Whole: Rethinking the Science of Nutrition
A book about holism versus reductionism in science, nutrition, and health policy
Posted Jul 16, 2013
Whole: Rethinking the Science of Nutrition by T. Colin Campbell, Ph.D., and Howard Jacobson, Ph.D., is a new book about the whole food plant-based (WFPB) diet discussed by Dr. Campbell and his son Thomas M. Campbell II, M.D., in their book The China Study. (A modified version of WFPB also appears in Prevent and Reverse Heart Disease by Calwell Esselstyn, Jr., M.D.) Campbell, the Jacob Gould Schurman Professor Emeritus of Nutritional Biochemistry at Cornell University, is one of the country's leading nutrition researchers and has served in a variety of policy-related roles, including participating in several National Academy of Sciences nutrition-related panels.
(Full disclosure—I have been on the WFPB diet for nearly a year.)
For people who are curious about WFPB nutrition, Whole is not the place to start. The movie Forks Over Knives—the title refers to changing what you eat to avoid surgery—is a good introduction, and for those who want to learn more about the scientific evidence, The China Study is the place to go—especially Part III: Diseases of Affluence.
Whole is about wholism in general—in contrast to reductionism—and about the wholistic perspective on nutrition in particular. (The word is conventionally spelled "holism," but Campbell uses the alternate spelling to emphasize that the term comes from "whole" and not "holy," and I will follow his preference here.)
The WFPB diet includes unlimited amounts of fruit, vegetables, whole grains, mushrooms, seeds, and nuts; minimal refined carbohydrates, added vegetable oils, and fish (though Esselstyn advises his heart patients to avoid these three and minimize the intake of avocados, nuts, and seeds); and avoidance of meat, poultry, dairy, and eggs, as well as products containing them.
The WFPB diet winds up consisting of roughly 80 percent carbohydrates, 10 percent fats, and 10 percent protein. I say, "winds up," because there is no counting of calories, fats, carbs, or anything else. People can eat as much as they want of the included foods, whenever they want, in any combination. In fact, variety is encouraged to increase the variety of micronutrients and—not coincidentally—of tastes.
Subjectively, the experience of the diet is similar to that of cultural or religious food preferences—Americans don't feel deprived of insect protein, because our culture avoids eating insects, though many other cultures do. Similarly, observant Hindus don't consider meat "food," and the same goes for observant Jews and Muslims with regard to pork. Once you get used to a WFPB diet, the feeling is one of normality, rather than deprivation. (My personal experience of the shift was comparable to shifting from a PC to an iMac. There was a transitional learning period, followed by a new habitual routine.)
The "whole food" part of WFPB emphasizes the importance—to fostering health and preventing disease—of the abundance and wide variety of nutrients that occur naturally in plants. In contrast, processed foods strip away many of these nutrients and add salt, sugar, and fat for taste, along with a bunch of chemicals for non-nutritional reasons, such as prolonging shelf life and changing color. For this reason, Campbell avoids referring to the diet as "vegan," since the description of processed foods in the last sentence applies to vegan cookies and similar widely available products.
The "plant-based" part of WFPB emphasizes both the causal role of animal fats and proteins in the high rates of "Western diseases"—obesity, diabetes, heart disease, cancer, and others—as well as the preventive and treatment effects of the nutrients found in plants. The China Study discusses likely mechanisms for the effects of diet on these diseases. But a point emphasized in that book, and Campbell's key point in Whole, is that individuals don't need to think in terms of specific nutrients and specific diseases—by following a healthy diet across the board, they experience a wide range of healthy effects in preventing or ameliorating diseases they may or may not have heard of or worried about.
In a sense, Whole is three books:
- A book about nutrition, emphasizing a wholistic perspective
- A book about an aspect of the philosophy of science, comparing wholism and reductionism as scientific strategies
- A book about the sociology of science as applied to nutrition—how to work outside the prevailing paradigm is stymied by government, industry, and the research establishment.
I'll discuss these three in order.
