US Family Physicians Overestimate Personal ω-3 Fatty Acid Biomarker Status: Associations with Fatty Fish and ω-3 Supplement Intake

Abstract

Background: The health benefits of ω-3 (n-3) fatty acids are well established. Only a small percentage of Americans consume the recommended amounts of fatty fish, the main dietary source of ω-3 fatty acids, and most have low ω-3 fatty acid blood concentrations.

Objective: We aimed to measure biomarkers of long-chain ω-3 fatty acid (EPA and DHA) status among family physicians, and determine whether having their ω-3 status tested would influence attitudes and patient recommendations.

Methods: Family physicians attending a medical conference (n = 340) completed an ω-3 intake survey and had a finger stick blood sample taken. ω-3 Index, percentage of ω-6 (%n-6) in highly unsaturated fatty acids (HUFAs), and EPA:arachidonic acid (AA) ratio were calculated from whole blood fatty acid profiles. Post-conference, a subsample of participants (n = 100) responded to a survey regarding attitudes and recommendations about ω-3s.

Results: Average age (mean ± SEM) of participants was 48.0 ± 0.7 y and 59% were women. Average ω-3 Index was 5.2% ± 0.1%, %n-6 in HUFA was 75% ± 0.4%, and EPA:AA ratio was 0.076 ± 0.004. 57% of family physicians reported consuming <2 servings/wk of fatty fish, and 78% reported using ω-3 supplements ≤1/wk. Although 51% believed ω-3 status was in a desirable range, only 5% had an ω-3 Index ≥8%. Biomarkers of ω-3 status were significantly associated with fatty fish intake and supplement use, and were correlated (R2 ranging from 0.59 to 0.77). Physicians who had ω-3 status tested (n = 65) were more likely to agree with statements affirming the health benefits of ω-3 fatty acids and more willing to recommend ω-3 fatty acids to their patients (P = 0.004).

Conclusions: Blood concentrations of ω-3 fatty acids in family physicians were below recommendations, and were associated with fatty fish intake and ω-3 supplement use. There was a discrepancy between perceived and actual ω-3 status. Increased awareness of personal ω-3 status among physicians may facilitate patient communication and recommendations about ω-3 fatty acid intake. This trial was registered at clinicaltrials.gov as, NCT03056898.

Keywords: DHA; EPA; docosahexaenoic acid; eicosapentaenoic acid; fatty fish intake; omega-3 status; omega-3 supplement use; physicians.

Figures

FIGURE 1

ω-3 Status biomarkers. (A) ω-3 Index, (B) %n–6 in HUFA, and (C) EPA:AA ratio by fatty fish intake and ω-3 supplement use among 340 family physicians (mean ± SE). For all 3 biomarkers, main effects of fatty fish consumption and supplement use were significantly different, and no interactions were observed (2-factor ANOVA, α = 0.05). Multiple comparisons of main effect levels (Tukey's highly significant difference test) indicated significant differences between fatty fish consumption categories for all 3 biomarkers. Different letters indicate significant differences among ω-3 supplement use categories. EPA:AA ratio was log transformed prior to statistical analysis. AA, arachidonic acid; HUFA, highly unsaturated fatty acid; %n–6, percentage of n–6 fatty acids.

FIGURE 2

Associations of (A) ω-3 Index with %n–6 in HUFA; (B) ω-3 Index with EPA:AA ratio; and (C) %n–6 in HUFA with EPA:AA ratio. AA, arachidonic acid; HUFA, highly unsaturated fatty acid; %n–6, percentage of n–6 fatty acid.