We know that the gut microbiome — the collection of bacteria, fungi, and viruses that reside inside us — influences our mental state through a powerful connection known as the gut-brain axis. So the big question is: Can we positively influence the gut?
Some scientists theorize that improving our gut health may offer new ways to improve mental health. While talk therapy, exercise, and medications can help boost mental health, some people don’t feel better even after trying these methods.
“Many studies support gut-brain axis impacting brain function,” says Atsushi Kamiya, a professor at Johns Hopkins University School of Medicine. “Thus, [a] healthy gut may positively affect our brain function and potentially keep our mental condition healthy.”
If you want to improve your gut health, there are a few compelling options. Some are just starting to be explored by scientists and supported by research, while others are so tried-and-true you might be surprised at how obvious and simple they are.
Three ways to help your gut
New research in both mice and humans published in Nature Immunology highlights a connection between having more Lactobacillus johnsonii in the gut and lower odds of depression and anxiety. Lactobacillus is a type of bacteria with a known anti-inflammatory effect.
In the study, stress-induced mice given a Lactobacillus supplement became less socially avoidant compared to mice not given the supplement. Intestinal immune cells that proliferated due to stress also returned to healthy levels in response to the supplement.
Probiotic supplements contain bacterial strains. But Kamiya, the study’s lead author, tells me that it’s too soon to say that Lactobacillus supplements will definitely help people with depression and anxiety. The research is still in its early stages.
But that doesn’t mean researchers aren’t excited about the possibility probiotics could help bolster mental health. Other research suggests people who pair antidepressants with probiotics experience more improvement in their symptoms than those who don’t, and gut bacteria strains beyond Lactobacillus may also be helpful.
In pre-clinical trials, bacteria from the genus Bacteroides appear especially exciting, says Jack Gilbert, a professor and director of the Microbiome Core at UC San Diego School of Medicine. So far, research suggests they can “reduce the phenotypes of depression or anxiety as well as ketamine,” Gilbert says. (Gilbert is an advisor to a company currently studying the bacteria.)
He’s excited about the potential of “augmenting the microbiome with a bacterium that is found in people with stable mental health, versus taking a chemical antidepressant.” Probiotics could be a potent treatment strategy.
“These treatments, however, need to be tested properly in people through blinded clinical trials before we are confident that they can be useful,” Gilbert adds.
Diet is the gut-augmenting tool scientists can endorse with the most confidence. It’s well-established that fermented foods benefit gut health, as do foods high in fiber. Gilbert says that food containing polyphenols — compounds found in fruits and vegetables — is also good for the gut.
“A plant-based diet is ideal,” he says. Gilbert recommends trying to eat 30 plants a week. It’s easier than you think — whether or not you’re dining on blueberries, carrots, or lettuce, those plants add up.
He also recommends drinking lots of water.
Specific plants might prove especially helpful. For example, in their study on mice, Kamiya and colleagues evaluated whether or not a compound called pachyman could confer any benefits. This compound is extracted from wild mushrooms, is known for its anti-inflammatory properties, and is used to treat depression in some Eastern medical traditions. The pachyman seemingly counteracted the inflammatory effects seen in the stressed mice and relaxed them.
While more research is needed to pinpoint the underlying reason why natural products like pachyman seem to benefit mental health, Kamiya tells me that he thinks they might be “useful tools to uncover novel potential therapeutic targets for depression.”
You can also support your gut through light exercise. “Exercise can help reduce inflammation and improve metabolic health,” Gilbert says.
Some research also suggests that exercise can increase the number of “good bacteria” in the gut and enrich the diversity of the microbiome. In part, this may be because exercise increases how often you need to do number two. Exercise also increases lactic acid bacteria, which helps the gastrointestinal tract kick out pathogens.
Scientists have also observed an interesting twist to this recommendation: Mice studies suggest that certain gut microbes can actually boost motivation to exercise. They found that the bacterial species Eubacterium rectale and Coprococus eutactus corresponded to greater athleticism more so than genetics. This may be because these bacterial species produce metabolites that kickstart a process that results in dopamine levels rising — a process that connects back to the gut-brain axis.