Diet's total antioxidant capacity and women's health: systematic review and meta-analysis

The primary causes of female mortality often involve diseases related to oxidative stress. Dietary total antioxidant capacity (TAC) evaluates its antioxidant content and potential health effects. This study, registered with PROSPERO (ID: CRD42024427784), explores the association between dietary TAC and women’s health outcomes, including endocrine conditions with gynaecological implications, obstetric outcomes, gynaecological conditions and oncological diseases related to the female reproductive system. We conducted a systematic search in MEDLINE (via PubMed), EMBASE, LILACS and CINAHL for observational studies published up to February 2024 that explored the relationship between dietary TAC and these health conditions. Data were analysed using RevMan 5·4 software. Nineteen studies met the eligibility criteria (sample sizes: 64–3209 women) and examined various conditions, including neoplasms (breast, endometrial and ovarian), bacterial vaginosis, menopause, polycystic ovary syndrome (PCOS), pre-eclampsia (PE), gestational diabetes mellitus (GDM), miscarriage, infertility and inflammation and oxidative stress markers. The meta-analysis identified a significant association between dietary TAC, measured in vitamin C equivalents, and breast cancer, revealing that women with the disease had a lower dietary TAC due to reduced antioxidant intake. Mixed results were found for endometrial cancer, while higher TAC levels were associated with a lower risk of PCOS and infertility. Among postmenopausal women, higher TAC correlated with fewer symptoms such as sleep issues and anxiety. In gestational conditions, higher dietary TAC was linked to a lower risk of miscarriage, GDM and PE. Twelve of the nineteen studies demonstrated significant associations between dietary TAC and the outcomes of interest.