Women who take probiotics while they’re pregnant and breastfeeding could be less likely to have children with eczema than mothers who don’t, a research review suggests.
Probiotic use during pregnancy and lactation was associated with a 22% lower risk of young children developing eczema, a common inflammatory skin disorder, the study found. This is the equivalent of preventing 44 cases of eczema for every 1,000 children.
While the study wasn’t designed to prove how probiotics might prevent eczema, it’s possible that taking these supplements changes the composition of breast milk and influences the way a child’s immune system and skin develop, said senior study author Dr Robert Boyle of Imperial College London and the University of Nottingham in the UK.
“There was already some evidence that probiotic exposure in early life may reduce risk of eczema in an infant,” Dr Boyle said.
“But this study makes it clearer that maternal probiotics during pregnancy and while breastfeeding seem to protect infants from eczema, whereas probiotics added to an infant’s diet directly do not seem to protect infants from developing eczema,” he added.
For the study, researchers analysed data from more than 400 studies including a total of about 1.5 million people.
There were 28 trials of probiotic use during pregnancy that involved about 6,000 women.
Probiotics include good bacteria and yeast that are similar to what’s in the body and help aid digestive tract health. Most of the trials focused on the bacteria lactobacillus, a common probiotic in yogurt and other fermented foods.
These studies found a reduced eczema risk for kids when their mothers took probiotics during the final weeks of pregnancy and the first six months of breastfeeding.
Avoiding potentially allergenic foods like nuts, dairy and eggs during pregnancy didn’t appear to influence a child’s risk of eczema, the study also found.
Another supplement, fish oil, was associated with a lower risk of egg allergies in kids.
Researchers looked at 19 trials of fish oil supplements during pregnancy, involving about 15,000 people. They found fish oil supplements associated with a 31% lower risk of egg allergies in kids, or an absolute reduction of 31 cases out of every 1,000 children.
These fish oil supplements contained omega-3 fatty acids, and women took them throughout the second half of pregnancy and the first three to four months of breastfeeding. Omega-3 fatty acids have anti-inflammatory properties and may be transferred from mothers to babies in breast milk.
One limitation of the current study is that the small trials in the analysis varied in duration, how they assessed mothers’ diets and supplement use, and how they determined whether children developed allergies or eczema, the authors note in PLoS Medicine.
Even so, the results add to evidence that dietary exposures may influence the development of allergic and autoimmune diseases, said Dr Ola Didrik Saugstad, a paediatrics researcher at the University of Oslo in Norway who wasn’t involved in the study.
Breastfeeding duration also plays a role, however, Saugstad said.
“There are many factors which may interplay with diet such as breastfeeding and whether it is exclusive, and how long it continues.”
Reducing the risk of eczema, food allergies and wheezing or asthma is one of the many reasons doctors advise women to exclusively breastfeed babies for at least four to six months, Saugstad added.
While some women may want to consider taking fish oil or probiotics to lower the risk of allergies and eczema in their children, studies to date don’t offer a clear picture of the ideal formulation and dose of these supplements for use during pregnancy, said Maria Jenmalm, an allergy researcher at Linkoping University in Sweden who wasn’t involved in the study.
“I believe further research is required to be able to translate these findings into practice guidelines,” Jenmalm said.