Does vitamin C intake protect against lead toxicity?

Although several animal studies suggest a protective relationship between blood lead concentrations and ascorbic acid, there are inconclusive results regarding the beneficial effect of ascorbic acid on lead concentrations in human studies. Data from the Third National Health and Nutrition Examination Survey examined the association between ascorbic acid and blood lead concentrations in 19,578 participants ages 6-90 years without a history of lead poisoning. Elevated blood lead concentrations were found in 0.4% of adults and 0.5% of youths. Serum ascorbic acid concentrations were inversely associated with the prevalence of elevated blood lead concentrations. However, there was no significant relationship between dietary ascorbic acid intake and blood lead concentrations. This study suggests that there may be a protective relationship between ascorbic acid and lead. Questions remain regarding the unique roles of dietary vitamin C versus supplemental vitamin C in explaining this relationship.