Vitamin E supplementation improves testosterone, glucose- and lipid-related metabolism in women with polycystic ovary syndrome: a meta-analysis of randomized clinical trials

Abstract

Aim

This systematic review and meta-analysis assessed the effect of vitamin E supplementation on testosterone, glucose, lipid profile, pregnancy rate, hirsutism, and body mass index (BMI) in women with polycystic ovary syndrome (PCOS).

Methods

A multi-database search was performed from inception to January 2022 for randomized controlled trials (RCTs) reporting the effects of vitamin E supplementation with or without another nutritional supplement on women with PCOS. A random-effects model was used to obtain mean differences (MDs) and its 95% confidence intervals (95%CI). Evidence certainty was assessed with GRADE methodology.

Results

We meta-analyzed eight RCTs reporting vitamin E supplementation alone or combined with other individual substances like omega-3, vitamin D3, or magnesium oxide in adult women ≤40 years old with PCOS. Vitamin E supplementation reduced fasting glucose (MD: −1.92 mg/dL, 95%CI: −3.80 to −0.05), fasting insulin (MD: −2.24 µIU/mL, 95%CI: −3.34 to −1.14), HOMA-IR (MD: −0.42, 95%CI: −0.65 to −0.19), total cholesterol (MD: −18.12 mg/dL, 95%CI: −34.37 to −1.86), LDL-cholesterol (MD: −15.92 mg/dL, 95%CI: −29.93 to −1.90), triglycerides (MD: −20.95 mg/dL, 95%CI: −37.31 to −4.58), total testosterone (MD: −0.42 ng/mL, 95%CI: −0.55 to −0.29), and increased sex hormone-binding globulin (MD: 7.44 nmol/L, 95%CI: 2.68 to 12.20). However, it had no impact on female sex hormones, HDL-cholesterol, BMI, and hirsutism. Two RCTs assessed pregnancy and implantation rates with inconsistent results. The certainty of the evidence was very low to moderate.

Conclusion

Vitamin E supplementation improves glucose, lipid, and androgenic-related biomarkers in women with PCOS.

摘要

目的：本系统综述和荟萃分析评估了补充维生素E对多囊卵巢综合征（PCOS）女性睾酮、葡萄糖、脂质、妊娠率、多毛症和体重指数（BMI）的影响。

方法：我们在多个数据库检索所有截止2022年1月关于补充维生素E（联合或不联合其他营养素）对多囊卵巢综合征患者影响的随机对照试验（RCTs）。采用随机效应模型获得均数差（MDs）及95%置信区间（95%CI）。采用GRADE系统对证据质量进行分级。

结果：我们对8项≤40岁成年PCOS患者的RCTs进行了荟萃分析, 包括单用维生素E或分别联用Ω-3、维生素D3或氧化镁。补充维生素E可降低空腹血糖（MD：-1.92 mg/dL, 95%CI：-3.80至-0.05）、空腹胰岛素（MD：-2.24μIU/mL, 95%CI：-3.34至-1.14）、HOMA-IR（MD：-0.42, 95%CI：-0.65至-0.19）、总胆固醇（MD：-18.12mg/dL, 95%CI：-34.37至-1.86）、低密度脂蛋白胆固醇（MD：-15.92mg/dL, 95%CI：-29.93至-1.90）、总睾酮（MD：-0.42ng/mL, 95%CI：-0.55至-0.29）以及性激素结合球蛋白（MD：7.44 nmol/L, 95%CI：2.68至12.20)。但是对女性性激素、高密度脂蛋白胆固醇、BMI和多毛症没有影响。两项评估妊娠率和着床率的随机对照试验结果不一致。证据分级为极低质量至中等质量。

结论：补充维生素E可改善PCOS患者葡萄糖、脂质和雄激素相关的生物标志物。

Keywords:

• Glucose
• insulin
• lipids
• meta-analysis
• polycystic ovary syndrome
• vitamin E

关键词:

• 葡萄糖
• 胰岛素
• 脂质
• 荟萃分析
• 多囊卵巢综合征
• 维生素E0

Author contributions

SYV, KOR and CAAR conceived the study. SYV and KOR completed the PROSPERO protocol. All authors contributed to the study design. SYV, KOR and CAAR carried out the data collection and guaranteed data integrity. CAAR and VBZ performed the statistical analysis. SYV and KOR wrote the first draft. All authors contributed to the revision and finalization of the manuscript. CAAR, WNG, VBZ and FRPL guaranteed all aspects of the reliability and freedom from bias of the presented data and the discussed interpretation.

Disclosure statement

The authors report no conflicts of interest and alone are responsible for the content and the writing of the article.

Funding

The author(s) reported there is no funding associated with the work featured in this article.

Data availability statement

The data that support the findings of this study are available on request from the corresponding author.