Dietary Alpha-linolenic Acid-rich Diacylglycerols Reduce Body Weight Gain Accompanying the Stimulation of Intestinal Beta-oxidation and Related Gene Expressions in C57BL/KsJ-db/db Mice

Dietary fat contributes to the development of obesity. We examined the effect of dietary diacylglycerol (DG), which is a minor component of edible oils, on the development of obesity and expression of genes involved in energy homeostasis in C57BL/KsJ-db/db mice. Mice were fed diets containing either 14 g/100 g (%) triacylglycerol (TG), 10% TG + 4% alpha-linolenic acid-rich TG (ALATG), or 10% TG + 4% alpha-linolenic acid-rich diacylglycerol (ALADG) for 1 mo. Mice fed ALADG, but not ALATG had less body weight gain and higher rectal temperature than the TG-fed controls. These effects were accompanied by up-regulation of acyl-CoA oxidase, medium-chain acyl-CoA dehydrogenase, fatty acid binding protein, and uncoupling protein (UCP)-2 mRNA and beta-oxidation activity in the small intestine. In contrast, the treatments did not affect beta-oxidation and related gene expressions in the liver or UCP-3 mRNA level in skeletal muscle. These results indicate that stimulation of lipid metabolism in the small intestine might be closely related to the antiobesity and thermogenic effects of dietary DG. In addition, structural differences between DG and TG, not variations in the composition of fatty acids, are responsible for the different effects of the lipids.