The effect of modifying dietary protein and carbohydrate in weight loss on arterial compliance and postprandial lipidemia in overweight women with polycystic ovary syndrome

The Influence of Dietary Patterns on Polycystic Ovary Syndrome Management in Women: A Review of Randomized Controlled Trials with and Without an Isocaloric Dietary Design

Polycystic ovary syndrome (PCOS) is an endocrine disorder that causes cardiometabolic and reproductive disorders in women of reproductive age. Women with PCOS are more likely to have obesity, type 2 diabetes mellitus, and cardiovascular disease. There is an inconclusive consensus on which dietary modification could be most effective in PCOS prevention and treatment. This review aimed to examine the effects of diverse dietary patterns on PCOS in women according to randomized controlled trials (RCTs) with and without an isocaloric dietary design. A literature search was performed in the PubMed®®/MEDLINE®® database up to 14 November 2024. A total of 21 RCTs were reviewed after screening the records, including 15 RCTs with a calorie-restricted dietary design and 6 RCTs with a non-calorie-restricted dietary design. This review found beneficial effects of the calorie-restricted Dietary Approaches to Stop Hypertension (DASH) diet on weight loss and glucose control in women with PCOS in four RCTs with an isocaloric dietary design. The calorie-restricted low-glycemic index (GI) diets from three RCTs and high-protein diets from four RCTs with an isocaloric dietary design showed no significant differences in anthropometric parameters, glucose control, lipids, and gonadal parameters compared with the control diet in women with PCOS. Non-calorie-restricted low-carbohydrate diets from four RCTs with an isocaloric dietary design showed similar results to the calorie-restricted low-GI diets and high-protein diets. However, the existing number of RCTs is insufficient to conclude the association between dietary patterns and PCOS in women. Further, well-designed dietary intervention studies are needed to assess the role of dietary patterns in PCOS beyond calorie restriction.

The Impact of Diet-Induced Weight Loss on Inflammatory Status and Hyperandrogenism in Women with Polycystic Ovarian Syndrome (PCOS)-A Systematic Review and Meta-Analysis

Background: Currently, the primary strategy for addressing polycystic ovarian syndrome (PCOS) involves lifestyle modifications, with a focus on weight loss. The purpose of this meta-analysis was to assess the impact of weight loss through dietary interventions on inflammatory status and hyperandrogenism in PCOS women. Methods: A comprehensive search was conducted to identify randomised controlled trials (RCTs) and cohort studies assessing the impact of diet-induced weight loss on circulating inflammatory markers (CRP, IL-6, IL-1β, TNF-α), androgens (testosterone, androstenedione), SHBG, and luteinising hormone (LH) in PCOS women. The quality and risk of bias of the included studies were assessed using the Cochrane Collaboration's tool for RCTs and the Newcastle-Ottawa Scale for cohort studies. Data were entered into RevMan software v5.9 for the calculation of standard mean difference (SMD) and the 95% confidence interval (95%CI) of circulating inflammatory markers, androgens, and LH between baseline and post-weight loss values. Results: Eleven studies (n = 323) were eligible for the systematic review, of which nine (n = 286) were included in the meta-analysis. Pooled analysis of data revealed a statistically significant decrease in circulating CRP (SMD 0.39, 95%CI 0.22, 0.56; 9 studies, n = 286), IL-6 (SMD 0.37, 95%Cl, 0.12, 0.61; 3 Studies, n = 140), TNF-α (SMD 0.30, 95%Cl, 0.07, 0.53; 4 Studies, n = 162), androstenedione (SMD 0.36, 95%Cl, 0.13, 0.60; 4 studies, n = 147) and LH (SMD 0.30, 95% Cl, 0.09, 0.51; 5 studies, n = 197) after weight loss compared to baseline levels among PCOS women. A meta-analysis of five studies (n = 173) showed a statistically significant increase in circulating SHBG after weight loss compared to baseline levels (SMD -0.43, 95%Cl, -0.65, -0.21). Conclusions: These findings suggest that weight loss induced by dietary interventions seems to improve PCOS-related chronic inflammation and hyperandrogenism. The possible causative relationship between the improvement in inflammation and hyperandrogenism remains to be determined.

