Interpreting The China Study

Awhile back, I wrote about a book called The China Study which my oncologist, Dr Gullion, had recommended to me. In the book, the author (T Colin Campbell) shares research and a number of studies which support the hypothesis that a typical "Western" diet (which includes relatively high amounts of animal protein and fat versus a "Eastern" diet that is more typically dependent upon vegetables, fruits and grains) is linked to many of the diseases for which our culture is known, such as diabetes, cancer, heart disease. I found the book to be fascinating to read -- in particular, because the author references such a huge number of studies which all seem to point to the same conclusion, but also because Campbell seems, from all measures, to be a highly-credited and reputable nutritionist (unlike many of the other authors of diet books on the market today.) He has authored hundreds of scientific papers, sat on numerous government expert panels and has helped to shape national and international diet and health organizations, including the World Cancer Research Fund.

Despite all of these credentials, however, I have still been left with a lingering sense of doubt since reading the book...How can eating foods such as yogurt or eggs or chicken be that bad for us -- haven't people been eating these foods for hundreds of years? Is a strict vegan diet the only path to healthy living or is there some middle ground? There are obviously millions of people who eat animal-based products every day and yet live to be almost a hundred (including my Grandma and Grandpa and my Aunt Jo!) -- how can this be so if what Campbell says is true?

I have read two things recently which have helped me to make better sense of what The China Study suggests and so I wanted to share them here in case some of you are also left wondering how to interpret the book's recommendations. The first comes from a daily newsletter to which I subscribe. In it, one of the members wrote:

As a faculty member at Hawthorn University (a health and nutrition university), I have debated the validity of The China Study dozens of times with my students. I think the study has a lot of value, but I disagree with the interpretation of the data. The China Study compares apples to oranges as far as I am concerned. Comparing the rural Chinese diet, which was mostly home-grown, whole organic foods, plus a VERY active lifestyle to the American diet, which is mostly processed foods fed to sedentary people seems like a poor comparison. They did look at the difference between rural and urban Chinese, but they failed to take into account the loss of nutrients from having food transported rather than fresh, the increase in pollution, the decrease in activity, increase in processed foods. If you look at the data you will see that they found that that the rural people had higher nutrient levels in their blood.

My other issue with The China Study is that it does not take into account biochemical individuality. Each person is different, and will thrive on a different diet. There are many different diets around the world which are healthy. What they have in common is whole foods, organic foods, animal foods and foods rich in the fat-soluble nutrients. What I take away from all this is that combining a fresh, local organic diet containing some amount of animal foods and rich in fat soluble vitamins with an active lifestyle leads to vibrant health.

The second perspective on the risk of animal protein came from a book that I just finished reading called Living Downstream by Sandra Steingraber. I will write more about this book in a separate blog entry since I think that it's an extremely important book for every parent of my generation to read, but for the purposes of understanding The China Study recommendations, I want to simply share what the author says about animal protein:

Ecologically speaking, a food chain consists of a series of organisms who pass chemical energy through each other. Each link of the chain is officially referred to as a "trophic level." At the bottom are the producers: the green plants that transform sunlight into food, thereby making chemical energy available to everyone else. The primary consumers (e.g, insects) feed on the producers directly, the secondary consumers (e.g., birds, rodents, etc) feed on the primary consumers, and so forth. About 90 percent of the energy transfered from one trophic level to the next is dissipated as heat and because so much food energy is lost, fewer organisms can be supported at each succeeding level. In order to survive, therefore, each individual must consume many individuals from a lower level. Thus, as organisms continue to feed on each other, any contaminants that accumulate in living tissue -- such as pesticides -- are funneled into a smaller and smaller mass of organisms.

Because of this, we see why a diet rich in animal products exposes us to more pesticide residue than a plant-based diet alone, even though the plants are directly sprayed. For the most part, the flesh of animals we eat contains more pesticides than the grasses and grains we feed to these animals. Indeed, the largest contributors to total adult intake of chlorinated insecticides are dairy products, meat, fish, and poultry. Similarly, the FDA's Total Diet Study, which regularly monitors the concentration of contaminants in cooked, table-ready foods, continues to find traces of DDT (a pesticide banned more than 30 years ago!) in many types of food, but particularly those of animal origin.

As someone who has taken more statistics classes than I care to remember, I find that I agree whole-heartedly with the first perspective: while I think that Campbell is on to something important, I don't think that he is necessarily comparing apples to apples. You cannot compare a largely organic, locally-grown, highly-vegetarian Chinese diet to a largely non-organic, industrialized (and hence, not locally grown), non-vegetarian Western diet and reach solid conclusions. There are just too many variables! There is no way of knowing whether animal products are bad in and of themselves or whether they are bad because they are not locally grown or if they are bad because they are not organic (and hence, contain significantly higher levels of toxins than a vegetarian-based diet). Teasing apart these issues would require numerous, complex studies. Some of these are likely going on today, but I have not read about any yet.

And so we're left to draw our own conclusions. For what it's worth, my family still eats animal products, although much less than we used to. Furthermore, we try, whenever possible, to make sure that we are buying products from animals that are organic and/or grass-fed. What does this mean on a day-to-day basis? Well, our kids still enjoy butter on their toast every morning, although now it's organic butter; I still pack organic cheese sticks in their lunch; they enthusiastically wolf down hot dogs every couple weeks (albeit nitrate-free hot dogs made from healthy, grass-fed cattle that are hormone and anti-biotic free!); we regularly eat meals such as lasagna or mac & cheese; and 4-5 times a week we eat some sort of meat for dinner, although we tend to stick with wild fish or free-range chicken, rather than red meat (beef, pork, ham, etc.) Furthermore, our proportion of animal products to veggies/fruits/grains has changed quite a bit since I was diagnosed. As I mentioned before, animal products used to constitute about ~50-75% of our diet but now they represent only about 30% (about 10% for me.) Instead, we stuff our kids full of tons of fruits and veggies (I literally pack them 2-3 fruits and/or veggies every day in their school lunches) and loads of fresh whole grains (bread, pasta, muffins, etc -- all made with minimal, wholesome ingredients.) These are the things which now make up ~75% of their diet.

I'll be the first to admit that I don't know what the right answer is regarding The China Study recommendations; I am also struggling to figure out the right balance of foods to live a healthy life. But I feel comfortable that the way that my family eats now makes sense and is much healthier than how we used to eat. I learned the hard way not to take my body for granted, and from my new "no regrets" perspective, I feel like I can't go wrong by sticking with organic, whole foods that come from the Earth.