The research, published on-line ahead of print in the Journal of Allergy & Clinical Immunology (doi: 10.1016/j.jaci.2006.09.009), is said to be the first to link the prevalence of eczema to specific gut bacteria, and "thus supporting the important role of commensal bacteria in the pathogenesis of eczema."
Eczema, also known as atopic dermatitis (AD), is one of the first signs of allergy during the early days of life and is said to be due to delayed development of the immune system. According to the American Academy of Dermatologists it affects between 10 to 20 percent of all infants, but almost half of these kids will 'grow out' of eczema between the ages of five and 15.
The research adds to a previous study from Finland that reported in 2003 that children who were exposed to the Lactobacillus rhamnosus GG (LGG) bacteria around the time of birth were 40 per cent less likely to develop atopic eczema at four years of age compared with children in a placebo group.
In the new study, Kaarina Kukkonen and colleagues from the University of Helsinki and Valio R&D built these earlier results by examining the effects of a probiotic and prebiotic combination on allergy prevention in a much larger population of allergy-prone infants than previously studied.
The researchers randomised 1223 pregnant women to receive either placebo or daily probiotic supplements containing four probiotic strains - Lactobacillus rhamnosus GG; L rhamnosus LC705; Bifidobacterium breve Bb99; and Propionibacterium freudenreichii ssp. shermanii JS.
The women were supplemented for the two to four weeks prior to delivery. The newborns were then supplemented with either the same probiotics in combination with galacto-oligosaccharides (461 babies) or placebo (464 babies) for six months.
Researchers have found that breast milk naturally contains prebiotic oligosaccharides, believed to stimulate bifidobacteria - so-called 'friendly' bacteria that help release energy and nutrients from food.
While no significant difference between the supplemented and placebo groups were observed for allergic disease overall, the researchers do report that supplementation with the probiotic, prebiotic mixture was associated with a 26 per cent reduction in eczema, while atopic eczema was reduced by 34 per cent.
Faecal samples revealed that the pro-, prebiotic group had significantly higher lactobacilli, propionibacteria, and bifidobacteria populations.
This result, said the researchers, indicated "successful intervention and good adherence."
"Our prospective study indicates, for the first time to our knowledge, an inverse association between the prevalence of eczema and the abundance of certain species of the indigenous gut microbiota, thus supporting the important role of commensal bacteria in the pathogenesis of eczema," wrote Kukkonen.
"Gut microbiota contact directly with extensions of dendritic cells, which orchestrate the mucosal immune homeostasis. Commensal bacteria stimulate the innate immune system and contribute to the generation of regulatory lymphocytes, which, through IL-10 and TGF-â, establish and maintain mucosal immune tolerance," said the researchers.
The results show, they said, that probiotics and prebiotics offer an "easily accessible, inexpensive, and safe" way of reducing eczema in infants, particularly high-risk infants.
The researchers said that continued follow-up on these same infants will show if this effect is maintained later in life, and if any impact on airway allergies such as asthma is observed.
The study was funded by Valio Ltd and the Helsinki University Central Hospital.