Colin Campbell was a nutritional biochemist at Cornell University. In the 1960s, he was involved in nutritional programs in the Philippines to help families provide for their critically undernourished children. Peanuts were one of their preferred sources of protein. It is a legume— great for improving the soil, easy to grow, and is nutritious and tasty.
At the same time, children younger than 10, were dying at alarming rates from liver cancer. Normally liver cancer is an adult disease— and the children dying from the disease were from the most affluent suburbs in Manila. These are the families that could afford the best housing and the best food.
Whilst in the Philippines, he read a paper in an obscure medical journal. Rats were fed aflatoxin— one of the deadliest carcinogens known. One group of rats was given a diet of 20% protein —and they all died of liver cancer. The second group was given a diet of 5% protein— and they all lived. 100% deaths compared to zero deaths. They were all fed aflatoxin— but only those rats that had a high protein diet died.
A 20% diet of wheat protein, gluten, or pea protein did not result in liver cancer deaths whereas casein, which comprises of 80% of the protein found in cow’s milk, and albumin, which is found in egg white, did result in liver cancer deaths. Plant-based diets are often considered to be lysine deficient. However, adding the amino acid lysine to the wheat protein to match the level found in casein also resulted in cancer deaths.
Significantly, peanuts and corn in the Philippines were often contaminated by aflatoxin— and the wealthy ate Western-style diets, one rich in protein.