Sex-specific differences in essential fatty acid metabolism.
Level 5 - mechanism / opinion, no new human data
Narrative review synthesizing tracer studies, observational cohorts, and trials without systematic review methodology.
PubMed 22089435 · doi:10.3945/ajcn.110.000893
What was done
Narrative review evaluating literature on sex-specific differences in long-chain polyunsaturated fatty acid (LC-PUFA) metabolism. The authors synthesized evidence from isotope tracer studies using U-(13)C α-linolenic acid (ALA), lipid composition studies including a cross-sectional dataset across 15 European regions (n > 3000), and a limited set of perinatal LC-PUFA supplementation randomized controlled trials.
What was found
Isotope tracer studies showed a considerably higher conversion rate of ALA to omega-3 LC-PUFAs in women than in men. Blood lipid studies generally found higher arachidonic acid (AA) and docosahexaenoic acid (DHA) in women, though not consistently across all studies. In a cohort of > 3000 European men and women, men had higher saturated and monounsaturated fatty acids and lower AA and DHA, but sex accounted for only ≈ 2% of the variability in plasma phospholipid DHA. Perinatal trial outcomes occasionally showed sex differences, but high heterogeneity in interventions and endpoints prevented firm conclusions on effect magnitude or direction.
Why it matters
This review establishes that sex hormones influence LC-PUFA synthesis and status, indicating that perinatal supplementation trials must pre-specify sex-stratified subgroup analyses.
Limits
The review lacks systematic search methods, quality assessments, and quantitative meta-analysis. Sex accounts for only ≈ 2% of plasma DHA variance in the largest analyzed cohort, leaving most variability unexplained. Interventions and measured outcomes in cited perinatal trials were highly heterogeneous.
Cited by
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