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This is How Stress Affects Your Digestion and Gut Health

Updated: Oct 11, 2023

The gastrointestinal tract and the immune system are especially susceptible to the effects of various stressors, whether dietary, environmental, or psychological. In this article, I will briefly discuss factors that have the biggest impact on gut health and focus on the connection between psychological stress and digestion. You will learn how stress affects digestion and why stress management and mindful eating may be some of the most important things you can do to optimize your gut health.




You have an approaching deadline at work, phone calls to make, a dozen unanswered emails, and only twenty minutes between the Zoom meetings. Not much time is left to eat lunch. You grab your lunch bag or run to the nearest cafe for a quick bite. You are eating on the go, checking your phone, or right in front of your computer without even looking at your food. Fifteen minutes later, a nagging burning sensation is starting to grow in your chest. You are already prepared for this, reaching into your desk drawer for Tums. You notice the bottle is almost empty. Sounds familiar?


This may not be the only digestive problem you are dealing with. Maybe you get bloated every night no matter what you eat. Or you often feel cramps or heaviness in your stomach after a meal. Are you keeping a supply of laxatives in your medicine cabinet because you feel you can't be "regular" without them?

All of these symptoms are signs that there is a problem with digestion and gut health.

Healthy digestion is essential for good health. We often hear we are what we eat, but it would be more accurate to say, we are what we can digest and absorb. When there is a problem with digestion, even the most clean and pure foods are of little use because the body simply cannot break them down efficiently. When the food is not digested properly, it is left to ferment in the colon causing excessive gas and bloating. Nutritional deficiencies will arise even with adequate calorie intake. Undigested foods can also feed pathogenic bacteria in the gut and can eventually result in dysbiosis.

Currently, over 74% of the US population is troubled with some form of digestive symptoms [1]. Heartburn, bloating, cramps, abdominal pain, gas, constipation, or diarrhea are the reasons why digestive aides are among the top best-selling over-the-counter drugs in the country. [2]. Over 60 million people in the US are suffering from more serious and debilitating conditions like irritable bowel syndrome (IBS), SIBO, Celiac disease, Crohn's disease, gallstones, food sensitivities, or allergies. While many of these conditions often require medical attention, a lot can be done to prevent them with the right nutritional and lifestyle habits.

The importance of gut barrier

The gut is a place where the internal environment of our bodies meets with the outside world. It is our first line of defense against harmful microbes and toxins that come with food. A large portion of the immune system is located in the GI tract, making it an organ of immunity.


The lining of the GI tract consists of only one layer of epithelial cells called enterocytes. These cells are responsible for the passage of nutrients into the circulation. The health of enterocytes and the tight junctions between them is what ensure the integrity of the gut barrier. Healthy gut lining allows nutrients to be absorbed, while at the same time keeping toxins and foreign particles out. When the gut wall loses its integrity undigested foods and pathogens can enter the circulation and trigger a cascade of immune and inflammatory reactions. This is known as a “leaky gut”. The concentration of the immune cells in the gut is so high for this reason- to protect our bloodstream and the rest of the body from foreign and toxic substances.

Healthy mucosal lining is of the utmost importance when it comes to digestion and absorption of nutrients. Stress, nutritional deficiencies, and environmental toxins can disrupt the gut barrier and significantly affect our ability to digest and absorb nutrients.


Let’s take a look at the factors that affect gut health the most.


1. Nutritional deficiencies.


A nutritionally poor diet is often the driver of poor digestion and health in general because, simply put, it cannot provide all the necessary nutrients for the GI tract to function optimally. Digestive organs require nutrients to work efficiently. You see, in order to metabolize nutrients, we need a sufficient amount of vitamins and minerals which often act as co-factors for the digestive enzymes and various secretions and GI hormones that facilitate digestion.

For example, if you are deficient in zinc, you may not be making enough stomach acid. Stomach acid is crucial for breaking down proteins. It also kills the pathogens that may come with food, it activates pepsin (the enzyme needed to break down protein peptides), and frees up bound nutrients like B12 and minerals, making them available for absorption in the small intestines. Frequent use of antacid medications blocks the production of gastric acid and compromises digestion and nutrient absorption.

If we look at the cellular level, deficiencies in various nutrients like B vitamins and minerals like magnesium will make it very hard for the cell to use its main fuel source glucose for energy. Lack of cellular energy will not only make you feel tired, but it will also weaken the nervous system that regulates the entire digestive tract. Low gut energy will result in sluggish and slow motility, causing constipation, and bacterial overgrowth.

