PLANT MONOTERPENES DO NOT RAISE PLASMA HIGH-DENSITY-LIPOPROTEIN CONCENTRATIONS IN HUMANS

Background: Low plasma concentrations of HDLs are associated with an i ncreased risk of coronary artery disease. Two uncontrolled studies sug gested that plant monoterpenes may have substantial HDL-cholesterol-el evating activity in humans. Each study used a proprietary mixture of 6 monoterpenes in olive oil. Objective: The present study was undertake n to test more rigorously the hypothesis that monoterpenes raise HDL c oncentrations in men with hypoalphalipoproteinemia. Design: A double-b lind, placebo-controlled crossover design was used. Twenty-four men ag ed 58-68 y ((x) over bar: 62.3 y) with plasma HDL cholesterol <1.1 mmo l/L, plasma triacylglycerols <3.5 mmol/L, and plasma total cholesterol <5.5 mmol/L at recruitment were randomly assigned to 6 capsules daily of a proprietary mixture of 6 monoterpenes in olive oil or 6 capsules daily of olive oil alone for 24 wk, followed by a washout period of 8 wk, and then the alternative capsules for 24 wk. Results: Five men dr opped out. In the others, compliance was excellent as judged by capsul e counts and urinary menthol glucuronide concentrations. No significan t effects were observed on plasma HDL-cholesterol or apolipoprotein A- I concentrations, nor on plasma triacylglycerol, LDL-cholesterol, or a polipoprotein B concentrations. Conclusions: Plant monoterpenes have n o HDL-elevating activity of potential value for coronary artery diseas e prevention.