Did you know we might be born with our own gut bacteria?
Scientists Working With Mice
Scientists assumed that babies were born without bacteria, and were exposed to them during their passage through the vagina, or when they reached the outside world.
How do they know the bacteria weren't from the outside?
Spanish scientists working with mice did an experiment to answer that question. First, they genetically labeled bacteria so they could identify them. Then they fed the bacteria to pregnant mice in a solution of milk.
They delivered the mouse pups by caesarean section into a sterile environment to make sure the pups weren't exposed to any outside bacteria. The unexpected result was that the pups had the labeled bacteria in their first feces, known as meconium.
And this can happen in humans as well as mice?
In a second study, scientists examined meconium samples from twenty human babies. Instead of being sterile, the samples contained four types of bacteria. Some were lactic acid-producing bacteria like Lactobacillus that can digest milk sugar. Others were bacteria commonly found in the digestive tract, such as E. coli.
So, how did the bacteria get there?
Scientists aren't sure yet. It's seems unlikely that bacteria were transported from the mother's digestive system into her blood, where they could cross the placenta into the baby. But bacteria have been found in placentas before. It will take much more research to show how the bacteria could be transferred from mother to child.