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Low-fat diets and testosterone in men: Systematic review and meta-analysis of intervention studies

Whittaker J, Wu K

The Journal of steroid biochemistry and molecular biology, 2021

206 participants

Abstract

BACKGROUND: Higher endogenous testosterone levels are associated with reduced chronic disease risk and mortality. Since the mid-20th century, there have been significant changes in dietary patterns, and men's testosterone levels have declined in western countries. Cross-sectional studies show inconsistent associations between fat intake and testosterone in men.

METHODS: Studies eligible for inclusion were intervention studies, with minimal confounding variables, comparing the effect of low-fat vs high-fat diets on men's sex hormones. 9 databases were searched from their inception to October 2020, yielding 6 eligible studies, with a total of 206 participants. Random effects meta-analyses were performed using Cochrane's Review Manager software. Cochrane's risk of bias tool was used for quality assessment.

RESULTS: There were significant decreases in sex hormones on low-fat vs high-fat diets. Standardised mean differences with 95 % confidence intervals (CI) for outcomes were: total testosterone [-0.38 (95 % CI -0.75 to -0.01) P = 0.04]; free testosterone [-0.37 (95 % CI -0.63 to -0.11) P = 0.005]; urinary testosterone [-0.38 (CI 95 % -0.66 to -0.09) P = 0.009]; and dihydrotestosterone [-0.3 (CI 95 % -0.56 to -0.03) P = 0.03]. There were no significant differences for luteinising hormone or sex hormone binding globulin. Subgroup analysis for total testosterone, European and North American men, showed a stronger effect [-0.52 (95 % CI -0.75 to -0.3) P < 0.001].

CONCLUSIONS:…

How strong is the evidence?

Evidence Hub reads this as a meta-analysis, done in people. Its evidence level is 1 of 5 (Highest · pooled evidence). Pooled evidence from several studies sits at the top of the evidence pyramid. Reported size: 206 participants or records.

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