OBJECTIVE

To assess the relationship between habitual fish intake and fatty acid levels in serum as well as in the LDL fractions of serum phospholipids and cholesteryl esters.

DESIGN

Cross-sectional study.

SETTING

Cohort of Gipuzkoa (Basque Country, northern Spain) included in the European Prospective Investigation into Cancer and Nutrition (EPIC) project.

SUBJECTS

Random sample of 120 healthy volunteers of both sexes aged 35-65 y, divided into various consumption groups according to daily fish intake.

METHODS

Data on habitual intake over the previous year was collected by trained interviewers by means of a computerized questionnaire based on the diet history method. Fasting venous blood samples were drawn and fatty acids were measured by gas-liquid chromatography.

RESULTS

Lean fish accounted for 78% of all fish consumption in the highest consumption group (>115 g/day) and for 60% in the lowest (<31 g/day). The mean concentrations of omega-3 polyunsaturated fatty acids (PUFA), eicosapentaenoic acid (EPA, C20:5, omega-3), and docosahexaenoic acid (DHA, C22:6, omega-3) in serum and in the LDL fractions of serum phospholipids and cholesteryl esters increased significantly from the lowest to the highest fish consumption categories. Fish intake showed a statistically significant relationship with omega-3 PUFA, EPA and DHA in serum and in the LDL fractions of serum phospholipids and cholesteryl esters both in the simple linear regression analysis and in a multiple regression model adjusted by age, body mass index (BMI) and vegetable intake.

CONCLUSIONS

Habitual fish intake is reflected in the content of EPA and DHA in serum and in the LDL phospholipid and cholesteryl esters fractions. The concentrations of very-long-chain omega-3 fatty acids are useful biomarkers for dietary fish intake, mainly lean fish.

SPONSORSHIP

Europe Against Cancer Programme of the European Union (agreement SOC 97 200302 05F02); 'Fondo de Investigaciones Sanitarias', Spanish Ministry of Health (FIS grant 99/0024-05); Government of the Basque Country; and 'Fundación Científica de la Asociación Española contra el Cáncer'.