Why are probiotics useful for kids? In children, when the composition of the GI flora is out-of-whack, a myriad of illnesses (similar to that of adults) can ensue. Probiotics exert a major influence on the microbiome. A kid’s microbiome begins to develop inside the womb and matures during infancy and childhood. The newborn leaves the germ-free environment of the mother’s womb and enters a highly contaminated world, which mandates potent defenses to prevent disease. The pro- and prebiotics confer long-term health benefits on the developing immune system of a child. This post will highlight the significance of adding probiotics to children’s diet.
Probiotics can Prevent Necrotizing Enterocolitis in Premature Infants
Some infants who are born prematurely can suffer from an intractable bloody diarrheal illness, called necrotizing enterocolitis (NEC). It is a condition in which the intestinal tissue undergoes inflammation, injury, and begins to die. Infectious agents seem to colonize the gut in these infants after the introduction of formula milk. Specific strains of bacteria, primarily the Lactobacillus and Bifidobacteria can preclude the occurrence of NEC when fed to the preterm babies. These probiotics break down carbohydrates to produce lactic acid, creating an acidic milieu in the gut. This promotes the growth of beneficial bacteria, whereas hampers that of the harmful ones. 
These beneficial bacteria also strengthen the gut barriers, which fends off the harmful agents against navigating from the GI tract to the outside systems – a process called bacterial translocation.
Moreover, the preterm infants afflicted with NEC lack the ability to tolerate anything through the mouth. Statistics show that probiotics given to these babies can improve oral (mouth) intake via accelerating maturation of intestine.  Probiotic preparations containing either lactobacillus alone or in combination with bifidobacterium are found to be highly effective at keeping NEC at bay. What’s more? Probiotics also appear to minimize the death rates associated with NEC. 
Probiotics to Aid in the Formation of Nutrients in Children
The favorable bacteria help to form nutrients otherwise not made by the body (like vitamin K) and other beneficial nutrients (such as amino acids and short‐chain fatty acids).
Probiotics May Benefit Kids with Allergies and Asthma
Type 2 helper T cells (Th2) are the white blood cells that play a triggering role in the recruitment of IgE antibody-producing cells of the body, which, subsequently precipitate allergic and airway diseases in children.  Probiotics might slow down this Th2 immune response, thereby improving the breathing issues in children with asthma. In addition, these beneficial microbes balance the pollen-specific antibody levels in seasonal allergic rhinitis that might alleviate the severity of symptoms of this condition.  These theories are nonetheless controversial.
An additional promising area suggesting the effectiveness of probiotics in kids is eczema. Research reveals that probiotics can reduce the risk of eczema in babies when given to pregnant women or breastfeeding mothers. 
Probiotics Ease Viral Diarrhea
The commonest cause of acute diarrhea in kids is rotavirus. A systematic analysis that merged the results from multiple studies demonstrated that probiotics (predominantly lactobacillus reuteri) decreased the duration of acute rotavirus diarrhea in children.  Also observed was a drop in the number of hospital admissions and the duration of the hospital stay in children infected with rotavirus.
Probiotics Can Control Antibiotic-Associated Diarrhea (AAD)
Just like adults, children who are given antibiotics are prone to microbiome perturbations and AAD. In these instances, probiotics stabilize the microbiome and prevent GI and non-GI-related illnesses.
- Ahmadi E, Alizadeh-Navaei R, Rezai MS. Efficacy of probiotic use in acute rotavirus diarrhea in children: A systematic review and meta-analysis. Caspian Journal of Internal Medicine. 2015;6(4):187-195.