In the past, it was thought that a fetus was sterile while in the womb and that a baby’s first food, breast milk, was also free of microbes. Recent research turns this idea on its head as Beth Skwarecki presents in a fascinating DoubleXScience post.
“Babies are born without a fully developed intestinal mucosa, and need interaction with bacteria to basically jump start their immune system,” says Lisa Funkhouser, who co-authored a paper with Seth Bordenstein last month on the many ways mothers across the animal kingdom transmit microbes to offspring.
What’s most fascinating about the microbes in breast milk and those that a fetus harbors before birth is where they originate. The idea is still in its, um, infancy, but evidence is accumulating that cells in the bloodstream pick up microbes from the intestine and transport them to destinations in milk-producing breast tissue … and across the placenta to the developing fetus.
These microbes make up the ground level floor of a baby’s gut ecosystem–preparing the immune system for future invaders. There’s a ton of interesting science jam-packed into this article–check it out.