Probiotics don't protect 'preemies' from serious illness

A new study has found that the probiotic Bifidobacterium breve provides no benefit.

The findings challenge previous research that suggested potential benefits from probiotics, which are good bacteria found in certain foods and supplements.

The study included more than 1,300 very preterm infants. The babies were given either the probiotic Bifidobacterium breve or a placebo. This probiotic was used because it was the only one previously reported to show any benefit when the study began, the study authors explained.

Neither this study, nor the previously published ProPrems study using different probiotic interventions, have shown efficacy to prevent sepsis or death. Although ProPrems did show reduced necrotising enterocolitis, this was in a setting with low background rates of this complication. The authors say: "These two large trials suggest that, while probiotics are generally safe in the short term, they are not universally effective, and that different strains and combinations should be investigated separately."

They conclude that the importance of gut microbes in the complex pathogenesis of necrotising enterocolitis is widely accepted. As understanding progresses so the rationale for the choice of probiotics that might have a therapeutic role either alone or in combination, and of which infants might benefit, should strengthen. In the meantime, the evidence from this trial does not support the routine administration of probiotics to the preterm infant and the validity of combining trials of different probiotics to perform meta-analyses must be questioned.

The study appears in The Lancet.