In 2010, University of Oklahoma researcher David Fields, Ph.D., was poring over research data when he discovered something he thought was odd: his data showed that at 6 months of age, formula-fed babies born of mothers who were categorized as medically obese weighed about 5% units less fat than breastfed babies in the same dataset.

That discovery struck him as unusual and led him on a research journey to better understand breast milk. Now, he’s studying the connections between maternal gestational diabetes, breastfeeding and infant health.

Fields is part of the research team behind a study in JAMA Network Open that examines the effects of breast milk on the children of mothers with gestational diabetes.

“Gestational diabetes is a big deal,” said Fields, an associate professor of pediatrics in the OU College of Medicine. “It’s bad for the mother because, while it goes away after giving birth, it usually portends that, later in life, the mother will get diabetes.”

Fields and his colleagues began studying mother-infant pairs with gestational diabetes in 2019, as part of his 2015 project with University of Minnesota researcher Ellen Demerath, Ph.D., called the Mothers and Infants LinKed for Health Growth (MILK) study, one of the largest and longest-running studies on breastfeeding in the country.

At that time, Fields suspected the breast milk composition of mothers with gestational diabetes would be different from mothers without the disease. When they began digging into the compositional differences between breast milk for mothers with and without gestational diabetes, the results told an unexpected story.

While nine differences existed between the breast milk of mothers with gestational diabetes and those without, three were significantly associated with growth and body composition. Those differences benefited the children of mothers with gestational diabetes.

Babies of mothers with gestational diabetes had faster linear growth: they were longer and growing faster. They also had a lower fat percentage in one month to three months.

“They weren’t putting on fat as much, which is totally opposite of what we would think. We thought that these babies would be gaining more fat, but they’re not,” Fields said.

When the MILK study began, very little was known about the composition of breast milk. “We didn’t know much beyond macronutrients, simply how much fat and how much protein is in the milk,” he said.

And while there is still more to learn about the differences between formula and breast milk, and their effects on children, Fields and his team are at the forefront of making those discoveries.

“Our ultimate take-home message is milk is medicine. Milk is the interface between the baby and the mother. What a mother eats and how they live, either good or bad, is being signaled and transferred to the infant,” Fields said.