Depression: A Mental Illness or Digestive Disorder?

Monday Oct 13 | BY |
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Depression may have more to do with our “gut feelings” than we thought.

After Robin William’s death in August 2014, the issue of depression was thrust front and center into the media. As sufferers and psychologists weighed in, scientists looked for more clues as to why people develop depression in the first place.

Is there some biological mechanism, aside from heredity, that’s at work, here?

Though we still have a long way to go before we understand how depression takes hold, we are breaking new ground in one area of research—gut health. Recent studies have connected the anxiety in our heads to imbalances in our guts, with promising potential solutions that may have a lot of people feeling a lot happier.

Gut and Brain Intimately Linked

Turns out that when you say you have a “gut feeling,” you may be speaking more literally than you thought. In a September 2013 study, researchers noted, “There is a growing awareness of the potential for microbiota to influence gut-brain communication in health and disease.” They go on to say that research so far has “supported the view that microbiota can influence brain chemistry and consequently behavior.”

Animal studies over the previous several years have shown that participants who are chronically stressed or suffering from depression have a corresponding disturbance in their gut bacteria. A link has also been found between major depression and anxiety and irritable bowel syndrome (IBS).

In one study, for example, researchers put gut bacteria from anxious mice into the guts of fearless mice. The result? The fearless mice became more anxious. Research from Texas Tech University Health Sciences Center has discovered new neurochemicals produced by gut bacteria. “These bacteria are, in effect, mind-altering mechanisms,” said university researcher Mark Lyte.

In 2011, researchers published results in Psychosomatic Medicine that showed people with higher quality diets were less likely to be depressed, whereas those with a higher intake of processed and unhealthy foods were more likely to be anxious.

Harvard University states that a person’s stomach or intestinal distress can be the cause or the product of anxiety, stress, and depression. “That’s because the brain and the gastrointestinal (GI) system are intimately connected—so intimately that they should be viewed as one system.” They note that a review of 13 studies showed that patients who used psychologically based approaches experienced better improvement in digestive systems than those who received conventional medical treatment.

Can We Treat Mental Health Issues Through the Gut?

If it’s true that an unhealthy or imbalanced gut microbiome can so seriously affect mental health, might there be some hope that getting the gut back into balance could improve symptoms of anxiety, depression, and other mental health disorders?

ABC News reported in 2013 that a Boston-area psychiatrist, Dr. James Greenblatt, cured his patient of attention deficit hyperactivity disorder (ADHD) and obsessive-compulsive disorder (OCD) with high-powered probiotics and antibiotics combined. Why antibiotics? He found elevated levels of the clostridia bacteria in the patient’s urine test. The antibiotics wiped it out, while the probiotics repopulated the healthy, “good” bacteria.

Autistic children, as well, may have critical gut imbalances. A 2010 study found that these children had higher levels of HPHPA bacteria. Once these were controlled with antibiotics, the children improved. Another 2013 study found that 35 percent of participants with depression had signs of a “leaky gut,” which allows bacteria to enter the bloodstream.

Even more exciting, however, is a November 2013 study review that strongly supported conducting clinical studies of probiotics for the treatment of depression.

A class of probiotics called “psychobiotics” is, according to lead author Timothy G. Dinan stated, “a live organism that, when ingested in adequate amounts, produces a health benefit in patients suffering from psychiatric illness.”

Studies have already showed this type of treatment to be promising. A recent study by UCLA researchers found that women who regularly consumed beneficial bacteria in yogurt showed altered brain function, both while resting and when performing an emotion-recognition task. “Our findings indicate that some of the contents of yogurt may actually change the way our brain responds to the environment.” They went on to note that the gut-brain connection “is a two-way street.”

A 2006 study found that participants who scored in the bottom third of the depressed/elated study reported themselves happy rather than depressed after consuming a probiotic-containing yogurt drink daily for twenty days.

It may not be as easy as consuming just any probiotics, though. Dinan noted that some are more effective than others when it comes to affecting brain health. “What is clear at this point is that, of the large number of putative probiotics, only a small percentage have an impact on behavior and may qualify as psychobiotics.”

What You Can Do to Improve Mental Health

Though we need a lot more research before we can completely understand this brain-gut connection and how it may affect mental illness, we can use what we know so far to help ourselves to be as mentally healthy as possible.

  • If you’re suffering from depression or anxiety, try adding probiotics to your daily diet either in the form of food (yogurt, kefir, sauerkraut, kombucha tea, miso, kimchi, and tempeh), or probiotic supplements.
  • Have your doctor test you for any unhealthy bacteria in your system.
  • Boost your intake of fermentable fibers like sweet potatoes, yams, artichokes, asparagus, dandelion root and greens, mushrooms, and okra.
  • Adopt an anti-stress technique that works for you—examples include regular exercise, sports, meditation, yoga, tai chi, massage, long walks, art therapy, etc.

Have you experienced improvements in mental health as a result of improving your gut health? Please share your story.

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Dinan TG, Cryan JF, “Melancholic microbes: a link between gut microbiota and depression?” Nerugastroenterol Motil., September 2013; 25(9):713-9,

Susan Donaldson James, “Anxiety in Your Head Could Come From Your Gut,” ABC News, September 12, 2013,

Rachel Champeau, “Changing gut bacteria through diet affects brain function, UCLA study shows,” UCLA Newsroom, May 28, 2013,

“The gut-brain connection,” Harvard Healthbeat, March 27, 2012,

Rob Stein, “Gut Bacteria Might Guide the Workings of Our Minds,” NPR, November 18, 2013,

Jacka FN, et al., “The association between habitual diet quality and the common mental disorders in community-dwelling adults: the Hordaland Health study,” Psychosom Med., Jul-Aug 2011; 73(6):483-90,

Shaw W., “Increased urinary excretion of a 3-(3-hydroxyphenyl)-3-hydroxypropionic acid (HPHPA), an abnormal phenylalanine metabolite of Clostridia spp. In the gastrointestinal tract, in urine samples from patients with autism and schizophrenia,” Nutr. Neurosci. June 2010; 13(3):135-43,

Timothy G. Dinan, et al., “Psychobiotics: A Novel Class of Psychotropic,” Biological Psychiatry, November 15, 2013; 74(10):720-726,

Lauren LeBano, “Can Probiotics Treat Depression?” Psych Congress,

D Benton, et al., “Impact of consuming a milk drink containing a probiotic on mood and cognition,” European Journal of Clinical Nutrition 2007; 61:355-361,

Elsevier, “Are probiotics a promising treatment strategy for depression?” ScienceDaily, November 14, 2013,

Tori Rodriguez, “Gut Bacteria May Exacerbate Depression,” Scientific American, October 17, 2013,

Colleen M. Story

Colleen M. Story

Colleen M. Story, a northwest-based writer, editor, and ghostwriter, has been creating non-fiction materials for individuals, corporations, and commercial magazines for over 17 years. She specializes in the health and wellness field, where she writes and ghostwrites books, e-books, blogs, magazine articles, and more.

Colleen is the founder of Writing and Wellness. Her fantasy novel, “Rise of the Sidenah,” was released with Jupiter Gardens Press in September 2015. Her literary novel, “Loreena’s Gift,” is forthcoming in spring 2016 from Dzanc Books. She lives in Idaho.

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