Objectives: We investigated whether a dietary supplement rich in eicosapentaenoic acid (EPA) increases fasting plasma ketones or postprandial ketone responses in healthy young and elderly subjects.
Methods: Ten young (22 +/- 1 y old) and 10 elderly (75 +/- 1 y old) subjects were recruited and participated in two identical study days, one before and one 6 wk after providing an EPA-enriched supplement (1.4 g/d of EPA and 0.2 g/d of docosahexaenoic acid). On the study days, blood samples were collected at fasting and every hour for 6 h after giving a breakfast. Fasting and postprandial plasma beta-hydroxybutyrate (beta-OHB), free fatty acid (FFA), triacylglycerol, glucose, and insulin responses were measured. Fatty acid profiles were assessed in fasting plasma samples before and after the EPA supplement.
Results: After the EPA supplement, postprandial plasma beta-OHB responses decreased by 44% in the young and by 24% in the elderly subjects, in addition to 20% and 34% lower FFA responses in the young and elderly adults, respectively. beta-OHB and FFAs were positively and significantly correlated in young but not in elderly subjects before and after the EPA supplement. In both groups, postprandial plasma triacylglycerols, glucose, and insulin were not significantly different after the intake of the EPA supplement. Before and after the EPA supplement, fasting plasma EPA was 50% higher in the elderly but increased by about five times in both groups after intake of the EPA supplement.
Conclusion: Contrary to our expectations, EPA supplementation lowered postprandial beta-OHB response and, in the elderly subjects, the concentration of postprandial beta-OHB was not lowered after intake of the EPA supplement.