Perinatal probiotic supplements do not prevent childhood asthma

By Sara Freeman, medwireNews Reporter

medwireNews: There is insufficient evidence to support the use of probiotic supplements during pregnancy or infancy to prevent the development of asthma in infants, Canadian researchers report.

Among 3257 infants enrolled in nine randomized clinical trials, the risk ratio (RR) for doctor-diagnosed asthma with perinatal probiotic use versus no probiotic use was 0.99. Probiotics also did not prevent the development of wheeze in the infants, at an RR of 0.97.

“We found no evidence to support a protective association between perinatal probiotics and doctor diagnosed childhood asthma or wheeze,” the researchers report in the BMJ.

Lead researcher Meghan Azad (University of Alberta, Edmonton, Canada) and colleagues found that the use of probiotics might even be harmful in early life, with data on 1364 infants enrolled in six trials showing a 1.26-fold increase in lower respiratory tract infections. Further research is warranted to explore this finding, the team notes.

For their systematic review and meta-analysis, Azad and colleagues identified 20 trials involving 4866 infants. The median duration of probiotic supplementation was 6.3 months.

Several different Bifidobacterium spp. or Lactobacillus spp. of probiotic organisms were given to infants aged 1 year or younger or to pregnant women by various oral methods, including capsules, oil droplets, fluid-based suspensions (ie, in water, milk, or infant formula), but not via consumer food products. The daily dose of probiotic used ranged from 10⁸ to 10¹¹ colony-forming units, although it was not quantifiable in six trials.

Subgroup analyses indicated that the effect of probiotics was similar regardless of whether the supplements were given before, after, or before and after birth. There was also no difference if the supplements were given to the mother, infant, or both.

Thus, Azad et al conclude: “Probiotics cannot be recommended for primary prevention of childhood asthma or wheeze at this time.”

Despite the negative findings, David Osborn and John Sinn, both from the University of Sydney in New South Wales, Australia, comment in an editorial that probiotics do have some potential health benefits in infants.

“Enteral supplementation in very preterm or low birthweight infants reduces the risk of severe necrotising enterocolitis,” Osborn and Sinn observe. Probiotic supplements can also prevent diarrhea induced by antibiotic use and infectious diarrhea in infants.

“The health benefits of probiotics are currently driven by considerations other than asthma and wheeze,” the editorialists conclude.

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