Study shows eating peanuts while breastfeeding may reduce risk of allergies

A new study from the Children's Hospital Research Institute of Manitoba shows eating peanuts while breastfeeding may actually prevent babies from developing peanut allergies later in life.

The study, released Tuesday in the Journal of Allergy and Clinical Immunology, used data from an allergy and asthma study that tracked 342 kids born in Winnipeg and Vancouver in 1995 from birth to the age of 15.

"At that time was the time period where we were recommending the avoidance of peanuts and thinking that that would help prevent allergies," explained Meghan Azad, assistant professor and research scientist at the Children's Hospital Research Institute of Manitoba, who decided to review the data from the previous research after a number of recent studies have shown early introduction of peanuts to a baby's diet may help to prevent peanut allergies.

It got Azad thinking about whether breastfeeding while eating peanuts would help too.

"I'm a breastfeeding researcher and the recent studies that have come out showing that early peanut introduction is better have really ignored breastfeeding, and to me that was curious because we know from some of the other research that peanut proteins actually make their way into breast milk," she said. 

"I realized that we had this old study and the data was still laying around and we might have a chance to address this question."

Because the previous study had divided the children into two groups — one was told not to introduce peanuts and the other wasn't given any recommendations — Azad and her fellow researchers were able to see exactly what happened to the kids whose moms hadn't eaten peanuts while breastfeeding.

"We looked back and sure enough we'd asked the moms about their peanut consumption and about their breastfeeding practices and then we followed the babies for a number of years and we knew which ones developed peanut sensitization and which ones didn't," explained Azad.

About 60 of the participants had mothers who ate peanuts while breastfeeding and had peanuts introduced in their diets early, she said. Only one developed a peanut sensitization.

"So it's under two per cent — whereas in the other categories it was up around 15 or 16 per cent," she said. 

Azad said around six per cent of the children studied who didn't receive either early exposure to peanuts or their mother didn't eat peanuts while breastfeeding developed allergies to peanuts.

"It seemed to be really that the combination was important — it had to be that the moms ate peanuts and breastfed, and the babies got peanuts before they turned one," said Azad of the findings. "If one or the other of those things happened then we didn't' see this effect."

Azad is hopeful the results of the study will be used for further research that may be used to develop strategies for preventing peanut allergies in the future.

"I think this is an important piece of the puzzle," she said. "We know that there are many amazing things in breast milk including antibodies and immune factors and all of these could be interacting with the peanut proteins to induce tolerance to peanut in the baby and the more that we can learn about that the better.

"It'll be really interesting now that this research is out there to see what other groups around the world doing allergy research will find in their data."