Evaluation of the safety, tolerance and efficacy of 1-year consumption of infant formula supplemented with Lactobacillus fermentum CECT5716 Lc40 or Bifidobacterium breve CECT7263: a randomized controlled trial.

Background: The microorganism present in breast milk, added to other factors, determine the colonization of infants. The objective of the present study is to evaluate the safety, tolerance and effects of the consumption of a milk formula during the first year of life that is supplemented with L. fermentum CECT5716 or Bifidobacterium breve CECT7263, two strains originally isolated from breast milk.

Methods: A randomized, double blind, controlled, parallel group study including healthy, formula-fed infants was conducted. Two hundred and thirty-six 1-month-old infants were selected and randomly divided into three study groups according to a randomization list. Infants in the control group received a standard powdered infant formula until 12 months of age. Infants in the probiotic groups received the same infant formula but supplemented with L. fermentum CECT5716 Lc40 or B. breve CECT7263. Main outcome was weigh-gain of infants as safety marker.

Results: One hundred and eighty-nine infants completed the eleven months of intervention (61 in control group, 65 in Lf group and 63 in Bb group). The growth of infants in the three groups was consistent with standards. No significant differences were observed in the main outcome, weight-gain (Control group: 5.77 Kg ± 0.95, Lf group: 5.77 Kg ± 1.31, Bb group: 5.58 Kg ± 1.10; p = 0.527). The three milk formulae were well tolerated, and no adverse effects were related to the consumption of any of the formula. Infants receiving B. breve CECT7263 had a 1.7 times lower risk of crying than the control group (OR = 0.569, CI 95% 0.568-0.571; p = 0.001). On the other hand, the incidence of diarrhoea in infants receiving the formula supplemented with L. fermentum CECT5716 was a 44% lower than in infants receiving the control formula (p = 0.014). The consumption of this Lactobacillus strain also reduced the duration of diarrhoea by 2.5 days versus control group (p = 0.044).

Conclusions: The addition of L. fermentum CECT5716 Lc40 or B. breve CECT7263, two probiotic strains naturally found in breast milk, to infant formulae is safe and induces beneficial effects on the health of infants.

Trial Registration: The trial was retrospectively registered in the US Library of Medicine ( www.clinicaltrial.gov ) with the number NCT03204630 . Registered 11 August 2016.