Two years of supplementation with L. rhamnosus strain HN001 led to less severe symptoms of eczema, scientists from the University of Otago and the University of Auckland report in the Journal of Allergy and Clinical Immunology.
“There has been controversy about whether probiotics prevent the development of eczema,” wrote the authors, led by Professor Julian Crane. “Our study provides further evidence that L rhamnosus is indeed an effective intervention for reducing the prevalence of eczema among high-risk children.”
However, no benefits were observed when children were supplemented with the bacterial strain Bifidobacterium lactis HN019. Both strains were provided by New Zealand’s Fonterra Co-operative Group, which also co-sponsored the study along with the Health Research Council of New Zealand.
“By comparing two different probiotics, we were able to demonstrate that not all probiotics are equally effective,” added the researchers. “Given the uncertainty about how probiotics exert their effects on allergic disease, future studies investigating their modes of action are required.”
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 per cent of all infants, but almost half of these kids will 'grow out' of eczema between the ages of five and 15.
Crane and his co-workers performed a double-blind, randomised placebo-controlled trial. Four hundred and fort-six pregnant women were recruited and randomly assigned to take daily supplements of L. rhamnosus HN001, B. animalis subsp lactis strain HN019 or placebo from 35 weeks gestation and for a further six months if breastfeeding. The infants received the same interventions from birth to two years of age.
All children were considered at ‘high-risk’ of inheriting eczema due to a family history of allergic disease.
Infants in the L. rhamnosus arm had significantly lower incidence of eczema, compared to the placebo group, said the researchers. However, no difference was observed between the placebo group and B. animalis subsp lactis group was observed.
Additionally, none of the interventions had any effect of measures of allergic hypersensitivity (atopy) after two years.
“Our study is unique in combining prenatal and postnatal probiotic supplementation, continued use of probiotics for two years post-natally, comparison of two different probiotics, and faecal sample analysis,” wrote the researchers.
“Understanding how Lactobacilli act to prevent eczema requires further investigation,” they added.
The news was welcomed by Karen Webber, global category manager paediatric nutrition at Fonterra. “As a result of this breakthrough, Fonterra Ingredients is looking to commercialise [L. rhamnosus strain HN001] with major global infant formula manufacturers as one of a range of initiatives helping Fonterra to expand its portfolio of specialty ingredients,” she said.
Source: Journal of Allergy and Clinical ImmunologyPublished online ahead of print 31 August 2008, doi:10.1016/j.jaci.2008.07.011“A differential effect of 2 probiotics in the prevention of eczema and atopy: A double-blind, randomized, placebo-controlled trial”Authors: K. Wickens, P.N. Black, T.V. Stanley, E. Mitchell, P. Fitzharris, G.W. Tannock, G. Purdie, J. Crane and Probiotic Study Group