It was observed that the supplement enabled for the significant increase in Bifidobacterium species within the gut of the infants, suggesting the ability to establish a Bifido-dominant microbiota within one week. These levels were further enhanced with a greater frequency of breastfeeding, highlighting the possible compatibility of the species with breast milk.
Furthermore, the study found increased levels of acetic acid and markers of immunity in the stool samples of these infants, suggesting the potential health benefits of such probiotic supplementation.
The Japanese researchers conclude: “Supplementation with B. infantis M-63 in healthy term infants was well tolerated and beneficially modulated the infant gut microbiota toward higher Bifidobacterium levels, accompanied by softer stool consistency. B. infantis M-63 enhances the secretion of intestinal acetic acid and sIgA, providing beneficial effects on digestive function.”
Infant microbiome importance
Forming a healthy gut microbiota during infancy is a critical stage to determine health outcomes later in life, with many factors thought to influence this composition. Specifically, it has been established that Bidifobacterium species are a vital inhabitant for the microbiota during this time, with their presence associated with a range of beneficial outcomes for the body including organic acid production, inflammation regulation, and immunity effects.
Factors such as caesarean births, early antibiotic usage, and low-birth-weight have been noted to reduce Bifidobacterium numbers. Such reduction in numbers during infancy has been linked with the later development of metabolic conditions as well as increased risk of all-cause mortality.
As a result, there has been increased discussion around administering probiotics to neonates to achieve the formation of a Bifidobacterium-dominant microbiota, with previous studies highlighting anti-inflammatory and growth promotion effects as well as prevention of associated conditions in at-risk infants.
The B. infantis M-63 species has been previously isolated from the faeces of infants and has shown an array of health benefits when administered in combination with further species of Bifidobacterium and Lactobacillus in a previous study. Following this, the researchers aimed to continue the research and establish the potential benefits of B. infantis M-63 alone administered to full-term infants.
The scientists conducted a double-blind randomised controlled trial in healthy infants, from birth and up to 3 months of age, investigating the potential effects of the species on the intestinal environment, gastrointestinal function, and immunity.
This involved 56 infants being given B. infantis M-63 1 × 109 CFU/day, whilst a further 54 infants were given a placebo. Subsequent faecal samples were collected to analyse the microbiota, stool pH, markers of immunity and SCFAs.
It was observed that the infants administered the B. infantis M-63 had significantly increased abundance of Bifidobaceterium in the microbiota, which was seen to a greater extent in those that were breastfed, with a positive correlation with frequency reported.
In addition, the supplemented group were noted to have a reduced stool pH compared to those given the placebo, as well as increased levels of acetic acid and IgA at one month of age; a marker noted to play an important role in mucosal immunity. Furthermore, infants given the supplement had a reduction in the frequency of watery stools, in addition to a general reduction in defecation occurrences.
The lack of negative reactions to the probiotic highlights the strong tolerance of the supplement in these infants. Thus, the results indicate the potential for early supplementation with B. infantis M-63 to achieve a Bifidobacterium-dominant gut and the associated long-term benefits.
With regards to the observed improvement of stool characteristics, they speculate: “Since this effect was observed immediately after ingestion, it is possible that administration of M-63 directly regulates intestinal functions via a decrease in intestinal pH, etc., rather than promoting the development of intestinal functions.
“A certain number of infants in the placebo group showed no bifidobacterial colonization even though they were breastfed a higher proportion of the time.
"These results suggest that there are cases in which Bifidobacteria do not colonize even with breastfeeding and that supplementation with B. infantis in the early postnatal period and either breastfeeding or supplementation of alternative breast milk components may be necessary to establish a high percentage of Bifidobacteria.”
The researchers note that long-term follow-up studies are required to establish the potential beneficial effects of B. infantis M-63 for future health.
“Early Probiotic Supplementation of Healthy Term Infants with Bifidobacterium longum subsp. infantis M-63 Is Safe and Leads to the Development of Bifidobacterium-Predominant Gut Microbiota: A Double-Blind, Placebo-Controlled Trial”
By Akari Hiraku, Setsuko Nakata, Mai Murata, Chendong Xu, Natsumi Mutoh, Satoshi Arai, Toshitaka Odamaki, Noriyuki Iwabuchi, Miyuki Tanaka, Takahisa Tsuno and Masahiko Nakamura