January 21, 2019

Breastfeeding: Have the Benefits Been Overblown?

by Jeanine Barone

If you’re a new mother and have decided to feed formula to your baby, you may be embarrassed to admit it in public. You wouldn’t be alone. Just about everyone has an opinion about breastfeeding, and it goes far beyond nourishment. Advocates promote it as a preventive for numerous ailments that may affect children well past their breastfeeding years, from allergies to diabetes, and as more healthful for mothers as well. In some circles, deciding to forgo breastfeeding is simply a sign of bad parenting.

But all other factors being equal—economic status, access to clean water and quality medical care, and the parents’ overall health, for example—is the breast really the best? The evidence is more nuanced than you might expect.

Why breastfeeding is encouraged

Breastfeeding offers a number of well-established benefits to babies and mothers. Breast milk provides the ideal amount and balance of nutrients for the baby’s development. It contains antibodies that help protect the infant from infections (including those that cause respiratory illness, diarrhea, and ear infections) and, at least in theory, that help guard against asthma and allergies. Breastfeeding helps moms and babies to bond, it’s inexpensive, and it’s better for the environment (since, unlike formula, it doesn’t have to be manufactured, packaged, and shipped).

Observational studiesshow that infants who are breastfed have a lower risk of sudden infant death syndrome, or SIDS, and that those who are breastfed exclusively for three months are less likely to develop type 1 diabetes. (Note that observational studies can only find associations, not establish causality.) Breastfeeding has also been linked with lower rates of teen and adult obesity. In women, breastfeeding makes it easier to lose pregnancy weight and helps the uterus contract to its normal size. It has also been associated with a reduction in premenopausal breast and ovarian cancer, especially if cumulative breastfeeding is longer than a year.

A number of professional health and medical associations and government agencies encourage women to breastfeed their babies for at least a portion of their first year. The American College of Obstetricians and Gynecologists recommends breastfeeding exclusively for the first 6 months, and ideally through the first year—and even after that, if possible. The American Academy of Pediatrics (AAP) has the same recommendation, noting in its most recent policy statement on breastfeeding, published in 2012, that it “provides the healthiest start for an infant.”

The CDC’s Healthy People 2020 goals includes increasing both the rate of breastfeeding and the length of time women breastfeed their children. And the federal Special Supplemental Nutrition Program for Women, Infants and Children (WIC) program—which offers grants to states to provide low-income pregnant and lactating women with nutrition education and supplemental food—rewards women who breastfeed by allowing them to receive food benefits for longer (up to a year, whereas women who report that they don’t breastfeed stop receiving food after six months).

What's Meant by Breastfeeding?

Studies of breastfeeding don't always distinguish between feeding from the nipple and pumping breast milk into a bottle, nor between breastfeeding exclusively and supplementing with formula.

Are breast benefits overblown?

The benefits attributed to breastfeeding generally come from observational studies, not clinical trials. So while children who have been exclusively breastfed tend to be healthier, that may be because women who choose to breastfeed differ from those who don’t breastfeed in other ways that affect infant health, such as the foods they feed their infants, how they interact with their children, or how hygienic their home is. In those cases, breastfeeding would be a marker of healthier childrearing, rather than the source of it.

Indeed, several well-designed studies in the United States have called into question whether breastfed infants really enjoy better health than similarly raised infants who are fed formula. In a study published in 2014 in Social Science & Medicine, researchers from Ohio State University looked at thousands of children from different families as well as siblings from families in which at least one sibling was breastfed and another bottle-fed. The children were assessed on math and reading skills and other aspects of intelligence and cognitive functioning, as well as obesity, asthma, body mass index, and other health markers. When the investigators simply looked at breastfed vs non-breastfed children in the entire study population, the breastfed children scored better on just about every measure. But when they looked at children within the same family, that disparity disappeared: There was no statistically significant difference between breastfed and the bottle-fed siblings on any of the variables measured.

