Western Dietary Pattern Reduced Male Fertility: A Systematic Review and Meta-Analysis of Observational Studies

Background: previous studies have investigated the associations between dietary patterns and male infertility, but found contradictory results. so, this meta-analysis was conducted to examine the association between dietary patterns and male infertility. methods: an electronic search was conducted to identify the studies over association between dietary patterns and male infertility. the western and healthy dietary patterns were selected in this regard. the random-effect model was used to compute the summary risk estimates. results: we found eight articles, of which five (n = 7679 participants) were included in our meta-analysis. this meta-analysis determined that the western dietary patterns containing high levels of processed, meat, high-fat dairy, and low levels of vegetables, fruit, and whole grains could significantly reduce the sperm concentration (md = -0.07, p = 0.01). however, no significant relationship was observed between this dietary pattern and the sperm motility and morphology (md = 0.01, p = 0.71, md = 0.2, p = 0.39, respectively). moreover, regarding the healthy dietary pattern, which contains high level of fruit, vegetables, whole grain, low-fat dairy, as well as low level of red meat and processed food, no significant relationship was observed (sperm concentration: md = 0.11, p = 0.11, morphology: md = -0.02, p = 0.42 and motility: md = 0.35, p = 0.09). conclusions: findings of our meta-analysis suggested that the western dietary patterns could decrease the sperm concentration and reduce male fertility. further prospective studies are required to confirm this result.