Effects of Diet High in Palmitoleic Acid on Serum Lipid Levels and Metabolism

A randomized crossover feeding study with a macadamia nut and oil based high monounsaturated fat diet HIMUFA and a typical American diet high in saturated fat HISAT was conducted on 27 healthy men and women aged 20 to 52. Fatty acid profiles were HIMUFA 22 MUFA, 9 SEA HISAT 11 MUFA, 20 SFA. Each diet was consumed for 8 weeks with a 2-month wash-out. Fasting plasma lipids and lipoprotein subclasses by using NMR or chemical analysis were measured on week 5 and the last two consecutive days of week 8 in each diet period. Isoenergenic substitution with 11 Kcal MUFA for SEA significantly reduced plasma total cholesterol, LDL, HDL, VLDL and TG in NMR. A small but significant reduction in both LDL and HDL particle size in the HIMUFA diet compared to the HISAT diet. These were due to the reductions in larger particles- L3, and HDL2 H5, H4. LDL particle concentrations in parallel with LDL levels were significantly reduced in the HIMUFA diet. The cholesterol lowering effects in total cholesterol and LDL of the HIMUFA diet are very prominent. Macadamia nut based MUFA can be a good alternative for SEA in the diet to lower CHD risks. Further investigations are warranted to evaluate the long-term beneficial effects of HIMUFA on CVD risk.