Your gut and your brain are always in close communication with each other—and the health of one impacts the health of the other. Stress and anxiety may cause symptoms in the gut, while gastrointestinal inflammation may send signals to the brain and has been linked to mental illnesses, including anxiety and depression.
“There’s a complex interplay between stress hormone levels, bowel function, and sensation of pain,” says David Poppers, MD, Ph.D., gastroenterologist and clinical associate professor of medicine at NYU Langone Health. “These are topics people often don’t want to talk about, but they’re among the most common reasons people seek care in the ER.”
How stress impacts the gut
The GI system contains the enteric nervous system (ENS), which is a group of neurons and glial cells. This system is sometimes called the “small brain” of the gut. There are networks of nerves that connect the esophagus to the anus and indirectly to the digestive system. “The network is very complex and we only understand part of it,” says Dr. Poppers. The ENS is responsible for regulating the secretion of various hormones and for the functioning and perception of pain and discomfort in the GI tract.
There is a two-way connection between the gut and the brain, with each influencing the other. The gastrointestinal system sending signals to the brain can trigger mood changes, while also mood signals from the brain can affect the gastrointestinal system. Dr. Poppers says that there is a huge interaction between gut health, stress, and emotional health and that it goes both ways.
The gut-brain axis is a communication pathway between the brain and the gut. When a person is stressed, this pathway carries high-alert signals from the brain to the gut. There is a direct connection between the digestive system and the body’s stress response, according to Christine Lee, MD, a gastroenterologist at Cleveland Clinic. Your brain releases stress hormones such as corticotropin-releasing factor (CRF), cortisol, adrenalin, and norepinephrine, and the receptors for these hormones are located throughout the gastrointestinal tract. Dr. Lee says that if you are faced with a very hungry bear, that is not the time when your body wants to focus on digesting. The hormone CRF has opposite effects on the upper and lower GI tract, causing constipation and diarrhea respectively.
Ghrelin and leptin are two other hormones that affect appetite and the sensation of fullness. According to Dr. Poppers, stress can lead to a hormonal imbalance which can make you hungry or cause you to lose your appetite.
The microbiome is a collection of healthy bacteria, viruses, and fungi in the body that’s mainly housed in the gut. The microbiome also plays a role in the stress-gut connection. A microbiome is a group of microorganisms that live in the body and are essential for good health. These microorganisms help to break down food, absorb nutrients, and produce mood-regulating chemicals like serotonin. According to some research, stress may cause alterations to the bacteria in the gut microbiome, which can impact its proper functioning. However, the effects of stress on the gut microbiome vary greatly between individuals. Dr. Poppers says that we do not know specifically what the virus is doing and whether the changes it causes are temporary or permanent.
Why does stress manifest differently in some people?
Everyone reacts to stress differently, and everyone experiences different gastrointestinal symptoms, explains Dr. Lee. How severe your symptoms are and what symptoms you experience are linked to many factors: hormones, receptors, genetics, metabolism, and the microbes in your body. Your anatomy and history of surgery can affect the severity of your GI symptoms.
Most of the body’s serotonin is made in the gut. According to Dr. Lee, there are more serotonin receptors in the gastrointestinal tract than in the brain. The neurotransmitter serotonin sends signals between the brain and the gut and promotes muscle contractions of the gastrointestinal tract. Having low serotonin levels can not only make you feel sad but can also cause gastrointestinal issues like constipation or discomfort. There are some people who, for genetic reasons, have a lot more serotonin receptors, or whose receptors are more sensitive. This is according to Dr. Lee. The imaging of people with gut disorders like IBS shows that their brains react differently to gut symptoms. Some people with IBS find that low doses of antidepressants help to ease their diarrhea, constipation, and stomach pain.
Since gut bacteria have been shown to play a role in the production of neurotransmitters, and everyone has a unique gut microbiome, a stressed-out microbiome can manifest differently in different people. Your personal microbiome is complex and influenced by many factors, including where you were raised, your diet, and whether or not you’ve taken a lot of antibiotics. “Bacterial content in people’s digestive systems can vary greatly, and this can produce different symptoms in different people,” says Dr. Poppers.
The severity of your gut symptoms is also affected by how you respond to stress. If you’re always envisioning the worst-case scenario, you may be catastrophizing. Do you deal with stress in a healthy way and look at things from different angles? In other words, learning to accept that you may not like something, but that you still have to deal with it, can make a big difference according to Karen Conlon, a psychotherapist in New York City who specializes in treating clients with functional bowel disorders like IBS.
Adapting to new situations and coming up with solutions to problems helps to reduce stress, which can have an impact on the gut. Learning to control your emotions and reactions can also help. If people lack the proper tools, Conlon believes it becomes much harder for them to not only improve their mental health but also their gut health.
Remember that some GI symptoms could be signs of a more serious disorder like Crohn’s or ulcerative colitis, such as rectal bleeding, a sudden, consistent change in bowel habits, unintentional weight loss, and sudden, severe abdominal pain. If you’re experiencing these symptoms, you should see your doctor as soon as possible.
What are the long-term impacts of a stressed gut?
Acute stress generally passes. Chronic stress can have a significant impact on the body in the long term. Chronic stress increases levels of the stress hormone cortisol. If cortisol levels are high for a long time, it can cause anxiety, make someone feel tired, and make it harder for the body to heal. Over time, this can lead to an increase in belly fat. Long-term exposure to cortisol decreases the body’s ability to heal, as explained by Dr. Lee.
