Branched-Chain Amino Acids and Testosterone in Older Adults With Type 2 Diabetes: Cross-Sectional and Longitudinal Findings From a Post Hoc Analysis of an Amino Acid Supplementation Trial

TL;DR

This study explores how branched-chain amino acids relate to testosterone levels in older adults with type 2 diabetes, finding no direct causal link.

Contribution

The study provides new insights into the relationship between BCAAs and testosterone in T2D patients through a post hoc analysis.

Findings

Baseline serum BCAA levels correlated negatively with testosterone in men but positively in women.

BCAA supplementation did not significantly alter sex hormone levels over 24 weeks.

SHBG levels showed consistent negative correlations with BCAA in both sexes.

Abstract

Introduction: Branched-chain amino acids (BCAAs) and sex hormones share anabolic effects on skeletal muscle. As cross-sectional associations in older adults with type 2 diabetes (T2D) remain unclear, we analyzed potential causal effects of BCAA supplementation in this population.

Methods: This was an exploratory, post hoc analysis of a 24-week amino acid supplementation trial in older adults with T2D (BCAA 8 g or soy protein 7.5 g). Thirty-five participants (22 men, 13 women) were included. Total testosterone (TT), free testosterone (FT), and sex hormone-binding globulin (SHBG) were measured. Spearman’s rank correlation assessed cross-sectional associations, and paired t-tests or Wilcoxon signed-rank tests analyzed pre- and post-supplementation changes.

Results: At baseline, men showed a negative correlation between serum BCAA and TT (ρ = -0.486) but not FT, whereas women showed positive correlations with both (ρ = 0.446 and 0.657). SHBG correlated negatively with BCAA in both sexes (ρ = -0.452 and -0.571). In the BCAA group, no significant changes in sex hormones were observed after supplementation.

Conclusions: Cross-sectional associations between serum BCAA and testosterone levels in older adults with T2D were not observed longitudinally and may not reflect direct relationships, but rather influenced by insulin resistance or SHBG levels related to body composition. As this was an exploratory analysis with a small sample size, the results should be interpreted with caution.

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