Associations of Dietary Index for Gut Microbiota and Flavonoid Intake With Female Infertility in the United States

Abstract

This study aimed to investigate the associations between a dietary index for gut microbiota (DI-GM), flavonoid intake, and female infertility, while exploring age-specific differences in these relationships to identify potential dietary strategies for female infertility prevention. This cross-sectional study focused on female participants aged 18–45 years, with data obtained from the 2017–2018 cycle of the National Health and Nutrition Examination Survey (NHANES). Weighted multivariable logistic regression models were employed to examine the associations between DI-GM, flavonoid intake, and self-reported female infertility. Age-stratified analyses were performed to evaluate whether these associations varied across reproductive life stages. Higher DI-GM scores were significantly associated with reduced infertility risk (aOR = 0.30, 95% CI: 0.13–0.71, p = 0.006), with the strongest protective effects observed in women aged < 35 years (Q3: aOR = 0.13, 95% CI: 0.03–0.58, p = 0.007; Q4: aOR = 0.27, 95% CI: 0.09–0.77, p = 0.015). Beneficial gut microbiota scores also showed a protective effect (aOR = 0.75, 95% CI: 0.57–0.98, p = 0.036). Among women aged ≥ 35 years, moderate flavonoid intake (Q2) showed a significant inverse association with female infertility risk (aOR = 0.19, 95% CI: 0.06–0.66, p = 0.009). Our findings reveal novel evidence that higher DI-GM scores and moderate flavonoid intake are significantly linked to a lower risk of female infertility, with age-specific patterns observed. Higher DI-GM scores showed significant protective effects in younger women (< 35 years), while moderate flavonoid intake was protective in women aged ≥ 35 years. These findings underscore the potential of personalized dietary strategies targeting gut microbiota composition and flavonoid intake as cost-effective approaches for female infertility prevention and management across different reproductive life stages.