We carry trillions of microbes in our bodies, which as a whole are called the microbiome. But did you ever think the germs in your gut could influence your brain?
That’s what researchers are beginning to find. For example, Sangram Sisodia, a neurobiologist at the University of Chicago, and some colleagues administered antibiotics to mice that were prone to develop a version of Alzheimer’s disease. The antibiotics killed off a large portion of the mice’s gut bacteria. Later, when the scientists examined the mice’s brains, they found far fewer protein clumps linked to dementia. After similar experiments, Dr. Sisodia suspects a few species in the gut are influencing the course of Alzheimer’s disease, maybe by releasing a chemical that alters how the brain’s immune cells function. Although right now this is only a suspicion, “there’s something’s in there,” he said. “And we have to figure out what it is.”
This is not an easy field of research because most of our microbes can’t live in a laboratory environment. A big breakthrough was the ability to sequence our germs’ DNA. The first thought was to research how the microbiome influences parts of our bodies where most of our bacteria live, like the gut and skin. Nobody thought of the brain; the blood-brain barrier would block any microbe entry. But now, in addition to Alzheimer’s disease, there is mounting evidence that our microbiomes also have a role in Parkinson’s disease, depression, schizophrenia, autism and probably other conditions.
Except there’s a lot we don’t know; research in this area is just beginning. Or as Katarzyna B. Hooks, a computational biologist at the University of Bordeaux in France, explains it, “We have the edges of the puzzle, and we’re now trying to figure out what’s in the picture itself.”
Taken from “Germs in Your Gut Are Talking to Your Brain. Scientists Want to Know What They’re Saying” by Carl Zimmer (https://www.nytimes.com/2019/01/28/health/microbiome-brain-behavior-dementia.html? ).