Effects of high-protein diets on the cardiometabolic factors and reproductive hormones of women with polycystic ovary syndrome: a systematic review and meta-analysis

The optimal dietary regimen for polycystic ovary syndrome (PCOS) has not been identified. High-protein diets (HPDs) are effective for weight control in individuals with metabolic abnormalities, but no systematic meta-analyses have yet summarised the effects of HPDs on PCOS. Seven electronic databases were searched from inception to 30 April 2023, and studies comparing the effects of HPDs and other diets on the anthropometrics, metabolic factors, and hormonal profiles for PCOS were identified. Data were pooled using random-effects models and expressed as weighted mean differences and 95% confidence intervals. The risk of bias was assessed by Cochrane Collaboration tool. Eight trials involving 300 women with PCOS were included. Compared with isocaloric balanced diets (BDs), HPDs significantly reduced fasting insulin (-2.69 μIU/mL, 95% CI [-3.81, -1.57], P < 0.0001, I2 = 46%) and homoeostatic model assessment for insulin resistance (HOMA-IR-0.41, 95% CI [-0.80, -0.02], P = 0.04, I2 = 94%) in women with PCOS. However, HPDs and BDs had comparable effects on weight loss, abdominal adiposity, lipid profiles, and reproductive hormones (all P ≥ 0.05). HPDs may benefit women with PCOS in terms of improving insulin resistance, supporting for their use as one of the dietary management options for PCOS, however further RCTs in larger and broader settings are required to confirm these observations and investigate the mechanism behind it.

Lifestyle management in polycystic ovary syndrome - beyond diet and physical activity

Polycystic ovary syndrome (PCOS) is a common condition affecting reproductive-aged women with reproductive, metabolic and psychological consequences. Weight and lifestyle (diet, physical activity and behavioural) management are first-line therapy in international evidence-based guidelines for PCOS. While these recommend following population-level diet and physical activity guidelines, there is ongoing interest and research in the potential benefit of including psychological and sleep interventions, as well as a range of traditional, complimentary and integrative medicine (TCIM) approaches, for optimal management of PCOS. There is limited evidence to recommend a specific diet composition for PCOS with approaches including modifying protein, carbohydrate or fat quality or quantity generally having similar effects on the presentations of PCOS. With regards to physical activity, promising evidence supports the provision of vigorous aerobic exercise, which has been shown to improve body composition, cardiorespiratory fitness and insulin resistance. Psychological and sleep interventions are also important considerations, with women displaying poor emotional wellbeing and higher rates of clinical and subclinical sleep disturbance, potentially limiting their ability to make positive lifestyle change. While optimising sleep and emotional wellbeing may aid symptom management in PCOS, research exploring the efficacy of clinical interventions is lacking. Uptake of TCIM approaches, in particular supplement and herbal medicine use, by women with PCOS is growing. However, there is currently insufficient evidence to support integration into routine clinical practice. Research investigating inositol supplementation have produced the most promising findings, showing improved metabolic profiles and reduced hyperandrogenism. Findings for other supplements, herbal medicines, acupuncture and yoga is so far inconsistent, and to reduce heterogeneity more research in specific PCOS populations, (e.g. defined age and BMI ranges) and consistent approaches to intervention delivery, duration and comparators are needed. While there are a range of lifestyle components in addition to population-recommendations for diet and physical activity of potential benefit in PCOS, robust clinical trials are warranted to expand the relatively limited evidence-base regarding holistic lifestyle management. With consumer interest in holistic healthcare rising, healthcare providers will be required to broaden their knowledge pertaining to how these therapies can be safely and appropriately utilised as adjuncts to conventional medical management.

Dietary Modification for Reproductive Health in Women With Polycystic Ovary Syndrome: A Systematic Review and Meta-Analysis

Objective

Diet has been reported as the first-line management of polycystic ovary syndrome (PCOS). However, the relationship between diet and fertility in PCOS is still controversial. This meta-analysis aimed to evaluate whether diet could promote reproductive health in women with PCOS while providing evidence-based nutrition advice for clinical practice.

Methods

Seven databases, including Cochrane Central Register of Controlled Trials, PubMed, Embase, Web of Science, and some Chinese database, were searched up to January 31, 2021. Randomized controlled trials evaluating the effects of diet in women with PCOS were included. Based on a preregistered protocol (PROSPERO CRD42019140454), the systematic review was performed following the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. Two reviewers made study selection, data extraction and bias assessment independently. Risk ratios and mean difference with 95% confidence intervals were assessed by a random-effects model. Statistical heterogeneity within comparisons was evaluated by Cochran's Q test and quantified by the I-squared (I2 ) statistic.

