Abstract
To elucidate the effects of dietary fat saturation levels on serum cholesterol and apoprotein A-I (ApoA-I) in humans with impaired glucose tolerance (IGT), six healthy controls and four subjects with IGT participated in this study. Three diets were designed for each subject. The polyunsaturated/ saturated fat ratio was 1.00 in study 1 (diet R), 3.10 in study II (diet P) and 0.25 in study III (diet S). Diet R was given for the first two weeks, diet P for the second two weeks and diet S for the third two weeks. Overnight fasting venous blood samples were collected at the end of each period. Changes in body weight were controlled to within ±0.3 kg during the study.
In the subjects with IGT, both total cholesterol and LDL-cholesterol levels were lower in study II than in study I and higher in study III than in study II. The alterations of these levels in the healthy controls were similar to those of the subjects with IGT. Although HDL-cholesterol levels did not change in the healthy controls, those of the subjects with IGT decreased in study II from the levels in study I and no changes were seen between those of study II and III. ApoA-I levels increased only in study III from the levels in study II and I in healthy controls, However, there were no changes in the subjects with IGT throughout the study.
The response of total cholesterol and LDL-cholesterol to the changes of dietary fat saturation was rapid while the response of HDL-cholesterol and ApoA-I was slow. Therefore, in humans with both IGT and hypercholesterolemia. A high P/S diet should be maintained continuously.
