Energy value and digestibility of dietary oil containing mainly 1,3-diacylglycerol are similar to those of triacylglycerol

Diacylglycerol (DAG) is a component of various vegetable oils. Approximatel y 70% of the DAC in edible oils are in the configuration of 1,3-DAG. We rec ently showed that longterm ingestion of dietary oil containing mainly 1,3-D AC reduces body fat accumulation in humans as compared to triacylglycerol ( TAC) oil with a similar fatty acid composition. As the first step to elucid ate the mechanism for this result, we examined the difference in the bioava ilabilities of both oils by measuring food energy values and digestibilitie s in rats. Energy values of the DAC oil and the TAG oil, measured by bomb c alorimeter, were 38.9 and 39.6 kJ/g, respectively. Apparent digestibility e xpressed according to the formula: (absorbed)x (ingested)(-1) x 100 = (inge sted - excreted in feces) x (ingested)(-1) x 100 for the DAG oil and the TA C oil were 96.3 +/- 0.4 and 96.3 +/- 0.3% (mean +/- SEM), respectively. The similarity in the bioavailabilities of both oils supports the hypothesis t hat the reduced fat accumulation by dietary DAC is caused by the different metabolic fates after the absorption into the gastrointestinal epithelial c ells.