The Role of the Mediterranean Diet in Assisted Reproduction: A Literature Review Original paper

What was reviewed?

This narrative review synthesized evidence from seven observational studies addressing the association between preconception adherence to the Mediterranean Diet and outcomes in assisted reproductive technologies (ART), such as in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI). The review emphasized the Mediterranean Diet as a holistic dietary pattern, high in plant-based foods, olive oil, and moderate fish/poultry, with low red/processed meat, rather than focusing on individual food components. Study selection spanned publications up to July 2023, with data extracted on Mediterranean Diet adherence (mainly via various food frequency questionnaires and scoring systems), ART protocol details, and primary fertility and ART outcomes, including oocyte and embryo quality, clinical pregnancy, live birth rates, and ovarian response. The review critically appraised methodological strengths and limitations, particularly the heterogeneity in Mediterranean Diet assessment and ART protocols, and lack of standardization across studies.

Who was reviewed?

The review encompassed 2,321 women experiencing infertility and undergoing ART, with individual study sample sizes ranging from 161 to 590 participants. Most participants were aged between their late 20s and early 40s, with studies from Europe (Netherlands, Greece, Italy), the USA, and China. All studies included women preparing for or undergoing IVF or ICSI; some focused on subgroups, such as non-obese women or those with normal BMI and ovarian reserve. Notably, male partners and their dietary habits were largely excluded from analysis, and studies focusing on specific infertility-related pathologies (e.g., PCOS, endometriosis) were not included.

Most important findings

Findings indicate that higher Mediterranean Diet adherence may be associated with modest improvements in ART outcomes: three studies reported increased clinical pregnancy rates or live birth rates, while others found improved embryo yield or ovarian response. However, the effect was not universal; two studies showed no significant associations with ART success rates, oocyte, or embryo quality. One cross-sectional study linked lower Mediterranean Diet adherence to an increased risk of poor ovarian response. Effects were sometimes age-dependent, with benefits seen predominantly in women under 35. Microbiome-related mechanisms are not directly studied, but the Mediterranean Diet’s anti-inflammatory and antioxidant properties are hypothesized to support fertility by promoting a favorable endometrial environment, potentially modulating the reproductive tract microbiome, reducing oxidative stress, and enhancing implantation. The major limitation is heterogeneity in Mediterranean Diet scoring, ART protocols, and lack of randomized controlled trials, which constrains causal inference and generalizability.

Key implications

While the Mediterranean Diet appears promising as a supportive intervention for women undergoing ART, current evidence is inconsistent and limited by methodological variability. Clinicians may consider recommending the Mediterranean Diet as part of preconception counseling for infertile couples, given its broad health benefits and potential to improve ART outcomes. However, robust randomized controlled trials with standardized dietary assessment tools are necessary to establish causality and clarify the magnitude of benefit. Understanding microbiome-mediated mechanisms could further inform personalized dietary recommendations to optimize reproductive success.