Key Numbers
Baseline measurements at 6 months (breast-fed or formula-fed, no solid foods):
- Total urinary arsenic: geometric mean ~3.5 µg/L, range 0.9–11.8 µg/L
- iAs: median ~1.8 µg/L
- Predominant arsenical: DMA (inorganic arsenic methylation already active)
Post-weaning measurements (12–18 months, after solid food introduction):
- Total urinary arsenic increased 1.5–2.0-fold from baseline
- iAs increased most dramatically (~3–4-fold increase on average)
- MMA and DMA both elevated
- AsB detected in all samples, consistent with seafood/seaweed exposure
Dose-response association:
- Infants with highest rice cereal/rice-based food consumption showed highest urinary iAs concentrations
- Fruit and vegetable consumption also correlated with elevated urinary arsenic
- Breast-fed infants showed lower baseline and weaning-period arsenic than formula-fed infants (formula-fed had higher baseline from formula water content)
Methods
Analytical: Ion chromatography coupled to inductively coupled plasma mass spectrometry (IC-ICP-MS). Speciation of four arsenicals (iAs as As(III) + As(V), MMA, DMA, AsB). Limits of detection ranged 0.008–0.011 µg/L. Urine samples collected at two time points (6 months and 12–18 months).
Study design: Prospective cohort, 15 exclusively breast-fed or formula-fed infants at baseline (6 months), followed through weaning transition. Dietary intake via parental 24-hour recall. Urinary samples analyzed blinded to dietary exposure.
Population: Healthy Spanish infants, born 2010–2011. All exclusively milk-fed at enrollment; all transitioning to solid foods during follow-up.
Implications
For ingredient risk profiles:
- Rice and rice-based infant cereals are high-exposure pathways for inorganic arsenic in infancy, consistent with pre-weaning rice-cereal data.
- Fruits and vegetables contribute measurably to dietary iAs exposure even at weaning ages.
- Breast-feeding conveys lower arsenic exposure than formula-feeding (water-dependent).
For regulatory baselines:
- Normal urinary iAs in breast-fed 6-month-olds: ~1.8 µg/L median. Doubling or tripling on weaning into rice-heavy cereals signals dietary driver.
- The 2–4-fold rise in iAs on rice introduction is documented in a cohort with careful dietary tracking, supporting epidemiological dose-response.
For evidence synthesis:
- Arsenical speciation is measurable in infant urine and shifts with diet. MMA presence indicates active metabolic pathway even in young infants.
- AsB detection in all samples suggests seafood/seaweed exposure pathway may be active earlier than previously documented in the literature.
Wiki Page Updates
- rice: Add Signes-Pastor (2018) as primary-evidence contribution to infant/toddler exposure via rice cereal.
- formula: Cross-reference water-dependent arsenic loading; formula-fed infants baseline >breast-fed.
- infant-rice-cereal: Evidence for dose-response between rice-cereal consumption and urinary iAs elevation.
- arsenic: iAs speciation in infant urine; MMA/DMA as metabolic products during early weaning.
- arsenobetaine: Early detection in infant urine (all 15 at 6 months) — earlier than typically noted.
Page history
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