High dietary intake of branched-chain amino acids is associated with an increased risk of insulin resistance in adults.

BACKGROUND: The aim of this study was to investigate the association between branched-chain amino acid (BCAA) intake and markers of insulin metabolism in adults.

METHODS: This cohort study was conducted within the framework of the Tehran Lipid and Glucose Study on 1205 subjects, aged ≥20 years, who were followed-up for a mean of 2.3 years. Dietary intake of BCAAs, including valine, leucine, and isoleucine, was determined using a valid and reliable food frequency questionnaire. Hyperinsulinemia, β-cell dysfunction, insulin resistance (IR), and insulin insensitivity were determined according to optimal cut-off values. Logistic regression was to estimate the occurrence of IR across tertiles of BCAA intake.

RESULTS: The mean (± SD) age and BCAA intake of participants (43% male) at baseline were 42.7 ± 13.1 years and 13.8 ± 5.1 g/day, respectively. The incidence of hyperinsulinemia, β-cell dysfunction, insulin insensitivity, and IR was 19.5%, 24.0%, 28.0%, and 12.5%, respectively. After adjustment for confounding variables, subjects in the highest tertile for total BCAAs (odds ratio [OR] 1.67; 95% confidence interval [CI] 1.03-2.71), leucine (OR 1.75; 95% CI 1.09-2.82), and valine (OR 1.61; 95% CI 1.01-2.60) intake had a greater risk of incident IR than subjects in the lowest tertile. A higher intake of isoleucine was not associated with risk of incident IR. There was no association of total BCAAs, leucine, isoleucine, and valine intake with the risk of hyperinsulinemia, insulin insensitivity, or β-cell dysfunction.

CONCLUSION: The findings of this study support the hypothesis that higher intakes of BCAAs may have adverse effects on the development of IR.