In a study presented at the 2015 annual meeting of the American College of Allergy, Asthma and Immunology, researchers looked at almost 200 children aged 4 to 18 years old who were diagnosed with hay fever. They were divided into two groups based on whether they were breastfed. There was no significant difference in allergies between the two groups. Another study, published in the online journal PLOS ONEin 2015, found that among a large sample of twins, from toddlers to teens, breastfeeding was linked with only a small (though statistically significant) increase in IQ in girls and no increase in boys.

In its policy statement encouraging breastfeeding, the AAP acknowledges that there is conflicting evidence about the longer-term effect of breastfeeding on the incidence of allergies. And the obesity data is confounded by problems defining whether the infant was actually breastfed or received breast milk from a bottle—the difference being that the former allows the infant to self-regulate how much they drink, which may affect their ability to self-regulate their food intake later in life.

Even the few rigorous clinical trials comparing breastfeeding to bottle feeding suggest that some of the former’s benefits may have been exaggerated. A 2012 paper in the Journal of Human Lactation reviewed numerous articles published from the Promotion of Breastfeeding Intervention Trial, or PROBIT, a large, long-term study conducted at hospitals in Belarus. Unlike most breastfeeding studies, which are observational, PROBIT was a randomized, controlled trial. Infants were divided into either an intervention that promoted breastfeeding (by, among other things, having health care workers help new moms to breastfeed soon after giving birth and show them how to maintain breastfeeding even when they were away from their babies) or a control group that did not encourage breastfeeding. After one year, the children in the intervention group had lower rates of gastrointestinal illnesses and rashes, and at 6.5-year follow-up, they had higher verbal IQ scores. But there were no differences between the groups in obesity, allergies, asthma, or dental health. Another PROBIT paper, published in 2013 in JAMA,did not find that breastfeeding prevented obesity or being overweight.

Public health experts also point out that the overall benefit of breastfeeding is more pronounced in the developing world, where lack of clean water means that infants who are fed formula (which is generally powder mixed with water) may be exposed to dangerous contaminants such as arsenic, lead, parasites, rotavirus and other viruses, or E. coli or other bacteria. In the United States and other developed countries, where the water supply is generally safe, bottle-feeding doesn’t carry the same risk.

Challenges to breastfeeding

In some communities, breastfeeding carries a sense of morality, not just health. If you want to be a good mom who cares about your baby, you’ll breastfeed. But not all women find breastfeeding equally feasible or desirable. For some, breastfeeding may be difficult or impossible because of their economic circumstances or professional demands. They may not be able to stay home, alter their work schedules, or express milk with a breast pump. Unlike in Scandinavian countries such as Norway, where almost all new mothers get about a year of paid maternity leave, in the U.S. there is no federal law mandating paid maternity leave, and even companies with what would be considered generous maternity leave policies don’t offer anything close to a year of paid leave.

Another challenge is that some women may not produce enough milk or may be in so much discomfort while breastfeeding that it’s not a viable option in terms of her and her family’s quality of life. Some women develop mastitis, a breast infection from bacteria that migrate into the milk ducts, or end up with bleeding nipples because of the way the baby latches on. In addition, difficulties with breastfeeding may contribute to postpartum depression, which affects some 13 to 19 percent of women who recently gave birth. Postpartum depression is a serious mental health condition with potentially devastating consequences for the mom, infant, and family, including an increased risk of the women experiencing obsessive compulsive disorder and anxiety, problems with mother-infant bonding, and suicidal thoughts. A Committee Opinion developed by the American College of Obstetricians and Gynecologists states that women who have difficulty breastfeeding are at a higher risk of postpartum depression and should be screened and, where appropriate, referred by their ob-gyn to a mental health professional.

Bottom line

Breastfeeding can be a healthy and enjoyable experience for babies and mothers, and it has some scientifically validated benefits. There are excellent reasons to encourage breastfeeding in developing countries, where water is often contaminated. But it isn’t a panacea in the developed world. If a woman is able to breastfeed and wants to breastfeed, she should try it. If she can't, she shouldn't feel shamed. A mother’s decision whether to breastfeed (or her success in doing so) is personal, and at most only one of many variables that will affect her child’s development and future health. As with so many other parenting decisions, new mothers and their partners should consider the options and do what’s best for themselves and their family.