Determinants of the omega-3 index in a Mediterranean population at increased risk for CHD

Br J Nutr. 2011 Aug;106(3):425-31. doi: 10.1017/S0007114511000171. Epub 2011 Mar 30.


The omega-3 index, defined as the sum of EPA and DHA in erythrocyte membranes expressed as a percentage of total fatty acids, has been proposed as both a risk marker and risk factor for CHD death. A major determinant of the omega-3 index is EPA+DHA intake, but the impact of other dietary fatty acids has not been investigated. In a cross-sectional study on 198 subjects (102 men and 96 women, mean age 66 years) at high cardiovascular risk living in Spain, the country with low rates of cardiac death despite a high prevalence of cardiovascular risk factors, dietary data were acquired from FFQ and blood cell membrane fatty acid composition was measured by GC. The average consumption of EPA+DHA was 0·9 g/d and the mean omega-3 index was 7·1 %. In multivariate models, EPA+DHA intake was the main predictor of the omega-3 index but explained only 12 % of its variability (P < 0·001). No associations with other dietary fatty acids were observed. Although the single most influential determinant of the omega-3 index measured here was the intake of EPA+DHA, it explained little of the former's variability; hence, the effects of other factors (genetic, dietary and lifestyle) remain to be determined. Nevertheless, the high omega-3 index could at least partially explain the paradox of low rates of fatal CHD in Spain despite a high background prevalence of cardiovascular risk factors.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Aged, 80 and over
  • Biomarkers / blood
  • Cell Membrane / metabolism
  • Cross-Sectional Studies
  • Dietary Fats / administration & dosage
  • Dietary Fats / blood*
  • Docosahexaenoic Acids / administration & dosage
  • Docosahexaenoic Acids / blood*
  • Eicosapentaenoic Acid / administration & dosage
  • Eicosapentaenoic Acid / blood*
  • Erythrocytes / metabolism*
  • Female
  • Heart Diseases / blood
  • Heart Diseases / etiology*
  • Heart Diseases / mortality
  • Humans
  • Male
  • Middle Aged
  • Multivariate Analysis
  • Nutrition Assessment*
  • Risk Factors
  • Spain
  • Surveys and Questionnaires


  • Biomarkers
  • Dietary Fats
  • Docosahexaenoic Acids
  • Eicosapentaenoic Acid