The two strains studied were Bifidobacterium animalis ssp. lactis CP-9 and Lactobacillus salivarius AP-32, which are both probiotics supplied by Glac Biotech, also the funder of the study.
Babies drinking infant formulas containing the two strains or without any probiotics also displayed similar growth rate in terms of their height and weight.
Writing in BMC Pediatrics, the researchers from China Medical University Children’s Hospital, China Medical University, Asia University, and Glac Biotech said that the study, which took place between 2020 and 2022, has confirmed the safety of probiotics use among infants.
“While supplementation with these strains did not affect normal growth or support the normal evolution of the gut microbiota, the available evidence confirms the safety of these bacterial strains for consumption in infants and validates the theoretical application of probiotics in this population,” said the researchers.
A total of 180 healthy infants born via vaginal delivery were randomised into three groups taking infant formulas containing either 1) 100bn CFU/g of Bifidobacterium animalis ssp. lactis CP-9 or 2) 100bn CFU/g of Lactobacillus salivarius AP-32 or 3) regular formula with no probiotics.
All infant formula used in the study was from Taiwanese brand YouLuck International.
They were fed with at least two scoops or 17.2g of the respective formulas that they were given for four months. Their growth parameters, such as weight and height were measured after the intervention.
Findings showed that infant formulas containing probiotics were safe and well-tolerated when compared to the regular infant formula.
For instance, the paediatricians did not observe adverse events that were related to the use of probiotics.
Across all three groups, 46 infants experienced one adverse event, and the number was spread out across the three groups.
“A total of 46 AEs were reported during the study, and none of them were diagnosed as being possibly related to the study product by paediatricians,” said the researchers.
The probiotic groups each had 16 babies with adverse event, while the placebo group had 14 babies with adverse event.
Infantile colic was one of the most common issues, with 15 babies experiencing it, 11 had atopic dermatitis, eight had seborrheic dermatitis, five had abdominal bloating, and two with reported rashes.
Only one case of constipation was recorded, similarly for enteritis, anal fissures, inguinal hernia, and infantile eczema.
“This result was similar to that of our recent study in which these two strains were supplied at a relatively high dosage to 1-month-old infants.
“A systematic review [also] revealed that supplementation with certain strains may reduce the number of colic episodes, days with fever, and antibiotic use, but no significant effects on infant weight or height were observed, with a mean duration of intervention of 5.6 ± 2.8 months," said the researchers.
In addition, the study showed that the two probiotic strains exhibited low resistance to antimicrobials or antibiotics.
For instance, B. animalis CP-9 did not exhibit resistance to the antibiotic tetracycline, even though it harboured four tetracycline resistance-related genes, including one tet(W) gene.
However, it showed greater resistance to the aminoglycoside antibiotic gentamicin when compared to the European Food Safety Authority’s (EFSA) standard for the Bifidobacterium genus.
Similarly, L. salivarius AP-32 did not exhibit tetracycline resistance even though it harboured two drug resistance-related genes, one related to tetracycline resistance, on the larger plasmid, said the researchers.
The antibiotic resistance of the probiotic strains was investigated to make sure that they could be suitable for intervention in infants.
“The present 4-month study findings suggested that the use of B. animalis CP-9 or L. salivarius AP-32 as formula additives is generally safe,” the researchers added.
Similar growth rate
There were also no significant differences in body weight and height among all three groups at the fourth month.
For instance, the body weight of infants fed with formula containing Bifidobacterium animalis ssp. lactis CP-9 was 7.05 ± 0.68 kg, while those taking Lactobacillus salivarius AP-32 was 6.95 ± 0.58 kg. The weight of babies on regular formula was 7.30 ± 0.83 kg.
Mean weight gain was also similar between the two probiotic groups and the placebo group, at 30.24 ± 5.30 g/day for the Bifidobacterium animalis ssp. lactis CP-9 group, 30.03 ± 4.23 g/day for the Lactobacillus salivarius AP-32 group, and 31.47 ± 5.35 g/day for the placebo group.
Gut microbiota composition
Interestingly, the supplementation of B. animalis CP-9 did not lead to a greater proportion of the B. animalis species, and the same case was seen for babies from the L. salivarius AP-32 group.
However, both probiotic groups had reported a significant increase in Bifidobacterium longum from baseline.
Source: BMC Pediatrics
Assessment of the safety and gut microbiota modulation ability of an infant formula containing Bifidobacterium animalis ssp. lactis CP-9 or Lactobacillus salivarius AP-32 and the effects of the formula on infant growth outcomes: insights from a four-month clinical study in infants under two months old.
https://doi.org/10.1186/s12887-024-05289-7
Authors: Shen, SP., Lin, HC., Chen, JF. et al.
