Can Your Diet Affect Fertility? New Study Finds Gut-Linked Dietary Score May Hold the Key
- The Female Body
- May 14
- 3 min read
A new study published in Frontiers in Nutrition reveals a nuanced and potentially transformative link between gut health and female fertility. Researchers investigating a novel dietary measure—the Dietary Index for Gut Microbiota (DI-GM)—found that while higher DI-GM scores were generally associated with lower infertility rates, there is a tipping point after which dietary improvements may actually reverse the benefit.
Fertility and the Gut: An Emerging Connection
Infertility currently affects approximately 12.5% of couples of reproductive age worldwide. It's a growing public health concern, ranking just behind cardiovascular disease and cancer in its impact. While ovulatory disorders, polycystic ovary syndrome (PCOS), endometriosis, and other gynecological conditions remain known contributors, attention is increasingly turning to modifiable lifestyle factors - particularly diet and the gut microbiome.
The gut microbiota, a complex ecosystem of microorganisms in the digestive tract, plays a critical role in hormonal regulation, metabolic health, and immune function. All of these processes intersect with reproductive health. Yet until now, the relationship between diet-mediated gut health and fertility had not been clearly quantified.
Inside the Study
Using data from 3,053 women aged 18 to 45 participating in the U.S. National Health and Nutrition Examination Survey (NHANES) between 2013 and 2018, researchers evaluated DI-GM scores based on 24-hour dietary recall questionnaires.
The DI-GM score, developed by Kase et al., reflects dietary habits known to influence gut microbiota composition. It includes 10 “beneficial” food groups—such as avocado, broccoli, chickpeas, green tea, fiber, and fermented dairy—and 4 “unfavourable” ones, including red and processed meats, refined grains, and high-fat diets.
Participants also answered questions related to their reproductive history to assess infertility, defined as failure to conceive after 12 months of unprotected intercourse.
The Surprising Curve of Risk
Initial analyses indicated that women with lower DI-GM scores—indicating poorer gut-related dietary patterns—were more likely to experience infertility. But the relationship wasn’t linear.
A non-linear “inverted U-shaped” association was uncovered, with a critical threshold around a DI-GM score of 8. Up to that point, higher scores corresponded to lower infertility risk. Beyond that, further increases in the score were associated with a surprising increase in infertility risk.
In simpler terms: eating for gut health helps—but too much of a good thing may backfire.
This inflection point remained statistically significant even after adjusting for confounding factors such as age, BMI, smoking status, marital status, and existing medical conditions like diabetes or pelvic inflammatory disease.
What This Means for Women’s Health
The study challenges the notion that “more is always better” when it comes to health-focused diets. It reinforces that balance, not extremism, is essential—especially when navigating complex, body-wide systems like the microbiome and reproductive health.
Interestingly, participants with lower DI-GM scores also had less favourable metabolic indicators, including higher triglycerides and fasting glucose, and lower HDL cholesterol—underscoring the interconnected nature of metabolic and reproductive health.
A New Tool for Reproductive Wellness?
While further longitudinal and intervention-based studies are needed, DI-GM could emerge as a powerful non-invasive screening and intervention tool in the prevention of female infertility. It may also help clinicians personalise dietary advice for patients trying to conceive.
Citation: Zhang, X., Wu, L., Li, H., Zhang, S., & Hua, W. (2025). Association between the dietary index for gut microbiota and female infertility: a cross-sectional study of NHANES 2013–2018. Frontiers in Nutrition, 12. DOI: 10.3389/fnut.2025.1583805
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