Palmitic acid in the sn-2 position of triacylglycerols acutely influences postprandial lipid metabolism

BACKGROUND: The triacylglycerol structure of saturated fats may influence postprandial lipemia. OBJECTIVE: We tested the hypothesis that high-fat meals rich in palmitic acid (16:0) in the sn-2 position decrease lipemia. DESIGN: Postprandial changes in plasma lipids, apolipoprotein B48, and cytokines were compared in healthy men (n = 25) and women (n = 25) by using a randomized crossover design after meals that provided 50 g fat supplied as high-oleic sunflower oil (control), palm olein (PO), interesterified palm olein (IPO), and lard containing 0.6, 9.2, 39.1, and 70.5 mol% 16:0, respectively, at sn-2. RESULTS: The sn-2-rich meals elicited different postprandial responses in plasma concentrations of nonesterified fatty acid (meal x time, P = 0.00014), triacylglycerol (meal x time, P = 0.002), and apolipoprotein B48 (meal x time x sex, P = 0.008). Nonesterified fatty acid concentrations were lower up to 3 h after lard and IPO meals that after control or PO meals. Triacylglycerol increased less steeply after lard and IPO meals than after control and PO meals; the incremental AUCs (iAUCs) were 34% (95% CI: 7%, 124%; P < 0.05) and 26% (95% CI: 16%, 132%; P < 0.05) lower after lard than after control and PO meals, respectively. In men, the maximal increment in apolipoprotein B48 was 14% (95% CI: 3%, 25%; P < 0.05) and 16% (95% CI: 2%, 30%; P < 0.05) lower for lard and IPO, respectively, compared with control. The postprandial iAUC in triacylglycerol was 51% lower in women (P = 0.001) than in men. Plasma IL-6 increased postprandially, but IL-8, TNF-alpha, and E-selectin decreased after all meals. CONCLUSION: Fats with a higher proportion of palmitic acid in the sn-2 position decrease postprandial lipemia in healthy subjects. This trial was registered at controlled-trials.com as ISRCTN20774126.