TURKU, FINLAND— Exposing infants very early in life to beneficial bacteria of the healthy gut microflora may prevent subsequent atopic disease, research is demonstrating. This type of prophylaxis—probiotic therapy—halved the incidence of atopic eczema among high-risk infants in a recent Finnish trial.[1]

The trial results apply mostly to developed nations, where atopic disease has risen sharply in recent years. Among the explanations for this increase is the hygiene hypothesis, which proposes that the rise in atopy stems primarily from reduced microbial exposure and infection due to better hygiene and reduced family size.[2] But the Finnish findings challenge this hypothesis.

“Our study … [demonstrates] that the gut microflora might be more important than infections in preventing atopic disease,” explained Erika Isolauri, MD, a principal investigator and Professor of Pediatrics at the University of Turku in Finland, in an interview with RESPIRATORY REVIEWS.

PROBIOTIC ADMINISTRATION

The randomized, double-blind, placebo-controlled trial included 159 pregnant women who had a mother, a father, and/or an older sibling with atopic eczema, allergic rhinitis, or asthma. Therefore, the women’s unborn infants were at high risk for atopic disease.

Each day for two to four weeks before their expected delivery date, half the women took two capsules of 1 X 10[10] colony-forming units of Lactobacillus rhamnosus; the other half received placebo capsules. L rhamnosus was selected for probiotic therapy because of its proven safety in infants and its effectiveness in treating allergic inflammation and food allergy.

The women continued their infants’ probiotic therapy or placebo for six months after delivery, by either taking the capsules themselves and passing the probiotics onto their infants through close contact or mixing the contents with water and spoon-feeding it to their infants. (Probiotics influence breast milk composition beneficially by enhancing immune protection.) Recurrent atopic eczema was the primary end point because it is the main sign of atopic disease early in life. The infants were assessed for atopic eczema, allergic rhinitis, and asthma at birth and ages 3, 6, 12, 18, and 24 months.

A REDUCTION IN ATOPIC ECZEMA

Of the 132 infants who completed the trial, 46 (35%) had evidence of atopic eczema by age 24 months. Atopic eczema was accompanied by asthma in six infants and by allergic rhinitis in one. The rate of atopic eczema was only 23% in the probiotic group versus 46% in the placebo group. The administration mode did not influence probiotic therapy’s efficacy: Atopic eczema developed in 25% of infants who were spoon-fed L rhamnosus and in 21% who got it from breast milk—a nonsignificant difference.

“These figures are remarkable, and if confirmed in other studies and applicable to other allergic diseases, probiotics would represent an important therapeutic advance,” wrote Simon H. Murch, PhD, FRCP, in an editorial.[3] Dr. Murch is with the Centre for Paediatric Gastroenterology at the Royal Free and University College School of Medicine in London.

—Timothy Begany