Scientific Study

The high concentration of omega-3 polyunsaturated fats, dietary fibers, vitamins, minerals and polyphenols found in nuts suggest their regular consumption may be a simple strategy for improving reproductive health. This systematic review and meta-analysis aimed to present up-to-date evidence regarding the association between nut intake and fertility outcomes in men and women. Ovid MEDLINE, Embase, CINAHL and Scopus were searched from inception to 30 June 2023. Eligible articles were interventional or observational studies in human subjects of reproductive age (18 – 49 years) that assessed the effects (or association) of dietary nut consumption (for a minimum of 3 months) on fertility-related outcomes. Random-effects meta-analyses were completed to produce a pooled effect estimate of nut consumption on sperm total motility, vitality, morphology, and concentration in healthy males. Four studies involving 875 participants (646 men, 229 women) were included in this review. Meta-analysis of two RCTs involving 223 healthy males indicated consumption of ≥ 60g nuts/day increased sperm motility, vitality, and morphology in comparison to controls, but had no effect on sperm concentration. Non-randomised studies reported no association between dietary nut intake and conventional sperm parameters in men, or embryo implantation, clinical pregnancy or live birth in men and women undergoing ART. Our meta-analysis shows that including at least 2 servings of nuts daily as part of a Western-style diet in healthy men improves sperm parameters, which are predictors of male fertility. Due to their nutritional profile, nuts were found to have potential to promote successful reproductive outcomes. https://doi.org/10.1016/j.advnut.2023.100153