Calcium Supplements Lower Blood Lead in Nursing Mothers

Howard Hu, M.D, Sc.D.
Harvard School of Public Health
R01ES07821, P42ES05947, P30ES00002

Background: Exposure to lead from a variety of sources has been known for centuries to cause adverse health effects. Children are especially vulnerable to learning and behavioral deficits resulting from lead exposure. Pregnancy and breast-feeding are known to cause a marked turnover of lead stored in bones, which account for 95% of lead found in adults. Therefore, lactation places women and their breast-fed infants at an increased risk of lead exposure. Dietary calcium supplements have been shown to reduce fetal lead exposure; however no reports in the literature exist of testing this hypothesis with a properly conducted clinical trial. To address this issue, these investigators conducted a double-blind randomized clinical trial to determine if taking 1,200 mg of calcium each day lowered blood lead levels in lactating women.

Advance: Calcium supplementation produced a small reduction in blood lead levels. The effect was more apparent for women with higher bone lead levels and who were more compliant with taking the supplements. Women with high bone lead levels experienced a 16% decline in blood lead levels.

Implication: This trial demonstrates that calcium supplementation may be effective in decreasing blood lead levels in lactating women. Because dietary lead absorption and bone lead mobilization are likely to be similar during pregnancy and lactation, calcium supplementation is likely to reduce lead exposure to the fetus as well. This kind of intervention is not intended to be a substitute for public health efforts to reduce environmental lead exposure from all sources; however, it may constitute an important secondary prevention effort, because dietary lead exposure is difficult to eradicate and lead exposure from long-lived bone stores is likely to persist for decades.

Citation: Hernandez-Avila M, Gonzalez-Cossio T, Hernandez-Avila JE, Romieu I, Peterson KE, Aro A, Palazuelos E, Hu H. Dietary calcium supplements to lower blood lead levels in lactating women: a randomized placebo-controlled trial. Epidemiology. 2003 Mar;14(2):206-12.