Whole contains some new and well-chosen information and examples that supplement the material in The China Study. For example, in pointing out the limitations of Recommended Dietary Allowances (RDA) lists and ingredient labels, Campbell discusses Dr. Rui Hai Liu's research on the nutrient composition of apples:
"Professor Liu and his research team began by choosing to focus on vitamin C and its antioxidant effect. They found that 100 grams of fresh apples (about four ounces, or half a cup) had an antioxidant, vitamin C-like activity equivalent to 1,500 milligrams of vitamin C (about three times the amount of a typical vitamin C supplement). When they chemically analyzed that 100 grams of whole apple, however, they found only 5.7 milligrams of vitamin C, far below the 1,500 milligrams that the level of antioxidant activity associated with vitamin C indicated. The vitamin C-like activity from 100 grams of whole apple was an astounding 263 times as potent as the same amount of the isolated chemical! ...there is a treasure trove of such vitamin-C-like compounds in apples. These include other antioxidants with names like quercetin, catechin, phlorizin, and chlorogenic acid found only in plants, each of which may exist in many forms within the apple. The list of these chemicals in apples and other fruits is long and likely reflects just the tip of the iceberg." (Pp. 152-153.)
Similarly, Figure 7-2, "Expanded chart mapping glucose metabolism and other metabolic pathways," is incomprehensibly complex, with hundreds of working parts interacting with one another in myriad ways involving complex feedback loops.
The figure reminds one of the intricate stitching of an Oriental rug—more a source of amazement than an aid to human comprehension. In another sense, the figure is reminiscent of a fractal, since any piece of it (as illustrated in Figure 7-3) can be expanded to show entirely new levels of complexity. Campbell comments that the "metabolic map in Figure 7-2 is only an infinitesimally small portion of all the reactions in each of our hundred trillion cells." (p. 95.)
And here is a final example of nutritional complexity:
"Calcium decreases iron bioavailability by as much as 400 percent, while carotenoids (like beta-carotene) increase iron absorption by as much as 300 percent. Theoretically, in comparing a high-calcium, low-carotenoid diet with a low-calcium, high-carotenoid diet, we might see an 800-1,200 percent difference in iron absorption... for some nutrients, tissue concentrations varying by more than 10-20 percent can mean seriously bad news... Nutrient pairs that were found to influence each other and, in turn, to influence components of the immune system include vitamin E-selenium, vitamin E-vitamin C, vitamin E-vitamin A, and vitamin A-vitamin D. The mineral magnesium influences the effects of iron, manganese, vitamin E, potassium, calcium, phosphorus, and sodium, and through them, the activities of hundreds of enzymes that process them; copper interacts with iron, zinc, molybdenum, and selenium to affect the immune system; dietary protein exerts different effects on zinc; and vitamin A and dietary fat affect each other's ability to influence the development of experimentally created cancer... the common belief that we can investigate the effects of a single nutrient or drug, unmindful of the potential modifications by other chemical factors is foolhardy. This evidence should also make us extremely hesitant to 'mega-dose' on nutrients isolated from whole foods. Our bodies have evolved to eat whole foods, and can, therefore, deal with the combinations and interactions of nutrients contained in those foods. Give a body 10,000 mg of vitamin C, however, and all bets are off." (Pp. 70-71.)
The take-away message from the nutrition-specific parts of the book is that nutrition is incredibly complex, with millions of working parts, interactions, and feedback loops, so that there is no known straightforward relationship between the amount of a given nutrient that your body takes in and either the amount it actually uses or its effect on a specific disease.
Wholism and Reductionism
Reductionism—studying a complex phenomenon in terms of its simpler parts—is a key scientific strategy, and perhaps the most important one. The essential idea behind a controlled experiment is to keep everything the same in the experimental group and control group except for a single element— call it X. For example, a single nutrient might be fed to (or withheld from) mice in the experimental group, but not the control group, or there might be a single way college students in the experimental group of a psychology study are treated differently from controls. Then, if differences are detected between the two groups—call it Y—e.g., control mice develop more cancer than experimental ones or control students do less well on a problem-solving test than those in the experimental group—we can conclude that X caused Y.
However, in addition to the strategy of reductionism, there is also the fallacy of reductionism—the assumption that a phenomenon is nothing more than a combination of its simpler parts. This is the kind of reductionism that Campbell argues against in Whole, and that is evident in the above quotations from the book.
Wholism provides an antidote to pushing a reductionist strategy too far. It involves considering phenomena at a higher level of organization. For example, a cell is a whole in relation to its constituent parts, but a part in relation to an organ, and an organ is a whole in relation to its cells, but a part in relation to an organism.
Campbell's wholistic argument is that the descent into ever more basic biochemical levels of nutritional research makes it increasingly impossible to derive meaningful dietary recommendations for the public at large. On the other hand, correlational studies—which, taken without additional supporting evidence, do not offer the causal explanations of controlled experiments—show strong relationships between levels of many diseases in countries around the globe and variations among those countries' diets. (Campbell does offer additional supporting evidence.)
