Postprandial triglyceridemia predicts cardiovascular events. Niacin might lower postprandial triglycerides by restricting free fatty acids. Immediate-release niacin reduced postprandial triglycerides, but extended-release niacin failed to do so when dosed the night before a fat challenge. The study aims were to determine whether extended-release niacin dosed before a fat challenge suppresses postprandial triglycerides and whether postprandial triglycerides are related to free fatty acid restriction.
A double-blinded, placebo-controlled, random-order crossover experiment was performed, in which healthy volunteers took 2 g extended-release niacin or placebo 1 hour before heavy cream. We sampled blood over 12 hours and report triglycerides and free fatty acid as means±standard deviation for incremental area under the curve (AUC) and nadir.
By combining 43 fat challenges from 22 subjects, postprandial triglycerides incremental AUC was +312±200 mg/dL*h on placebo versus +199±200 mg/dL*h on extended-release niacin (33% decrease, P=.02). The incremental nadir for free fatty acid was −0.07±0.15 mmol/L on placebo versus −0.27±0.13 mmol/L on extended-release niacin (P<.0001), and free fatty acid incremental AUC decreased from +2.9±1.5 mmol/L*h to +1.5±1.5 mmol/L*h on extended-release niacin (20% decrease, P=.0015). The incremental AUC for triglycerides was strongly related to the post-dose decrease in free fatty acid (r = +0.58, P=.0007). Conclusions: Given right before a fat meal, even a single dose of extended-release niacin suppresses postprandial triglyceridemia. This establishes that postprandial triglycerides suppression is an acute pharmacodynamic effect of extended-release niacin, probably the result of marked free fatty acid restriction. Further study is warranted to determine whether mealtime dosing would augment the clinical efficacy of extended-release niacin therapy. The American Journal of Medicine