Dietary intake of polyunsaturated fatty acids, their food sources and fertility in females and males: a preconception prospective population-based cohort study.

Abstract

BACKGROUND: Seafood, nuts, and seeds are key dietary sources of polyunsaturated fatty acids (PUFAs), which may benefit reproductive health. OBJECTIVES: This study aims to investigate associations of periconception dietary intake of PUFA-rich foods and omega-3 and omega-6 PUFAs with fecundability and subfertility in females and males. METHODS: Among 830 females and 651 males, participating in a population-based prospective cohort study from preconception onwards, we assessed periconception dietary intake at median 12.4-wk gestation (95% range: 10.9, 18.4) and time to pregnancy via questionnaires. Fecundability was defined as the probability of conceiving within 1 mo and subfertility as time to pregnancy ≥12 mo or use of assisted reproductive technology. Cox proportional hazards and logistic regression were used to assess associations between PUFA(-rich foods) with fecundability and subfertility. RESULTS: In females, PUFA-rich food intake was not significantly associated with fertility. Higher omega-3 PUFA intake, especially docosahexaenoic acid and alpha-linolenic acid, but not omega-6 PUFA, was per standard deviation score (SDS) increase associated with increased fecundability and reduced subfertility. Strongest effects were observed for females in the highest quartile. A lower omega-6 to omega-3 PUFA ratio was associated with increased fecundability and lower subfertility risk [fecundability ratio (FR): 0.92, 95% confidence interval (CI): 0.87, 0.96; odds ratio (OR): 1.14, 95% CI: 1.02, 1.26, per unit increase in omega-6:omega-3 PUFA ratio]. In males, higher intake of nuts/seeds, but not seafood, was associated with increased fecundability and lower subfertility (FR: 1.10, 95% CI: 1.01, 1.20; OR: 0.78, 95% CI: 0.63, 0.97 per SDS increase in nuts/seeds). Strongest effects were present for those who consumed the highest amount. No associations were observed for omega-3 or omega-6 PUFA intake in males. CONCLUSIONS: In females, higher dietary omega-3 PUFAs intake may benefit fertility. Increased nuts and seeds consumption may improve fertility in males, independent of PUFA intake. These findings suggest potential for gender-specific dietary interventions to support reproductive health.