Association of dietary intake of branched-chain amino acids with long-term risks of CVD, cancer and all-cause mortality

OBJECTIVES: We aimed to investigate the associations between dietary branched-chain amino acids (BCAA) intake and long-term risks of CVD, cancer and all-cause mortality in nationwide survey participants aged ≥ 18. DESIGN: This was a prospective cohort study. Dietary intakes of BCAA (leucine, isoleucine and valine) were determined from the total nutrient intake document. The main outcomes were CVD, cancer and all-cause mortality. SETTING: A nationally representative sample of US adults were recruited by the National Center for Health Statistics (NCHS) from 1988 to 1994. PARTICIPANTS: A total of 14 397 adults aged ≥ 18 who participated in the United States National Health and Nutrition Examination Survey III (NHANES III) were included. RESULTS: During 289 406 person-years of follow-up, we identified 4219 deaths, including 1133 from CVD and 926 from cancer. After multivariate adjustment, the hazard ratios (95 % confidence intervals) of all-cause mortality in the highest dietary BCAA and isoleucine intake quintile (reference: lowest quintiles) were 0·68 (0·48, 0·97) and 0·68 (0·48, 0·97), respectively. Each one-standard-deviation increase in total dietary BCAA or isoleucine intake was associated with an 18 % or 21 % decrease in the risk of all-cause mortality, respectively. The serum triglyceride (TAG) concentration was found to modify the association between the dietary BCAA intake and all-cause mortality (P (for interaction) = 0·008). CONCLUSIONS: In a nationally representative cohort, higher dietary intakes of BCAA and isoleucine were independently associated with a lower risk of all-cause mortality, and these associations were stronger in participants with higher serum TAG concentrations.