Chronic Fatigue Syndrome Linked with Differences in Gut Bacteria

A drawing of a rod-shaped bacterium
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People with chronic fatigue syndrome may have imbalances in their gut bacteria, a new study suggests.

The study found that people with chronic fatigue syndrome  had higher levels of certain gut bacteria and lower levels of others compared to healthy people who didn't have the condition.

The researchers then checked to see if these imbalances also characterized the subset of patients in the study who had irritable bowel syndrome (IBS), an intestinal disorder that is common in people with chronic fatigue syndrome. Results showed that  patients did indeed have different patterns of gut bacteria disturbances depending on whether they had only chronic fatigue syndrome or both chronic fatigue syndrome and IBS.

The findings suggest that researchers may be able to divide chronic fatigue syndrome patients into different groups depending on their gut bacteria imbalances, which could aid in the diagnosis and treatment of the disease, the researchers said. [5 Ways Gut Bacteria Affect Your Health]

Chronic fatigue syndrome is a disorder in which people have extreme fatigue that is not improved by rest and is not the result of another medical condition. An estimated 35 percent to 90 percent of patients with chronic fatigue syndrome also report abdominal discomfort consistent with symptoms of IBS, the researchers said.

The reason for the link between chronic fatigue syndrome and IBS is not clear; chronic fatigue syndrome may predispose patents to developing IBS, or the two conditions might share underlying causes, the researchers said.

Previous studies have already found district differences in gut bacteria in chronic fatigue syndrome patients compared to healthy people. But the new study is one of the first to look for differences between gut bacteria in chronic fatigue syndrome patients who have IBS and bacteria in those who do not have IBS.

The researchers analyzed fecal samples from 50 patients with chronic fatigue syndrome and 50 healthy people who did not have the condition. Nearly half of the chronic fatigue syndrome patients, 21 out of 50, also had IBS.

The researchers found that differences in the levels of six types of gut bacteriaFaecalibacterium, Roseburia, Dorea, Coprococcus, Clostridium, Ruminococcus and Coprobacillu — were strongly linked with chronic fatigue syndrome. In fact, the relative abundance of these species in participants' guts could be used to predict whether the patients had chronic fatigue syndrome, the researchers said.

In addition, researchers found that people with chronic fatigue syndrome and IBS had higher levels of a type of bacteria called Alistipes and lower levels of a type of bacteria called Faecalibacterium. Meanwhile the patients who had chronic fatigue syndrome but not  IBShad higher levels of a genus of bacteria called Bacteroides but lower amounts of a specific species in this genus called Bacteroides vulgatus.

Some researchers have hypothesized that altered gut bacteria may play a role in the causing chronic fatigue syndrome, because some research shows that a person's gut bacteria may affect their central nervous system and immune system. However, it's also possible that changes in gut bacteria are a consequence of having chronic fatigue syndrome.

Future studies should look further into gastrointestinal symptoms and their relation to gut bacteria disturbances in people with chronic fatigue syndrome, the researchers said.

It's possible that one day researchers could use information about a patient's gut bacteria, the metabolic pathways that those bacteria are involved in and the immune molecules present in the blood to more accurately diagnosis people with chronic fatigue syndrome and develop more specific treatments for the condition, the researchers said.

The study was published online April 26 in the journal Microbiome.

Original article on Live Science.

Rachael Rettner

Rachael is a Live Science contributor, and was a former channel editor and senior writer for Live Science between 2010 and 2022. She has a master's degree in journalism from New York University's Science, Health and Environmental Reporting Program. She also holds a B.S. in molecular biology and an M.S. in biology from the University of California, San Diego. Her work has appeared in Scienceline, The Washington Post and Scientific American.