10 Medical Reasons Why You Keep Getting Diarrhea

Having the runs is no fun, but when diarrhea sticks around, it could be a sign of one of these medical conditions.

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Irritable Bowel Syndrome

01-Medical-Reasons-Why-You-Keep-Getting-Diarrhea-379009879-zizi_mentosNicole Fornabaio/Rd.com, zizi_mentos/shutterstockIrritable Bowel Syndrome (IBS) can cause frequent loose bowel movements, along with cramping and bloating. About 10 to 15 percent of the adult population has IBS, according to David Levinthal, MD, PhD, a gastroenterologist at the University of Pittsburgh Medical Center (UPMC). IBS is more common in women and people under 50. Unfortunately, doctors are still trying to unravel the mystery of what causes IBS. "Ultimately, IBS is diagnosed by the presence of core symptoms of altered bowel movements and abdominal pain, in the absence of alarm signs or symptoms such as weight loss or blood in the stool," Dr. Levinthal says. "There is a large amount of research being conducted into the underlying disease mechanisms that are at play in a patient with IBS." He says possible causes include imbalances in gut bacteria, changes in gut motility (meaning food goes right through you), problems with fermentation of sugars, which causes a laxative-like effect, and even problems with the neural pathways that communicate with the GI tract. So if doctors don't know what causes it, what can you do about it? The U.S. Department of Health and Human Services suggests keeping a food diary to see what your triggers are—common culprits are dairy, caffeine, alcohol, artificial sweeteners, and some fruits and veggies. Try to get more fiber in your diet, drink a lot of water to combat dehydration from diarrhea, and avoid eating large meals. Some research has suggested a gluten-free diet may help as well. Does IBS often get mistaken for cancer?

Inflammatory Bowel Disease

02-Medical-Reasons-Why-You-Keep-Getting-Diarrhea-379009879-zizi_mentosNicole Fornabaio/Rd.com, zizi_mentos/shutterstockNot to be confused with IBS, Inflammatory Bowel Disease (IBD) is caused by inflammation in the GI tract. IBD affects 1.6 million Americans, and includes two major types of IBD, Crohn's disease and ulcerative colitis, according to the Crohn's and Colitis Foundation. Although Dr. Levinthal says the majority of chronic diarrhea is not due to IBD, it's definitely a major symptom of people who have it. IBD is diagnosed by the scary symptoms that are used to rule out IBS. "Most patients with true Crohn's disease, or related ulcerative colitis, experience bloody bowel movements, nocturnal diarrhea, more constant abdominal pain, rapid weight loss, and a variety of 'extra-intestinal' manifestations of disease including mouth ulcers, joint pains, or skin lesions," Dr. Levinthal says. The inflammation occurs when the body's immune system thinks food or gut bacteria are harmful foreign substances that must be attacked, which causes inflammation. Doctors don't know why this immune response happens, although a recent study from Arizona State University and Mayo Clinic Arizona identified some biomarkers for Crohn's disease, a promising step toward figuring out its underlying causes. For now, anti-inflammatory drugs are one step in treatment. As with IBS, keeping a food diary to figure out what foods worsen symptoms is a good idea, and a registered dietitian can help you come up with an individualized diet plan to manage your symptoms. Read about diets to consider if you have digestive problems.

