THE EFFECTS OF AN ORAL FAT LOAD ON SERUM-LIPOPROTEINS IN OBESITY

Postprandial triglyceride-rich lipoproteins have been suggested to be involved in premature atherosclerosis. This report describes the respo nse to a dietary fat load in patients with obesity. In a case-comparis on study, serum triglycerides (TGs), and serum very low-density lipopr oteins (VLDL), low-density lipoproteins (LDL), and high-density lipopr oteins (HDL) were analyzed 12 h after the last meal and 6 h after an o ral fat load (100 g fat) in a convenience sample of 12 obese patients [body mass index (BMI) 38.4+/-5.9 kg/M2 (mean+/-SD)] and 12 control pe rsons matched on the basis of comparable age (BMI 21.7+/-2.2). During fasting obese patients had significantly higher levels of TGs (P<0.01) , VLDL-TG (P<0.05), LDL-TG (P<0.05), VLDL cholesterol (C) (P<0.05), an d apolipoprotein B (P<0.01), and lower levels of apolipoproteins A-I ( P<0.01), and A-II (P<0.05) and HDL-C (P<0.05). Six hours after an oral fat load significant increases in serum TG (P<0.05), VLDL-TG (P<0.05) , and VLDL-C (P<0.01) were observed in the obese patients, but not in the controls. In the obese patients, the waist to hip ratio correlated with the magnitude of the postprandial responses of TG (r=-0.650, P<0 .03), VLDL-TG (r=-0.564, P<0.05), and VLDL-C (r=-0.663, P<0.05) 6 h af ter fat intake. The pattern of lipoproteins and the lipoprotein change s after an oral fat load show that in obese patients there is a specif ic risk of atherosclerosis.