Metabolism of diacylglycerol in humans

Obesity resides upstream of the constituents of metabolic syndromes such as diabetes, hypertension, hyperlipidemia, and arteriosclerosis. Postprandial hyperlipidemia is also implicated in atherogenesis. Therefore, factors that influence the body adiposity and the magnitude of postprandial hyperlipidemia have been intensively investigated. Diacylglycerol (DAG) oil, which is defined to contain DAG 80% (w/w) or greater in the present presentation, is an edible oil with similar taste and usability compared with conventional edible oil rich in TAG. Safety of DAG has been widely evaluated and listed as a GRAS (Generally Recognized as Safe) substance by US FDA. The aim of this review was to summarize the metabolism and nutritional functions of DAG based on the data from scientific journals and conference publications. Effect of DAG ingestion on postprandial elevations of serum lipids was investigated in several dosages, food formula, and in subjects in various conditions. Postprandial triglyceride in serum and the chylomicron fraction are significantly smaller after DAG consumption compared with TAG with a similar fatty acid composition in healthy subjects, and was remarkably reduced in subjects with insulin resistance. Long-term DAG ingestion in controlled diet or free-living condition significantly decreased body adiposity and improved type II diabetic complications. A single dose DAG consumption significantly increased fat oxidation as compared to eucaloric TAG ingestion. DAG oil consumption might be beneficial in reducing the risk factors for lifestyle-related diseases such as obesity, visceral obesity, postprandial hyperlipidemia, insulin resistance, and atherosclerosis.