The Connection Between Probiotics and Your Mood
Small studies in rodents and humans hint at an answer
The human gut contains a host of life forms with their own genes that make up our gut microbiome. Over 10 trillion microorganisms live inside human intestines, with some recent estimates putting the number as high as 39 trillion. That means people have more microbes in their large intestine than human cells throughout their body. The human gut is also home to a sophisticated network of over 100 million neurons , which many experts refer to as the body’s “second brain.”
These microbial environments are now revealing new insights about psychology and behavior.
Gut flora are an indispensable army of microbes that assist in metabolism and support people’s immunity, but scientists have only recently begun to uncover the fast-acting connections between the gut and brain. In mice, it takes only two nerve cells for communications to travel from the intestines to the brain stem. This means the gut and brain can communicate with each other in a few seconds or less, rather than relying on slower signals that require the release of hormones. The human gut can also send signals about the presence of nutrients and microbes to the brain, and the brain can use this information to help control metabolism, digestion, and satiety. In a sense…
