Diet quality (adequacy, variety, moderation) in relation to biomarkers of metal exposure in school-age children

Abstract

BACKGROUND AND AIM: The relationship between dietary consumption and exposure to toxic metals/metalloids is complex. Foods may be a source of toxicant exposure, but they also provide many nutrients that compete with toxicants for intestinal absorption or contribute to lowering the toxicity of toxicants. Previous studies found associations between specific foods and blood or urinary lead (ex., diary), arsenic (rice) or cadmium (grains) biomarkers in children. Basing dietary recommendations on individual foods or single toxicants could result in contradictory or potentially harmful guidance. Our objective was to relate measures of overall diet quality with biomarkers of arsenic, lead and cadmium exposure in school-age children. METHODS: We constructed measures of dietary variety (servings of meats/eggs, dairy/beans, grains, fruits, vegetables), adequacy (intake of vegetables, fruit, grains, fiber, protein, iron, calcium and vitamin C) and moderation (intake of total fat, sugar sweetened beverages, pastries, sweets and chips) based on two non-consecutive 24-hr diet recalls conducted among parents of ~7 year old children in Montevideo Uruguay. Blood lead levels (BLL) were measured using atomic absorption spectrometry and total urinary arsenic (U-As) and cadmium (U-Cd) were measured via IC-PMS. Using linear regression models, we estimated the association between dietary quality and toxicant biomarkers, adjusting for child age, sex, and household socioeconomic status. RESULTS:U-As (median [5%, 95%]: 9.9 [4.1, 27.3] μg/L), U-Cd (0.06 [0.02, 0.15] μg/L) and BLL (3.8 [0.8, 7.8] μg/dL) indicated low-to-moderate exposure. Mean variety, adequacy and moderation scores were, respectively: 9.7±3.9 (out of 20), 25.0±4.7 (out of 40) and 12.3±4.8 (out of 30). Biomarkers of lead or arsenic were not associated with diet quality. Dietary variety and moderation were inversely associated with urinary cadmium concentrations. CONCLUSIONS:Diets that are varied and provide adequate levels of nutrients do not contribute to biomarkers of children’s exposure to arsenic, cadmium and lead. KEYWORDS: diet quality, lead, cadmium, arsenic, child