We give the name “microbiome” to the microorganisms that make up the normal flora in living species. Most of our organ systems have their own microbiome, including the gut, which contains lactobacilli and other bacteria that includes streptococci, Bacteroides, Escherichia coli, Escherichia faecalis, and staphylococcus aureus and many more types. Healthy bacteria are considered healthy because they are less virulent, so they rarely cause disease. Instead, they do a lot of functions which are beneficial for us.
The majority of newborns (almost 85%) have sterile meconium (stool of the newborn). This means that there is no bacteria in their stool. A few organisms, probably acquired during labor (either normal delivery or caesarean section), may be present in 15% to 20% of newborns. Within 1 day of birth, bacteria invade the gut, partly from mouth and party from the anal orifice. Lactobacillus (L. bifidus is present as the total 99% of the normal flora in breast fed infants), enterococci and colon bacilli constitute the biome of gut in breast fed infant while the gut if artificially fed child has more L. acidophilus and colon bacilli. As the child grows, the meals change and he is exposed to different bacteria, which keep on influencing the gut biome.
The importance of populating the gut with bacteria
The human body contains 10 to 100 trillion microorganisms, that is more than the total number of cells a human has. That includes bacteria, fungi, and viruses, which are mostly present in the gut. Microbiota flourishes in the gut as a symbiont with toddlers, and these microorganisms provide them with different benefits, getting nutrition and shelter in return. The gut bacteria are beneficial for toddlers in the following ways:
- Contributes to a toddler’s nutrition: Intestinal bacteria such as Bifidobacterium and Lactobacillus help us synthesize several vitamins such as vitamin K, riboflavin (vitamin B2), biotin (vitamin B9), and cobalamin (vitamin B12). Deficiency of Vitamin K, which is one of the important component for blood clotting as it activates clotting factors, is very important in a newborn. Several other vitamins of the vitamin B complex are necessary for the production of blood cells, and redox reactions. These vitamins are also vital for the immune system.
- Provides anti-bacterial effect: Colicins are antibacterial substances produced by the normal gut bacteria. This anti-bacterial effect prevents the growth of pathogenic bacteria in the gut. This leads to the inhibition of the colonization of harmful bacteria which can otherwise cause infections.
- Contributes to digestion: Bacteroides thetaiotaomicron help digest plant substances by producing enzymes that otherwise cannot be digested. These indigestible sugars from plants provide one tenth of our daily energy requirements.
- Trains an immature immune system: Bacteroides fragilis Is another intestinal bacteria that interacts with our body’s immune system by producing of a compound called polysaccharide A. This substance is recognized by our dendritic cells, training our immune system to fight similar bacteria that produce similar compounds. This training of the immune system makes it stronger and allows it to fight off disease whenever required.
- Contributes to various parts of the immune system at the same time: Some bacteria produce a substance called butyrate, which helps boosting cell-mediated immunity. Meanwhile, some members of the normal gut flora produce an endotoxin in a small amounts. This stimulates our body’s defense mechanism to activate the alternative compliment pathways. Some gut bacteria are involved in the production of anti-inflammatory cytokines.
Probiotic strains recommended for toddlers
Children exposed to more diversity of food have a healthier and more varied flora. These children’s mental and physical health typically surpasses those who eat less diverse food. Toddlers are babies between 12 to 36 months of age (1 to 3 years). At the age of 12 months, the gut of the child contains a number of bacteria influenced by breast milk and solid food, which started to be given at 6 months. After 24 months of age, in most cases, the normal microbiome of toddlers is similar to adults.
Still, it will never hurt to strengthen this microbiota with recommended probiotic strains. Here’s a list of the important bacterial species recommended for toddlers to improve their overall health, and especially their immune system:
- Bacteroides species: They contribute to the production of vitamins, the digestion of food, and trains the immune while decreasing the levels of blood cholesterol. Examples of Bacteroides spp. present in the gut are Bacteroides fragilis, Bacteroides thetaiotaomicron and Bacteroides vulgatus.
- Lactobacillus rhamnosus: It helps preventing diarrhea in toddlers at high risk. Lactobacilli produce lactic acid, which is bactericidal; it can kill bacteria. It also helps to decrease blood cholesterol and sugar levels and plays role in prevention of urinary tract infections and dental caries.
- Bifidobacterium species: Bifidobacterium of the gut include B. infantalis also known as B. bifidum, and B. animalis. The role of B. infantalis in the gut health is mainly preventing allergic reactions. Another stain of Bifidobacterium species is B. Lactalis, which can be useful in cases of constipation.
- Lactobacillus acidophilus: Almost all lactobacilli of the gut contribute to boosting the immunity. This stain of lactobacillus is also used in a skin disorder called eczema due to its anti-inflammatory properties by inhibition of proinflammatory mediators.
- Lactobacillus reuteri: This stain of lactobacillus is good for colic/abdominal pain associated with the gut. They also help in the breakdown of bile salts.
- Streptococcus thermophiles: It can be used in children with lactose intolerance. It has important properties that reduce irritability in cases of food intolerance.
A careful combination of all of these bacteria can be achieved through promoting food variety, which is also important for a toddler’s nutrition. However, if you want to make sure your child gets an adequate dose of each, probiotics are especially formulated for that purpose.
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Di Gioia, D., Aloisio, I., Mazzola, G., & Biavati, B. (2014). Bifidobacteria: their impact on gut microbiota composition and their applications as probiotics in infants. Applied microbiology and biotechnology, 98(2), 563-577.