Kinetics of plasma apolipoprotein C-III as a determinant of diet-induced changes in plasma triglyceride levels

To compare the effect of a high monounsaturated fatty acid (MUFA) diet and of a control low-fat diet consumed under ad libitum conditions on plasma apolipoprotein (apo) C-III metabolism.

Randomized, two-arm parallel dietary trial.

Diets were prepared and consumed at the metabolic kitchen of the Department of Food Sciences and Nutrition, and laboratory analyses were performed at the Institute of Nutraceuticals and Functional Foods at Laval University.

Eighteen men were randomly assigned to either the high MUFA diet or the low-fat control diet, which they consumed for 6-7 weeks. Before and after the dietary intervention, subjects received a primed-constant infusion of [5,5,5-D(3)]-L-leucine for 12 h under constant feeding conditions for the determination of plasma apoC-III kinetics.

The high-MUFA diet and the low-fat control diet had no significant impact on plasma apoC-III production rate (PR) or fractional catabolic rate. However, diet-induced variations in plasma apoCIII PR predicted the reduction in plasma triglycerides and apoC-III levels (r=0.85, P<0.01 and r=0.73, P<0.05, respectively) in the high MUFA group only.

These results suggest that the hypotriglyceridemic effect of a high-MUFA diet may be attributable in part to a reduced hepatic production of apoC-III.

This study was supported in part by an operating grant from the Canadian Institutes of Health Research (CIHR), and the Canada Research Chair in Nutrition and Cardiovascular Health (B Lamarche).