MEAT CAUSES CANCER. REALLY? - PART 2

In the last Newsletter we looked at solid research evidence showing the link between the progression of cancer and the consumption of animal protein in rats and transgenic mice. We also looked at the evidence that showed no link when they were fed plant protein.

To do similar studies in humans would be impossible. But we can look at population studies - and there is an excellent, large scale, long-term population study available in China (T. Colin Campbell, The China Study, Dallas:BenBella Books, 2006)

Let’s talk quickly about science and truth. Proof in science is elusive. Even though in the core sciences like biology, chemistry and physics proof may be more achievable, it can also be ephemeral. For example, from the time of Charles Darwin, scientists have believed that barnacles mated in a certain fashion. It was only in 2012 that researchers at the Bamfield BC Marine Sciences Center discovered spermcast mating in a common stalked species of barnacle. (Proceedings of the Royal Society B rspb.2012.2919 (published 16 January 2013). So even in a core science “truth” is not eternal.

In nutrition studies in humans, scientists conduct observational studies and interventional studies. In observational studies scientists observe and measure pre-existing differences between groups of people and measure different rates of specific diseases. In interventional studies, scientists intervene with a hypothetical treatment to test its effectiveness by measuring the treatment against a placebo, a look alike substance that has no active ingredients. This is the method used in drug testing and in testing specific vitamins and minerals.

Studies will often find a correlation between a diet and certain diseases; or a specific vitamin and lower rates of a specific disease. But that does not mean there is a causal link. To illustrate with a ludicrous example – there are more blondes per capita in the USA than any other country and there is a high rate of obesity in the USA. Therefore being blonde causes obesity. Obviously that’s ludicrous. So there is a correlation but not a proven link or cause. Therefore scientists use tests of statistical significance to determine the probability that the correlation is either one of high probability or one of random chance. A probability of 95% indicates a 19 in 20 probability that the observation is real; a 99% certainty means a 99 in 100 probability that the observation is real; and a 99.9% certainty means a 999 in 1000 probability that the observation is real and not random. (Campbell, p. 77) Now that’s a simple explanation of a complex topic that includes different ways of testing the probability. But for the lay person it’s still pretty heavy. So let’s look at something a tad lighter.

Here’s a 30 second classic ad from Wendy’s. Click Here (Opens new window). If the China Study had been available in 1984 perhaps these ladies wouldn’t have been blasting around town to find the beef. Click Here for Seniors' Driving Moment (Opens in new window).

The China Study had over 8,000 statistically significant correlations. That’s an amazing Whopper of a series of important findings.

What We Can Learn From China

Astonishingly the geographic variations were quite high, especially for a country where 87% of the population was in the same ethnic group, the Han. Counties with the highest rates of some cancers were more than 100 times (10,000%) higher than those with the lowest rates. If it was NOT different genetic backgrounds, then what was the reason for these drastic differences? To give another comparative perspective it is helpful to note that the overall aggregate rate of cancer in China was less than that of the USA? (pp. 70-72)

Campbell, the author of The China Study led a team that included two leading Chinese scientists and a UK member who was one of the world’s leading epidemiologists, a winner of several awards for cancer research. From the Chinese mortality study they had access to mortality rates from over 4 dozen diseases that were plotted geographically. This data allowed Campbell and his team to cross-list every disease rate with every other disease rate and two groups emerged; what he terms Diseases of Affluence (Nutritional Extravagance) and Diseases of Poverty (Nutritional Inadequacy and Poor Sanitation). The Diseases of Affluence centered on Cancers (colon, lung, breast, leukemia, childhood brain, stomach and liver), diabetes, and coronary heart disease). (p.76)

To determine whether diet had any impact on these disease rates, Campbell’s study gathered data on 367 variables with data from 65 counties across China and the results of administered blood tests, urine samples, and dietary questionnaires from 6,500 adults. The counties selected were semi-rural or rural, based on the hypothesis that a high percentage were likely to have lived their whole life there – actually an average of 90-94% lived in the same county all their life. (pp. 72-3)

The rural Chinese diets were rich to very rich in plant-based foods, while USA diets were rich to very rich in animal-based foods. In the USA 15-16% of total calories comes from protein and about 80% of this is animal-based protein. In rural China 8-10% of calories came from protein and only about 10% of this is animal=based protein. Note the incredible difference - “the difference between rural Chinese diets and Western diets, and the ensuing disease patterns, is enormous.”(p. 75)

One of the key findings in Campbell’s work in China is the link between diseases of affluence and diets with a greater dependence on higher levels of animal-based protein. Having established that a diet that was whole food plant-based did not see significant rates of diseases of affluence he then hypothesized that “when animal protein consumption and blood cholesterol levels were as low as they are in rural China, there would be no further association with Western diseases [diseases of affluence]. But we were wrong. Even these small amounts of animal-based food in rural China raised the risk for Western diseases”. (p. 80).

The findings explained in The China Study are so important because of the very strong methodology used with a large population base – 6500 people, measuring so many variables – 367 across wide geographic areas – 65 counties. The high levels of statistical probability he found make his conclusions very important.

In brief Campbell makes a very strong and persuasive argument for a whole foods plant-based diet. His book is well worth reading.

How Early in Life is Diet Important?

Campbell makes a very strong case for a whole foods plant-based diet. But he also argues that we can get all the vitamins and minerals we need from that diet. But is that assertion valid? What does the research tell us? Chick peas, the main ingredient of Hummus, are a good source of plant-based protein, provided the soil is healthy. So join us in the next Newsletter to learn when Humus is necessary for a healthy Hummus. And no it is not a pun.