What is the benefit of probiotics for babies?

The microbiota refers to the collection of microorganisms that inhabit our bodies. There are several microbiotas, the main one being the gut microbiota. In infants, it is greatly influenced by the way they are brought into the world. Indeed, it has been shown that the populations of bacteria present in the intestines of babies differ depending on whether the child is born vaginally or by caesarean section. In the former case, their gut microbiota will be similar to that of their mother's vagina and primarily composed of bacteria of the type Lactobacillus and Prevotella. In the latter, it will rather contain bacteria such as Streptococcus, Corynebacterium and Propionibacterium in a manner similar to the skin microbiota of their mother.

The infant's gut microbiota is also influenced by their diet. Several studies have shown that babies exclusively breastfed have fewer Gammaproteobacteria type bacteria compared to those fed with formula milk. On the other hand, their gut microbiota is richer in Bifidobacteria. Finally, studies have highlighted a predominant role of the bacterium Escherichia coli in the development of the infant's gut microbiota. Indeed, this microorganism promotes the multiplication of epithelial cells lining the digestive tract as well as the production of mucus by these cells. This action ensures the nutrition of other bacteria, which contributes to the formation of the microbiota.

In contrast to probiotics (literally "for life" in Greek), antibiotics are medicines designed to kill bacteria. They can be prescribed for babies in the event of abacterial infection, particularly respiratory or ear infections. While they are very effective in combating diseases caused by bacteria, it is important to remember that antibiotics have no effect on viral infections. Furthermore, antibiotics can sometimes cause diarrhoea, especially in babies, whose microbiota is still developing. Indeed, antibiotics do not only target the bacteria causing the disease but can also attack others living in the intestine. This can disrupt the balance of the intestinal flora and lead to an overgrowth of harmful bacteria, releasing toxins that cause diarrhoea.

In order to avoid this undesirable effect associated with the use of antibiotics, it is sometimes recommended to use probiotics. These microorganisms, external to our body, serve to strengthen the bacterial populations of the intestine in order to preserve the balance of the microbiota disrupted by antibiotics. Several studies have reported their effectiveness in preventing diarrhoea, including in infants. Among the most commonly used strains, we find the Lactobacillus rhamnosus, the Lactobacillus reuteri and the Saccharomyces boulardii. It is also worth noting that no adverse effects have been encountered in the various studies conducted on the intake of probiotics by children. However, it is always better to apply the precautionary principle and seek the advice of a paediatrician before supplementing a baby with probiotics.

Infant colic is common and affects approximately 20% of newborns. It is characterised by intense crying for no apparent reason. Infant colic can be very challenging for parents who see their child crying for several hours without being able to reassure and calm them. The causes of this crying are poorly understood, but it seems they may be due to involuntary spasms of the intestine. Moreover, some studies suggest that the intestinal flora of infants suffering from colic differs from that of other babies.

Given this information, it would appear that the use of probiotics could be beneficial in restoring the balance of the flora and providing a landscape of a healthier gut microbiota. Some scientists have indeed reported a certain effectiveness of certain probiotics such as Lactobacillus, Bifidobacterium and Streptococcus in alleviating infant colic. However, at present, this is not the subject of a real consensus in the scientific community and evidence is still lacking.

Atopic dermatitis is a very common skin condition in children. It is indeed estimated that it affects approximately one in five infants. Linked to a genetic predisposition, atopic eczema leads to the appearance of itchy red patches on the body, which can be very bothersome for children. Numerous research studies have been conducted on infant eczema and its causes. Several researchers have investigated to highlight potential links between this dermatosis and infant nutrition, although the results have not been particularly conclusive. The possibility of a correlation between eczema and the gut microbiota has also been investigated.

The preventive effect of probiotics on the development of atopic dermatitis remains controversial to this day. However, a double-blind, placebo-controlled trial seems to suggest that probiotics could be of interest. During this study, 112 pregnant women with a history of family eczema received a supplement once a day from eight weeks before childbirth and up to six months after. They were given either a mixture of Bifidobacterium bifidum, Bifidobacterium lactis and Lactobacillus acidophilus, or a placebo.

The infants born from this study were exclusively breastfed for the first three months, then fed with either breast milk or cow's milk from four to six months. The clinical symptoms of the infants were monitored until they reached the age of one year, when the levels of total and specific Immunoglobulin E against common allergens were measured. The prevalence of eczema at one year in the probiotics group was significantly lower than in the placebo group (18.2% versus 40.0%). It would thus appear that prenatal and postnatal supplementation with the aforementioned probiotics is an effective approach to prevent the development of eczema in the most at-risk babies.

• KUITUNEN M. & al. Probiotics in the Treatment and Prevention of Allergy in Children. World Allergy Organization Journal (2009).

• JI G. & al. The impact of a probiotic blend (Bifidobacterium bifidum, Bifidobacterium lactis, Lactobacillus acidophilus) on the primary prevention of eczema: a double-blind, randomised, placebo-controlled trial. Paediatric Allergy and Immunology (2010).

• WAKE M. & al. Probiotics to enhance colic outcomes in the community: Protocol for the Baby Biotics randomised controlled trial. BMC Pediatrics (2012).

• ANDREA M. & co. Probiotics for Prevention and Treatment of Diarrhoea. Journal of Clinical Gastroenterology (2015).

• AKOBENG A. & et al. Probiotics for the prevention of infantile colic. Cochrane Database of Systematic Reviews (2019).