Although parents typically give babies rice as their first food, a new study reveals that infants fed a rice diet have higher "inorganic" arsenic concentrations in their urine than babies that never eat rice.
The team used diet information and urine samples from 759 infants born to mothers that were a part of the New Hampshire Birth Cohort Study between 2011 and 2014. The researchers kept track of the infants through phone interviews that were conducted every four months until they turned 1. After this point, a final interview was conducted to determine dietary patterns during the last week.
The study revealed that infants who ate baby rice cereal often had the highest arsenic concentrations in their urine, with levels more than three times than those observed in babies with no rice in their diet. In addition, babies who ate foods that were mixed with rice or ate rice-based snacks possessed almost double the arsenic levels than babies who did not eat rice.
"The arsenic in their urine increased with the number of servings of rice or rice-containing food," said Margaret Karagas, chair of epidemiology at Dartmouth University's Geisel School of Medicine and lead author of the study.
The findings require more research and follow-up, but as of now they are enough to raise the attention of health experts.
"It certainly sounds concerning," said Ruth Milanaik, director of the neonatal neurodevelopmental follow-up program at Cohen Children's Medical Center, who was not involved in the research. "It certainly requires more study."
Milanaik also noted that there are numerous variables that weren't controlled for in the study, suggesting that the findings might have been influenced by other aspects of the babies' diets, including arsenic in apple juice or drinking water.
There is evidence that arsenic - a known carcinogen - can increase susceptibility to heart disease as well as compromise the immune system and intellectual development in early life. Inorganic arsenic is common in infant plant-based foods such as apple juice and applesauce due to pesticides, although the U.S. Food and Drug Administration recently proposed limits on the chemical's levels in rice cereals for infants.
"Even though in this country we've outlawed it, we used it for so long that it's leached into our soil and really becomes part of our vegetation," Milanaik said.
The findings were published in the April 25 issue of JAMA Pediatrics.