Study looks to get to bottom of breastfeeding benefits

The poop from hundreds of eight-year-old Manitobans is being tested to find out how the bacteria in their gut affects their health, and if being breastfed as babies has a lasting impact.

It's part of a larger national study that has already shown exclusive breastfeeding in the first three months of life provides more protection against an infant becoming overweight at one year of age than either partial breastfeeding or formula feeding.

The research published Monday in JAMA Pediatrics — a peer-reviewed, American Medical Association journal — found a 63 per cent increased risk of becoming overweight among infants who were partially (versus exclusively) breastfed at three months of age, and a 102 per cent increased risk among exclusively formula-fed infants.

"Breastfeeding is one of the most influential factors in shaping the infant gut microbiome" — the community of micro-organisms or bacteria that live in the human digestive tract — says co-author Meghan Azad, a researcher at the Children’s Hospital Research Institute of Manitoba.

It was one of the largest infant-microbiome studies in the world, identifying more than 900 types of bacteria from 2.6-million DNA sequences generated from more than 1,000 infants, researchers said in a news release.

They found breastfed infants supplemented with formula were at increased risk for becoming overweight at one year of age, and had a different microbiota composition than exclusively breastfed infants. Whereas breastfed infants supplemented with complementary foods only and no formula were similar to exclusively breastfed infants with no increased risk. An infant’s gut microbiome was different in formula-fed babies, said Azad.

"In a normal, healthy breastfed baby, usually the dominant bacteria is bifidobacteria," she said. In formula-fed babies it is a bacteria called lachnospiracae, which has been associated with infants being overweight, she said.

"There is quite a lot of data that shows being overweight (as a baby) tracks later into childhood and adulthood," and being overweight has been linked to health concerns, said Azad. Breast milk helps to prevent childhood infections, obesity, and asthma, and has many health benefits, she said.

"We know know how important it is in setting the stage in life for a healthy trajectory," said Azad, research chair in developmental origins of chronic disease at the University of Manitoba. "We've come to appreciate how important microbiome is."

The study included 1,087 babies and moms participating in the Allergy, Genes and Environment Network's CHILD Study. Researchers studied diaper biome samples from the infants, but stopped in later years when they were no longer in diapers.

"The logistics of getting kids to poop on demand" delayed checking the children's microbiome again until they had turned eight last fall, said Azad.

The national birth cohort CHILD study collects a wide range of health, lifestyle and environmental exposure information from nearly 3,500 families and children from pregnancy to school age.

Participants are in Vancouver, Toronto, Edmonton and Manitoba, with 850 in Winnipeg and 150 in the Morden-Winkler area — the only rural component of the nationwide, said Azad, and one that might offer a hint as to why children in urban areas are more prone to allergies.

"Kids in rural areas and farms have lower rates of allergy," Azad said. Researchers hope to keep following the children and learn more about the makeup of their microbiome and beyond, she said.

"We can ask more sophisticated questions."

carol.sanders@freepress.mb.ca