How does the gut microbiome affect chronic fatigue syndrome?

ME/CFS is a chronic illness affecting up to 24 million people around the world.

The main symptom of the disease is a feeling of intense fatigue that does not improve with rest. This feeling of tiredness may worsen after both physical and mental activities.

Other symptoms of ME/CFS include:

There is currently no specific treatment or cure for ME/CFS. Different treatments and lifestyle changes are aimed at helping to alleviate and manage symptoms, and these include:

In one of the studies, researchers compared microbiome samples from 74 people with ME/CFS that had been diagnosed in the previous four years to samples from 75 people who had received their ME/CFS diagnosis at least 10 years prior. Scientists also included samples from 79 healthy participants who acted as the study’s control.

Upon analysis, the research team found patients with shorter-term disease had changes in their microbiome with regard to diversity, including a lower number of microbes known to produce butyrate.

Butyrate plays an important role in the health of the gut microbiome, and previous research shows it is a source of sleep-promoting signals in the body.

“This points to potential mechanisms by which the microbiome can impact the immune system, as immune irregularities have been observed in ME/CFS,” Dr. Julia Oh, an associate professor at the Jackson Laboratory and senior author of this study, explained to Medical News Today.

“Butyrate, tryptophan, and other microbial metabolites have been linked to mucosal immune regulation, and our team previously showed a striking immune dysbiosis in different blood immune markers,” she told us.

“This is an exciting association because each of these cell types has been linked to bacterial or fungal infections, responds to microbial metabolites, and has been linked to the pathogenesis of autoimmune or chronic inflammatory diseases. Thus, it is possible that the microbiome primes or sustains an aberrant immune response following disease onset.”

– Dr. Julia Oh

In the second study, researchers examined the microbiomes of 106 people with ME/CFS and 91 participants without the disease matched by age, sex, geography, and socioeconomic status. Additionally, scientists examined the microbial species levels in stool samples from all participants.

Scientists found a correlation between the severity of a participant’s fatigue symptoms and the levels of specific species of gut bacteria, mainly Faecalibacterium prausnitzii.

Past studies have shown that F. prausnitzii is one of the body’s main producers of butyrate, and it has anti-inflammatory properties.

“F. prausnitzii is an important, abundant bacteria in the microbiome, with health-promoting properties associated with its role in butyrate production and controlling inflammation,” Dr. Brent L. Williams, an assistant professor of epidemiology, pathology, and cell biology in the Center for Infection and Immunity at Columbia University’s Mailman School of Public Health and senior author of this study explained to MNT.

“Deficiency of F. prausnitzii has been associated with a range of other human diseases and may be considered as a biosensor of human health,” he pointed out.

“It has also been previously associated with fatigue experienced by some individuals with inflammatory bowel disease,” Dr. Williams continued. “Thus, it perhaps should not be a complete surprise that F. prausnitzii is also correlated with fatigue symptoms experienced by individuals with ME/CFS.”

“Of course,” he cautioned, “this is just a correlation and doesn’t show causation. Further research will be needed to establish any causal link.”

MNT also spoke with Dr. Hector Bonilla, medical director of the Stanford ME/CFS Clinic, about these two studies.

He commented these studies help explain when people with ME/CFS change their diet, their symptoms improve.

“What people eat affects the gut flora — the microbiome,” he detailed. “The human gut microbiota is a powerful modulator of host immune responses and metabolism.”

“There is increasing evidence that chronic low-grade inflammation plays a significant role in mortality and the pathogenesis of chronic inflammatory-related diseases such as ischemic heart disease, diabetes, stroke, cancer, chronic kidney disease, non-alcoholic fatty liver disease, and autoimmune and neurodegenerative diseases,” Dr. Bonilla noted.

“In ME/CFS, analysis of the composition of the gut microbiomes had shown a decreased bacterial diversity (Firmicutes phylum), and changes such as increased Alistipes and reduced Faecalibacterium, can be considered a top biomarker of ME/CFS, more specifically the abundance of F. prausnitzii was inversely associated with fatigue severity,” he continued.

“Furthermore, those changes in the microbiome population are associated with an increase in pro-inflammatory species and a reduction in anti-inflammatory species.”

For the next steps in this research, Dr. Bonilla said he would like researchers to validate these studies in different populations and “see what symptoms are more associated with changes in the microbiome.”

“And besides bacteria, see what kind of proteins have been linked with these panel changes, because knowledge can help us start to develop some targets for therapeutics,” he added.