Food allergy or sensitivity

03-Medical-Reasons-Why-You-Keep-Getting-Diarrhea-379009879-zizi_mentosNicole Fornabaio/Rd.com, zizi_mentos/shutterstockA food diary is once again useful in figuring out if your body is having an adverse reaction to something you're eating. One possibility is that you're lactose intolerant, meaning you can't digest dairy products, which results in a laxative-like effect. "Interestingly, people of all ethnicities are born with the capability of digesting lactose, but after the toddler years most humans worldwide actually become lactose intolerant to varying degrees," Dr. Levinthal says. For some reason, people of northern European ancestry tend to be able to digest it better than other ethnic groups. "Greater than 90 percent of the adult Asian population is lactose intolerant, while only about five percent of those of northern European ancestry are," he says. Another food digestion problem that may cause diarrhea is Celiac disease. "In patients with true Celiac disease (CD), gluten exposure from any source triggers an immune response that leads to localized inflammation of the small intestine, which can interfere with digestion and absorption of nutrients," Dr. Levinthal says. "Avoiding exposure to gluten is the best treatment." Another lesser-known food-related cause of diarrhea could be certain sugar-like molecules with the acronym FODMAPs (Fermentable Oligosaccharides, Disaccharides, Monosaccharides and Polyols), a concept developed at Monash University in Australia. They are found in certain foods like mushrooms, pears, apples, prunes, artificial sweeteners, and many other foods. "Diarrhea due to such poorly digested FODMAPs should resolve with changes in diet to reduce or eliminate the consumption of culprit foods," Dr. Levinthal says. "This mechanism of diarrhea is quite common and is under appreciated in the general population." See a registered dietitian to make a plan to test and eliminate problem foods from your diet. Try these tips to decide if it's gluten that's causing your tummy troubles.

Sleep deprivation

04-Medical-Reasons-Why-You-Keep-Getting-Diarrhea-379009879-zizi_mentosNicole Fornabaio/Rd.com, zizi_mentos/shutterstockYou might not suspect that sleep issues have anything to do with chronic diarrhea—but they might. A study from the University of Michigan showed that nurses who work rotating shifts have a higher incidence of bowel problems and pain compared to those working a regular daytime schedule. "There is a clear link between poor sleep and GI tract dysfunction, but the details are not fully understood," says Dr. Levinthal. "Sleep deprivation may impact bowel function through a few potential means, including alterations in the nerve signals along pathways that link the brain and the gut, changes in hormone levels such as the stress hormone cortisol, and shifts in melatonin levels." Part of being "regular" is having a regular sleep schedule, so your body knows when to go. If your circadian rhythms are off, your gut's response could be diarrhea. Here's what else happens to your body when you don't get enough sleep.


05-Medical-Reasons-Why-You-Keep-Getting-Diarrhea-379009879-zizi_mentosNicole Fornabaio/Rd.com, zizi_mentos/shutterstockAccording to the U.S. National Library of Medicine, about half of adults over 60 have diverticulosis, in which small pouches that bulge outward from the colon or intestine develop. "They are exceptionally common and linked with aging, low-fiber diets, and chronic constipation, but in most individuals, they cause no issues," Dr. Levinthal says. But, if one of the pouches becomes inflamed, it can cause diverticulitis, which can cause diarrhea and other symptoms like abdominal pain, nausea, and fever. "Acute diverticulitis attacks are most often diagnosed using blood tests and some form of abdominal imaging, such as a CT scan," Dr. Levinthal says. "Most cases are treatable with antibiotics." However, diverticulitis can recur, and if you've had an episode you should talk to your doctor about the best foods to help avoid another attack. According to the National Institute of Diabetes and Digestive and Kidney Diseases, in the past you might have been told to avoid certain food thought to get "stuck" in the pouches like popcorn, nuts, and seeds; but recent research has shown no benefit in avoiding these foods. Instead, you'll probably be recommended a diet high in fiber.

Intense exercise

06-Medical-Reasons-Why-You-Keep-Getting-Diarrhea-379009879-zizi_mentosNicole Fornabaio/Rd.com, zizi_mentos/shutterstockA study from Brazil showed that up to half of elite athletes suffer from this condition—so if you're always in the gym or running long-distance, your high-intensity exercising could be giving you stomach trouble as well. As with many other GI conditions, it's not known exactly why this happens, but "it may relate to changes in the distribution of blood flow away from the gut, or in the nervous system regulation of gut function during prolonged, intense exercise," Dr. Levinthal says. To help relieve the runs, avoid caffeine, high-fat, and high-fiber foods before an intense workout, and drink plenty of water. Take this quiz to find out exactly what workout you should be doing.

