The U.S. Food and Drug Administration Risk Assessment on Lead in Women's and Children's Vitamins Is Based on Outdated Assumptions
Miodovnik, Amir, Landrigan, Philip J., Environmental Health Perspectives
BACKGROUND: Following a recent report of lead in certain commercial vitamin products, the U.S. Food and Drug Administration (FDA) conducted a nationwide survey to determine the Pb content in 324 multivitamin/mineral products labeled for use by women and children. The FDA compared estimated Pb exposures from each product with safe/tolerable exposure levels, termed provisional total tolerable intake (PTTI) levels, previously developed for at-risk population groups in 1992.
OBJECTIVE: We investigated the FDA's conclusions that Pb concentrations in all vitamin products examined do not pose a hazard to health because they are below the PTTI levels for all groups considered.
DISCUSSION: For their initial estimations of PTTI levels, the FDA used a blood lead level (BLL) of 10 [micro]g/dL as the threshold for adverse effects in children and in pregnant or lactating women. Studies have repeatedly linked chronic exposure to BLLs < 10 [micro]g/dL with impairments in cognitive function and behavior in young children despite the absence of overt signs of toxicity. The FDA analysis also omitted any consideration of nonfood sources of Pb exposure, which is inconsistent with our current understanding of how most children develop elevated BLLs.
CONCLUSION: We feel that based on these oversights, the FDA's conclusions are unduly reassuring and that reconsideration of their current recommendations appears warranted.
KEY WORDS: fetal and child neurobehavioral development, Food and Drug Administration, lead, provisional total tolerable intake levels, vitamins. Environ Health Perspect 117:1021-1022 (2009). doi: 10.1289/ehp.0900573 available via http://dx.doi.org/ [Online 25 March 2009]
In early 2007, following a report of elevated lead levels in certain commercial vitamin products, the U.S. Food and Drug Administration (FDA) conducted a nationwide survey in the United States to determine the Pb content in 324 multivitamin/mineral products (hereafter, vitamin products) labeled for use by women and children (U.S. FDA 2008). Four categories of vitamin products were examined, defined by the population groups for whom they are intended: young children (0-6 years of age), older children ([greater than or equal to] 7 years of age), pregnant or lactating women, and adult women.
To estimate the range of Pb exposures that might result from consumption of each vitamin product in the study, the FDA multiplied the amount of Pb in each product (the mass fraction) by the maximum recommended daily consumption, as indicated on the package label instructions (Mindak et al. 2008).
The amounts of Pb measured in these 324 vitamin products ranged from nondetectable to 2.88 [micro]g/day in products intended for young children; from 0.0276 to 1.78 [micro]g/day in vitamins for older children; from nondetectable to 8.97 [micro]g/day in vitamins for pregnant and lactating women; and from 0.0146 to 4.92 [micro]g/ day in vitamins for other adult women.
To determine whether estimated Pb consumption from these vitamin products posed a hazard to human health, the FDA compared estimated Pb exposures with safe/tolerable exposure levels previously developed for age and sex groups, termed provisional total tolerable intake (PTTI) levels (Carrington and Bolger 1992). These PTTI levels were developed by the FDA in 1992 and are based on the assumption that food is the sole source of Pb exposure. Their goal was to predict the dietary intakes that would result in a blood lead level (BLL) of 10 [micro]g/dL for children and pregnant or lactating women and of 30 [micro]g/dL for other adults, including women of childbearing age. Accordingly, PTTI levels for dietary intake of Pb were set at 6 [micro]g/day for young children and 25 [micro]g/day for pregnant or lactating women.
Through this comparison, the FDA determined that five vitamin products would have resulted in exposures that exceeded 4 [micro]g/day, the highest being 8. …