Dietary intake of branched-chain amino acids in relation to general and abdominal obesity

Despite the huge evidence on the link between dietary protein intake and obesity, limited studies have examined the role of individual amino acids in this regard. This study aimed to investigate the association between dietary total and individual BCAAs intake and odds of general and abdominal obesity in a large group of adults.

This cross-sectional study was conducted among 8691 adults aged 18-55 years in Isfahan, Iran. Dietary BCAAs were assessed using a validated dish-based 106-item semi-quantitative food frequency questionnaire (DS-FFQ). Information about weight and waist circumference was collected through a self-reported validated questionnaire. General obesity was defined as body mass index (BMI) ≥ 30 kg/m², and abdominal obesity was defined as waist circumference (WC) ≥ 88 cm for women and ≥ 102 cm for men.

Mean age of study participants was 36.8 ± 8.1 years. Prevalence of general obesity was 9.2% in men and 9.7% in women and that of abdominal obesity was 13.3% and 36.2% in men and women, respectively. We found that participants in the top tertile of total BCAAs intake had higher odds of general obesity compared with those in the bottom tertile (OR: 1.42; 95% CI: 1.09-1.84). Such significant association was seen in men (OR: 1.57; 95% CI: 1.05-2.34), but not in women (OR: 1.33; 95% CI: 0.94-1.89) in our stratified analysis. We found no significant association between total BCAAs intake and odds of abdominal obesity. Stratified by sex, no significant association was observed between total BCAAs intake and odds of abdominal obesity [for men: (OR: 1.10; 95% CI: 0.74-1.65) and for women: (OR: 1.08; 95% CI: 0.84-1.38)]. Assessing the association with individual BCAAs, a significant positive association was observed between dietary intake of valine (OR: 1.42; 95% CI: 1.10-1.84), leucine (OR: 1.43; 95% CI: 1.10-1.86), and isoleucine (OR: 1.42; 95% CI: 1.09-1.84) with general obesity. We observed no significant association between dietary intake of individual BCAAs intake and odds of abdominal obesity.

Dietary BCAAs intake was associated with an increased odds of general obesity, in particular among men. No significant association was observed between dietary BCAAs and abdominal obesity.

Level V, descriptive cross-sectional study.