# Heavy metal exposures in aerodigestive clinic cohort of infants with reflux or dysphagia

## TL;DR

The study found no significant differences in arsenic levels in infants with reflux or dysphagia using different thickeners, but higher arsenic was linked to alternative food sources.

## Contribution

This is the first study to compare heavy metal exposure in infants using different thickeners for reflux or dysphagia.

## Key findings

- No significant difference in urinary arsenic levels between infants using different thickeners.
- Higher arsenic levels were associated with more servings of alternative arsenic sources in solid foods.
- Molybdenum levels varied significantly between thickener groups.

## Abstract

Infant cereals (rice/oatmeal), purees, and anti-reflux formulas are often first line treatments for thickening in infants with reflux and oropharyngeal dysphagia. However, there has been growing concern about heavy metal contamination, especially arsenic, in these commonly used thickeners. This is a particular concern in infants who may be more susceptible to heavy metal neurotoxicity. The study aimed to assess whether there are differences in heavy metal levels, particularly arsenic, in infants with reflux or oropharyngeal dysphagia while on different thickeners. We performed a single center study in infants (< 1 year of age) with diagnosis of reflux or oropharyngeal dysphagia who were seen between December 2021–2023. Participants submitted urine samples and completed dietary questionnaires to assess their elemental exposures. The primary outcome of interest was urinary arsenic concentrations, though other elements were also measured. Of the 56 infants, 27 were on gelmix® or purees, 19 were on Enfamil AR and 10 were on infant oatmeal/rice cereal as a thickener. The median total urinary arsenic concentration did not differ between groups (p = 0.086) and levels between groups were well below the Agency for Toxic Substances and Disease Registry (ATSDR)’s toxicity limits. Infants with higher number of servings of alternative arsenic sources via their solid food were more likely to have higher urinary arsenic level (p = 0.001), suggesting a potential need for the FDA to implement stricter food supply regulations. Only molybdenum had significant difference in levels between thickeners (p = 0.0012). Even in high-risk patients, urinary arsenic concentrations did not differ between thickener groups.