Maternal and child health advocates have long promoted the myriad benefits of breastfeeding. However, the science behind it — why it’s so good for babies, what it contains that is different or better than store-bought formula, which parts of the process confer the benefit to babies’ immunity — still remains something of a mystery.

At Nutrition 2018, the first flagship meeting of the American Society of Nutrition, held June 9-12, 2018, American researchers will be presenting their newest discoveries to the science of breastfeeding. Below is a summary of those findings.

These presenters were selected by a committee of experts but have not generally undergone a rigorous peer review process such as that required for publication in a scientific journal. As such, the findings should be considered preliminary.

Findings point to short and long-term benefits for mother and baby

Breastfeeding may help reduce mom’s risk of type 2 diabetes after gestational diabetes
A study of 4,400 women followed for more than 20 years suggests breastfeeding for a longer period of time could help women diagnosed with gestational diabetes during pregnancy lower their risk of developing type 2 diabetes later in life. Women with gestational diabetes who lactated for more than one year total (for all children combined) reduced their risk of type 2 diabetes by about 30 percent compared to those who did not breastfeed at all. The research suggests the long-term beneficial impact of lactation may persist across the lifespan of aging women. (Sylvia Ley, Brigham and Women’s Hospital and Harvard T.H. Chan School of Public Health)

Breastfeeding appears protective against metabolic syndrome in teen years
Metabolic syndrome is a cluster of conditions that raise the risk of heart disease and diabetes. A study of overweight and obese Hispanic teens with a family history of type 2 diabetes found that those who were breastfed for at least one month as babies were substantially less likely to have metabolic syndrome in their teen years compared to those who were not breastfed. This protective benefit of breastfeeding was seen among those born to mothers with and without gestational diabetes during pregnancy. (Sarvenaz Vandyousefi, University of Texas at Austin)

Breastfeeding appears protective against overweight in babies who gain weight rapidly
Gaining weight rapidly during early life puts infants at increased risk for obesity later on. In a new study, babies who gained weight rapidly in the first four months of life were significantly more likely to be classified as overweight by one year of age if they were exclusively formula fed rather than breastfed for 11 months or longer. (Jillian Trabulsi, University of Delaware)

B. infantis probiotic boosts benefits of breastfeeding in developed countries
Although breastfeeding is known to support a healthy gut microbiome in infants, babies in developed countries do not reap the same benefits as those in developing countries. A new study conducted in collaboration by the University of California, Davis and Evolve BioSystems finds supplementing breastfed infants in developed countries with the probiotic B. infantis ECV001 improves their gut microbiome health, as long as they continue to breastfeed. (Bethany Henrick, University of California, Davis)

New insights into the composition of breast milk

Evidence that a woman’s weight influences what’s in her breastmilk
Preliminary findings from a new study reveal that breast milk of obese women has higher levels of total fat, the inflammatory marker C-reactive protein, and hormones including leptin and insulin compared to breast milk of normal-weight women during the first six months postpartum. The implications of these differences for infant growth and development are unknown. (Clark Sims, Arkansas Children’s Nutrition Center/University of Arkansas for Medical Sciences)

A breastfeeding mom’s diet may influence her baby’s intestinal microbiome
The fat, carbohydrate, protein and calorie contents of a breastfeeding mom’s diet have been found to be associated with the kinds of bacteria found in her baby’s stool. This study, the first of its kind relating a mother’s diet to her infant’s microbiome, sheds new light on how the intestinal microbiome is shaped during the first months of life. (Janet E. Williams, University of Idaho)

Drinking sweetened beverages causes fructose spike in breastmilk
Researchers report the concentration of fructose in breastmilk rose and remained high for up to 5 hours after lactating women consumed a 20-ounce bottle of soda containing 65 grams of sugar. Fructose levels in breastmilk were unaffected by drinking an artificially-sweetened beverage containing zero grams of sugar. (Paige K. Berger, University of Southern California)