Clinical Study Highlight
Randomized, double-blind, placebo-controlled trial of probiotics for primary prevention: no clinical effects of Lactobacillus GG supplementation.
Pediatrics. 2008. 121(4):e850-6.
Kopp MV, Hennemuth I, Heinzmann A, Urbanek R. Randomized, double-blind, placebo-controlled trial of probiotics for primary prevention: no clinical effects of Lactobacillus GG supplementation. Pediatrics. 2008. 121(4):e850-6.
Back in 2001, Kalliomaki et al. were the first to report that a probiotic strain, rhamnosusGG, was able to reduce the incidence of atopic dermatitis in at-risk infants at the age of 2 yrs. Follow up studies with this intervention group continued to confirm these results through age of 7 yrs, but protection did not extend to other allergic diseases such as asthma or allergic rhinitis. Recently, Kopp and colleagues (2008) used an experimental design very similar to Kalliomaki, administering 1010 cfu per day of rhamnosus GG to pregnant women and their babies. One notable difference in the protocols, however, is that in the Kopp study, probiotic supplementation during the first three months after birth was only to the breastfeeding mother, not directly to the infant. The Kopp study did not confirm the Kalliomaki study findings, and in fact found no reduction in incidence or severity of atopic dermatitis. Furthermore, this study showed an association between probiotic treatment and increased rate of recurrent episodes of wheezing bronchitis. The authors concluded that rhamnosus GG should not be generally recommended for primary prevention of allergy in infants. This is in contrast to a recent publication [Floch et al. 2008; J Clin Gastroenterol 42 (Supp. 2): S104-S108] which recommends this strain for both treatment and prevention of atopic eczema associated with cowâ€™s milk allergy. Another recent study (Taylor, et al. 2007; J Allergy Clin Immunol 119:184-91) with a similar design but using a different probiotic agent ( acidophilus LAVRI-A1) also showed no impact on incidence of atopic dermatitis but an association with an increased risk of allergen sensitization.
These contrasting results should be carefully considered. It is possible, but unconfirmed, that the lack of direct supplementation to the newborn infant accounts for differences in efficacy in two very similar studies. Although numerous studies with neonates being administered probiotics have been conducted with no report of adverse effects associated with the intervention, the presence of statistically significant increases in adverse events reported in Taylor et al. (2007) and Kopp et al. (2008) justifies the need for further careful investigation on the strategy of infant probiotic supplementation for the prevention of atopic disease. For example, in addition to the dose and strain, other factors may be critical in affecting clinical outcomes, such as the timing of the probiotic exposure (e.g., during the prenatal or perinatal or neonatal period, etc.), as well as underlying genetic predisposition or family history for atopic disease.