A global review shows that heavy metal contamination is far more common in baby foods than expected, revealing high-risk products and highlighting the urgent need for stronger safety standards.
Study: Concentrations of Heavy Metals in Processed Baby Foods and Infant Formulas Worldwide: A Scoping Review. Image Credit: Iryna Inshyna / Shutterstock
In a recent study published in the journal Nutrition Reviews, researchers compiled evidence on the concentrations of heavy metals in infant formulas and processed baby foods.
Heavy metals such as cadmium, lead, mercury, and arsenic are toxic elements present in the environment. They can damage organ systems even at low levels of exposure. In infancy, exposure to heavy metals is linked to neurocognitive and behavioral disorders, intellectual disability, cardiovascular diseases, and respiratory issues.
Growing concerns highlight the need for comprehensive evidence on heavy metal levels in infant products.
Search Strategy and Evidence Synthesis Methods
In the present study, researchers synthesized evidence on the presence of heavy metals in various types of infant formulas and processed baby foods. ScienceDirect, Scopus, Web of Science, and PubMed were searched for eligible studies.
Studies were included when they reported heavy metal levels in products for infants under 36 months and described the analytical detection methods used. Total Diet Studies and non-governmental reports were included when they met the same criteria.
Classification of Baby Food and Infant Formula Types
Baby foods were categorized into cereals, fruits and vegetables, fish and fish mixes, mixed foods, meat and meat mixes, roots and tubers, and rice and rice mixes. Infant formulas were grouped into stage 1, stage 2, stage 3, stage 1 and 2 combined, specialty formulas, and formulas without a stage. Formulas were further stratified by protein source, including soy-based, cow-based, or unspecified.
Comparison of Heavy Metal Levels with International Standards
The mean heavy metal concentrations were compared to maximum levels defined by international agencies, primarily those from the European Commission and the Food and Agriculture Organization of the United Nations or the World Health Organization.
For mercury, maximum levels were inferred using analogous food categories due to the absence of infant-specific limits. Median and interquartile range concentrations for each heavy metal were calculated by food type, and findings from infant health risk assessments were summarized.
Overview of Included Studies and Heavy Metal Determinations
Overall, 75 studies were included. Twenty-four studies reported data on infant formulas, 23 on baby foods, and 28 on both. These studies covered 251 infant formulas and 580 baby foods. Among baby foods, 1,766 heavy metal determinations were reported, including 484 for lead, 483 for cadmium, 478 for arsenic, and 321 for mercury.
Detection Frequencies Across Baby Food Products
Heavy metals were detected in 65% of baby foods. Lead, cadmium, arsenic, and mercury were found in 69%, 72%, 73%, and 34% of products, respectively. Lead, arsenic, and mercury were detected in all fish and fish mix items, while lead and cadmium were detected in 97% of roots and tubers.
Heavy Metal Presence Across Infant Formula Categories
Heavy metals were detected in 63% of infant formulas. Lead, cadmium, arsenic, and mercury were detected in 74%, 61%, 63%, and 42% of formula samples, respectively. Lead was detected in 89% of stage 1 and 2 formulas, 85% of stage 2 formulas, and 56% of stage 1 formulas.
Cadmium was detected in 81% of stage 1 and 2 formulas and 76% of specialty formulas. Arsenic was present in 79% of specialty formulas.
Heavy Metal Levels by Protein Source and Food Category
Lead was present in 84% of soy-based and 73% of cow-based formulas. Cadmium was detected in 91% of soy-based formulas, arsenic in 85%, and mercury in 47% of cow-based formulas. Fish and fish mixes, as well as rice and rice mixes, had the highest median lead concentrations, at 0.008 milligrams per kilogram.
Thirty-three percent of fish and fish mixes, 31% of rice and rice mixes, and 21% of cereal baby foods exceeded maximum lead levels.
Exceedances of Maximum Levels Across Heavy Metal Types
Cereals had the highest median cadmium concentration at 0.013 milligrams per kilogram, with 17% exceeding cadmium limits. Fish and fish mixes had the highest median arsenic levels at 0.165 milligrams per kilogram, with 89% exceeding arsenic limits.
Stage 2 and Stage 1 formulas had the highest median lead levels, at 0.015 milligrams per kilogram, with 72% and 60% exceeding the lead limits, respectively. Stage 2 formulas also had the highest median cadmium level at 0.006 milligrams per kilogram.
Formulas without stage contained the highest median arsenic levels at 0.052 milligrams per kilogram, and 71% exceeded arsenic limits. These formulas also had the highest median mercury concentration.
Findings from Infant Health Risk Assessments
Forty-one studies performed infant health risk assessments. Fifteen studies identified risks associated with the consumption of infant formulas and baby foods. Health risks associated with arsenic exposure were identified in four studies, three of which involved rice and rice-based products.
Risks related to cadmium exposure were reported in three studies involving rice and rice-based products. Two studies identified risks from lead exposure in cereals, roots, and tubers. Six, four, and four studies on infant formulas reported health risks related to arsenic, lead, and cadmium exposure, respectively.
Interpretation of Widespread Heavy Metal Contamination
In summary, more than 60% of infant formulas and baby foods contained detectable levels of cadmium, lead, and arsenic, and more than 30% contained mercury. Baby foods containing fish, rice, and cereals were of particular concern because of their higher concentrations of lead and arsenic.
The findings highlight the widespread presence of heavy metals in infant products, emphasizing the need for stricter regulations and the use of internationally defined maximum level frameworks, including methods for estimating mercury limits when infant-specific standards are unavailable.