Dietary intake of branched-chain amino acids in relation to depression, anxiety and psychological distress

BACKGROUND: There is no previous study that examined the association between branched-chain amino acids (BCAAs) intake and odds of psychological disorders. The aim of this study was to investigate the association between dietary BCAAs and odds of psychological disorders including depression, anxiety, and psychological distress in a large sample of Iranian adults. METHODS: In this cross-sectional study on 3175 Iranian adults aged 18–55 years, a validated food frequency questionnaire was used to assess dietary intakes. BCAAs intake was computed by summing up the amount of valine, leucine, and isoleucine intake from all food items in the questionnaire. Psychological health was examined through the use of Iranian validated version of the Hospital Anxiety and Depression Scale (HADS). Psychological distress was assessed using General Health Questionnaire (GHQ). For depression and anxiety, scores of 8 or more on either subscale were considered as psychological disorders and scores of 0–7 were defined as “normal”. In terms of psychological distress, the score of 4 or more was defined as psychological distress. RESULTS: Mean age of study participants was 36.2 ± 7.8 years. Overall, 26.4% (n = 837) of study subjects had depression, 11.9% (n = 378) had anxiety and 20.9% (n = 665) were affected by psychological distress. After controlling for potential confounders, participants in the highest tertile of total BCAAs intake had lower odds of depression (OR: 0.76; 95% CI: 0.60–0.96) and anxiety (OR: 0.66; 95% CI: 0.47–0.91) compared with those in the lowest tertile. Participants in the top tertile of valine intake had a lower odds of depression (OR: 0.76; 95% CI: 0.60–0.96) and anxiety (OR: 0.65; 95% CI: 0.47–0.90) compared with those in the bottom tertile. A significant inverse association was also seen between leucine intake and depression (OR: 0.77; 95% CI: 0.61–0.98) and anxiety (OR: 0.66; 95% CI: 0.47–0.91). In addition, a significant inverse association was observed between isoleucine intake and odds of depression (OR: 0.75; 95% CI: 0.59–0.95) and anxiety (OR: 0.62; 95% CI: 0.45–0.86). There was no significant association between isoleucine intake and odds of psychological distress. CONCLUSION: Evidence indicating an inverse association between dietary intake of BCAAs and odds of depression and anxiety was found. Prospective studies are required to confirm these findings.