Determinants of erythrocyte omega-3 fatty acid content in response to fish oil supplementation: a dose-response randomized controlled trial.
Level 2 - randomized trial
Individual randomized controlled trial
PubMed 24252845 · doi:10.1161/JAHA.113.000513
What was done
A randomized, double-blind, placebo-controlled, parallel-group trial examined 115 healthy men and women assigned to one of five daily EPA+DHA doses (0, 300, 600, 900, or 1800 mg) via fish oil or placebo supplements for approximately 5 months. The erythrocyte membrane content of EPA and DHA (Omega-3 Index, O3I) was measured at baseline and study completion to model predictive determinants of the O3I response.
What was found
O3I increased in a dose-dependent manner (P < 0.0001). Supplement dose alone accounted for 68% of response variability (quadratic model, P < 0.0001), while dose adjusted per unit body weight (g/kg) accounted for 70% (linear model, P < 0.0001). Incorporating baseline O3I, age, sex, and physical activity alongside dose further improved prediction, collectively explaining 78% of the response variability (P < 0.0001).
Why it matters
This study provides quantitative models showing that body weight, baseline omega-3 levels, and demographic factors significantly influence erythrocyte EPA+DHA incorporation, supporting personalized dosing regimens to achieve target Omega-3 Index levels.
Limits
The sample size was relatively small (115 participants divided across five arms, averaging ~23 per group). The study was conducted only in healthy adults, so response kinetics in clinical populations with cardiovascular or metabolic diseases were not evaluated. The abstract does not report baseline dietary intake, absolute baseline/post-treatment index values, adherence measures, or clinical outcomes.
Cited by
- supports Supplementing with approximately 2 grams of fish oil per day raises most people's red blood cell omega-3 index from 4% to 8%.