MEAT CAUSES CANCER. REALLY?

Let's examine some of the evidence.

This is not a topic I spent a lot of time thinking about until I read The China Study: Startling Implications for Diet, Weight Loss and Long-Term Health (Dallas: BenBella Books, 2006)

T. Colin Campbell PhD is a leader in the field of research on nutrition. He and his colleagues received over 74 grant-years of research funding; he is the author or co-author of over 350 scientific articles. He has won numerous awards including the 1998 American Institute for Cancer Research award "in recognition of a lifetime of significant accomplishments in scientific research... in diet, nutrition and cancer". (22)

His son, Thomas M. Campbell II, MD is the co-author of this examination of ground-breaking research conducted over 4 decades.

Some of this fascinating research was conducted in lab settings in a controlled environment using rats and mice. Studies in his research lab on the effects of casein (milk and thus animal protein) vs. vegetable (gluten and soy) protein on the formation of cancer.

"For all these experiments we were using casein, which makes up 87% of cow’s milk protein. [They found that casein fed at 20% of diet along with a carcinogen – aflatoxin – dramatically increased cancer cells in rats, but at 5% of diet did not.] So the next logical question was whether plant protein tested in the same way, has the same effect on cancer promotion as casein. The answer is an astonishing “NO”. In these experiments, plant protein did not promote cancer growth, even at the higher levels of intake. [Initially they used gluten – wheat protein]… We also examined whether soy protein had the same effect as casein on foci development. Rats fed 20% soy protein diets did not form early [cancer] foci… .(59-60)

These findings are astounding, and they have been replicated many times. "Like flipping a light switch on and off, we could control cancer promotion merely by changing the levels of protein, regardless of initial carcinogen exposure. But the cancer promoting factor in this case was cow's milk protein". (59)

Campbell then launched a very large study of several hundred rats and found that the "effects of protein feeding on tumour development were nothing less than spectacular".(60)

Rats live for about 2 years so they ran the study for 100 weeks. "All animals that were administered aflatoxin [the carcinogen]and fed the regular 20% levels of casein [animal protein] either were dead or near death from liver tumours at 100 weeks. All animals administered the same level of aflatoxin but fed the low 5% protein diet were alive, active and thrifty, with sleek hair coats at 100 weeks." (60) That's a score virtually 100 to 0. Those are very significant results.

Subsequently Dr. Campbell used transgenic mice who had Hepatitis B Virus-induced liver cancer. It's important to note that this study examined a different species with cancer resulting from a different cause. They found intense early cancer formation in the mice fed a diet of 22% casein (animal protein); much less in the group fed a diet of 14% casein; none in those fed a diet of 6% casein; and none in the control group of mice with no HBV induced cancer.

Another research group at the University of Illinois Medical Center working with mammary - breast, cancer in rats, found that increasing intakes of casein promoted the development of breast cancer in "rats dosed with two experimental carcinogens (7,12-dimethylbenz(a)anthracene (DBMA) and N-nitroso-methyllurea (NMU)" and that this process operates through a network of reactions that combine to increase cancer". (65)

Perhaps even more importantly this operates "through the same female hormone system that operates in humans" (65)

Campbell and his colleagues replicated these results "using several different nutrients including fish protein, dietary fats and antioxidant carotenoids". (66)

IMPLICATIONS FOR HUMANS?

"First, rats and humans have an almost identical need for protein. Second, protein operates in humans virtually the same way it does in rats. The level of protein intake [as a % of diet] causing tumour growth is the same level that humans consume. And fourth, in both rodents and humans the initiation stage is far less important than the promotion stage of cancer." (65) In other words, although we all carry cancer, how it is promoted, is the important question.

But it was clear that in rodent studies "nutrients from animal-based foods increased tumour developments while nutrients from plant-based foods decreased tumour development."(66)

But the big question remained unanswered despite the stunningly positive consistency. "Are these principles regarding animal protein and cancer critically important for all humans in all situations, or are they merely marginally important for a minority of people in fairly unique situations?"(66)

Now that's a BIG question. We'll look at that in the next E-zine.

YOURS IN HEALTH AND WELLNESS Roger Elmes