Breast milk is considered the perfect food for babies; not only is it a better source of nutrition compared to formula, but infants find it easier to digest all the proteins, calcium, and iron it contains. Now a new study offers mothers one more good reason to breastfeed their babies. Dartmouth College researchers found formula-fed infants have higher arsenic levels than breast-fed babies.

While some women find it impossible to breastfeed, those who are able to breastfeed should do so for the entire first year of their infant’s life, as recommended by the American Academy of Pediatrics. Not only is this practice optimal for babies, it also helps mothers in two important ways. First, it speeds a mother’s physical recovery after delivery, and second, it reduces her future risk of breast and ovarian cancers. While breastfeeding is at least attempted by 75 percent of all American mothers, major differences exist among various groups and ethnicities.

For instance, among Hispanic or Latino mothers the breastfeeding rate ranges as high as 81 percent, while just 58 percent of non-Hispanic black or African-American mothers make an attempt to feed their infants in this way. Meanwhile, high income mothers are more likely to breastfeed than low-income mothers, and mothers under 20 are less likely to breastfeed than mothers over 30. No matter where a mother falls in the demographic pile, she should ignore the statistics, make an attempt, and do her best to give breastfeeding a try. When in doubt, she can find help from other mothers here.

Arsenic and Well Water

For the current study, a team of researchers investigated whether breast milk or formula contributed greater arsenic exposure during early infancy in a small United States population. Occurring naturally in bedrock, arsenic is a common contaminant of well water worldwide and is said to cause cancers and other diseases. Fetal exposure is linked to increased mortality, decreased birth weight, and even diminished cognitive function. In many rural areas, private well water, which is not subject to regulation by the Environmental Protection Agency, is the primary water source.

The researchers began their study by measuring arsenic levels in home tap water in New Hampshire. Next, they measured arsenic levels in the urine of 72 infants at 6 weeks old and in the breast milk of nine women. They discovered urinary arsenic was 7.5 times lower among the breast-fed babies when compared to formula-fed infants. For most participants, both the powdered formula and the water contributed to arsenic exposure, but tap water concentrations of arsenic far exceeded the formula concentrations.

"We advise families with private wells to have their tap water tested for arsenic," Dr. Margaret Karagas, senior author and professor at Dartmouth’s Children’s Environmental Health and Disease Prevention Research Center, said in a press release. Meanwhile, her colleagues predict the level of arsenic exposure increases during the second half of an infant’s first year of life — that's the time most mothers switch to formula-feeding.

Source: Carignan CC, Cottingham KL, Jackson BP, et al. Estimated Exposure to Arsenic in Breastfed and Formula-Fed Infants in a United States Cohort. Environmental Health Perspectives. 2015.