Circulating n-3 fatty acids and linoleic acid as indicators of dietary fatty acid intake in post-myocardial infarction patients

Abstract

Background and aims: Population-based studies often use plasma fatty acids (FAs) as objective indicators of FA intake, especially for n-3 FA and linoleic acid (LA). The relation between dietary and circulating FA in cardiometabolic patients is largely unknown. We examined whether dietary n-3 FA and LA were reflected in plasma lipid pools in post-myocardial infarction (MI) patients.

Methods and results: Patients in Alpha Omega Cohort filled out a 203-item food-frequency questionnaire from which eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), alpha-linolenic acid (ALA), and LA intake were calculated. Circulating individual FA (% total FA) were assessed in cholesteryl esters (CE; n = 4066), phospholipids (PL; n = 838), and additionally in total plasma for DHA and LA (n = 739). Spearman correlation coefficients (r_s) were calculated for dietary vs. circulating FA. Circulating FA were also compared across dietary FA quintiles, overall and in subgroups by sex, obesity, diabetes, statin use, and high alcohol intake. Patients were on average 69 years old and 79% was male. Moderate correlations between dietary and circulating levels were observed for EPA (r_s∼0.4 in CE and PL) and DHA (r_s ∼0.5 in CE and PL, ∼0.4 in total plasma), but not for ALA (r_s ∼0.0). Weak correlations were observed for LA (r_s 0.1 to 0.2). Plasma LA was significantly lower in statin users and in patients with a high alcohol intake.

Conclusions: In post-MI patients, dietary EPA and DHA were well reflected in circulating levels. This was not the case for LA, which may partly be influenced by alcohol use and statins.

Keywords: Biomarkers; Cardiac patients; Circulating fatty acids; Dietary fatty acids; Food frequency questionnaire; Linoleic acid; Plasma fatty acids; n-3 fatty acids.