An excerpt from Reader’s Digest
Yes, you read that right: Getting dirty may reduce your risk of depression. But before you start rolling in the mud or even worse, eating it, let’s take a step back.
The hygiene hypothesis has been bandied about for ages. In a nutshell, it suggests that we are too clean, which is why we get sick. Early childhood is the time when we should be exposed to all sorts of germs that will educate our immune system. When this doesn’t occur (because of our overly sanitized environments), the immune system doesn’t learn to recognize friend from foe and then tends to overreact to perceived threats, upping our risk for many ailments, from allergies to depression.
“Kids who play in the sandbox are exposed to a wide variety of germs, which in turn programs their young immune systems,” explains Nigma Talib, ND, a naturopathic doctor with clinics in London and New York, and the author of Younger Skin Starts in the Gut: 4-Week Program to Identify and Eliminate Your Skin-Aging Triggers – Gluten, Wine, Dairy, and Sugar.
Enter the microbiome—the name given to the microbe (bacteria) population living in our guts. Science is increasingly uncovering its powerful role in influencing immune function and chemical signaling in the brain, to the point that it’s been dubbed “the second brain.” “When you are anxious, your stomach may act up, and this is because we have more serotonin receptors in the gut than in the brain,” Dr. Talib explains. (Serotonin is the same feel-good brain chemical that is targeted by antidepressants such as Prozac). “When the bacteria in your gut is out of whack, serotonin receptors don’t function as well.”
Of course, the multi-million dollar question, which can’t be answered definitely yet, is whether increasing exposure to bacteria in dirt offsets this risk.
The Down and Dirty Depression Cure?
A 2007 study in Neuroscience found that when mice were injected with a bacteria found in dirt, Mycobacterium vaccae, it activated a particular group of brain neurons that produce serotonin—just like an antidepressant does.
“There is pretty strong evidence that microbes are involved in depression,” adds B. Brett Finlay, PhD, a professor of microbiology at the University of British Columbia and author of Let Them Eat Dirt.