Increased Plasma Availability of L-arginine in the Postprandial Period Decreases the Postprandial Lipemia in Older Adults

Abstract Objective Older adults have exaggerated postprandial lipemia, which increases their risk for cardiovascular disease. We sought to determine the effects of increased plasma l -arginine (L-ARG) availability on the oxidation of ingested fat (enriched with [1,1,1- 13 C]-triolein) and plasma triacylglycerol (TG) concentrations during the postprandial period in older subjects. Methods On one day, eight healthy subjects (67.8 ± 1.3 y old) received an intravenous infusion of L-ARG during the first hour of the postprandial period (L-ARG trial), while on a separate day, and in a randomized order, they received saline (control trial). Results The 8-h area under the plasma concentration–time curve describing the postprandial plasma TG concentrations was considerably lower in the L-ARG trial than in the control trial (−4 ± 21 versus 104 ± 21 mg ∙ dL −1 ∙ h −1 , P P −1 ∙ h −1 , P Conclusion Increasing the plasma L-ARG availability during the postprandial period decreases the postprandial lipemia in older adults, in association with a decrease in the postprandial contribution of ingested lipids into TGs of the plasma small TG-rich lipoproteins.