Short and sweet. Accurate nutritional assessment requires blood sampling (until other less-invasive measures are developed). Self-reported dietary intake instruments are poorly, in statistical terms the term would be ‘weakly’, correlated with blood biomarkers.
Lassale and colleagues asked 198 adult volunteers complete dietary records on 3 non-consecutive days. Two blood samples were taken 3 weeks apart to measure plasma concentrations of vitamin C, β-carotene, and omega-3 fatty acids – eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA) and eicosapentaenoic acid (EPA).