Branched-chain Amino Acid Intake and the Risk of Diabetes in a Japanese Community

Dietary supplementation with branched-chain amino acids (BCAAs), including leucine, isoleucine, and valine, has shown potential benefits for the metabolic profile. However, higher blood BCAA levels have been associated with insulin resistance. To our knowledge, there has been no study on dietary BCAAs and the risk of diabetes. We examined the association between BCAA intake and risk of diabetes in a population-based cohort study in Japan. A totalof 13,525residents ofTakayamaCity,Japan,whoenrolledin acohortstudyin1992respondedto afollow-up questionnaire seeking information about diabetes in 2002. Diet at baseline was assessed by means of a validated food frequency questionnaire. A high intake of BCAAs in terms of percentage of total protein was significantly associated with a decreased risk of diabetes in women after controlling for covariates; the hazard ratio for the highest tertile versus the lowest was 0.57 (95% confidence interval: 0.36, 0.90; P-trend = 0.02). In men, leucine intake was significantly marginally associated with the risk of diabetes; the hazard ratio for the highest tertile versus the lowest was 0.70 (95% confidence interval: 0.48, 1.02; P-trend = 0.06). Data suggest that a high intake of BCAAs may be associated with a decrease in the risk of diabetes. amino acids; branched-chain amino acids; cohort studies; diabetes; diet