2 Environmental toxins.


Our digestive system is constantly under attack from various environmental stressors. Pesticides, preservatives, additives, heavy metals, pollutants, and antibiotics that come in contact with our gut every day disrupt the delicate gut lining. These compounds further deplete our nutrient and antioxidant reserves and damage the cells of the gut lining and the tight junctions between them. "Leaky" GI lining will result in gut inflammation and a host of reactions like food sensitivities and intolerances. Eating organic vegetables and fruits, and sustainably raised animal products can help reduce exposure to harmful toxins and protect the gut.

3. Stress and stressful eating

Stress and stressful eating can have detrimental effects on the gut and overall health. When we are stressed, we either eat too much, or too little or give in to cravings. We use food for comfort and reach for processed foods high in sugar, salt, and fat. It is important to understand and recognize the role of stress if we are looking for the underlying causes of gut dysfunction.


In our fast-paced society where the emphasis is put on high productivity and big results, things like eating and sleeping are viewed more like chores that distract us from “real work”. They are considered insignificant and unimportant. We often find ourselves eating on the go, in the car, talking on the phone, and in front of a computer, or TV. We often eat when we are upset, depressed, or bored. We don't chew our food long enough and often gulp water or other beverages during the meal. We often roam for food, constantly snacking, making it difficult for our gut to do the “clean up “ work that happens between meals. This clean-up work, known as migrating motor complex (MMC) is one of the main mechanisms by which our gut keeps the bacterial population in the small intestines in check. These "cleansing waves" of the gut happen only during the periods of fasting. We feel it when we experience rumbling noises when hungry. MMC impairment usually results in small intestinal bacterial overgrowth (SIBO). [3]

In the long run, chronic stress and elevated levels of stress hormones can change our metabolism and contribute to unwanted weight gain, inflammation, and chronic disease.


So, how exactly stress affects digestion and gut health?

During digestion, food gets broken down into tiny molecules. Absorption of nutrients happens primarily in the small intestines. It is a sophisticated interplay of the multiple processes orchestrated by our autonomic nervous system.

The autonomic nervous system has two branches, sympathetic and parasympathetic which work together in a synergistic and complementary fashion.

The sympathetic system activates when we experience physical or emotional stress. It is also known as the “fight or flight”, or “go, run, do” system. The sympathetic system slows and inhibits digestion as part of the acute stress response. This is because the main evolutionary purpose of stress is survival. Various stress hormones increase blood pressure, heart rate, and respiration. Under stress, the sympathetic system down-regulates systems and functions that are not critical for its survival, like digestion and sleep.

Stress response will slow down the movement of food through the GI tract, leading to bloating and constipation. Sympathetic dominance also inhibits the production of digestive enzymes and gastric acid. This makes the breaking down of nutrients very difficult. This is how Dr. L. Korn, the author of the book "Nutrition Essentials for Mental Health" describes digestion compromised by stress:


" Imagine putting a stock pot full of meat and vegetables on the stove and forgetting to light the fire to cook it. In a matter of hours and days, it will spoil and become putrid. This is what happens in the gut of someone with compromised digestion." Leslie Korn, MD [4]

The Vagus nerve and the "Gut-Brain Axis".


The parasympathetic system, on the other hand, is our “rest, digest, relax” system. It stimulates the digestive tract, its hormones, and secretions, and promotes healthy motility. Gut motility, or peristalsis, makes the digestive process possible.


The vagus nerve, the longest nerve of the parasympathetic system, stimulates intestinal contractions through the action of acetylcholine. This way food moves through the GI tract. Healthy vagal tone is very important because if peristalsis is too fast we will not have enough time to break down and absorb nutrients. If it is too slow, it can cause chronic constipation and bacterial overgrowth. The Vagus nerve through its extensive neural network also stimulates the digestive enzymes in the pancreas, gastric acid in the stomach, and the release of bile from the liver and the gall bladder. Poor bile flow and low stomach acid are usually seen in many gut conditions like IBS and SIBO.


Research also shows that the vagus nerve is the key player in keeping the gut lining intact, protecting us from the detrimental effects of the “leaky gut” [5]. The Vagus nerve is also a powerful regulator of intestinal inflammation in the gut. Acetylcholine, released by the vagal nerve inhibits the release of pro-inflammatory mediators in the gut. [6]


What happens in the gut doesn’t stay in the gut.


