Which lifestyle factors change Omega-3 Index?

The Omega-3 Index (EPA+DHA percentage in red blood cell membranes) is most strongly modified by dietary intake of long-chain omega-3 fatty acids. Fatty fish (salmon, mackerel, sardines) and high-quality EPA/DHA supplements reliably increase the index. Lifestyle factors also matter: smoking lowers the index via oxidative stress, while moderate alcohol (especially red wine) may slightly raise it. Physical activity improves omega-3 utilization but the effect is modest compared to direct intake. The overall dietary fat quality (omega-6 to omega-3 ratio) modulates the index. Genetic variants (e.g., FADS1/2) affect conversion of ALA to EPA/DHA, so some people benefit less from plant sources. Evidence is human-strong for fish/supplements, human-moderate for smoking and exercise. Caveat: The index is a biomarker, not a direct health outcome; individual variability is large. Blood measurement before and after intervention is recommended.