In this randomized double-blind, placebo-controlled, multicentre trial, 291 mother-infant pairs were supplemented for 16 weeks with either Lc40 (1 capsule/day containing 3×109 CFU of Lactobacillus fermentum CECT5716) or placebo (1 maltodextrin containing capsule/day).

Results showed a positive and significant correlation of the Staphylococcus load between breast milk and infant faeces was only observed in control group. Additionally, the weight z-score of the infants whose mothers had higher values of Lactobacillus in their breast milk were significantly higher for the Lc40 group. A significant lower incidence of conjunctivitis in the infants whose mothers received Lc40 was also noted. A higher load of Staphylococcus in infant faeces significantly increased the risk of respiratory infections. Such incidence, under an absent or low Staphylococcus load in the faeces, was significantly 36 times higher in the infants in the control group than in the infants in the Lc40 group. However, the protective effect of Lc40 was gradually reduced as the Staphylococcus load of the milk increased.

In conclusion, administration of Lc40 to nursing women might influence infant growth and health but it seems to depend on its interactions with mother or infant microbiota.

Pastor-Villaescusa B, Hurtado JA, Gil-Campos M, et al. Effects of Lactobacillus fermentum CECT5716 Lc40 on infant growth and health: a randomised clinical trial in nursing women [published online ahead of print, 2020 Mar 27]. Benef Microbes. 2020;1–10. doi:10.3920/BM2019.0180