The Effect of Low Carbohydrate Diet on Polycystic Ovary Syndrome: A Meta-Analysis of Randomized Controlled Trials.
Level 1 - systematic review of randomized trials
Meta-analysis of randomized controlled trials
PubMed 31885557 · doi:10.1155/2019/4386401
What was done
A systematic review and meta-analysis of 8 randomized controlled trials evaluated the effects of a low-carbohydrate diet (LCD) compared to control diets in 327 women with polycystic ovary syndrome (PCOS). Evaluated outcomes included changes in body mass index (BMI), homeostatic model assessment for insulin resistance (HOMA-IR), lipid profiles (TC, LDL-C, HDL-C), and reproductive hormones (FSH, LH, total testosterone, SHBG), alongside subgroup analyses by diet duration and macronutrient composition.
What was found
Compared to control diets, LCD significantly reduced BMI (SMD = -1.04, 95% CI -1.38 to -0.70, P < 0.00001), HOMA-IR (SMD = -0.66, 95% CI -1.01 to -0.30, P < 0.05), total cholesterol (SMD = -0.68, 95% CI -1.35 to -0.02, P < 0.05), and LDL-C (SMD = -0.66, 95% CI -1.30 to -0.02, P < 0.05). In stratified analyses, diets lasting longer than 4 weeks significantly increased FSH (MD = 0.39, 95% CI 0.08 to 0.71, P < 0.05) and SHBG (MD = 5.98, 95% CI 3.51 to 8.46, P < 0.05) and decreased total testosterone (SMD = -1.79, 95% CI -3.22 to -0.36, P < 0.05). Low-fat, low-carbohydrate diets (fat <35%, carbohydrate <45%) showed greater increases in FSH and SHBG than higher-fat low-carbohydrate diets.
Why it matters
This meta-analysis provides pooled clinical trial evidence that carbohydrate restriction can improve both metabolic dysregulation and hormonal markers in women with PCOS, with duration and fat quality influencing endocrine outcomes.
Limits
The total pooled sample size was small (327 patients across 8 studies), resulting in wide confidence intervals for some hormonal and lipid parameters. The abstract does not report specific adherence rates, dietary control specifics, or long-term clinical endpoints such as ovulation or live birth rates.
Cited by
- supports Temporarily restricting carbohydrates improves insulin sensitivity and glucose disposal in women with type 2 diabetes or PCOS.