Effects of Synbiotic Supplementation and Lifestyle Modifications on Women With Polycystic Ovary Syndrome

Izabela Chudzicka-Strugała; Anna Kubiak; Beata Banaszewska; Barbara Zwozdziak; Martyna Siakowska; Leszek Pawelczyk; Antoni J. Duleba


J Clin Endocrinol Metab. 2021;106(9):2566-2573. 

In This Article

Abstract and Introduction


Context: Polycystic ovary syndrome (PCOS) is the most common endocrinopathy affecting women of reproductive age.

Objective: This study was designed to evaluate effects of lifestyle modifications and synbiotic supplementation on PCOS.

Design: A randomized (1:1) double-blind, placebo-controlled trial.

Setting: Academic hospital.

Patients or Other Participants: Overweight and obese women with PCOS were identified according to the Rotterdam criteria. Evaluations were performed at baseline and repeated after 3 months of treatment.

Intervention: Lifestyle modifications in combination with synbiotic supplementation or placebo.

Main Outcome Measures: Change in body mass index (BMI) and testosterone level.

Results: In the placebo group, a 5% decrease in BMI was accompanied by significant decreases of the waist, hip, and thigh circumferences. The synbiotic group experienced an 8% decrease in BMI, which was significantly greater than that in the control group (P = 0.03) and was accompanied by decreases in the waist, hip, and thigh circumferences. Testosterone did not decrease significantly in the placebo group (decrease of 6%), whereas in the synbiotic group it decreased by 32% (P < 0.0001). The decrease of testosterone was significantly greater in the synbiotic group than in the placebo group (P = 0.016).

Conclusions: Synbiotic supplementation potentiated effects of lifestyle modifications on weight loss and led to significant reduction of serum testosterone.


Polycystic ovary syndrome (PCOS) is the most common endocrine disorder among women of reproductive age; key features of this syndrome are hyperandrogenism and ovulatory dysfunction.[1–4] Obesity is one of the most common comorbidities of PCOS with 2.8-fold higher prevalence than in healthy patients.[5] Furthermore, PCOS is associated with a wide range of metabolic derangements aggravated by obesity including insulin resistance and dyslipidemia.[6–9] Lifestyle modifications such as dietary restrictions and exercise leading to even a modest reduction of body weight have been shown to improve metabolic status and reduce androgen levels in women with PCOS.[10] Another approach to management of obesity is diet based on probiotic or synbiotic supplementation.[11] Probiotics, as defined by the World Health Organization, are live microorganisms that show beneficial effect on the health of the host.[12] Synbiotics refer to dietary supplements composed of probiotics and prebiotics: compounds in food that stimulate growth and activity of probiotics.[13] The mechanism of action of these supplements is most likely from the effects on gut flora.[14]

The concept that probiotics and synbiotics may be beneficial to women with PCOS is based on the Dysbiosis of Gut Microbiota theory proposed by Tremellen and Pierce in 2012.[15] This theory postulated that poor diet contributes to altered bowel bacterial flora, with resultant increase in gut mucosal permeability and hence an increase in the lipopolysaccharides (LPS) in the circulation of women with PCOS. Furthermore, Dysbiosis of Gut Microbiota theory proposed that activation of the immune system by LPS leads to insulin resistance, compensatory hyperinsulinemia, and ultimately increased androgen synthesis by the ovaries. Indeed, consistent with these concepts, we found that women with PCOS have evidence of endotoxemia manifested by elevation of circulating LPS and LPS-binding protein; in addition, these markers of endotoxemia correlated positively with testosterone level and hirsutism.[16]

The meta-analysis of studies evaluating the effects of probiotics in women with PCOS revealed that probiotic supplementation reduced fasting insulin, improved insulin sensitivity, and reduced triglycerides levels.[17] More recently, another meta-analysis demonstrated that probiotics and synbiotics significantly reduced blood sugar, improved insulin sensitivity, and reduced testosterone even in the absence of significant weight loss.[18]

These observations raise the question of whether the use of probiotic/synbiotic supplementation in combination with lifestyle modifications would lead to a greater reduction of weight and testosterone in overweight and obese women with PCOS. The present study was designed to address this question.