Early life nutrition: the importance of good development of gut microbiota

Infant Nutrition

More specifically, the gut microbiota contains these 10,000 billion gut bacteria [1]. In this article, learn how this living ecosystem develops after birth, its different roles in the infant, and the influence of probiotics on the development of the gut microbiota.

The microbiota: an essential ally

Present from birth

At time of birth, the baby’s intestinal microbiota is poorly diversified and closely resembles the mother’s cutaneous and vaginal microbiota[2], which it acquires upon contact, particularly when delivery is vaginal. It has been suggested that the foetal digestive tract is already colonised by the microorganisms present in the intrauterine environment. This is called prenatal colonisation[2].

Microbiota develops in a chaotic progression during the first months of life, being influenced by the environment. In effect, type of birth, urban or rural living environment, antibiotic therapy, probiotics, etc., will modulate the microbiota’s bacterial composition. Bacteria will then gather successively until a definitive microbiota is established after weaning, around the age of 2-3 years old.[2;3]

A balanced composition

Microbiota composition varies depending on where it is in the gastrointestinal tract. Generally speaking, the microbiota contains two types of intestinal flora: core flora, which are perennial resident bacteria, and transient flora, which depend on food, drug treatments and the environment (water, air, etc.). The gut microbiota of a healthy individual consists of 2 dominant phyla, Firmicutes and Bacteroidetes. Around 1013 microorganisms colonise our digestive tract.[4]

However, an imbalance in the composition of bacteria, called dysbiosis, may increase the risk of diseases such as IBD (Chronic Inflammatory Bowel Disease) like Crohn’s disease.[5]

Essential roles of infant microbiota

The intestinal flora has numerous roles. The best known to date are 6:

  • metabolism of fibre, ensuring its fermentation
  • metabolism of xenobiotics
  • production of vitamins (K, B12, B8)
  • assimilation of micronutrients by means of a group of enzymes not present in our body
  • intestinal physiology for ensuring motor function and vascularisation
  • collecting energy
  • maturation of the immune system, which plays a barrier role against pathogens

Source: R. BURCELIN, L. ZITVOGEL. (2016, 1 February). Intestinal microbiota. INSERM

Infant microbiota and bifidobacteria

Bifidobacteria belong to the family of lactic acid bacteria. They help ferment milk during the manufacture of cheeses and preparations similar to yoghurts. They have therefore been consumed since ancestral times.

Bifidobacteria are largely dominant in the infant flora and often become subdominant after the weaning period (Mitsuoka et al., 1989).

The case of the BB12 strain

The BB-12® strain of Bifidobacterium animalis subsp. lactis is the most documented strain of Bifidobacterium in the world. Since 2007 in Europe, Bifidobacterium animalis has held Presumption of Recognised Safety status awarded by EFSA. To date, no claim is authorised by the European regulations on BB12. However, many studies have looked at the value of using it to change the bacterial composition of the microbiota, stimulate the immune system7 and modulate intestinal transit[8], or even reduce diarrhoea9 in infants. The BB-12® strain could offer promising avenues in early life nutrition.

What are the actions of BB12 on child microbiota?

Bifidobacterium Lactis BB-12® is able to implant itself temporarily in the intestinal microbiota[9;10] where it performs several beneficial functions for preventing infection.

First of all, supplementation with BB-12® induces modulation of the microbiota composition, the main consequence of which is to strengthen the intestinal barrier by limiting colonisation by a pathogen[9;11]. Enriching the microbiota with BB12 would also modulate the immune system by boosting the immune response[10;12;13]. These physiological effects could lead to functional effects in babies, in particular reducing the frequency of diarrhoea in infants(14). Given to its immuno-modulating effect, supplementation with BB-12® might reduce the intestinal inflammation observed when infants are suffering from colic. Effectively, a study in 2008 showed that consumption of a formula supplemented with BB-12® (109 CFU/g powder) for 21 days reduces intestinal inflammation (measurement of faecal calprotectin) in comparison with consumption of a formula without probiotics[13].

