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Heal Your Gut, Heal Your Brain


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Are you among the 20 percent of adults suffering from anxiety and depression? Find out how nourishing your gut microbiome can make you happier and more relaxed.

leaky gut and anxiety
There is a strong connection between the gut and the brain. AntonioGuillem/istock/Thinkstock

In my work, a significant number of patients list anxiety or depression as one of their top three health concerns. This is not at all surprising given that anxiety and depression are two of the most common mental health issues in our society, with anxiety disorders affecting approximately 18% of adults in the U.S. (1) Anxiety and depression are not the same, but they are often experienced together as a complex set of emotional and functional changes. (2)

Both anxiety and depression, along with other mood and neuropsychiatric disorders, such as eating disorders, bipolar disorder or sleep disorders, generally result from a complex interplay of factors. These may include a combination of nutritional, physical, environmental, social, emotional, and spiritual factors, affecting your genetic tendencies and brain biochemistry (meaning that your neurotransmitters, or the chemical messengers within your brain, can be affected by these key components of well-being). You can think of anxiety and depression as disruptions in brain health.

Treating the Cause Not Just the Symptoms

While conventional medicine, not surprisingly, offers medications to treat the symptoms of anxiety and depression with somewhat limited success (data suggests that 30 to 40% of patients do not respond to current drug strategies), we take a very different approach in functional medicine. (3, 4) It’s important to recognize that medication, particularly antidepressants, can be essential for some people, particularly those with more severe depression, and a decision to start or stop antidepressants needs to be discussed with your health care provider. I never recommend coming off antidepressants too quickly, and there are times when patients clearly benefit from the support of these medications.

What surprises many new patients who ask for help with their anxiety or depression is that we start by looking at the health of the gut. For those of you who have followed this blog for any amount of time, you’ve probably picked up on a common theme here that you have to have a healthy gut microbiome for optimal well-being.

Having trained in conventional medicine, this idea was not intuitive to me even five years ago. But now, after reading the scientific literature on the microbiome-gut-brain axis, and working with patients to heal their gut and seeing the incredible improvements in mood, I’m convinced this is the starting place to heal anxiety and depression.

Anxious, stressed, or depressed? Healing your gut may be the solution. #guthealth #microbiome #mentalhealth

A Growing Body of Evidence Shows That Our Beneficial Gut Bacteria Support Positive Mood and Emotional Well-Being

The gut microbiome, which we’ve discussed in a number of prior articles and podcasts (here and here), refers to the microorganisms, predominately bacteria (somewhere on the order of 10 to 100 trillion) and their genes, living within the human gut. Many of these microorganisms are in fact essential for good health. When the balance of beneficial bacteria in the gut is disrupted, disease can occur.

The relatively new understanding of how microorganisms affect every system of our body, along with the incredible volume of research on the microbiome is leading to a shift within medicine, and specifically a shift towards appreciating how important it is to care for our healthy gut bacteria.

Differences in the Gut Microbiome Exist between People with Anxiety and Depression and Those Without

Numerous studies in animal models show convincing evidence of a strong relationship between the gut microbiome and mood. For example, studies have found significant differences in the types of gut bacteria in animals exposed to various types of stress such as maternal separation early in life, social stressors, or prolonged restraint. (5, 6, 7)

One study, published this month, examined the specific differences in the bacterial make-up of the microbiome in patients with major depressive disorder in comparison with healthy individuals. (8) Significant differences were identified between these two groups. Additionally, the severity of depressive symptoms was related to the amount of a specific bacterium. A lower relative abundance of Faecalibacterium was associated with more severe depression.

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Altering the Gut Microbiome with Probiotics Can Decrease Feelings of Anxiety and Positively Affect Emotional Processing

Several studies show evidence for reduced feelings of anxiety and improved aspects of well-being after taking probiotics. (9, 10, 11)

One study used functional MRI (magnetic resonance imaging), which is a type of imaging that looks at brain activity, to evaluate the influence of gut microbes on emotional behavior and underlying brain mechanisms. (12) Specifically, three groups of women were given either fermented milk with probiotics, non-fermented milk, or no intervention, twice daily for four weeks. Functional MRI was performed both at the start and completion of the study to look at brain activity in response to an emotional attention task.

The women who consumed the fermented milk with probiotics showed changes in regions of the brain crucial in emotional processing. This study provides further evidence that supporting the gut microbiome can provide measurable changes in emotional processing within the brain.

Additional support for the connection between the gut microbiome and mood came from a study that showed the use of specific probiotics significantly decreased anxiety-like behavior in rats and reduced psychological distress in humans. (13)

Nourishing Your Beneficial Gut Bacteria Will Also Reduce Anxiety and Decrease Stressishing your beneficial gut bacteria will also reduce anxiety and decrease stress

A recent study evaluating the effects of prebiotics on well-being provided additional evidence of the gut bacteria positively affecting mental health. (14)  Prebiotics are carbohydrates that humans cannot digest, but bacteria in our guts can.

