Cholesterolaemic Effects of the Saturated Fatty Acids of Palm Oil

Abstract

Dietary saturated fats are implicated as a major risk factor in hypercholesterolaemia and cardiovascular disease. Palm oil is a major source of the world's supply of oils and fats, but because of its relatively high content of saturated fatty acids (principally palmitic acid), its consumption has come under intense scrutiny over the last decade owing to potential health implications. Based on studies carried out more than thirty years ago, the hypothesis was developed that lauric, myristic, and palmitic acid were the three principal cholesterol-raising saturated fatty acids. Since palmitic acid is the most abundant fatty acid in the diet, the cholesterol-raising effect of all saturated fatty acids was accordingly assigned to it. However, recent studies from both humans and experimental animals suggest that not all saturated fatty acids are cholesterol-raising. When all dietary fatty acids are equalized, with the exception of the two being tested, palmitic acid appears to have no impact on the plasma cholesterol in normocholesterolaemic subjects when dietary cholesterol intake is below a certain critical level (400 mg per day). Only when cholesterol consumption exceeds this level, or when hypercholesterolaemic subjects are studied, does palmitic acid appear to increase the plasma cholesterol. These differential effects of palmitic acid on plasma cholesterol are thought to reflect differences in LDL-receptor status. Collectively these data imply that, for most of the world's population, palm oil would be an inexpensive and readily metabolized source of dietary energy with minimal impact on cholesterol metabolism.