Comparison of the Habitual Dietary Intakes of Omega-3 Fatty Acids from Three Dietary Screening Tools
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Background: Unlike water-soluble nutrients, omega-3 fatty acids are stored in the body. Dietary assessment of omega-3 fatty acids should be focused on habitual intakes. A newly developed omega-3 questionnaire (O3Q) designed to capture habitual intakes of omega-3 fatty acids was previously validated based on the blood markers. It is important to compare this tool with existing “gold standard” dietary tools. Objective: This study compared the estimated habitual intakes of omega-3 fatty acids assessed from three dietary assessment tools including O3Q and two other commonly used methods (24-hour diet recall and Diet History Questionnaire). Study Design: Estimated omega-3 intakes from the O3Q, multiple 24-hour recalls, and Diet History Questionnaire collected from an observational study (n = 49) were compared to corresponding whole blood levels of eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and Omega-3 Index. Spearman’s correlation was calculated to evaluate the relationship between estimated omega-3 intake for each diet assessment method and biomarkers. Stepwise multiple linear regression was determined to evaluate the relationship between estimated dietary intakes of EPA+DHA from the three intake methods and the Omega-3 Index level. Results: The estimated intakes from the O3Q were better correlated with the corresponding blood biomarkers (EPA, rs=0.75; DHA, rs=0.74; Omega-3 Index, rs=0.77; p<0.001 for all) compared to the DHQ (EPA, rs=0.53; DHA, rs=0.41; Omega-3 Index, rs=0.45; p<0.001 for all) and 24 hr diet recall (EPA, rs=0.61; DHA, rs=0.45; Omega-3 Index, rs=0.55; p<0.001 for all). The regression also demonstrated that the O3Q, but not the other diet assessment tools, associated with the Omega 3-Index level (r2=42.7%, p<0.001). Conclusions: The estimated dietary intake of omega-3 fatty acids from the O3Q was best associated with the corresponding biomarkers from the study participants when compared to the numbers from 24-hour diet recall and Diet History Questionnaire.