Serum Lipids and Diet: A Comparison between Three Population Groups with Low, Medium and High Fat Intake

Abstract

Serum cholesterol, serum total and polyunsaturated fatty acids and diet of three populations were compared. Of two groups of African negoes examined, one took 6.8 and the other 37.8% of its calories as lipids, almost exclusively of vegetable origin. The third group (negroes from Nashville) consumed 48.3% of its dietary calories as fats, mainly of animal origin. Their dietary linoleic acid represented, respectively, less than 1, 2 and 6% of their total caloric intake. The Nashville group had the highest serum cholesterol level, but there was little difference in the serum cholesterol of the other two groups. Serum total fatty acids of the three groups were not very different. From the observations of total and individual polyenoic fatty acids in these groups, it appears that there is a threshold value of dietary linoleic acid governing the pattern of serum fatty acids: below this threshold, serum total polyunsaturated fatty acids are low owing to a decline in dienoic and tetraenoic acids, despite relatively high trienoic, pentaenoic and hexaenoic acid levels. Above this threshold value, the opposite phenomenon was observed. In this range, a change from 2 to 6% dietary linoleic acid did not alter the serum polyenoic fatty acid levels appreciably, except perhaps for the trienoic acid.