In this study, 45 healthy individuals were asked to take either a prebiotic or placebo every other day for three weeks. Cortisol measurements were taken from saliva samples at the beginning and end of the study to evaluate the hypothalamic-pituitary-adrenal (HPA) axis activity (an important factor contributing to anxiety and depression). After three weeks, the participants completed a series of tests designed to assess how they processed emotional information, such as processing facial expressions of the six basic emotions, and responding to positive and negatively charged words.

The results showed that individuals who had taken the prebiotic had significantly lower cortisol after three weeks, meaning they showed physiologic evidence of a decreased stress response. And the prebiotic group paid more attention to positive information and less attention to negative information when compared to the participants who were given placebo. This suggests that when confronted with negative stimuli, the prebiotic group would have less anxiety, similar to that which has been observed in some people taking antidepressant or anti-anxiety medication.

Use an Integrated Approach

Therapy and, in some cases, antidepressant or anti-anxiety medications can be important pieces of treatment. But if underlying imbalances in the gut microbiome are to blame (which is often the case in our experience), you won’t heal until they are addressed.  This functional medicine approach to mood disorders is something that I frequently find to be more effective than conventional treatments, allowing many patients relief from their symptoms of anxiety and depression.

Amy Nett

About Amy:  Amy Nett, MD, graduated from Georgetown University School of Medicine in 2007.  She subsequently completed a year of internal medicine training at Santa Barbara Cottage Hospital, followed by five years of specialty training in radiology at Stanford University Hospital, with additional subspecialty training in pediatric radiology.

Along the course of her medical training and working through her own personal health issues, she found her passion for Functional Medicine. She works with patients through a Functional Medicine approach, working to identify and treat the root causes of illness.  She uses nutritional therapy, herbal medicine, supplements, stress management, detoxification and lifestyle changes to restore proper function and improve health.

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Join the conversation

  1. Do you recommend a test or a way to check the status of your gut health? I’m a healthy person and don’t have any noticeable issues, but like to learn more about my health and understand it all.

  2. These gut-brain connections in regard to anxiety and depression are so real! I learned by accident over two years ago when I started taking the Plexus probiotics to help unlock my weight problems, and found that they also improved my mood and stress level to the point of NEEDING to back off my anti-depressants! (Breaking out into random giggles isn’t right anymore than the depression is!)

    As an over-50 Grandma, I had spent most of my life since I was a child struggling with anxiety and depression, being sad and withdrawn all the time or spiking fits of rage, going on and off meds depending on the severity during that season of life. The last 2.5 years being on the Plexus ProBio5 consistently has been the happiest most relaxed and fun time of my life! While being able to lose 40lbs was nice, this balanced difference with my mood has made the biggest difference in my daily life! I finally feel like a sane, happy person, which my family likes a lot more too!

    I’ve since turned into a research junkie trying to understand how it happened since I hadn’t expected all that. Thank you for this article and the research you’re doing to help others at the core health level!

  3. I had a brain tumor removed in March of 2015 and my mental health was affected greatly. Not only did I have cognitive issues like memory loss and analytical thinking, but I had severe depression and anxiety attacks almost daily. This went on for almost a year and a half. I did some research on gut health and decided to try supplementation with Plexus products and to change my diet. I started in August of 2016. Within a few short weeks I had a considerable change in the brain fog, memory, and calculating issues, as well as my energy level that was previously non-existent. The biggest surprise came when my husband asked me about, a month after starting, when the last time I had an anxiety attack was, and I couldn’t tell him. I found myself looking forward to family gatherings and events that used to overstimulate me and keep me from being out of the house. I also went back to work the next month, in a very public role. I truly believe that my gut health was what was holding me back after my ABI. I have gone on to study more about the gut-brain connection and I am convinced a healthy gut makes all the difference in the world.

  4. Who would of thought that gut bacteria could be used as a nootropic. Guess I am going to try out some probitoics and see how it goes for me. Any recommendation on dosages and time frames?

    • Clausen Pickles, Saurkraut or Kimchee with lunch and dinner. This is a good and inexpensive start. Add Papaya and Pineapple enzymes to help digestion.

  5. I just received the ‘confirm follow’ email. It said ‘howdy’. Stop being childish, we’re not playing cowboys.

  6. I have been on many brands/types of pro and prebiotics, and never felt any improvement whatsoever. Always gave something at least 3 months, usually more.

    • HAve you tried full fat kefir I am gonna start taking it for anxiety this week