'Good' Bacteria May Thwart Allergies in Toddlers
By Keith Mulvihill
NEW YORK (Reuters Health) - Giving soon-to-be mothers and newborns doses of "good" bacteria may help prevent childhood allergies up to age four, continuing research suggests.
The findings, a follow-up from a study that initially looked at allergies in newborns up to age two, may offer evidence that harmless bacteria can train infants' immune systems to resist allergic reactions, according to the report in the journal The Lancet.
In the ongoing study, researchers in Finland used a type of bacteria found naturally in the gut -- called Lactobacillus rhamnosus strain GG -- to try to prevent allergy development in at-risk infants.
Lactobacillus bacteria have long been used in food fermentation and are commonly found in items such as yogurt. Some forms of the bacterium dwell normally in the human intestines. Lactobacillus-laden foods and supplements -- commonly referred to as "probiotics" -- have grown increasingly popular because they are believed to promote good gastrointestinal health.
In the original study, Dr. Marko Kalliomaki and colleagues at Turku University Hospital gave a group of pregnant women either probiotic capsules or placebo capsules every day for a few weeks before their due dates. For 6 months after delivery, women who breast-fed continued on the probiotics or placebo, while bottle-fed infants were given probiotics or placebo directly. All of the babies were considered to be at high risk of developing allergies because a parent or sibling was affected.
Kalliomaki's team originally published results of the study when the children were two years old. Now, the researchers report that the youngsters in the probiotic supplement group were less likely at age 4 to have developed an allergic skin condition called atopic eczema.
"The main finding is that administration of probiotics (shortly before and after birth) may prevent the development of atopic eczema during the first 4 years of life in high-risk children," Kalliomaki told Reuters Health. Children at high risk, he said, are those whose mother, father or older sibling has asthma, atopic eczema or allergic rhinitis.
"The new finding is that the preventive potential of Lactobacillus GG may extend beyond infancy ... to the age of 4 years," the researcher added.
Probiotics have been shown to have favorable effects on the gut, according to Kalliomaki. Moreover these agents have clear effects on the developing immune system, he explained.
By the age of four years, 25 of 54 children in the placebo group had developed allergic eczema, a condition in which the skin becomes irritated, red and itchy. But just 14 of the 53 children who had received probiotics developed the skin condition -- a 43-percent reduction, according to report.
The study was funded by the Academy of Finland and Turku University Hospital.
SOURCE: The Lancet 2003;361:1869-1870.