Many of these relationships are presented in the Charts in The China Study. For example, Chart 4.8: Animal Fat Intake and Breast Cancer; Chart 5.3: Heart Disease Death Rates for Men Aged 55 to 59 Years and Animal Protein Consumption Across 20 Countries; Chart 8.4: Female Colon Cancer Incidence and Daily Meat Consumption; Chart 9.3: Association of Cow's Milk Consumption and Incidence of Type 1 Diabetes in Different Countries; Chart 9.5: Association of Cow's Milk Consumption and Multiple Sclerosis; Chart 10.2: Association of Animal Versus Plant Protein Intake and Bone Fracture Rates for Different Countries. (Advocates of a reductionist strategy might argue that by relying on correlational data, Campbell may unintentionally be cherry-picking results to support his position. While the variety, depth, and breadth of the data seemed convincing to me, I am a psychologist, not a nutritionist, so I do not have the background to wade into this debate.)
Social Forces Against Wholism
Perhaps the largest amount of space in the book is devoted to a discussion of the array of forces Campbell has bumped up against in his attempt to make his research and nutritional recommendations more widely known. These include business interests—dairy, ranching, sugar, and other processed food and agribusiness corporations and organizations; pharmaceutical companies and organizations—various medical specialties and organizations, as well as charitable organizations concerned with cancer, heart disease, and other medical conditions; government bureaucracies and research institutes with their ties to the aforementioned interests; professional journals with their commitment to reductionist research and ties to funding sources with their own agendas; and the mass media, which get their information from all of the above.
In fact, my impression is that it was Campbell's frustration with what appeared to him as an emperor's new clothes situation—he had important information with major public health and environmental implications, but he couldn't get people to listen—that motivated him to write Whole. Since he has broad career experience spanning many decades, roles, and organizations, he is able to give an insider's view of the forces behind and compromises involved in nutritional labels, food pyramids, and other official information.
For example, Chart 16.1: Sample Menu That Fits Into the Acceptable Nutrient Ranges, from The China Study, lists a breakfast of Froot Loops, skim milk, M&Ms, and fiber and vitamin supplements; a cheeseburger for lunch; and pepperoni pizza, soda, and sugar cookies for supper. One can imagine the exasperation of a researcher who participated in developing nutritional guidelines with such an "approved" menu and its apparent relationship to obesity, diabetes, heart disease, and other widespread health problems.
On the other hand, it has been a half-century since the publication of Thomas S. Kuhn's The Structure of Scientific Revolutions, so it should not come as a surprise that when a new scientific paradigm emerges, it is not greeted by widespread acceptance. Science, as an institution, has a built-in corrective offered by the scientific method. So, if Campbell is correct, he can be confident that—in the long run—he will be vindicated. Since he is 79 years old, however, that day may not come during his lifetime.
Campbell believes that a WFPB diet could prevent much disease and control health care costs. Some critics, who agree partially or completely with him, seem to believe that since the public would never follow the WFPB diet and would dismiss it out of hand, there is no point in informing them about it. It would be better to make some watered-down recommendations and hope that people will eat more plant foods and fewer animal products.
The problem with this "practical" approach is that setting goals too low virtually guarantees failure. Instead, it would seem that a long-term, broad-based strategy aiming at uncompromised goals would offer better prospects for success. Such a plan would involve creating a social movement to foster changes in the mass media, medical education, teacher education, parent education, nutrition curricula in primary and secondary schools, and, of course, in school lunches. That way, since unhealthy food is less addictive than cigarettes, we should, over the course of a generation or two, be able to improve Americans' eating habits even more than their smoking habits.
When I read The China Study, my reaction was: "Why haven't I heard of this before?" I believe that people should be made aware of the evidence and allowed to choose for themselves; offering them watered-down recommendations deprives them of this option.
As things stand now, my guess is that some would follow the diet, some would eat more WFPB foods, and less animal and refined foods, and the great majority would not change their eating habits. Unfortunately, when offered nutritional evidence, many might even say, "I don't know, and I don't want to know!"
My view is that informing the public and the powers-that-be about the research of Campbell and his graduate students and associates might have a significant public health impact now, but less than he imagines. Over the long term, however, I am more optimistic. And in terms of democratic values, if individuals knew, they would be in a position to make an informed choice.