The Gut-Brain Connection

As I sit in my living room looking out at the winter wonderland around me, I am reflecting on how the winter can occasionally give me a case of the melancholies. Living in Seattle, land of angsty grunge music and seasonal depression, gave me healthy appetite for sunshine….and a bit of a winter phobia. Though I am generally a happy person, I remember, in the midst of 60 straight days of rain, ticking off the symptoms of clinical depression in myself, one by one. Tired all the time, drinking a wee bit too much wine, craving comfort foods, waking early in the morning and not being able to get back to sleep, stressing over leaving my cave to go out into the world and interact with people. Granted the symptoms of depression look different for each individual, but this was definitely it. As it turns out, most people in northern latitudes become depressed during the winter. While we can shore ourselves up as best we can with the sunshine vitamin (D, for those who don’t know…TAKE IT!!), seasonal depression and depression of any sort, goes beyond this supplement. Everyone in the Pacific Northwest and the New England states has low Vitamin D levels, but only some experience depression. What is the difference? Two big ones: life circumstances and neurotransmitter balance.

Why is it that some people are better at producing balanced neurotransmitters? Certainly genetics plays a role, as children of depressed people are more likely to experience depression themselves, even when they grow up without the influence of their parents. Another large factor is life circumstances leading to depression: people who hate their jobs or are in bad marriages, etc… Yet, there are lots of people who hate their jobs AND are in bad marriages and are still happy people. And there are also lots of people who have ideal lives (even by their own standards) and can’t get out of bed in the morning because they are so depressed. In this day and age of Primary Care Doctors handing out anti-depressants like candy, it is important to educate ourselves on the WHY of depression. Treating the symptoms of depression with anti-depressants doesn’t make the disease go away. Rather, anti-depressants cover up the REASON for the depression and cause a whole lot of undesirable side effects to boot. Though necessary in some critical situations, the treatment of depression with pharmacology (especially prescribed by a PCP who has no training to prescribe these medications) is not ideal.

The Dual Brain Theory, or the Enteric Brain (enteric meaning the gastrointestinal tract) is an old concept that has more recently been scientifically explained. Early on in the development of the Naturopathic profession, many of the alternative practitioners started noting the connection between digestive issues and depression in their patients. Naturopaths always try to blame everything on the gut, so this connection is not a huge surprise, but as modern medicine advanced, the theory that mental and digestive health are related proved to hold water. As the field of histology (the microscopic examination of cells) discovered, the lining of the gut is full of the same types of tissues found in the brain and spinal cord. Most importantly, there are many cells lining the gut that are capable of producing neurotransmitters and as it turns out 90% of the serotonin produced in the body is from the gastrointestinal tract. Whoa! (That happiness that comes from stuffing yourself full of comfort foods? That’s not a coincidence.) It follows, then, that if the gut is not working very well, it’s going to be tough to produce enough happy neurotransmitters to be a happy person.

There are two mental health disorders in which the gut-brain connection is demonstrated really well: Autism and Obsessive Compulsive Disorder. Parents of Autistic children will tell you that their child’s symptoms of aggression and anger vary greatly with what they consume. Many children with Autism are sensitive to dairy and gluten (which, sadly, are all kids’ favorite foods) and when they consume these foods, digestive disturbances occur. These disturbances often coincide with outbursts and temper tantrums, which makes sense in terms of our theory: when the gut is being challenged, production of happy neurotransmitters shuts down almost completely, leading to angry and depressive mood swings. Under the umbrella of Obsessive Compulsive Disorder, Functional Medicine has created a diagnosis called PANDAS, or Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcal infections. That’s a mouthful, eh? This is a group of children with Strep infections in their intestines AND OCD tendencies, whose OCD tendencies disappear when the infection in the gut is treated. Crazy, right?

So, how do we use this information to improve our mood? How many of us have digestive issues? Digestive issues include all of the following: constipation, diarrhea, heartburn, bloating, gas and hemorrhoids. Fun stuff. And how many of us have symptoms of depression? I think we all know these by heart, but just in case, the way I differentiate someone who is depressed from someone who just needs to get a better job is with the following statement: “I just don’t feel like myself”. So, let’s put 2 and 2 together and take care of out guts so that we can be happier people, shall we?

Here’s a few of my favorite ways to improve digestive health:

Avoid inflammatory foods.

Yup, there it is again. Foods fried in vegetable oils, refined wheat products, sugar, MSG, artificial flavorings/colorings/sweeteners, excessive alcohol….these things are not your friends in terms of gut health OR being a happy, well-adjusted person.

Eat your good bacteria.

Yogurt and other cultured foods like Sauerkraut, Cottage cheese, Tempeh, Kombucha and Kefir all contain those probiotics we love so much. We love them because they take up residence in our gut and help us to digest our food and starve out the unfriendly bacteria and yeasts growing there as well. I often have my patients take a probiotic supplement as well.


Ginger is the plant with the most digestive enzymes in the entire plant kingdom. A cup of ginger tea after meals (especially during the winter, when it really warms you up) is key for helping to process those heavy winter comfort foods. Other plants that contain tons of digestive enzymes: pineapple and papaya, if you feel like getting a little tropical.

As always, if you have serious digestive or depressive concerns, seek the help of a health care professional, including your friendly neighborhood Naturopath.