Signes-Pastor 2018 — Infants’ dietary arsenic exposure during transition to solid food
During the transition to solid foods, infants’ urinary arsenic concentrations increase substantially, with rice cereal emerging as the dominant dietary source. This study followed 15 healthy US infants from the New Hampshire Birth Cohort Study, measuring urinary arsenic speciation at 4 and 6 months of age paired with dietary intake records. Urinary total arsenic increased 3.8-fold between these time points, driven primarily by increased consumption of rice-based cereals and plant foods. The findings establish quantitative evidence that early infant feeding practices—particularly introduction of rice cereal—create a distinct exposure pathway during critical neurodevelopmental periods.
Key numbers
Median urinary inorganic arsenic (iAs): 0.23 µg/L at 4 months, 0.35 µg/L at 6 months (1.5-fold increase, p = 0.04)
Median urinary monomethylarsonic acid (MMA): 0.027 µg/L at 4 months, 0.15 µg/L at 6 months (5.5-fold increase, p = 0.002)
Median urinary dimethylarsinic acid (DMA): 0.045 µg/L at 4 months, 0.26 µg/L at 6 months (5.8-fold increase, p = 0.002)
Median urinary sum of arsenic species: 0.31 µg/L at 4 months, 1.18 µg/L at 6 months (3.8-fold increase, p = 0.0009)
Limit of detection: 0.011 µg/L for all arsenic species
Rice cereal intake correlation with urinary iAs at 6 months: Spearman’s ρ = 0.90, p = 0.003
Fruit intake correlation with urinary iAs at 6 months: Spearman’s ρ = 0.70, p = 0.034
Vegetable intake correlation with urinary iAs at 6 months: Spearman’s ρ = 0.86, p = 0.013
Sample size: 15 infants with 30 paired urine samples (one at 4 months, one at 6 months per infant)
Median urinary specific gravity: 1.004–1.006 g/mL
Methods
The study enrolled 15 healthy infants from the New Hampshire Birth Cohort Study at baseline (gestation) with follow-up measurements at 4 and 6 months of age. At each time point, mothers recorded 3-day food diaries documenting all infant dietary intake, and urine samples were collected. Urinary arsenic speciation (iAs, MMA, DMA, arsenobetaine) was quantified by ion chromatography inductively coupled plasma mass spectrometry with a limit of detection of 0.011 µg/L. Within-subject changes between time points were assessed using Wilcoxon signed-rank tests, and associations between dietary intake and urinary arsenic were evaluated using Spearman’s rank correlation.
Implications
This study provides the first quantitative characterization of arsenic speciation during the critical weaning period in US infants and identifies rice cereal as the dominant dietary source of inorganic arsenic exposure. The extremely strong correlation between rice cereal consumption and urinary iAs (ρ = 0.90) aligns with the FDA action level of 100 µg/kg total arsenic in infant rice cereals and validates that regulatory focus. The 3.8-fold increase in total urinary arsenic species within 2 months demonstrates that solid food introduction represents an acute transition in exposure magnitude and provides quantitative evidence that early infant feeding practices substantially elevate dietary arsenic intake during critical neurodevelopmental windows. The methylated arsenic species measured at 6 months (MMA, DMA) reflect in vivo biotransformation of ingested inorganic arsenic. These findings support inclusion of this source in infant rice cereal, infant formula, and infant solid foods product pages; in the fruits, vegetables, and rice ingredient pages; and in discussions of US exposure patterns and the 4–6-month age window as a distinct exposure scenario.
Wiki pages updated
- arsenic
- breast-milk
- formula
- rice
- cereals
- fruits
- vegetables
- fish
- seafood
- infant-rice-cereal
- infant-formula
- infant-solid-foods-mixed
- united-states
- ic-icp-ms
- fda-action-level-infant-rice-cereals
Page history
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