Racial differences in correlations between reported dietary intakes of carotenoids and their concentration biomarkers.

BACKGROUND The predictive ability of dietary assessment methods to estimate specific circulating plasma carotenoid concentrations has been compared between African Americans and whites in only one study to date. OBJECTIVE The predictive abilities of 24-h dietary recalls and a food-frequency questionnaire in reporting dietary carotenoids when measured against concentration biomarkers were assessed in African Americans and compared with the findings in whites. DESIGN Data were collected from 250 generally healthy, nonsmoking white and African American participants aged 21-69 y, who completed 8 self-administered online 24-h dietary recalls and one National Cancer Institute diet-history questionnaire in the University of California Los Angeles (UCLA) Energetics Study. Mean intakes from 4-d dietary recalls were correlated with plasma xanthophyll concentrations (lutein + zeaxanthin and β-cryptoxanthin) and hydrocarbon carotenoids (lycopene, α-carotene, and β-carotene). RESULTS Adjusted correlations of plasma carotenoids with reported dietary intakes for African Americans in the 24-h dietary recall ranged from 0.03 for β-carotene to 0.40 for β-cryptoxanthin. For whites, the correlations ranged from 0.13 for lycopene to 0.51 for β-cryptoxanthin. CONCLUSIONS Despite stronger validity in reported energy intakes for African Americans than for whites in the 24-h dietary recall in the Energetics Study, both recalls and food-frequency dietary assessment methods yielded lower correlations in African Americans than in whites. This finding might be attributable to reporting differences in both dietary sources and food preparation or to racially related genetic variants influencing circulating concentrations. The current findings support the need to account for differences in race, age, sex, and body mass index in regression calibrations of dietary reports and measurement error adjustments.