SUNDAY, Jan. 3 (HealthDay News) -- Reports on the benefits of breast-feeding continue to accumulate as researchers evaluate the breast-over-bottle option.
It's been shown to help a baby's later performance in school, to reduce the odds of problem behavior and to help kids cope with stress. And moms stand to benefit later on as well, studies show.
But what is it about breast-feeding that's so helpful and healthy?
For starters, breast milk is loaded with health-promoting nutrients. "It's not just one mechanism," said Melinda Johnson, a spokeswoman for the American Dietetic Association, a lecturer in nutrition at Arizona State University and a dietitian in private practice in nearby Chandler, Ariz.
"The nutrition [provided by breast-feeding] is perfect for the growing child," Johnson said. Take, for example, DHA (docosahexaenoic acid), an omega-3 fatty acid. "DHA is critical for brain development and also for nervous system development," Johnson said.
The presence of DHA in breast milk, she said, might explain the finding that breast-fed kids do better academically.
Breast milk also contains the amino acid taurine, considered important for neurological development, said Dr. Ruth Lawrence, who chairs the American Academy of Pediatrics' section on breast-feeding and is a professor of pediatrics and obstetrics-gynecology at the University of Rochester School of Medicine and Dentistry in New York.
"Newborns and preemies cannot manufacture taurine," Lawrence said, although adults do. "Taurine is one of the amino acids needed for brain growth. The brain will double in size in the first year of life." That makes it critical to have nutrients that help brain growth.
"We in the breast-feeding field have been focusing on brain growth [and its importance] for a number of years," she said. Those who manufacture formula, Lawrence said, focus more on how much weight babies can gain with their product.
Breast milk also has been shown to jump-start a baby's immune system, and researchers think that's due at least in part to a protein found in breast milk. Called soluble CD14, it helps develop beta cells, a type of immune cell that helps produce antibodies, which are needed to protect against illnesses.
Breast milk also contains live and active organisms that can never be duplicated in formula, Johnson said. In one of the newer areas of research, experts have found that breast-fed babies' guts have different bacteria than those of formula-fed babies, and that the breast-fed babies' gut bacteria appears to be healthier, she said.
Other research has found that the intestinal bacteria present early in life play a role in whether a person will suffer from allergies, have an overactive immune system or tend to put on excess weight later in life, Johnson said.
Breast-feeding also has emotional and bonding benefits, according to Lawrence and Johnson, although they say it's harder to explain the "why" and "how" of those.
Though a mother who bottle-feeds also holds her baby, the child has actual physical attachment while breast-feeding. "Certain hormones, feel-good hormones, are released when a woman is breast-feeding," Johnson said, citing oxytocin and prolactin as examples. "The theory is, that's how the moms bond."
DHA has also been linked to mood, she said, and "if you have the right amount of DHA, you may be heading off mood disorders."
The U.S. Department of Health and Human Services has more about the benefits of breast-feeding.
SOURCES: Ruth Lawrence, M.D., professor, pediatrics and obstetrics-gynecology, University of Rochester School of Medicine and Dentistry, Rochester, N.Y.; Melinda Johnson, R.D., lecturer, nutrition, Arizona State University, Mesa, Ariz.; Jan. 16, 2001, Proceedings of the National Academy of Sciences; June 2009, Current Opinion in Allergy and Clinical Immunology; U.S. National Women's Health Information Center (www.womenshealth.gov)