Congruence of individual responsiveness to dietary cholesterol and to saturated fat in humans

Previous experiments have shown that differences between humans in the response of serum cholesterol to dietary cholesterol are at least partly reproducible and stable over a prolonged period. In this study it was investigated whether enhanced sensitivity to dietary cholesterol and saturated fat go together. The subjects had also participated in three or four experiments dealing with the reproducibility of the effect on blood cholesterol of either adding cholesterol to the diet in normal subjects (NORM-EGG group; n = 23) or of cessation of egg consumption in subjects with a high habitual egg intake (HAB-EGG group; n = 24). In the present experiment the NORM-EGG subjects were fed a mixed natural diet providing 21% of energy as polyunsaturated and 11% as saturated fat (P/S2 ratio, 1.9) for 3 weeks, and one providing 5% of energy as polyunsaturated fat and 23% as saturated fat (P/S ratio, 0.2) for the next 3 weeks. The HAB-EGG group was fed the same diets in reverse order. The serum cholesterol concentrations were higher on the low P/S diet than on the high P/S diet (on average 23% in normal subjects and 16% in habitual egg eaters). The correlation coefficient between each subject's serum cholesterol response to fatty acids and his or her average response to dietary cholesterol in the dietary cholesterol experiments was 0.62 for the normal subjects (P less than 0.01) and 0.15 for the HAB-EGG group. We conclude that modest differences in responsiveness of serum cholesterol to dietary saturated fat do exist in humans, and that, in people of normal cholesterol intake, responsiveness to dietary cholesterol and to saturated fat tend to go together.