When parents first introduce solid foods to their babies, rice products are typically among the first foods offered. Choking or allergy risks are low with rice products, and they feature in many types of infant foods. However, a new study advises caution, as it finds that infants who consume rice products have higher concentrations of arsenic in their urine, compared with those who do not eat rice products.
The study – led by Margaret R. Karagas, PhD, from Dartmouth College in New Hampshire – is published in JAMA Pediatrics.
According to the study authors, the recommendation from the World Health Organization (WHO) for inorganic arsenic concentrations in polished white rice is 200 nanograms per gram (ng/g), and the proposed US Food and Drug Administration (FDA) limit for infant rice cereal is 100 ng/g.
However, the researchers say many infant rice cereals may contain inorganic arsenic concentrations that exceed these limits.
Until now, rice consumption in early childhood in the US has not been well defined, and previous research has suggested that arsenic exposure in utero and in early life could be linked with adverse effects on fetal growth, as well as infant and child immunity and neurodevelopment.
The researchers note that arsenic found in rice and rice products can be in either an inorganic or organic form; nearly all arsenic in drinking water is inorganic.
They say that, although the toxic effects of inorganic arsenic have been established, laboratory evidence has suggested that organic forms could also present a health risk. They add, however, that “further data are needed.”
To further investigate, Karagas and colleagues looked at how often infants ate rice products during their first year of life and examined the link with urinary arsenic concentrations.
In total, there were 759 infants born between 2011-2014 who were included in the New Hampshire Birth Cohort Study. The researchers conducted phone interviews with the infants’ parents every 4 months until 12 months of age.
When the infants were 1 year old, the team assessed dietary patterns during the past week, which included information on whether the infant had eaten rice cereal, white or brown rice, or foods made with rice or sweetened with brown rice syrup.
Staring in 2013, the researchers collected infant urine samples, along with a 3-day food diary. For 129 infants, more detailed data was available, including information on diet and total urinary arsenic at 12 months of age. Additionally, for 48 infants, the researchers had data on urinary arsenic species.
The team found that of the 759 infants, 80% had rice cereal in their first year of life, and 64% started between 4-6 months of age. Additionally, at 12 months of age, 43% of the babies ate some type of rice product in the past week. Of these, 13% ate white rice and 10% ate brown rice, with an average of one to two servings each week.
Of the total infants, 24% ate food made with rice or sweetened rice syrup in the past week. According to the food diaries, 55% of the infants consumed some type of rice product in the 2 days before the urine sample collection.
Results from the urine samples at 12 months of age showed that arsenic levels were higher in infants who ate rice or foods mixed with rice, compared with those who ate no rice.
Furthermore, among the infants who ate brown or white rice, their total urinary arsenic concentrations were twice as high as those who ate no rice.
The researchers say their results suggest consuming rice increases infants’ arsenic exposure, and they suggest introducing regulations to reduce exposure “during this critical phase of development.”
“In addition to being more highly exposed to As [arsenic], children appear to be far more sensitive to the potential carcinogenic effects of As, and have a heightened risk for adverse growth, adverse immune response and adverse neurodevelopmental outcomes, even at relatively low levels of exposure.”
Although their study benefits from a large sample size, the researchers say that because their study group is from northern New England and used private, unregulated water systems, it may affect the generalizability of their results.
Additionally, other dietary sources of arsenic could contribute to urinary arsenic concentrations – such as apple juice – which were not accounted for in the study.
Still, the results certainly give parents and regulators some food for thought.
In other food news, Medical News Today recently reported that consuming alcohol and processed meat may be linked to stomach cancer.