Scientists have long known that the microbes living in your gut impact your health. More studies are looking at whether using probiotics to alter your gut microbiome can reduce symptoms of mental illness.

While most people may take probiotics to improve their gut health and potentially reduce their risk for gastrointestinal conditions like IBS, more and more people are investigating if probiotics can help with their mental health in addition to their gut.

Probiotics have risen in popularity in recent years thanks to studies that have found evidence that “good” bacteria in the gut may be associated with a variety of conditions like type 2 diabetes, obesity, and colon cancer.

Taking probiotics in pill and powdered form are thought to boost your health by altering your gut microbiome, the collection of bacteria, yeasts, and fungi inside your gastrointestinal track.

However, the field is relatively new and researchers are still trying to understand the complex interactions of probiotics with naturally occurring bacteria, Healthline says.

One of the connections they’re trying to understand is how the gut impacts the brain and mental illness.

As researchers learn more about this connection, probiotics are being marketed for better mental health in addition to improved digestive function, lower cholesterol, and weight loss.

The gut may seem to be the last place to treat a mental illness, but experts say that understanding the microbiome may help them find issues, such as inflammation, that can take a toll on the brain.

“It’s an exploding area of research,” said Nicole Beurkens, a licensed psychologist and certified nutrition specialist in Caledonia, Michigan. “The research that’s been done so far really shows a lot of connections between gut health, the gut microbiome, and mental health symptoms.”

This is true not only for anxiety, but also for other mental illnesses such as depression, bipolar disorder, and schizophrenia. Researchers are even looking into whether probiotics can help ease the symptoms of autism.

Probiotics being used to support your brain even have their own name: psychobiotics.

Dr. Asim Shah, professor and executive vice chair in the Menninger Department of Psychiatry and Behavioral Sciences at Baylor College of Medicine, said “there’s a lot of hope that we’ll be able to use probiotics down the road to treat anxiety or depression, maybe even as a first-line treatment.”

Shah said that we’ve known for a while that gut microbes play an important role in keeping us healthy, including protecting us from germs, producing vitamins in our gut, and helping us digest our food.

But in recent years, researchers have turned their attention to the microbial gut-brain connection.

Bacteria in the intestines produce many chemicals, including neurotransmitters such as serotonin, melatonin, and acetylcholine. These may directly impact brain function and mental health and help explain the benefits of probiotics.

One small study published last year in Gastroenterology found that 64 percent of people with mild-to-moderate anxiety or depression who took a daily probiotic for six weeks had fewer depression symptoms during that time. Only 32 percent of people taking an inactive placebo improved.

Brain imaging with functional MRI also showed that people taking the probiotic had changes in areas of the brain involved in mood. The researchers say this suggests that the “probiotic has antidepressive properties.”

Probiotics may also help with other mood disorders. Another preliminary study published earlier this year suggests that daily probiotics — taken alongside regular medication — may reduce manic attacks in people with bipolar disorder.