Professor T. Colin Campbell is widely acknowledged as the intellectual grand-daddy of the whole food plant-based nutrition movement. In fact, he coined the phrase ‘whole food plant-based’, in order to distinguish his ideas about optimal nutrition for humans from vegetarian and vegan eating patterns, which include animal products in the former case, and not infrequently highly processed plant foods in both.
In his presentation at the 3rd International Plant-Based Nutrition Healthcare Conference (PBNHC), Professor Campbell outlined 6 principles that he believes are absolutely key to understanding nutrition, planning and executing worthwhile nutrition research projects, and developing a healthy eating plan.
Principle 1: Nutrition controls gene expression.
The co-discoverer of the structure of DNA, Francis Crick, formulated what he called “the central dogma of molecular biology” as follows: DNA codes for RNA, which codes for proteins. In other words, our genes control our health and disease outcomes.
But the emerging field of epigenetics has made it abundantly clear that external or environmental factors – including nutrition – can switch genes on or off, and affect how cells read genes, and thus bring about changes in cellular function, all without causing any changes in the DNA sequence of those genes. (Read my summary of Dr Dean Ornish’s presentation at the PBNHC to learn more about how nutrition affects the expression of genes involved in cancer, and my article on the epigenetics of cancer for a more in-depth understanding of this topic.)
Animal research is a controversial topic among vegans, who object on principle to this or any other form of exploitation of animals, and Dr Campbell is respectful of this view. However, in his defence he points out that research was pivotal to his scientific discoveries that led him to champion a movement that encourages people to eschew eating animals! You’ll have to make up your own mind on this one.
In any case, his laboratory research proved that even in experimental animals deliberately genetically bred to have more more cancer genes, feeding them a diet low in animal protein diet dramatically reduced the number of tumours they grew when exposed to potent carcinogens.
Principle 2: Each nutrient acts by countless mechanisms.
When Dr Campbell first made the alarming – not to mention heretical – discovery that a diet high in animal protein promoted the growth of liver tumours in animals exposed to aflatoxin (as described in The China Study), he and his research team sought to discover the mechanism by which protein caused this effect.
But it turned out that there was not one single mechanism at work, but multiple mechanisms operating at every stage of cancer formation and development. Animal protein:
- Ramped up the activity of enzymes that made carcinogens (cancer-causing substances) more dangerous;
- Made carcinogens more likely to bind the DNA in a way that cause the gene mutations that lead to cancer;
- Increased the amount of carcinogens entering cells;
- Increased the rate of proliferation of damaged cells, raising the likelihood that they would develop into a tumour;
- Increased the rate of growth of tumours once they had developed;
- And a host of other actions that promoted the development and spread of cancer throughout the body.
Medical research – and most nutrition research – tends to focus on single nutrients and their effect. A researcher might spend years of their career focusing on the effect of one nutrient on one enzyme pathway, in an attempt to understand exactly how that enzyme affects the body’s function. Dr Campbell calls this ‘scientific reductionism’, and points out that while it is an important element of science, at some point the researcher must step back and attempt to put their reductionist research into the broader context of how organisms function as whole entities – what Campbell calls ‘wholism’.
By analogy, if I wanted to gain an understanding of how an internal combustion engine powers my car, I wouldn’t get very far if all I learned about was how the carburettor works. I would also need study spark plugs, fuel injection systems, cylinders, crankshafts, pistons, fan belts.. and then, after gaining an understanding of how each part worked, I would have to see the entire engine in operation to grasp how each component works within the system.
The human body is infinitely more complex than an internal combustion engine, and can only be understood by a combination of reductionistic and wholistic research methods.
Principle 3: Animal and plant proteins act differently.
Professor Campbell, who grew up on a dairy farm and did his doctoral dissertation on methods of deriving more protein from animal foods, was shocked and disturbed by the implications of his laboratory research on the harmful effects of protein. The protein he used in his initial animal experiments was casein, the primary protein found in cows’ milk, but he became curious about whether all proteins would have the same effect.
It turned out that feeding experimental animals either soy or wheat protein had completely different effects than feeding them animal protein, when it came to cancer promotion. Even at 20% of daily energy intake, plant proteins did not promote cancer growth.
From very early on in the study of the role of protein in human and non-human animal nutrition, animal proteins had been classed as “high quality” because they stimulated faster growth in the animals fed them, while plant proteins were dismissed as “low quality” due to the slower growth rates of animals fed them. Now this notion was turned on its head for Campbell. Faster growth rates, it seemed, also meant faster cancer growth rates. Better to take your time growing to your full adult height, lest you aster growth trajectory spur grow the growth of a tumour along the way!
Campbell points out that research stretching back into the first half of the 20th century had also established that animal protein consumption elevates cholesterol level (regardless of cholesterol or saturated fat consumption), while plant proteins do not.
Principle 4: Protein acts both directly and indirectly on disease risk.
As described above, animal protein consumption raises the risk of both heart disease and at least some types of cancer, by mechanisms that are well understood. But Campbell pointed out that as the consumption of animal protein (and the foods that contain it) goes up, the consumption of plant foods – which contain a multitude of nutrients that protect against a multitude of diseases via a multitude of mechanisms, goes down. There’s only so much food that any human can eat each day, and if animal foods are looming large on your plate at most or all of your meals, you just won’t have enough room in your stomach to take in the high amounts of minimally-processed plant foods that you need to regain and maintain your health.
Principle 5: Experimental cancer is reversible by nutrition.
Campbell, careful scientist that he is, is at pains to point out that his research on lab animals, and his field research in China, does not prove that animal protein consumption causes cancer in humans, or that removing it from the diet will cure cancer (although, as Dr Ornish has found, the growth of prostate cancer can certainly be controlled by this means).
However, in an experimental setting (in which an animal is either deliberately exposed to a carcinogen, or a tumour grown from a culture of human cancer cells is implanted in the animal), reducing animal protein intake from high to low intake reduces tumour growth, and raising animal protein intake from low to high accelerates growth.
Dr Campbell also reported that added fat, in the form of corn oil, was found to have similar effects on pancreatic cancer in experimental animals – raising intake from low to high promoted tumour growth, and reducing it from high to low contained tumour growth.
Principle 6: The nutritional effects of a whole food, plant-based diet (WFPBD) are broad and rapid, so long as the dietary change is sustained.
While the reductionist mode of thinking encourages researchers and clinicians to focus on one disease, and the means by which it may be treated, Dr Campbell pointed out that most chronic diseases – and even many acute ones – share similar biological pathways, and adopting a WFPBD may result in improvement, and even complete resolution, of multiple health conditions at the same time.
My client Dennis is the poster-child for this phenomenon – he resolved type 2 diabetes, high blood pressure and rheumatoid arthritis within a couple of months of adopting a WFPBD, shedding 10 medications and over 20 kg in the process.
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