Minor dietary effects of HDL in physically active men.

In a preceding prospective study an increased high-density lipoprotein (HDL)-cholesterol and apolipoprotein (apo) A-I concentration occurred in healthy, non-obese, initially sedentary men, aged 30--44 years, after 3 months of physical training. Dietary history data revealed an increase in the absolute amount of fat-intake. In the present study we investigated whether a changed fat intake would influence the levels of lipoproteins, especially the HDL fraction, in twenty-three regularly conditioning men, aged 30--44 years, with a maximal aerobic capacity of 53.4 ml/kg x min--1 +/- 0.8, mean +/- SE. Ten subjects participated in an experimental group and thirteen in a control group. The experimental group studied before, after 4 weeks on a fat-rich diet (fifty-four energy-% fat, twenty-nine energy-% carbohydrate) and after 4 weeks on a fat-poor diet (twenty-nine energy-% fat, fifty-three energy-% carbohydrate). The data reveal that these large dietary changes did not influence HDL-cholesterol concentrations (1.71 +/- 0.10, 1.69 +/- 0.12, 1.59 +/- 0.13 mmol/l, mean +/- SE, during ordinary, fat-rich and fat-poor diet, respectively) and only influenced apo A-I levels to a minor degree after the fat-poor diet (134 +/- 6.1, 134 +/- 7.1 and 123 +/- 4.7 arbitrary units, mean values +/- SE) during ordinary, fat-rich and fat-poor diet, respectively). No changes were observed in the controls before and after 8 weeks. During the study training habits and body weight were constant. These findings show that large variations in the intake of dietary neutral fat only to a minor extent influence the level of HDL-cholesterol and apo A-I in physically active subjects.