In 1968 Indian researcher performed a study on lab rats that showed milk protein (casein) as cancer promoting.
In this research all rats were administered with aflatoxin, a liver cancer causing toxin. Aflatoxin is one most carcinogenic chemicals ever discovered, at least for rats. Then, they were divided in two groups. Group one was fed 20% cow’s milk main protein (casein) and group two was fed only 5% cow’s milk main protein (casein). The results were astonishing, the whole group of rats given 20% casein got cancer, whereas none of the group of rats given 5% casein got cancer (1). That study was buried in the medical library to be forgotten.
Dr. T. Colin Campbell author of over 300 scientific papers and “The China Study”, one of the greatest nutrition books written to date, came across the above mentioned study in the 70s. He was trying to discover the source of the high liver cancer incidence in Filipino children, which happened to be caused by aflatoxin (a fungal toxin found on mouldy peanuts and corn).
After this discovery, Dr. Campbell performed a series of studies to verify the results of the Indian research. He organised a large study of several hundreds rats and examined tumour formation over their lifetime using several different approaches (2,3). The effects of protein feeding on tumour development were spectacular. All rats that were administered aflatoxin and fed the regular 20% levels of casein either were dead or nearly dead from liver tumours after 100 weeks. While all rats administered the same levels of aflatoxin but fed 5% protein (casein) diet were alive and active after the 100 week period. Something almost never seen in research and nearly identical to the original research in India.
In the same experiment, they switched the diets of some rats after 40-60 weeks, to investigate the reversibility on cancer promotion. Rats switched from high protein to a low protein diet had significantly less tumour growth, 35-40% less than rats fed a high protein diet. Rats switched from a low protein diet to a high protein diet, started growing tumours again. This meant that nutritional manipulation can turn cancer on and off, in rats at least.