Researchers of the Otago and Auckland universities investigated the use of two probiotic supplements in 446 mothers and babies.
"Our study has found when you give pregnant women the probiotic supplement L. rhamnosus during the last five weeks of pregnancy, and for six months after birth while mothers are breast feeding, and then you give their infants the same probiotic up to two years of age there is a 50 per cent reduction in eczema by the age of two," says Professor Julian Crane from the University of Otago Wellington.
Probiotics are naturally occurring microbes often found in the intestines of infants, but in recent years their natural occurrence has decreased, which may explain why there has been an increase in the prevalence of eczema.
"This is an exciting and interesting result because we have compared the effect of two different probiotics in the same study and shown that one has an effect while the other is no different from placebo. This is important because it shows that the beneficial effects of probiotics vary considerably depending on which probiotics is used."
The study found there was no similar preventive effect for eczema with the second probiotic, Bifidobacterium lactis.
The skin disease eczema affects 30 per cent of infants in New Zealand by the age of two. Severity varies from a small patch of scaly dry skin to large weeping areas covering much of a child's body. There is no way to prevent it, and treatment relies on skin moisturising and corticosteroid creams. Currently the prevalence of eczema is increasing in New Zealand and around the world, although the reasons are not clear.
The researchers are currently following up these children to see if the benefits are sustained. They also plan to see whether there has been any effect on asthma or hay fever as the children grows up.
It is not known how probiotics work - one theory is that they alter an infant's developing immune system in a way that reduces allergy. The alternative theory is that some probiotics may alter the early infant intestine so that allergens cannot pass so easily into the circulation and set up allergic reactions.
Professor Crane says the positive findings regarding the use of L.rhamnosus and eczema warrant further study to determine how this particular probiotic actually works to reduce this troublesome skin disease in children.
This research has been published in the Journal of Allergy and Clinical Immunology, and funded jointly by the Health Research Council and Fonterra Cooperative Group.