Science Says Breast Is Best for Babies’ Health

News that the United States government sought to block a World Health Organization resolution to encourage breastfeeding has drawn criticism from clinicians and public health experts. The American Public Health Association condemned the move, writing, “scientific evidence overwhelmingly supports breastfeeding and its many health benefits for both child and mother.” Mailman School faculty, some of whom contributed to this body of research, outlined a number of the many ways breastfeeding is beneficial.

“Breastfeeding saves lives by providing no-cost infant nutrition and immunologic protection,” says Terry McGovern, JD, the Harriet and Robert H. Heilbrunn Professor and Chair of Population and Family Health. “This is particularly important in resource-poor settings throughout the world. Baby formula is needlessly expensive and is not the optimal choice for the health of the infant and mother.”

According to a 2016 Lancet review of scientific literature, babies who are breastfed for longer periods have fewer infections than those who are breastfed for shorter periods or not at all—an advantage that extends into adulthood. Breast milk may also play a role in the development of the infant microbiome, supporting the development of helpful bacteria.

“There is ample evidence that breast milk offers immunological protections to the baby,” says Melissa Stockwell, MD, MPH ’07, associate professor of Pediatrics and Population and Family Health. “Along with regular vaccinations, breastfeeding is one of the most important ways a mother can safeguard the health of her child. Moms also help themselves by lowering their risk for breast cancer.”

Helping Moms to Stay With Breastfeeding

The World Health Organization, whose breastfeeding resolution was adopted despite the U.S. efforts to block it, recommends exclusive breastfeeding up to 6 months of age, with continued breastfeeding along with appropriate complementary foods up to 2 years of age or beyond. Yet few mothers breastfeed anywhere close to the recommended length of time.

According to the Lancet review, women in high-income countries, on average, breastfeed for a shorter period of time than low- and middle-income countries. Even in low and middle-income countries, only 37 percent of infants younger than 6 months are exclusively breastfed.

In the United States and elsewhere, many women stop breastfeeding when they have to go back to work, especially women without paid maternity and without childcare staff trained to handle breast milk that has been pumped. Many mothers are also reluctant to breastfeed in public. While the law explicitly protects public breastfeeding in nearly every state, those who choose to do so are often given a hard time and told to “cover up.”

According to Gretchen Van Wye, PhD, adjunct professor at the Mailman School and assistant commissioner at the New York City Department of Health and Mental Hygiene, a greater effort is needed to create an environment “where the social norm is that anyone can breastfeed anywhere” with structures in place to do so privately.

Breastfeeding and Childhood Obesity

Sally Findley, PhD, a professor of Population and Family Health, says among the many ways helping mothers to be less reliant on the baby formula will be pay dividends is in the area of childhood obesity. Her research found that infants enrolled in the New York State Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) whose mothers were encouraged to breastfeed were significantly less likely to be obese than those whose mothers were not.

Not only is breast milk more nutritious than formula, but it helps forge a bond between mother and child around feeding habits. “Breastfeeding appears to promote early learning of self-regulation,” says Findley. The mother too learns to pick up on cues from the child that gives her a leg up when it’s time to move on to solid foods. “She knows when the child has had enough.”

On the other extreme, some mothers who bottle-feed their children mix-in sweeteners like cocoa and cereal—a practice common in moms who thought their overweight child was normal weight or underweight.  And mothers who “topped up” were nearly five times more likely to give their child juice or a sweetened beverage before age six months, a study by Findley found.

No Exception for HIV

For some mothers, such as those who are receiving chemotherapy, doctors advise against breastfeeding. Traditionally, HIV-positive mothers were included in this category due to the risks of mother-to-child transmission. However, several studies, including one by Louise Kuhn, PhD, a professor of Epidemiology, in the New England Journal of Medicine, demonstrated that the risk of transmission is outweighed by the benefits conferred by breastfeeding by reducing their risk for death and disease from diarrhea and pneumonia.

“This balance is especially strong in favor of breastfeeding when HIV-infected breastfeeding women are treated with effective antiretroviral therapy essentially removing any risk of HIV infection for the breastfed child,” says Kuhn. “In general, the benefits of breastfeeding extend across all socioeconomic strata but are especially important for the most economically-disadvantaged members of the global community.”

for future generations

While infant formula is always second best to breast milk, the stakes are even higher in communities with poor sanitation and contaminated water. If powdered formula is mixed with impure water, it can lead to life-threatening infections. Meanwhile, the immune-boosting properties of breastmilk protect against these same infections. For this reason, Save the Children and other advocacy groups argue that it is unethical for companies to market formula to developing nations.

“Mothers in low-income countries often do not have access to accurate information about the risks of breast milk substitutes,” says Kuhn. “They may also lack access to supportive services to assist them with lactation.”

According to the WHO resolution, if all infants under the age of six months were exclusively breastfed, experts estimate that about 820,000 children’s lives would be saved every year. Children who breastfeed are also known to have higher IQ scores.

“The international community must join together to support mothers’ ability to breastfeed, through policies that strengthen education, job opportunities, and healthcare,” says Terry McGovern. “Future generations depend on it.”