Manganese levels in infant formula and young child nutritional beverages in the United States and France: Comparison to breast milk and regulations

Abstract

Exposure to high levels of manganese (Mn) in children has recently been associated with adverse neurodevelopmental effects. Current infant formula regulations for Mn content were set between 1981 (United States), 2006 (European Union, France), and 2007 (Codex Alimentarius) prior to the publication of much of the growing body of research on the developmental neurotoxicity of Mn. In this study, we sought to measure the concentrations of Mn in some infant formulas and young child nutritional beverages available on the United States (US) and French markets using ion beam analysis by particle induced X-ray emission (PIXE) spectrometry and then compare the analytical results to concentrations reported in the literature for breast milk and applicable infant formula regulations and guidelines. We were particularly interested in measuring Mn concentrations in product types for which there is very little data from previous surveys, especially soy-based, rice-based, goat-milk based, chocolate-flavored, and nutritional beverages for young children that are not regulated as infant or follow-on formulas (e.g. “toddler formulas” and “toddler powders”). We purchased 44 infant formulas and young child nutritional beverage products in the US and France with varying protein sources (cow-milk, goat-milk, soy, rice) labelled for birth to 3 years. We selected these samples using maximum variation sampling to explore market extremes to facilitate comparisons to regulatory limits. Since this sampling method is non-probabilistic, other inferences cannot be made beyond this set of samples to the overall markets. We used ion beam analysis to measure the concentrations of Mn in each product. The range of measured Mn concentrations in the products is 160–2,800 μg/L, substantially higher than the 3–6 μg/L mean Mn concentration reported in human breast milk. All products satisfied national and Codex Alimentarius Commission (CAC) international standards for minimum Mn content in infant formulas; however, 7/25 of the products purchased in the US exceeded the CAC Guidance Upper Level of 100 μg Mn/kcal for infant formula.

Estimating daily intakes of manganese due to breast milk, infant formulas, or young child nutritional beverages in the United States and France: Comparison to sufficiency and toxicity thresholds

“…For the range of Mn content in infant formulas and young child nutritional beverages available in the US and France, we relied on our recent market basket survey of 44 products [42]. In this survey, we purchased 25 products in the US and 19 products in France using maximum variation sampling [43], purposively selecting products to explore the range of Mn concentrations, the potential effects of specific ingredients such as soy on Mn content, and to cover a wide range of ages.…”

“…Similarly, we calculated µg Mn/100 kcal using the measured µg Mn/g dried prepared product and the reported kcal/mass of dried product or final volume of prepared product from the manufacturer's label. Since the sampling method was non-probabilistic, market extreme values for Mn concentrations (minimum and maximum) were used for comparison, but not mean values for Mn concentrations from this study [42,43].…”

“…For estimates of intakes of breast milk or formula for ages 3 weeks and 4.25 months, we chose to use average intakes reported by Sievers et al [49]. We converted the intakes in fluid weights [49] to fluid volumes by assuming a density of 1,031 g/L for breast milk [56], or by the average measured density of the products that we tested (mean = 1,010 g/L for US "infant formulas" and French "stage 1" products) [42].…”

“…We used data on kcal/L for breast milk (3,103.7 kJ/L for 2-6-montholds, 3,683.2 kJ/L for 12-39-month-olds) during prolonged lactation from Mandel et al [59] with these energy intake figures to estimate breast milk intakes of 0.579… L/day for 7-month-olds and 0.2303… L/day for 18-month-olds. For formula-fed infants, we used average energy content reported on the labels for the products we tested in our market basket survey (669.0… kcal/L for 7-month-olds, 621.6… kcal/L for 18-month-olds) together with the energy estimates due to formula, yielding estimated formula intakes of 0.671… L/day for 7-month-olds and 0.3351… L/day for 18-month-olds [42].…”

“…Table 2. These intake estimates relied on the weight, intake, and Mn data described in the Materials and Methods section (Table 1) [42,49,50,58]. These intake estimates are compared to reference weights and intake assumptions used by advisory and regulatory agencies in Table 3.…”