Background: Previous research has shown an inverse relationship between long-chain n-3 polyunsaturated fatty acids (n3PUFA) and insulin resistance (IR), however, intervention trials have generated equivocal results. Previous findings by our research group suggest that the relationship may be sex-dependent, potentially accounting for inconsistencies in the literature. The aim of this systematic review and meta-analysis is to determine whether the responsiveness to n3PUFA interventions for type 2 diabetes prevention is sex-dependent.
Methods: Five databases (Medline, EMBASE, CINAHL, Scopus and Pub-Med) were searched to identify randomized controlled trials that include: dietary or supplement n3PUFA intervention in adult populations; measures of IR; and a report of the relationship between the two. Subgroup analysis was used to explore sex-dependent differences.
Results: Thirty-two trials matched the inclusion criteria, including a total of 2326 participants (mean age 53.4yrs; BMI 29.7). Five trials were conducted in males only; seven in females and the rest (n=20) were combined. There was considerable heterogeneity in terms of trial duration (mean 12.8 weeks; range 3-48 weeks), n3PUFA dosage and placebo used. The main primary outcome measure reported was HOMA-IR. Studies in combined males/females did not show a significant relationship between n3PUFA intervention and measures of IR. In females, trials >12 weeks showed a significant improvement in HOMA-IR (p<0.05). None of the intervention trials conducted in males provided positive outcomes.
Conclusion: This review supports a sex-dependent relationship between n3PUFA and IR. Future intervention trials of at least 12 weeks duration should be designed to further elucidate sex-dependent differences.
Funding Source: NA