Results

Twenty RCTs with 1113 participants were included. Results showed diet significantly related to improved fertility outcomes (increasing clinical pregnancy, ovulation and menstrual regularity rate; reducing miscarriage rate), reproductive endocrine [increasing sex hormone-binding globulin (SHBG); decreasing Anti-Müllerian Hormone (AMH), free androgen index (FAI), total testosterone (T)] and clinical hyperandrogenism (hirsutism assessed by Ferriman-Gallwey score) in PCOS. Specifically, subgroup analyses indicated low-carbohydrate diets were superior in optimizing reproductive outcomes and calorie restriction was critical in ameliorating hyperandrogenism. Additionally, the positive effects were associated with the treatment duration. The longer the duration, the greater the improvement was.

Conclusion

Overall, diet is an effective intervention for improving fertility health, thus professional and dynamic dietary advice should be offered to all PCOS patients, based on the changeable circumstances, personal needs and expectations of the individuals.

Effect of Diet on Insulin Resistance in Polycystic Ovary Syndrome

OBJECTIVE

The effect of diet on insulin resistance (IR) in polycystic ovary syndrome (PCOS) is controversial. Thus, we conducted this systematic review and meta-analysis to evaluate whether diet could reduce IR in women with PCOS while providing optimal and precise nutrition advice for clinical practice.

DESIGN

The search was conducted in 8 databases through June 30, 2019. The systematic review was performed following the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. A random-effects model was adopted to calculate the overall effects.

RESULTS

A total of 19 trials (1193 participants) were included. The analysis showed that diet was significantly related to improvements in IR and body composition (eg, homeostasis model assessment of insulin resistance, fasting insulin, fasting plasma glucose, body mass index [BMI], weight, and waist circumference) in PCOS patients. The Dietary Approaches to Stop Hypertension diet and calorie-restricted diets might be the optimal choices for reducing IR and improving body composition, respectively, in the PCOS population. Additionally, the effects were associated with the course of treatment. The longer the duration, the greater the improvement was. Compared with metformin, diet was also advantageous for weight loss (including BMI and weight) and had the same effects on insulin regulation.

CONCLUSION

Overall, our findings suggest that diet is an effective, acceptable and safe intervention for relieving IR, and professional dietary advice should be offered to all PCOS patients.

Lifestyle changes in women with polycystic ovary syndrome

BACKGROUND

Polycystic ovary syndrome (PCOS) affects 8% to 13% of reproductive-aged women and is associated with reproductive and metabolic dysfunction. Obesity worsens the presentation of PCOS and weight management (weight loss, maintenance or prevention of excess weight gain) is proposed as an initial treatment strategy, best achieved through lifestyle changes incorporating diet, exercise and behavioural interventions.

OBJECTIVES

To assess the effectiveness of lifestyle treatment in improving reproductive, anthropometric (weight and body composition), metabolic and quality of life factors in PCOS.

SEARCH METHODS

We searched the Cochrane Gynaecology and Fertility Specialised Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, PsycINFO, CINAHL and AMED (date of last search March 2018). We also searched controlled trials registries, conference abstracts, relevant journals, reference lists of relevant papers and reviews, and grey literature databases, with no language restrictions applied.

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing lifestyle treatment (diet, exercise, behavioural or combined treatments) to minimal or no treatment in women with PCOS.

DATA COLLECTION AND ANALYSIS

Two authors independently selected trials, assessed evidence quality and risk of bias, and extracted data. Our primary outcomes were live birth, miscarriage and pregnancy. We used inverse variance and fixed-effect models in the meta-analyses. We reported dichotomous outcomes as an odds ratio and continuous outcomes as a mean difference (MD) or standardised mean difference (SMD).

