The cooking oil and the margarine containing medium-chain fatty acid (MCFA) have been approved as Foods for Specified Health Use (FOSHU). We introduce recent researches on the nutritional characteristics of MCFA in this review. We conclude that intake of 5-10g of medium-chain triacylglycerols (MCT) suppresses body fat accumulation compared with intake of LCT in Japanese with a high BMI of ≥23 kg/m2. In addition, it is suggested that intake of 14g of medium- and long-chain triacylglycerols (MLCT) containing 1.7 g of MCFA is useful for suppressing body fat accumulation compared with intake of LCT in Japanese individuals. With regard to the mechanism responsible for the suppressive effect on body fat accumulation, we found that the change of serum triacylglycerol of subjects with BMI ≥23 kg/m2 receiving 5-10g of MCT lower than those receiving LCT. Furthermore, intake of MCT at a daily dose of 5-10 g led to higher DIT compared with intake of LCT. Accordingly, the decrease in body weight and body fat weight following MCT intake in subjects with BMI ≥23 kg/m2 might be due largely to the difference in LCT metabolism between these subjects and those with BMI <23 kg/m2. We consider that the difference in BMI greatly affects the oxidation and synthesis of fat in the liver and other tissues, thus explaining the observed difference in the body fat accumulation profile.
