bligh, Registered Dietitian Nutritionist




Categories: categoryHealthy Eating categoryNutrition Education

1 Comments


  • Lana Olsson, MS RD CSG 45 days ago
    I appreciated this review and want to add that the study "pooled blood". Individual differences would not have been recognized, and there may have been more individual variation in blood results than acknowledged. Also, one incorrect claim in the book is that Burkitt proved that dietary fiber prevents cancer. This was never proven; in fact, it has never been proven in controlled studies. Campbell is loose with facts, strong with anecdote, and what was his son doing as a co-author? Was this a project to put junior through medical school? And there is a cookbook to follow, based on the diet, written by a Campbell! Its a shame that people think that this is a real controlled scientific study; its really an epidemiologic survey.

    Reply

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