Fångström et al. 2008 — Breastfeeding Protects Against Arsenic Exposure in Bangladesh
This 2008 prospective cohort study from high-arsenic Bangladesh demonstrated that exclusive breastfeeding substantially reduces infant arsenic exposure compared to formula feeding or early complementary feeding, even when the mothers themselves have elevated arsenic exposure from drinking water.
Key numbers
Breast milk arsenic (n=79 mothers, 2–3 months postpartum): Median: 1 µg/kg; range: 0.25–19 µg/kg. Speciation: predominantly AsIII; DMA detected in some samples; MA detected in 19/79 samples.
Infant urinary arsenic at 3 months by feeding mode:
| Group | n | Median (µg/L) | 10th–90th pct (µg/L) |
|---|---|---|---|
| EBF (exclusively breastfed) | ~50 | 1.1 | 0.27–6.7 |
| NEBF (non-exclusively breastfed) | ~48 | 1.9 | 0.36–140 |
The NEBF group’s 90th percentile was 140 µg/L vs 6.7 µg/L for EBF — a 20-fold difference at the high end — driven by contaminated drinking water used to reconstitute formula or given as supplemental fluids.
Maternal urinary arsenic (gestational week 30 and 8): GW30 median 67 µg/L, range 10–1,130 µg/L; GW8 median 49 µg/L, range 12–810 µg/L.
Drinking water arsenic exposure context: 10–1,100 µg/L in maternal urine reflects range of groundwater As concentrations in Matlab.
Methods
HPLC-ICP-MS speciation for arsenic species. Prospective cohort; 98 mother-infant pairs. Breast milk, maternal blood/urine/saliva, infant urine measured at 3 months.
Key finding: breast milk acts as a protective barrier — mothers with high As exposure from groundwater still transfer relatively little As to infants through milk (median only 1 µg/kg in milk). The primary risk to NEBF infants is the contaminated water used to reconstitute powdered formula or given as a beverage.
Implications
Certification: In high-As contexts (groundwater), the matrix risk for formula-fed vs breastfed infants diverges dramatically. Water quality in formula preparation is a critical determinant of infant As exposure, not the formula powder itself.
Health: Provides strong epidemiological support for extended exclusive breastfeeding in arsenic-affected regions.