Furthermore, several studies[15;16;17] have also shown that supplementation with Bifidobacterium lactis improves atopic dermatitis symptoms at a dose of 109 CFU/day.

The composition of the infant microbiota therefore results from a delicate balance.A lot of research remains to be done on strains identified more recently, in order to confirm the prospects that probiotics could offer in early life nutrition.


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Mitsuoka, T. Intestinal flora and aging, Nutr Rev 50, 1996. 438-446.

Jimenez E,Marin ML,Martin R,Odriozola JM,Olivares M,XausJ et al. Is meconium from healthy newborns actually sterile? ResMicrobiol, 2008. 159:187–93.doi:10.1016/j.resmic, 2007.12.007

Sender R, et al. Revised Estimates for the Number of Human and Bacteria Cells in the Body. PLoS Biol, 2016. 14:e1002533

Swidsinski A, Weber J, Loening-Baucke V, Hale LP, Lochs H. Spatial organization and composition of the mucosal flora in patients with inflammatory bowel disease. J Clin Microbiol, 2005. 43:3380-3389.

Jandhyala SM, Talukdar R, Subramanyam C, Vuyyuru H, Sasikala M, Reddy DN. Role of the normal gut microbiota. World J Gastroenterol, 2015. 21(29): 8787-8803 [PMID: 26269668 DOI: 10.3748/wjg.v21.i29.8787]

R. BURCELIN, L. ZITVOGEL. 2016. Microbiote intestinal. INSERM

Rautava S, Arvilommi H, Isolauri E.Specific probiotics in enhancing maturation of IgA responses in formula-fed infants. Pediatr Res, 2006. 60(2):221-4.

Saavedra JM, Abi-Hanna A, Moore N, Yolken RH.Long-term consumption of infant formulas containing live probiotic bacteria: tolerance and safety.Am J Clin Nutr, 2004 . 79(2):261-7

Mohan, R., et al., Effects of Bifidobacterium lactis Bb12 supplementation on intestinal microbiota of preterm infants: a double-blind, placebo-controlled, randomized study. J Clin Microbiol, 2006. 44(11): p. 4025-31.

Holscher, H.D., et al., Bifidobacterium lactis Bb12 enhances intestinal antibody response in formula-fed infants: a randomized, double-blind, controlled trial. JPEN J Parenter Enteral Nutr, 2012. 36(1 Suppl): p. 106s-17s

Jungersen, M., et al., The Science behind the Probiotic Strain Bifidobacterium animalis subsp. lactis BB-12((R)). Microorganisms, 2014. 2(2): p. 92-110.

Fukushima, Y., et al., Effect of a probiotic formula on intestinal immunoglobulin A production in healthy children. Int J Food Microbiol, 1998. 42(1-2): p. 39-44.

Mohan, R., et al., Effects of Bifidobacterium lactis Bb12 supplementation on body weight, fecal pH, acetate, lactate, calprotectin, and IgA in preterm infants. Pediatr Res, 2008. 64(4): p. 418-22

Weizman, Z., G. Asli, and A. Alsheikh, Effect of a probiotic infant formula on infections in child care centers: comparison of two probiotic agents. Pediatrics, 2005. 115(1): p. 5-9

Larsen, N., et al., Predominant genera of fecal microbiota in children with atopic dermatitis are not altered by intake of probiotic bacteria Lactobacillus acidophilus NCFM and Bifidobacterium animalis subsp. lactis Bi-07. FEMS Microbiol Ecol, 2011. 75(3): p. 482-96.

Isolauri, E., et al., Probiotics in the management of atopic eczema. Clin Exp Allergy, 2000. 30(11): p. 1604-10

Gøbel, R., et al., Probiotics to young children with atopic dermatitis: a randomized placebo-controlled trial. International Journal of Probiotics and Prebiotics, 2010. 5(2): p. 53-60.

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