MAIN RESULTS

We included 15 studies with 498 participants. Ten studies compared physical activity to minimal dietary and behavioural intervention or no intervention. Five studies compared combined dietary, exercise and behavioural intervention to minimal intervention. One study compared behavioural intervention to minimal intervention. Risk of bias varied: eight studies had adequate sequence generation, seven had adequate clinician or outcome assessor blinding, seven had adequate allocation concealment, six had complete outcome data and six were free of selective reporting. No studies assessed the fertility primary outcomes of live birth or miscarriage. No studies reported the secondary reproductive outcome of menstrual regularity, as defined in this review.Lifestyle intervention may improve a secondary (endocrine) reproductive outcome, the free androgen index (FAI) (MD -1.11, 95% confidence interval (CI) -1.96 to -0.26, 6 RCTs, N = 204, I2 = 71%, low-quality evidence). Lifestyle intervention may reduce weight (kg) (MD -1.68 kg, 95% CI -2.66 to -0.70, 9 RCTs, N = 353, I2 = 47%, low-quality evidence). Lifestyle intervention may reduce body mass index (BMI) (kg/m2) (-0.34 kg/m2, 95% CI -0.68 to -0.01, 12 RCTs, N = 434, I2= 0%, low-quality evidence). We are uncertain of the effect of lifestyle intervention on glucose tolerance (glucose outcomes in oral glucose tolerance test) (mmol/L/minute) (SMD -0.02, 95% CI -0.38 to 0.33, 3 RCTs, N = 121, I2 = 0%, low-quality evidence).

AUTHORS' CONCLUSIONS

Lifestyle intervention may improve the free androgen index (FAI), weight and BMI in women with PCOS. We are uncertain of the effect of lifestyle intervention on glucose tolerance. There were no studies that looked at the effect of lifestyle intervention on live birth, miscarriage or menstrual regularity. Most studies in this review were of low quality mainly due to high or unclear risk of bias across most domains and high heterogeneity for the FAI outcome.

Luteal function during the estrous cycle in arginine-treated ewes fed different planes of nutrition

Functions of corpus luteum (CL) are influenced by numerous factors including hormones, growth and angiogenic factors, nutritional plane and dietary supplements such as arginine (Arg), a semi-essential amino acid and precursor for proteins, polyamines and nitric oxide (NO). The aim of this study was to determine if Arg supplementation to ewes fed different planes of nutrition influences: (1) progesterone (P4) concentrations in serum and luteal tissue, (2) luteal vascularity, cell proliferation, endothelial NO synthase (eNOS) and receptor (R) soluble guanylate cyclase β protein and mRNA expression and (3) luteal mRNA expression for selected angiogenic factors during the estrous cycle. Ewes (n = 111) were categorized by weight and randomly assigned to one of three nutritional planes: maintenance control (C), overfed (2× C) and underfed (0.6× C) beginning 60 days prior to onset of estrus. After estrus synchronization, ewes from each nutritional plane were assigned randomly to one of two treatments: Arg or saline. Serum and CL were collected at the early, mid and late luteal phases. The results demonstrated that: (1) nutritional plane affected ovulation rates, luteal vascularity, cell proliferation andNOS3,GUCY1B3, vascular endothelial growth factor (VEGF) andVEGFR2mRNA expression, (2) Arg affected luteal vascularity, cell proliferation andNOS3,GUCY1B3,VEGFandVEGFR2mRNA expression and (3) luteal vascularity, cell proliferation and the VEGF and NO systems depend on the stage of the estrous cycle. These data indicate that plane of nutrition and/or Arg supplementation can alter vascularization and expression of selected angiogenic factors in luteal tissue during the estrous cycle in sheep.

Consensus on women's health aspects of polycystic ovary syndrome (PCOS): the Amsterdam ESHRE/ASRM-Sponsored 3rd PCOS Consensus Workshop Group

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder in females, with a high prevalence. The etiology of this heterogeneous condition remains obscure, and its phenotype expression varies. Two widely cited previous ESHRE/ASRM sponsored PCOS consensus workshops focused on diagnosis (published in 2004) and infertility management (published in 2008), respectively. The present third PCOS consensus report summarizes current knowledge and identifies knowledge gaps regarding various women's health aspects of PCOS. Relevant topics addressed-all dealt with in a systematic fashion-include adolescence, hirsutism and acne, contraception, menstrual cycle abnormalities, quality of life, ethnicity, pregnancy complications, long-term metabolic and cardiovascular health, and finally cancer risk. Additional, comprehensive background information is provided separately in an extended online publication.