To understand your baby, you need to understand their gut microbiome. Like all people, the bacteria in a baby’s GI system, or microbiome, do most of the work breaking down food and converting it into vitamins and minerals that a baby uses. The waste product from the bacteria are what create the thick, protective lining of a baby’s intestines and colon. And the bacteria interact with a baby’s growing system, affecting everything from the immune system to hormones, and more.
What a Baby’s Microbiome Looks Like
In the first couple months of a baby’s life, a baby’s gut microbiome is specialized to thrive on what they eat - formula or breastmilk. A baby’s early gut biome is generally simple and made of Bifidobacteria and Lactobacillus species that are capable of eating the sugars present in milk.
When a baby moves to a solid food-based diet, this shifts the gut bacteria to species that thrive on foods, while the species that thrive on milk die off. Clostridiales and Bacteroidetes species are more common later in infancy. What foods a baby eats, how high in fiber or sugar or fat they are, will determine exactly which species of bacteria thrive.
Do All Babies Have the Same Microbiome?
One surprising finding is that very young babies have very different gut biomes, not only from adults, but from each other. Breastfed baby guts are generally very diverse at the species level, and more diverse than formula-fed babies. The specific bacteria are even affected by ethnicity, perhaps because mothers of different ethnic backgrounds produce milk with different types of milk sugars.
Older babies seem to have far more similar gut bacteria to each other -- perhaps because babies & toddlers in a country tend to eat similar food. And once food is introduced, a baby’s gut bacteria look very similar to an adult’s gut, because babies are eating the same foods, just mashed up.
Because the gut biomes of 6-12 month old babies are all very similar, it implies that a baby’s gut biome from birth to age 6 months is really what determines the risk of future allergic disease.Beyond the 3 B’s of early onset allergies, the use of a breastfeeding or formula support probiotic can ensure that babies early gut biomes are healthy and able to regulate their immune system to stay away from allergic diseases.