To add or not to add probiotics to infant formulae? An updated systematic review

We updated evidence on the effects of the administration of probiotic-supplemented infant formulae (IF) compared with unsupplemented IF. Five databases were searched up to September 2016 for randomised controlled trials. Twenty publications were identified, including five new RCTs. Supplementation of IF with Bifidobacterium lactis Bb12, either alone or with Streptococcus thermophilus, had no effect on growth, respiratory illness, antibiotic use, stool frequency or consistency. However, there was a significant reduction in the number of episodes of gastrointestinal infections (Bb12) and a lower frequency of colic or irritability (when both strains were used). Lactobacillus johnsonii La1 had no effect on growth, gastrointestinal infections, or respiratory illness episodes. There were no effects of supplementation of IF with Bifidobacterium longum BL999, alone or with Lactobacillus rhamnosus LPR. L. rhamnosus GG was associated with better growth; it had no effect on colic/crying, or irritability, and it was associated with greater indexes of loose stools and a higher defecation frequency. Lactobacillus reuteri ATCC 55730 had no effect on growth, colic, crying, irritability, respiratory illness, antibiotic use, stool frequency, or stool consistency; however, it reduced the number of episodes of diarrhoea. L. reuteri DSM 17938 had no effect on growth, night-time sleeping, or flatulence, but it reduced the number of spitting episodes. Lactobacillus salivarius CEC5713 had no effect on growth, colic, crying, or irritability; however, it resulted in a significant reduction in the rate of diarrhoea and the number of episodes of respiratory symptoms. In conclusion, the administration of probiotic-supplemented formulae to healthy infants does not raise safety concerns with regard to growth and adverse effects. Some beneficial clinical effects are possible; however, there is no existing robust evidence to recommend their routine use. The latter conclusion may reflect the small amount of data on a specific probiotic strain(s) and outcomes, rather than a genuine lack of an effect.