Influence of soy protein or casein on pre-established atherosclerosis in rabbits

Atherosclerosis was established in rabbits by feeding 1% cholesterol and 4% corn oil for two months. The rabbits were placed into five groups of equal average cholesterol level (2876 mg/dl) one of which was autopsied. The four remaining groups were placed on commercial ration (CR), CR plus 4% corn oil, or semipurified diets containing 14% coconut oil and 25% soy protein or casein. After two months, serum cholesterol levels in CR, CR plus corn oil, soy and casein groups had fallen by 91, 80, 81, and 64%, respectively. Aortic sudanophilia (%) in these four groups had increased by 106, 213, 238, and 25%, respectively. The findings confirm earlier observations that rabbit atherosclerosis does not regress when the atherogenic stimulus is removed.