Breast-Fed Babies Exposed to Less Arsenic than Formula-Fed Babies

Breast-fed babies are typically exposed to less arsenic than babies who are fed formula, according to a new study published in Environmental Health Perspectives.

Arsenic, which can be found in groundwater, has been linked to cancer, cardiovascular disease, diabetes, obesity, and altered immune systems. Babies exposed to arsenic may have decreased birth weight and lower cognitive functioning, and in utero exposure has also been linked to an increased chance of infections.

“Effects of lower-dose exposures are still under investigation, but emerging evidence suggests similar effects as higher doses,” lead study author Kathryn L. Cottingham, MS, PhD, a professor in the Biological Sciences Department at Dartmouth College, told Pharmacy Times.

Dr. Cottingham and her fellow researchers measured arsenic levels in home tap water, urine from 72 6-week-old infants, and breast milk from their mothers. The results showed that while urinary arsenic concentrations were generally low, they were 7.5 times higher in infants fed formula compared with the infants fed only breast milk. In addition, the average estimated daily arsenic intake was 5.5 times higher for formula-fed infants than for infants who were breast-fed.

Both formula powder and tap water can be sources of arsenic exposure for babies, according to the researchers. They estimated that formula powder accounted for roughly 70% of median exposure among the formula-fed babies. Breast milk, on the other hand, has been shown to have low levels of arsenic, even if the woman is exposed to high levels of arsenic in drinking water.

Public water must be below a maximum contaminant level of 10 mcg of arsenic per liter of water, the researchers stated in their study. However, since private wells are not regulated and do not have to be tested, some families may not know they are using water with a high level of naturally occurring arsenic, Dr. Cottingham explained.

“Pharmacists can help by asking patients whether they use private or public drinking water, and if private, encourage them to have their drinking water tested,” Dr. Cottingham told Pharmacy Times. “State health departments can provide guidance on how to test and any other elements to test for—for example, nitrates in agricultural areas.”

To avoid higher levels of arsenic, families with new babies can make sure the water they use to mix powdered formula is low in arsenic, Dr. Cottingham added. Otherwise, mothers who are able to breast-feed can reduce arsenic exposure that way.