Stress and digestion are undeniably connected—and this link may explain some of your most worrisome health concerns. After all, half our U.S. population (162 million Americans) suffer from, and are medicated for, symptoms of poor digestive health. 
Perhaps you are exhausted and bloated. Maybe you can’t sleep or your weight is undesirable. Or your nails may be brittle and your skin dry and irritated. Perhaps you have acne or rosacea. Maybe you are forgetful sometimes. You might even have a constant low-grade illness, such as allergies or the common cold.
When you finally take precious time out of your hectic day to visit a doctor, he or she immediately suggests a simple blood test, and the results come back "in range.” As your doctor hands you a prescription for an antidepressant and refers you to a therapist, you likely feel let down, unheard, and alone. And maybe you are depressed—you certainly don’t feel like yourself.
But there has to be another answer, right?
So, how does stress affect the digestive system? There’s a connection between your brain and your digestive system that’s been getting a lot of attention lately. It’s called the "Brain-Gut Axis," or BGA. Research shows there are trillions of bacteria currently living in your digestive system (or “gut”) that communicate directly with your brain. 
In your gut, the bacteria’s messages are processed and turned into commands for other parts of the body. In turn, your brain sends messages back to your gut, altering their flora production. The BGA is highly involved in the actions of our immune system, neurotransmitters, hormone signaling, and even weight management. 
Stress heavily influences the communication between your brain and bacteria and the functions they dictate. It also impacts the way you digest and absorb nutrients and even your body’s ability to remove toxins, which often results in poor health. Is there any part of the body that isn’t impacted by this amazing communication system? Nope, not really.
So, maybe your doctor is right and you are depressed, but is he or she possibly missing something here? Can emotional stress cause digestive problems? The answer to both of these questions is a resounding yes! He or she missed looking at the connection between stress and digestion—and how that is impacting your overall health.
Here’s the truth: Your body relies on the absorption of food and water and the removal of toxins via your GI tract to function properly. Given this, it seems crazy that the current trend in conventional medicine is to generally dismiss both the root cause of digestive disorders and their symptoms (such as heartburn and constipation) by suppressing these symptoms with medication. Instead, doctors should focus on figuring out the possible relation of these symptoms to other common, unresolved symptoms.
These symptoms can include:
If you cannot effectively absorb what you need from what you eat and eliminate what you don’t need, how can the result be anything other than health problems?
When you’re startled, you feel a rush of adrenaline. That’s your endocrine system—a key part of your sympathetic nervous system(SNS)—at work. In times of stress, your endocrine hormones stimulate the release of neurotransmitters to address the stress response, preparing your body for a “fight-or-flight” situation.
This has a direct impact on the function of your gastrointestinal system, changing the way you digest and eliminate food, until the stressor is removed and calm is restored. And gastrointestinal function has been shown to have a strong association with the hormones in the endocrine system even beyond times of stress. Stress also can indirectly affect the bacteria in your gut and even impact on the way you utilize thyroid hormones, produce sex hormones, create and utilize neurotransmitters, detoxify harmful substances, and more.
Though none of this is new knowledge to your doctor, general physicians rarely consider discussing these impacts and effects during an appointment for a seemingly “simple” digestive concern such as heartburn or constipation.
These are just a few examples of how stress can impact your digestive system. Here are a few other effects of stress and digestion.
When you’re under stress and you enter into “fight-or-flight,” your digestive system slows. You’re likely to experience spasms in your gut that can result in constipation, nausea, excessive gas, or cramping stomachaches.
Likewise, stress has been linked to diarrhea and other digestive upset for almost a century. A famous and commonly-cited study from the 1940s showed that stress can lead to intestinal cramping, which, in turn, may result in diarrhea and other digestive issues. 
Stress and digestion are connected in another way: Mental stress has been known to decrease stomach acid, which can cause major discomfort and indigestion. 
If you eat, and 30 minutes later it feels like a rock is sitting in your stomach, you likely have low stomach acid. If you experience bloating and/or fatigue after eating, it’s possible your body isn’t properly breaking down your food into useable energy. People are often surprised to hear that heartburn actually can be a sign of too little acid, not too much.
While there are a few tests that your doctor can order to assess stomach acid production, there’s also a test you can do at home. So, if you’re concerned about your stress and digestion to do this quick experiment: Try consuming a little apple cider vinegar before meals. (And in case you’re wondering, yes, you heard me. And I promise it works, so just stick with me here.)
Take 1 tablespoon of raw apple cider vinegar and mix it with 1 teaspoon of lemon juice (for taste). Next, add 1 tablespoon or less of warm water (just enough to make it palatable but not enough to eliminate the acidity).
Now, you have two choices (I prefer the latter). You can either shoot the mixture like tequila about 10 minutes before your meal, or you can slowly sip on the mixture like a fine scotch for about 30 minutes prior to the meal. Both situations should start the churning process in the stomach. If you find that you’re hungry sooner than 30 minutes, eat something! After all, the goal is to stimulate hunger and digestion.