Long-term effects from a GI bug

07-Medical-Reasons-Why-You-Keep-Getting-Diarrhea-379009879-zizi_mentosNicole Fornabaio/Rd.com, zizi_mentos/shutterstockYou thought you kicked that nasty infection out of your symptom, but Dr. Levinthal says up to 30 percent of people who've had a bacterial or viral infection experience lasting changes in gut function, called post-infectious IBS. "Some of the best evidence of this phenomenon comes from studies of previously healthy individuals exposed to communicable GI illnesses, such as on a cruise ship, or food-borne illnesses during large outbreaks," he says. Research has shown some factors that determine whether a bug leads to longer-term problems is the severity of the initial infection, and also psychological factors like anxiety or depression (more on this connection later). As with regular IBS, diet regulation can help lessen symptoms. Studies have shown some alternative therapies like acupuncture, hypnotherapy, and peppermint oil may help as well. According to the International Foundation for Functional Gastrointestinal Disorders, 50 percent of patients with PI-IBS will eventually recover without specific treatment. Here are smart tricks to not get sick on a cruise.


08-Medical-Reasons-Why-You-Keep-Getting-Diarrhea-379009879-zizi_mentosNicole Fornabaio/Rd.com, zizi_mentos/shutterstockFor women, if you can't figure out why your diarrhea keeps coming back, try keeping track of it against your monthly cycle. "Reproductive hormones fluctuate greatly over the course of a woman's menstrual cycle, and some of these hormones can have broad impacts on body-wide physiology," Dr. Levinthal says. For example, he says, prostaglandins, which stimulate menstrual cramps, can also work to stimulate the muscles of the colon, speeding up motility and causing diarrhea. A study from UCLA showed that women who had "smoother than usual" bowel movements had higher levels of prostaglandins. Another study found that women with IBS had worse symptoms during their periods, so that time of the month may exacerbate existing bowel problems. Ibuprofen may help, as well as eating a fiber-rich diet to help get you regular. These period mistakes could make your time of the month even worse.


09-Medical-Reasons-Why-You-Keep-Getting-Diarrhea-379009879-zizi_mentosNicole Fornabaio/Rd.com, zizi_mentos/shutterstockStudies have shown a connection between bowel issues and fibromyalgia, a condition marked by musculoskeletal pain and fatigue. Unfortunately, doctors don't yet understand the link. "Fibromyalgia, much like IBS, is a common functional disorder of unknown cause," Dr. Levinthal says. "Diarrhea is not a specific symptom of fibromyalgia, but many patients with IBS have co-morbid fibromyalgia." This means that while fibromyalgia doesn't exactly cause IBS, it's likely that if you have fibromyalgia you also have IBS symptoms. According to some research, the link could be in how the body processes pain. If you're dealing with both syndromes, other lifestyle factors in addition to diet, like exercise and stress management, may help relieve symptoms. Here are 10 natural ways to treat fibromyalgia.

Mood disorder

10-Medical-Reasons-Why-You-Keep-Getting-Diarrhea-379009879-zizi_mentosNicole Fornabaio/Rd.com, zizi_mentos/shutterstockResearchers are learning more about the connection between the mind and the gut—and it turns out, having "butterflies in your stomach" or a "stomach in knots" is a real thing. "Changes in mood are inexorably linked with changes in GI tract function because many of the neural pathways in the brain involved in mood regulation and emotional processing also impact our body physiology," Dr. Levinthal says. "Thus, chronic changes in mood—anxiety or depression—can have profound impact on our gut function." A study from China showed this link, and other research has also found that stress can have an impact on our gut as well. Because of this mind-body connection, doctors are now treating IBS with antidepressants, and stress reduction may also help. "Many IBS patients experience improvement of bowel function with psychological therapies, or stress-relieving practices such as mindful meditation," Dr. Levinthal says. Here are other signs stress could be making you sick.

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