Murphy · Nutrients 2015 · cross-sectional survey · n=1386

Suboptimal Plasma Long Chain n-3 Concentrations are Common among Adults in the United States, NHANES 2003-2004.

Cited 29 times in the scientific literature.

Level 4 - case-series / case-control

Cross-sectional population biomarker survey

PubMed 26690213 · doi:10.3390/nu7125534 · record verified 2026-08-29

What was done

A cross-sectional analysis evaluated fasting plasma long-chain omega-3 polyunsaturated fatty acid (LCn-3 PUFA) concentrations—calculated as the percentage sum of EPA, DPA, and DHA relative to total fatty acids—in 1,386 US adults aged ≥20 years from the National Health and Nutrition Examination Survey (NHANES) 2003–2004. Biomarker levels were compared against reference thresholds for cardiovascular health and recommendations for seafood intake.

What was found

Mean plasma LCn-3 PUFA concentration was 2.07% (95% CI 1.95–2.19%). Overall, 80.6% of participants had LCn-3 concentrations below levels recommended for cardiovascular health, and 95.7% were below concentrations associated with cardiovascular protection. Older participants (≥60 years) had higher concentrations than those aged 20–39 years (no difference compared to ages 40–59). Hispanic participants had lower concentrations relative to non-Hispanic Black participants and were the most likely to have levels below recommendations.

Why it matters

This study provides representative biomarker evidence that suboptimal long-chain omega-3 status was pervasive among US adults in 2003–2004, falling well below targets for cardiovascular protection.

Limits

The data are cross-sectional and derived from a single survey period in 2003–2004, which may not reflect current intake patterns. Fasting plasma fatty acid levels reflect shorter-term intake than erythrocyte membrane fatty acids, and prospective cardiovascular outcomes were not assessed.

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