COMPARISON OF THE EFFECTS OF MEDIUM-CHAIN TRIACYLGLYCEROLS, PALM OIL,AND HIGH OLEIC-ACID SUNFLOWER OIL ON PLASMA TRIACYLGLYCEROL FATTY-ACIDS AND LIPID AND LIPOPROTEIN CONCENTRATIONS IN HUMANS

Although medium-chain triacylglycerols (MCTs, composed of medium-chain fatty acids 8:0 and 10:0) have long been described as having neutral effects on serum cholesterol concentrations, experimental evidence sup porting this claim is limited. In a randomized, crossover, metabolic-w ard study, we compared the lipid effects of a natural food diet supple mented with either MCTs, palm oil, or high oleic acid sunflower oil in nine middle-aged men with mild hypercholesterolemia. Rather than havi ng a neutral effect, MCT oil produced total cholesterol concentrations that were not significantly different from those produced by palm oil (MCT oil: 5.87 +/- 0.75 mmol/L; palm oil: 5.79 +/- 0.72 mmol/L) but s ignificantly higher than that produced by high oleic acid sunflower oi l (5.22 +/- 0.52 mmol/L). Low-density-lipoprotein (LDL)-cholesterol co ncentrations paralleled those of total cholesterol. MCT oil tended to result in higher triacylglycerol concentrations than either palm oil o r high oleic acid sunflower oil, but this difference was not significa nt. There were no differences in high-density-lipoprotein cholesterol concentrations. The palmitic acid and total saturated fatty acid conte nt of plasma triacylglycerols in the MCT-oil diet was not significantl y different from that in the palm oil diet. On the basis of percentage of energy, this study suggests that medium-chain fatty acids have one -half the potency that palmitic acid has at raising total and LDL-chol esterol concentrations.