Effect of dietary vitamins in oral bioaccessibility of lead in contaminated soils based on the physiologically based extraction test.

To determine the effect of vitamin supplements on the oral bioaccessibility of Pb in soils, Pb bioaccessibility was measured in the presence of 9 vitamins by a physiologically based extraction test. Gastric Pb bioaccessibility (G-BA, 2.6-83.3%) was found to be mostly reduced (1.1-3.1 fold) in the presence of B vitamins, specifically vitamins B1, B6, and B9. In contrast, a significant increase in Pb G-BA was observed with vitamin C and E involved. In the small intestinal phases, Pb bioaccessibility (I-BA) ranged from 0.1% to 16.0%, being 5-50 fold lower than the corresponding G-BA values. Vitamin C supplementation showed a 7-fold increase in Pb I-BA, with a similar increase presented in approximately 30% of samples treated to vitamin B involvement. Lead liberation in gastrointestinal digests was associated with the dissolution of Fe and Mn regulated by vitamins. In conclusion, the addition of B vitamins resulted in the reduction of gastric Pb bioaccessibility, but the bioaccessibility value increased in participation of vitamin C and E. Elevated intestinal bioaccessibility was found especially for vitamin C. This should contribute to more accurate assessment of health risks from contaminated soils. Nutritional management aimed at preventing Pb-induced toxicity can benefit from knowledge of vitamin influence on soil Pb bioaccessibility.