Dietary medium-chain triacylglycerol prevents the postprandial rise of plasma triacylglycerols but induces hypercholesterolemia in primary hypertriglyceridemic subjects.

BACKGROUND

Previous studies showed divergent results concerning the influence of medium-chain triacylglycerol (MCT) on lipoprotein metabolism.

OBJECTIVE

The objective of this study was to compare the effects of MCT and corn oil on plasma lipids in primary hypertriglyceridemic patients.

METHODS

Ten subjects ate different proportions of corn oil and MCT for 12 wk. The subjects first ate a low-fat diet for 2 wk and during the next 4 wk, corn oil was added as the sole source of fat. Thereafter, for 2-wk periods, the subjects were sequentially fed corn oil and MCT mixed in the following proportions: 3:1, 1:1, and 0:1. Fasting plasma total cholesterol, triacylglycerol, and HDL-cholesterol concentrations were measured at the end of each period. At the end of the 100%-corn oil and of the 100%-MCT periods, subjects were fed a test meal containing the respective oil (40 g fat/m(2) body surface area) and total cholesterol and triacylglycerols were measured at 2-h intervals over 8 h; fasting lipoprotein composition was also measured.

RESULTS

Compared with corn oil, MCT was associated with a higher mean (+/-SD) fasting total cholesterol concentration (6.39 +/- 1.14 compared with 5.51 +/- 0.98 mmol/L, respectively; P < 0. 05); non-HDL-cholesterol concentrations were also higher with MCT (5. 36 +/- 1.11 mmol/L) than with corn oil (4.51 +/- 0.92 mmol/L; P < 0. 005). In response to the liquid test meal, plasma total cholesterol did not change with either diet but triacylglycerols increased with the 100%-corn oil diet.

CONCLUSIONS

MCT prevents the risk of pancreatitis due to postprandial hypertriglyceridemia but has the inconvenience of raising total cholesterol concentrations in primary hypertriglyceridemic subjects.