The network of nerves responsible for digestion is so extensive that it is commonly referred to as the “enteric nervous system “ or “second brain”. The Vagus nerve has another important function. It conducts communication between the gut and our “first” brain. About 80% of the vagus nerve fibers carry signals from the gut to the brain, not the other way around [5].


It means that everything that happens in the gut directly affects our brain function. This is how the intestinal microbiome is thought to communicate with the central nervous system. This route is known as “the gut-brain axis”. When we have intestinal inflammation, “leaky gut”, and imbalanced gut flora, it can affect our mood, sleep, memory, focus, and overall well-being.

Stress weakens the vagus nerve, inhibits its function, and can even stop digestion. When the production of gastric secretions such as gastric acid, digestive enzymes, and bile is low, it will result in poor digestion and nutrient use, a damaged gut wall, an imbalanced microbiome, and eventually will cause intestinal inflammation and disease.


Stress managing and mindful eating.


When it comes to gut health, stress management is a must. Chose something that works for you, but do it consistently. Go for daily walk in the park, forest, or beach, listen to relaxing music, sing, dance, laugh, breathe, have a cup of tea, soak in the tub with a candlelight. Do something you love every day.


If you are struggling with poor digestive health, consider stress and stressful eating as possible culprits. Take a closer look at how you eat, where you eat, and how you feel when you are about to have a meal. Are you getting your breakfast through the drive-through window and eating it in the car on the way to work? Are you eating your lunch in front of a computer, or your dinner in front of the TV? Do you eat because you feel bored, sad, anxious or upset? Addressing these eating patterns may help resolve your lingering gut problems.


Next time, when you are having your meal, pay close attention to the food in front of you, notice its colors, textures, position on the plate, its aroma. Take a small bite, chew slowly, and savor every bite. Notice how the food is filling your stomach. Stop when you feel full. Notice the feelings and sensations you have after the meal.


This is a way of mindful eating and it is so much more than just an eating behavior. Besides improving your gut health and digestion, it can balance the central nervous system keeping vagal tone healthy. It also has been shown to improve cardiometabolic health [7], and maintain healthy weight [7]. It can repair a broken relationship with food, and bring a sense of presence into other areas of life [8].


Now that you understand how stress affects the gut, I hope you will take to a closer look at your own stressors and will take the steps to reduce them by choosing whole, real foods, finding time to unwind and relax, and practice mindful eating.


Want to become a mindful eating pro? Stay tuned for my soon-to be-published article, “From Mindless to Mindful in 10 Simple Ways".

Want to uncover the reasons behind your poor digestion and gut health?


Is your gut affected by stress? How do you manage stress? I would like to know!

Drop a comment below!





References:


1. Fox News (2015, October 28). Survey shows 74 percent of Americans living with GI discomfort. Retrieved from: https://www.foxnews.com/health/survey-shows-74-percent-of-americans-living-with-gi-discomfort


2. Stone K. (2020, March 1) List of Best-Selling Over-the-Counter (OTC) Drugs https://www.verywellhealth.com/top-selling-otc-drugs-by-category-2663170


3. Deloose, E., Janssen, P., Depoortere, I., & Tack, J. (2012). The migrating motor complex: control mechanisms and its role in health and disease. Nature reviews. Gastroenterology & hepatology, 9(5), 271–285. https://doi.org/10.1038/nrgastro.2012.57

4. Korn L. Nutrition Essentials for mental health. A complete guide to the food-mood connection. W.W.Norton & Company, Inc

5. Bonaz, B., Bazin, T., & Pellissier, S. (2018). The Vagus Nerve at the Interface of the Microbiota-Gut-Brain Axis. Frontiers in neuroscience, 12, 49. https://doi.org/10.3389/fnins.2018.00049


6. Matteoli, G., & Boeckxstaens, G. E. (2013). The vagal innervation of the gut and immune homeostasis. Gut, 62(8), 1214–1222. https://doi.org/10.1136/gutjnl-2012-302550

7. Hayashi, L. C., Benasi, G., St-Onge, M. P., & Aggarwal, B. (2021). Intuitive and mindful eating to improve physiological health parameters: a short narrative review of intervention studies. Journal of complementary & integrative medicine, 10.1515/jcim-2021-0294. Advance online publication. https://doi.org/10.1515/jcim-2021-0294


8. Schnepper, R., Richard, A., Wilhelm, F. H., & Blechert, J. (2019). A combined mindfulness-prolonged chewing intervention reduces body weight, food craving, and emotional eating. Journal of consulting and clinical psychology, 87(1), 106–111. https://doi.org/10.1037/ccp0000361




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