How Your Gut Health Affects Your Anxiety

Credit: Flickr Creative Commons, Nedral

Credit: Flickr Creative Commons, Nedral

A teenager in Boston was treated for severe obsessive–compulsive disorder (OCD), as well as attention deficit hyperactivity disorder (ADHD) and an array of digestive problems using probiotics and antibiotics.  In essence, mental health was treated by focusing on gut health. According to the treating physician, “after six months, Mary’s symptoms began to disappear. And by a year, they were gone. Today, three years later, Mary is a senior in high school and has no sign of either mental disorder.” In another case, a high school boy, Adam, struggled with ADHD, anxiety and mood disorders. After being taken off a lifetime of medication, she was treated with probiotics (live bacteria and yeasts) – the results and positive outcomes from this treatment amazed her friends, family and teachers.

While you and your loved ones may not be affected by conditions as severe and disruptive as OCD and ADHD, what if we told you that what you ate could be impacting your anxiety?

Anxiety impacts quite a few people – it has become the most common mental illness in the U.S., with 40 million adults affected (18% of the U.S. population). While highly treatable, only about one-third of those suffering receive treatment.

We’ve talked before about the gut connection to your immunity, but the connection to mood and emotions? “I’m always by profession a skeptic, but I do believe that our gut microbes (the bacteria in your intestines) affect what goes on in our brains.”  says Dr. Emeran Mayer, a professor of medicine and psychiatry at the University of California, Los Angeles, who has performed MRI brain scans on thousands of volunteers and compared brain structure to the types of bacteria in their gut.

How the Gut and Brain are Connected

About 5 lbs. of bacteria reside in your intestine – your digestive system is teeming with them.

The small intestine of your body breaks down the food and absorbs much of its nutrients. Inside your small intestine is a combination of good and potentially harmful bacteria. In a healthy gut, the goal is for these these types of bacteria to be in balance.

Gut bacteria both produce and respond to neurochemicals—such as GABA, serotonin, norepinephrine, dopamine, acetylcholine and melatonin—that the brain also uses to regulate mood and cognition. In fact, gut bacteria manufacture about 95 percent of the body’s supply of serotonin, according to the American Psychology Association. Serotonin, as described by, has a profound effect on regulating mood, sleep, cognition, sexual behavior, and appetite. High levels of serotonin can lead to a cheerful disposition and the ability to withstand everyday stress. Depression can result from chronically low serotonin levels. Serotonin can also help you override your immediate impulses.

Now, scientists have recognized a connection between the brain and gut for some time – Anxiety often causes nausea and diarrhea, and depression can change appetite – but it was thought to be one-way communication–that what’s in your brain manifests in your digestion.  Only in recent years of cutting-edge research have scientists started to recognized what’s in the gut to impact the brain.

Now Enter: The vagus nerve.

The vagus nerve is the primary neural conduit between the gut and the brain, as described by the American Psychology Association.  There’s one vagus nerve on each side of your body, running from your brainstem through your neck to your chest and abdomen. Bacteria (in the gut) stimulate the vagus nerve, which stimulates the production of the various neurotransmitters we just mentioned e.g.  GABA, serotonin, etc. Those chemicals then talk to your brain, stabilizing your body’s hormonal balance and improving your mood.

This puts a whole new meaning to “having a gut feeling.”

Of Mice and Men: Some Examples of the Gut Brain Connection

In studies, probiotic-fed mice produced lower levels of the stress hormone corticosterone, and have demonstrated increased anxiety-ridden behavior in the absence of a probiotic diet.

In one study involving mice, researchers found that gut microbiome’s influence on behavior begins at the start of life. Taking that into consideration, it’s just one more reason to what we feed kids may be as important as what we feed adults.

In one human study published in Gastroenterology on the effects of probiotics on the human brain, healthy women were given yogurt that contained probiotics, twice a day for four weeks. The result? There were signs that the brain circuits involved in anxiety were less reactive.

Could you imagine the prep for your next stressful project at work could involve eating a bowl of greek yogurt?

What now?

Research on this gut-brain connection is still in in early stages. According to John Cryan, a neuroscientist at the University of Cork in Ireland and a main investigator at the Alimentary Pharmabiotic Centre, scientists still aren’t sure exactly which microbial species are part of a healthy microbiome, nor do they know whether certain bacterial strains are absolutely vital to mental functioning, versus whether it is the right balance that’s key.

So maybe we’re not at the point of Gut Bacteria Transplants for anxiety just yet, but there are increasing numbers of cases in which improving gut health improved mental health. Conversations, public awareness, and treatments around gut health and its connection to the brain are sure to continue to grow alongside. And yes. That last line was an intentional pun.

Gut Health: Want more?

For a more obvious (and quite musical) take on the matter, you could try this song.

This topic definitely interests us, so you can read more on the gut with our blog post on 4 Consequences of an Unhealthy Gut (and what you can eat to promote a healthy one), and even learn about how antibiotics are being over prescribed, and what you can do to supplement.

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The posts on this blog are for information only, and are not intended to substitute for a doctor-patient or other healthcare professional-patient relationship nor do they constitute medical or healthcare advice of any kind. Any information in these posts should not be acted upon without consideration of primary source material and professional input from one's own healthcare professionals.