Recommended Reading for those wanting to make sense of nutritional science
T. Colin Campbell, Professor Emeritus of Nutritional Biochemistry at Cornell University and author of the ground-breaking China Study, is one of the world’s most knowledgeable, experienced, and passionate WFPB advocates, and Whole is his magnum opus. Campbell is persuasive. Reading the China Study helped to convince Bill Clinton to take up a wholefood, plant-based diet with dramatic health benefits.
At over 300 pages and at times written in fairly technical language, Whole is not a light read, but it is well worth the effort if you want to understand: the importance of wholism in nutritional science (and all science for that matter); why supplements are often ineffective at best and harmful at worst; the power of whole plant foods over medicine, and; how industry influences both dietary recommendations and the science behind these recommendations.
The book is based on a critique of reductionism – which can be defined as a focus on the details without looking at the context – i.e. not seeing the wood for the trees. Wholism, by contrast, views the whole as greater than the sum of its parts – a molecule is not the sum of its atoms, a cell is not the sum of its constituent parts, an organ is not the sum of its cells, and so on. Campbell argues that we need both wholism and reductionism, but, since the industrial revolution the balance has swung way too far to the reductionist end of the spectrum.
Nutritional science has been particularly influenced by successes of reductionist science such as the discovery of single vitamin deficiency diseases such as scurvy, rickets and beriberi. This has led to the idea that we require precise quantities of particular nutrients for particular physiological functions without a focus on the actual food we eat (“we eat food, not nutrients”) and the body’s ability to process this food to power a multitude of physiological functions.
Campbell charts his personal journey from a childhood spent on his family’s dairy farm, to his early quest to ensure that children in developing countries consume more protein, to his realisation that many health problems, including cancers, are actually caused by excess animal protein, to the China Study where his team discovered that a raft of western diseases were practically unknown where people ate wholefood plant-based diets. He also documents his growing dissolution with the nutritional establishment, giving an insider’s account of how the truth about health is consistently watered down or covered up when it threatens vested interests. One caveat here. Campbell is from America, where industry lobbying is ubiquitous. Industry influence is not as extreme in many other countries. Indeed, industry representatives were excluded from the consultations used to produce Canada’s 2019 Dietary Guidelines. This, unfortunately, is not the case in most countries including UK.
The section on the nutritional establishment is interesting but, to be honest, Campbell’s experiences will probably come as no surprise. The real insight for me is his focus on the complexity of the processes whereby the body turns the food we eat into you and me. An apple, for example, famously keeps the doctor away. We have an idea of some of the reasons for this such as fibre, vitamins, minerals, and protective phytochemicals, but we have very little insight into the precise impact of the symphony orchestrated by the thousands of chemicals in an apple at any one time or in any one place as: 1) there are so many substances, and; 2) the nutrients we extract from this apple will depend on the body’s requirements in any particular moment. Our cells, organelles, organs and physiological systems are not passive sieves. It is the complexity of whole foods, the whole body that consumes them and the interactions between the two, that explains why the dominant focus on single nutrients, single genes, single biochemical pathways, and single drugs is naïve at best and destructive at worst.
Campbell uses the classic example of vitamin A and cancer to illustrate this naivety. What most people call Vitamin A is actually a group of Vitamin A precursors - the carotenoids, famously abundant in the eponymous carrot. The carotenoids are powerful antioxidants. There are about six hundred known carotenoids in food. Studies have shown that intake of foods rich in one of these carotenoids, beta-carotene, is associated with lower rates of cancer, notably lung cancer in smokers. This led to recommendations for smokers to take beta-carotene supplements to reduce lung cancer risk. However, beta-carotene supplementation in large clinical trials actually increased lung cancer incidence and cardiovascular mortality rates. The effects were so great that the trials had to be terminated early. The precise mechanism is not known but it may be that beta-carotene from supplements is overwhelming the body’s ability to absorb the myriad other carotenoids that should be coming from food. This and other examples illustrate the foolishness of the endless quests for isolated chemicals to resolve our health issues while ignoring the context within which these chemicals weave their magic. I think the Campbell’s focus on the shortcomings of supplements is important as many in the field of complementary medicine are quick to condemn synthetic drugs while giving “natural” supplements a free pass. The supplement industry is worth billions, so invoking the “follow the money” principle, we need to examine health claims made for supplements with a vigilance many reserve only for the products of the food and drug industries.
Campbell also focuses on reductionism in genetics, characterising genetic medicine as the ultimate reductionist fallacy, and medicine as a whole with its focus on symptoms with less attention paid to root causes.
The book’s take-home message for me is that the body is highly intelligent and exquisitely designed to seek optimal health as far as possible in any given circumstance. So, most people will be healthy if they eat what they were designed to eat and live as naturally as possible. The exquisitely complex biochemistry of our food and our bodies interacts to ensure that we don’t need to sweat over the small details. This is empowering as it means we do not have to fixate on the quantities or proportions of nutrients we consume or obsessively count calories. Instead, we can follow Michael Pollan’s dietary manifesto to “Eat [real] foods, not too much, mostly plants.” It took 300+ pages of reading and reflection to reach that eight word conclusion!