Fibromyalgia: What’s Your Gut Got to Do With It?

Research suggests that this chronic pain disorder may be connected to digestive health. Certain dietary changes might help alleviate fibromyalgia symptoms.

By Kate Jackson

Medically Reviewed by Samuel Mackenzie, MD, Phd

Fibromyalgia has been linked to small intestinal bacterial overgrowth along with irritable bowel syndrome.
Fibromyalgia has been linked to small intestinal bacterial overgrowth along with irritable bowel syndrome.Shutterstock; iStock

If you have fibromyalgia and also experience digestive issues, your gut problems may be more than a coincidence.

“There’s a definite correlation between gut health and fibromyalgia,” says R. Swamy Venuturupalli, MD, a rheumatologist in Beverly Hills, California, whose practice focuses on treating autoimmune and inflammatory diseases. Though researchers vary in their estimates, “there’s a higher incidence of irritable bowel syndrome (IBS) in people with fibromyalgia,” Dr. Venuturupalli says. “Some reports say approximately 60 percent of people with fibromyalgia have IBS, and conversely, 60 or 70 percent of people with IBS also have fibromyalgia.” And, he notes, a study published in March 2015 in the journal Medicine found that people with fibromyalgia were 1.5 times more likely than others to have IBS, the symptoms of which include chronic abdominal pain, constipation, diarrhea, and nausea.

In addition to IBS, fibromyalgia has been linked to small intestinal bacterial overgrowth (SIBO), a condition with similar symptoms in which the small intestine is colonized by colon bacteria. According to Bharat Kumar, MD, an assistant professor of internal medicine at University of Iowa Health Care in Iowa City, while some studies have linked SIBO with increased pain in fibromyalgia, “the evidence linking the two diseases is still a little weak.” He points, however, to a study in which 42 of 42 participants with fibromyalgia “had tests that were strongly suggestive of SIBO.” The big question, Dr. Kumar says, “is can these findings be generalized to the larger population of people with fibromyalgia? The answers aren’t quite there yet.”

Venuturupalli observes that the study Kumar references, which was done by researchers at Cedars-Sinai Medical Center, involved very sick people with fibromyalgia who were tested for SIBO, so the sample was likely skewed. Venuturupalli hasn’t found so high a percentage in his clinical practice, but he agrees that people with fibromyalgia and gut symptoms often have SIBO, estimating it occurs 20 to 30 percent of the time.

A Connection Between Fibromyalgia and ‘Leaky Gut’?

Kumar points to another study that indicates having SIBO increases fibromyalgia pain in areas outside the gut. This may happen due to a somewhat controversial condition called leaky gut. “The gut is a barrier between the outside world and our inner organs,” explains Kumar. “In SIBO, this barrier becomes leaky, so chemicals that are released by or processed by bacteria get into our bloodstream. While the research is still very preliminary, it’s thought that these can activate the immune or nervous systems. This may lead to the symptoms that people with fibromyalgia often relate to their doctors.”

According to Venuturupalli, leaky gut remains a theoretical concept that’s not widely accepted in Western medicine. The theory, he says, promoted largely by alternative medicine practitioners, is that allergens cause a leakage of proteins, which in turn cause inflammation that transcends the gut to other parts of the body. It hasn’t been proved without a doubt, says Venuturupalli. “Having said that,” he adds, “conceptually, it makes some sense.” Hypersensitivity to certain foods can trigger inflammation, but the exact way that happens is unknown. It’s not unlikely, he says, that it could give rise to fibromyalgia symptoms.

“Fibromyalgia can be thought of as a central pain sensitization disorder,” says Kumar. “When there’s chronic pain, due to any reason, the brain starts to rewire itself in a way that prioritizes pain. It’s believed this was originally a survival mechanism to alert the brain about injuries, but that was when people lived very short lives and there was no such thing as chronic pain. The link between poor gut health and fibromyalgia adds a wrinkle to this. Maybe the fibromyalgia related to poor gut health is because of that same survival mechanism alerting the brain that there’s something going on with the gut.”

RELATED: Gut Health and Rheumatoid Arthritis: What You Need to Know

Venuturupalli acknowledges the connection. In his practice, he’s seen people whose fibromyalgia symptoms flair when their gut symptoms flair. “That’s a known phenomenon, but it’s not across the board,” he says. “There are probably subsets of people for whom gut health plays a role in causation of the fibromyalgia, and treatment needs to be directed there. There may be other types for whom fibromyalgia may not be due to the gut.”

Treating Digestive Symptoms to Help With Fibromyalgia

If you have fibromyalgia and also have gut symptoms, Venuturupalli advises making your doctors aware of this connection and requesting a consultation with a gastroenterologist, particularly one with some expertise in SIBO. “Working on gut issues is good for overall health, and I recommend that for all patients,” Venuturupalli says.

Kumar doesn’t recommend that everyone get tested for SIBO, however. “Up to 20 percent of the general population may have abnormal lab tests, and this might lead to overtreatment. Antibiotics, which are used in treating SIBO, have their own side effects and should be used very carefully,” he says.

And is the reverse also true? Should people with SIBO and IBS investigate whether they have fibromyalgia? Kumar believes that they should be evaluated by primary care physicians. “Fibromyalgia is treated largely through physical therapy and addressing the root causes for the central pain sensitization,”  he says. “Identifying fibromyalgia can make treatment plans more focused and guided.”

Treatment of gut issues may improve digestive symptoms. “Because there are many different reasons for having SIBO, working with doctors to craft a comprehensive and personal treatment approach is essential,” says Kumar. “While it may not necessarily improve the other symptoms of fibromyalgia, by reducing the abdominal pain, SIBO treatment may improve the quality of life for people with concomitant fibromyalgia.”

RELATED: Fibromyalgia Treatment

The Role That Diet and Eating Habits May Play

Kumar advises patients to discuss diet, which he says is extremely important, with their physicians. “The food we eat not only nourishes our bodies but also the millions of bacteria that live in our gut,” he says. “So the types of food that you eat can make SIBO better or worse.” Eating yogurt with live active colonies, he says, is supported by research as helpful for SIBO.

“I also recommend a low-FODMAP diet to people who have irritable bowels,” says Kumar. FODMAP (fermentable oligosaccharides, disaccharides, monosaccharides, and polyols) are carbohydrates that are naturally present in foods and “are particularly appealing to bacteria that can overgrow and cause SIBO,” he explains. Talk to your doctor before beginning a low-FODMAP diet, he cautions, to determine whether it really may be helpful. The concern, he says, is that you could excessively or unnecessarily restrict your diet, preventing you from obtaining needed nutrients. And dietary changes, he warns, need to be maintained over the long term or SIBO is likely to reoccur.

RELATED: Fibromyalgia: What to Eat, What to Avoid

Don’t Ignore the Connection Between Gut Health and Chronic Pain

“Fibromyalgia is more than just chronic pain,” says Kumar. “Although there’s a lot left unknown about it. We are now understanding that it’s more than just a muscle and joint illness. It can be affected by any number of other organ systems, like the gut.”

If you have fibromyalgia and suspect you may have gut issues, or vice versa, you may have to be your own best advocate. “People with fibromyalgia are sometimes not taken very seriously by doctors when there may be other issues complicating the diagnosis,” says Kumar. “The growing recognition of a link between SIBO and fibromyalgia is a great example of this.”

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