The present study investigated the health effect of two types of diacylglycerol (DG) produced from (i) palm kernel (PK) oil of medium-chain saturated fatty acids and (ii) soy-canola oil (SC) blend of long-chain unsaturated fatty acids in C57BL/6N mice. As compared to diet containing 30% PK triacylglycerol (TG), 16 wk feeding trial on C57BL/6N mice with a diet consisting of 30% PKDG and 30% SCDG significantly (p<0.05) reduced the fat accumulation in epididymal and retroperitoneal regions. Serum glucose, cholesterol, leptin and insulin levels were significantly (p<0.05) suppressed in PKDG- and SCDG-fed mice. In terms of gene expression, PKDG diet induced expression of acyl-CoA synthase long chain (ACSL) and acyl-CoA synthase medium chain mRNA in the small intestine of the mice while SCDG fed mice upregulated ACSL in liver and small intestine. This suggests that the difference in fatty acid composition of DG may potentially induce β-oxidation in different organs in mice. Besides, expression of apolipoprotein B mRNA were reduced in mice fed with PKDG and SCDG, indicating the ability of PKDG and SCDG to reduce LDL levels. In conclusion, structural differences between DG and TG markedly influenced the metabolism of lipids in the body while fatty acid composition has only showed a minor effect.
Practical applications: Medium chain type of DG oil, if proven to have similar effects to long chain type DG in this study, can be incorporated into food for health purposes and can replace conventional cooking oil as healthy functional cooking oil.