Study: Formula Changes Gut Bacteria, Contributes to Childhood Obesity

June 7, 2018 at 6:16 pm

Breast-fed babies have lower childhood obesity rates than formula-fed babies because they have better gut bacteria, new study finds

A new study published in the Journal of Pediatrics might explain why breast-fed babies are less likely to be obese later in life — because of their gut bacteria.

The study found breast-fed babies had different microbiomes, or different types of bacteria in their guts –- and lower obesity levels as they grew -– than babies who were primarily fed formula.

Receiving breastmilk during infancy has long been associated with lower rates of childhood and adult obesity later on, but the new study brings us closer to understanding why.

“Breastmilk is a very specialized food –- not just for babies, but also for their gut bacteria,” Dr. Meghan Azad, lead researcher and pediatrics professor at the University of Manitoba, told ABC News.

“Breastmilk contains oligosaccharides, which are complex sugars that feed specific gut bacteria.”

The “good” bacteria in babies’ digestive systems affects how they burn and store fat, as well as how they use energy, the researchers theorize.

For the study, they looked at data from the Canadian Healthy Infant Longitudinal Development, which followed more than 1000 Canadian infants for the first year of life.

Mothers reported on breastfeeding and when they introduced formula and other foods. The babies’ stool samples were taken at 3 to 4 months and 12 months to test for the variety of gut bacteria.

By 3 months, only 54 percent of infants were still solely breastfed. 30 percent of the babies were partially breastfed, and 16 percent solely formula fed.

The effects of formula feeding on the babies’ weight began to show immediately.

At 3 months old, 33 percent of the formula-fed babies were overweight or at risk of being overweight, while only 19 percent of exclusively breastfed babies were overweight or at risk.

The difference is likely connected to what’s happening in the gut, researchers said.

Gut microbes, especially in infants and children, help develop the digestive tract and immune system. These “new friends” to the growing infant are affected by the type of delivery, either vaginal or Cesarean, whether the baby or mother gets antibiotics and, most importantly, what the baby is fed and when solid foods are introduced.

These microbes “help us digest and extract energy from food, which can influence weight gain,” the researchers said.

Breastfeeding introduces a helpful bacteria called Bifidobacterium into the infant’s gut that helps digest complex sugars called oligosaccharides.

When solid foods are introduced, a more “adult” blend of microbes, including Bacteroidetes and Firmicutes, is created, which is not beneficial to babies in terms of weight, the researchers said.

Helpful bacteria such as Bifidobacteriaceae, Veillonellaceae and Proteobacteria were thriving in infants who were still breastfeeding at 12 months and low in those who were not.

Breastmilk has “many important bioactive components that influence appetite and weight gain … which are not present in infant formulas,” the researchers say.

While formula feeding appeared to negatively affect gut bacteria, introducing complementary solid foods, along with breastfeeding, did not.

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