Milk, serum cholesterol, and the Maasai. A hypothesis.

The Maasai of East Africa have been found to have low serum concentrations of cholesterol and a low incidence of cardiovascular disease in spite of apparently very high milk intakes. On that basis it has been frequently suggested that milk contains a "hypocholesterolaemic factor". The hypocholesterolaemia of the Maasai had also been attributed to a genetic adaptation. We feel that the milk intakes reported for the Maasai are excessively high and that the low incidence of cardiovascular diseases and low levels of serum cholesterol may be adequately explained by their variable and generally low energy intakes.