If the apple cider vinegar doesn’t cause you heartburn, then you’re probably suffering from low stomach acid. And if you stick with this routine for a few weeks, you will likely see a reduction of symptoms. (Note: If you have a hiatal hernia or other structural abnormality, you would not do well with this experiment, as your heartburn has causes beyond your acid level. Also, about 2 percent of people get heartburn when they try this experiment. If you fall into these categories, speak with your doctor about other options.)
Heartburn affects more than 60 million Americans every month (that’s about 20 percent of the U.S. population). And acid blockers are some of the biggest selling over-the-counter medications in this country.  This means that many Americans are regularly dealing with heartburn and other digestive discomforts. (As a naturopathic physician, the long-term side effects of these medications, such as osteoporosis and dementia, cause me great concern. But I’ll save that for another time.)
While stress can (and does!) cause heartburn and regurgitation, those symptoms are not always due to high stomach acid. They actually may be the result of your sympathetic output (your “fight-or-flight” mode) preventing your food from being properly digested. Instead, it’s causing your food to climb its way back up into your esophagus. Low stomach acid needs to be treated by adding acid, not blocking it.
Irritable bowel syndrome (IBS) is known as a “stress-sensitive” disorder that causes abdominal pain or discomfort along with a change in the consistency or frequency of stools. It affects over 11 percent of the global population, making it one of the most common stomach problems.
In a 2014 review of over 50 studies, researchers noted that because psychological stress has a marked impact on intestinal sensitivity, motility, secretion and more, IBS treatment should focus on “managing stress and stress-induced responses.” They even noted that psychological stress could exacerbate IBS symptoms. So, what does this mean? Well, it means that IBS and anxiety are undeniably linked … and all of the small but daily stressors in your life may actually be causing your IBS symptoms! 
Additionally, stress has been linked to irritable bowel disease (IBD). IBD includes several conditions such as celiac disease, ulcerative colitis, and Crohn’s disease, which are caused by chronic inflammation in the digestive tract.
In fact, a review of 149 studies revealed that psychological stress not only plays a major role in certain IBD conditions, it’s also responsible for continued relapses. In addition, the review authors noted that creating a protocol based on stress reduction would not only benefit those who suffer from IBD, but also “shed further light” on what causes it. 
Did you know that roughly 60-80 percent of your body’s immunity is housed in your gut? This makes your digestive system the largest immune organ in your body. In fact, if you were to spread out the area of your digestive system, it would more than cover a tennis court!
You can have pounds (yes, pounds!) of bacteria in your gut. Some of these bacteria are good and some bad. Your good bacteria help you fight off viruses, digest your food, and produce chemical reactions (via the BGA) to help your brain and body function properly. These good bacteria are vital to your body’s immune function.
In regards to stress and digestion? Over time, your body’s response to chronic stress can lead to a weakened immune system and overall inflammation of the body.
A 2015 review of 44 studies showed that stress can result in a dysfunctional immune system, which can impact immunity and result in the development of a myriad of diseases and stomach problems. 
Ready to start fighting the effects of stress and digestion? Here are my top three tips on how to improve your digestive health.
By removing high allergenic foods such as corn, wheat (and gluten), eggs, soy, and dairy, you’ll reset your system so that you can recognize any negative reactions once you reintroduce them. It’s also beneficial to remove any processed foods, red meat, refined sugar, and artificial sweeteners and colors, since these have all been associated with increased markers of inflammation. [11, 12]
For the best results, try to keep these foods out of your diet for anywhere from four to six weeks. Why? Well, that’s the amount of time it takes to get all of those foods out of your system.
Some of the amazing foods that you will be able to enjoy regularly during your cleanse and beyond are: green leafy vegetables, kale, asparagus, non-nightshade vegetables, berries, pineapple, nuts, sprouted seeds, beans, lentils, nuts and nut-based milks, celery, broccoli, flax seed, avocado,cabbage, unsweetened coconut milk yogurt, coconut milk kiefer, sauerkraut, and kimchi. And if you eat meat and animal products, stick with organic, grass-fed eggs and poultry along with wild-caught pacific seafood.
These are anti-inflammatory foods, which will help prevent developing further inflammation in your digestive tract.
Did you know that mild to moderate exercise has been linked to better gastrointestinal digestion and elimination?  Not only does it increase blood flow to promote movement, but it strengthens supportive muscles in the pelvic floor and abdominal wall. Strengthening these muscles helps to keep your body more upright, which allows for proper movement of stool through the colon.
Calming routines such as yoga and Tai Chi have been shown to not only fight stress and support feelings of relaxation, but they also promote better digestive health by keeping your food moving through your digestive tract. [14,15]