The effect of resistant dextrin as a prebiotic on metabolic parameters and androgen level in women with polycystic ovarian syndrome: a randomized, triple-blind, controlled, clinical trial
A 3-month randomized, triple-blind, placebo-controlled clinical trial tested whether resistant dextrin, a prebiotic fiber, could improve the metabolic and hormonal markers behind polycystic ovary syndrome (PCOS). Researchers in Tabriz, Iran screened 150 women and enrolled 62 with a confirmed PCOS diagnosis, ages 18-45 and a BMI between 25 and 40, randomly splitting them into two groups of 31. One group took 20 grams of resistant dextrin (a commercial fiber called NUTRIOSE FM06) dissolved in water daily; the other took a matched 20-gram dose of maltodextrin on the same schedule. Researchers measured blood lipids (LDL, HDL, triglycerides, total cholesterol), fasting blood glucose, a marker of inflammation (hs-CRP), two androgen markers (DHEA-S, and free testosterone), and two clinical symptoms of PCOS including the interval between menstrual cycles and hirsutism (excess hair growth), using the Ferriman-Gallwey scale.
Compared with the placebo group, women taking resistant dextrin showed significant improvements across nearly every marker measured. LDL cholesterol dropped by an average of 29.8 mg/dL more than placebo, triglycerides fell by 38.5 mg/dL more, and total cholesterol fell by 30.0 mg/dL, while HDL rose 5.8 mg/dL over placebo. Fasting blood glucose dropped by 11.2 mg/dL more than placebo, and the inflammatory marker hs-CRP fell significantly. The hormonal markers DHEA-S (p=0.017) and free testosterone (p=0.010) decreased significantly compared to placebo. Menstrual cycles also grew shorter and more regular, and hirsutism scores dropped, both significantly more than placebo. The authors point to cholesterol as one likely link between these changes, as it’s a direct precursor to testosterone and DHEA-S, which may have helped lower androgen levels along with it, alongside likely shifts in gut bacteria such as Lactobacillus and Bifidobacterium that the authors tie to changes in appetite-regulating hormones like ghrelin, leptin, and GLP-1.
The authors name the main limitation as a small sample size and a trial restricted to women with a BMI of 25 or higher, so the results do not speak to what would happen in normal-weight women with PCOS. Tolerability was excellent, with no GI side effects appearing in either group. This trial did not measure gut microbiota directly, so its proposed mechanism is a plausible explanation drawn from other research, not something this study confirmed. Even with those caveats, this is a properly randomized, triple-blind, placebo-controlled trial in women with PCOS, with consistent, statistically significant improvement across metabolic, inflammatory, hormonal, and clinical symptom measures.
