Scientist - News - 19-01-2009:
«BackLong-term Finnish study on probiotics and allergic disease Beintema, Nienke According to a large, five-year study, probiotics may prevent eczema when assessed at 2 years of age, while this effect does not extend to 5 years. However, there does seem to be an effect among caesarean-delivered children. The researchers concluded earlier that these probiotics have no adverse health effects on small children, and reduce respiratory tract infections. Microbial exposure in early childhood is associated with allergic disease at a later age. In comparison with healthy children, allergic children have a different gastrointestinal microflora, with less lactobacilli and bifidobacteria. Against this background, probiotic treatment has often been proposed and studied in relation to allergy prevention. The conclusions vary greatly across studies, with some noting no significant results and others showing positive effects. A five-year study, carried out at the University Central Hospital of Helsinki, Finland, now brings some additional insights. The study, which was published in the January issue of the Journal of Allergy and Clinical Immunology, complements earlier publications by the same research group. Two-year effect The researchers randomly assigned 1223 women pregnant with high-risk children to receive either a probiotic preparation (Lactobacillus rhamnosus GG, L. rhamnosus LC705, Bifidobacterium breve Bb99, and Propionibacterium freudenreichii ssp. shermanii JS) or a placebo for two to four weeks before delivery. Their infants received the same probiotics plus prebiotic galacto-oligosaccharides, or a placebo for six months. After two years and after five years, the researchers studied the effect of these treatments on the incidence of allergic diseases (food allergy, eczema, asthma, and allergic rhinitis). The two-year result appeared in the January 2007 issue of the same journal. Although the probiotics had no effect on the cumulative incidence of allergic diseases, they did significantly reduce the incidence of atopic eczema by 34%. The most recent article was interestingly different. After five years, no significant difference appeared in frequencies in any of the studied allergic diseases, at least not when the entire cohort was taken into account. However, when the researchers singled out the caesarean-delivered children, they found 40% less atopic disease in the group receiving probiotics. "It is possible that stronger and longer stimulation of the infant immune system, possibly by varying the strains of bacteria, may result in better allergy-preventive effects," said lead author Mikael Kuitunen in his University’s press release. He emphasizes that more research is needed into the reasons why the earlier-observed benefits do not extend to age 5, but notes that in any case, pro- and prebiotics offer interesting potential in the prevention of atopic eczema in high-risk infants. Respiratory tract infections An earlier study by the same group, which appeared n the July 2008 issue of The Lancet, had identified no adverse effects of this probiotic mixture in terms of neonatal morbidity, feeding-related behaviors (such as infantile colic), or other serious adverse events. During the six-month intervention, antibiotics were prescribed less often in the probiotic group than in the placebo group, and throughout the follow-up period, this group experienced fewer respiratory tract infections. More information: Finnish study in the Journal of Allergy and Clinical Immunology, January 2009 Earlier Finnish study in the Journal of Allergy and Clinical Immunology, January 2007 Finnish study in The Lancet, July 2008 Related publications: Australian/British study in the Cochrane Library New Zealand study in the Journal of Allergy and Clinical Immunology, October 2008 |