Conlon states that if the brain is constantly sending signals to the gut that things are not going well, the digestive process will be negatively impacted. She adds that constant high-alert signals may contribute to functional GI disorders like IBS.
Improve your gut health, optimize your stress response
The microbiome is a collection of beneficial bacteria that help the body to respond better to stress and stay healthy.
Your gut flora helps to keep stress in line by producing compounds that have a calming effect on the body.
Your gut bacteria play an important role in regulating your mood by producing neurotransmitters like serotonin that communicate with your brain. These neurotransmitters are essential for coping with mental turmoil.
The presence of other healthy bacteria in the gut helps to lower cortisol levels, which is known to contribute to increased stress levels. The students who drank fermented milk reported less anxiety, depression, and fatigue during the exam. In a study, medical students who drank probiotic-rich fermented milk or a placebo for eight weeks before an important exam reported less anxiety, depression, and fatigue during the exam.
The students who drank the fermented milk showed lower levels of the stress hormone cortisol, increased levels of the neurotransmitter serotonin, and fewer gastrointestinal symptoms typically associated with stress and anxiety than the students in the control group.
The indigestible fibers that probiotics feed off of also increase the number of neurotransmitters that affect stress levels, according to human studies.
Both taking probiotics and making sure they are well-fed can help reduce stress and its negative effects on your system.
Here are some of the best ways to support your friendly microbes and prioritize your long-term health and wellness:
Optimize your diet.
When you are busy or tired, it is easy to make bad choices about what to eat. However, that is all the more reason to make sure you are giving your body the food it needs to stay healthy.
Your microbiome refers to the collection of microbes that live in your body, which changes based on the foods you eat. To maintain a healthy microbiome, it is important to eat a diet rich in whole and plant-based foods with an emphasis on prebiotic fiber. Prebiotics feed the probiotics in our gut in the same way that fertilizer helps plants grow in a garden.
Take a daily probiotic supplement.
The probiotic must be effective and taken on a consistent basis to replenish the good bacteria populations. Choose a probiotic that has several different strains of bacteria that can survive the harsh stomach acid and reach deep into the GI tract.
Make movement a priority.
Research shows that people who are physically active have healthier and more diverse microbiomes. Exercising is a great way to de-stress from a busy day. You can reduce stress by walking for just 30 minutes a day, which also has positive effects on your microbial health.
Get plenty of sleep.
A good night’s sleep has more benefits than just reducing stress levels; it also positively affects gut bacteria. A disruption to your normal sleep schedule can throw off the balance of good and bad bacteria in your stomach, leading to an unhealthy gut.
It is important to get a good night’s sleep by trying to get 7 to 9 hours of sleep every night. This will help improve your long-term health and vitality.
Don’t be afraid of a little dirt.
Contrary to what we have believed for the last century, exposure to dirt and bacteria is actually beneficial for us. The microbes present in soil can help teach our immune system how it should function. You should go outside and do some gardening, or play with the dog. Going camping is also a good way to have some dirty fun.
Try to clean up with water and natural soap instead of using antibacterial products that kill all bacteria, not just the bad ones.
Say no to antibiotics whenever possible.
The overuse of antibiotics in our food and as medicine is harmful to the colonies of good bacteria in our bodies. These antibiotics kill the good bacteria along with the bad bacteria. Try to stay away from meat, fish, and dairy that might have antibiotics in them. Check with a doctor to see if you really need antibiotics before taking them.
Try to find ways to make things simpler, change your perspective, relax, and enjoy more.
It’s a top priority to put first things first and take care of yourself.
The importance of maintaining mental and emotional health cannot be overstated. Supportive practices like saying no more often, minimalism, meditation, and taking time to appreciate the present moment with loved ones can help you live a life that aligns with your goals and improve your gut and overall health.
Although it can sometimes feel like it is normal to be constantly stressed, disconnected, tired, and frazzled in today’s world, we need to remember that we are in control of our own lives and we can choose to slow down and find our balance.
It’s better to make the decision to change your lifestyle before you have health problems that force you to reevaluate.
While some stress is inevitable, it can also help you figure out and go down the path to a healthy and successful life. No matter what life throws at you, you can always choose to prioritize your health and happiness. By living in harmony with your microbes and making decisions that support your entire being, you can make sure that your mind and body are always in sync.
Habits to limit stress for your gut
- Try not to skip meals. “When [people] start to experience gut issues, many people also start to under-eat out of fear of causing symptoms. When blood sugar dips too low, however, the body releases cortisol, which is one of our major stress hormones. To prevent adding more fuel to the fire in this way, make sure you include protein and fat at each meal and consider eating every 3-5 hours,” says Maya Rose, MS, CNS.
- Cut back on caffeine. Dr. Hendija says, “You can also cut back on food that increases stress, such as caffeine.” Even though many of us run on caffeine, there are some pretty stressful side effects, including insomnia, anxiety, and dehydration, all of which can contribute to poor gut health, the Cleveland Clinic explains.
- Alcohol consumption. Along with caffeinated drinks, alcoholic beverages can wreak havoc on your mind and gut health. Yes, sometimes it’s tempting to have a glass of wine to relieve stress. Still, alcohol can cause stress responses (not to mention stomach issues), according to the National Institute on Alcohol Abuse and Alcoholism (NIAAA) at the National Institutes of Health. So limiting it won’t be the worst thing for your gut health.
You should speak to your doctor if you are struggling with stress or gut health problems, as they may be able to offer some helpful advice.