Low-fat diets and testosterone in men: Systematic review and meta-analysis of intervention studies.
Level 1 - systematic review of randomized trials
Systematic review and meta-analysis of dietary intervention studies
PubMed 33741447 · doi:10.1016/j.jsbmb.2021.105878
What was done
Systematic review and random-effects meta-analysis of intervention studies comparing the effect of low-fat versus high-fat diets on sex hormones in men. Nine databases were searched through October 2020. Six eligible intervention studies involving a total of 206 participants were identified and analyzed using Cochrane Review Manager and the Cochrane risk of bias tool.
What was found
Low-fat diets resulted in significant reductions across several androgens compared to high-fat diets (standardized mean differences): - Total testosterone: SMD -0.38 (95% CI -0.75 to -0.01, P = 0.04) - Free testosterone: SMD -0.37 (95% CI -0.63 to -0.11, P = 0.005) - Urinary testosterone: SMD -0.38 (95% CI -0.66 to -0.09, P = 0.009) - Dihydrotestosterone: SMD -0.30 (95% CI -0.56 to -0.03, P = 0.03) No significant differences were found for luteinising hormone or sex hormone binding globulin. A subgroup analysis of European and North American men showed a stronger decrease in total testosterone: SMD -0.52 (95% CI -0.75 to -0.30, P < 0.001).
Why it matters
This review synthesizes intervention evidence indicating that low-fat dietary patterns reduce circulating androgens in men, providing a possible dietary contributor to observed longitudinal declines in male testosterone levels.
Limits
The total evidence base is small, consisting of only 6 studies and 206 participants. The abstract does not define the exact macronutrient percentages used for low-fat versus high-fat diets, the duration of interventions, or baseline health characteristics of participants.
Cited by
- supports Eating less than 10% of calories from fat, especially when combined with a hypocaloric diet over a long period, can cause endocrine disruption, sleep problems, impaired cell membrane integrity, and long-term health issues.