- A recent study shows a link between the gut microbiome and symptoms of multiple sclerosis (MS).
- The findings confirm previous research that suggests that MS is an autoimmune disease that may be linked to gut health.
- Measures to improve bowel health could help people with MS manage the symptoms associated with the condition.
Multiple sclerosis (MS) is a condition that affects the central nervous system (primarily the brain, spinal cord, and optic nerves), meaning it can cause symptoms throughout the body.
According to the National Multiple Sclerosis Society, there are nearly 1 million people with MS.
Research suggests that MS is an autoimmune disease. Now scientists have found that a person’s intestinal microbiota can also play a role.
In a new study, researchers from the Department of Neurology at Rutgers Robert Wood Johnson Medical School confirm a previously observed link between microbes in the gastrointestinal tract, known as the intestinal microbiota, and MS.
The results were recently published in Frontiers in Immunology.
MS: An autoimmune degenerative disease
Autoimmune diseases occur when the immune system attacks healthy tissue.
In MS, the immune system targets the myelin sheath, which surrounds and protects nerve fibers, leading to inflammation. Myelin is important because it protects nerves and ensures that electrical signals pass through them quickly and efficiently.
Multiple sclerosis means “scar tissue in multiple areas.” The most common MS symptoms include:
The link between gut health and MS symptoms
For the present study, the researchers used a mouse model to observe the relationship between bowel health and MS symptoms.
The mice were genetically engineered to have genes associated with MS, which allowed researchers to investigate the link between changes in gut bacteria and a condition called experimental autoimmune encephalomyelitis (EAE), which is similar to MS.
Dr. Achillefs Ntranos, a neurologist and MS specialist in Santa Monica, California, who was not involved in the study, told Medical News Today that the article discusses the possible link between MS and intestinal dysbiosis, which refers to an imbalance in the microbial composition of the intestine.
“The authors conducted a study using humanized transgenic mice that were genetically modified to express specific human genes to investigate the link between intestinal inflammation and the development of experimental autoimmune encephalomyelitis (EAE), a condition similar to MS in humans. They found that the mice contracted EAE and colitis, a type of inflammatory bowel disease, at the same time, which suggests a connection between autoimmune diseases of the central nervous system and intestinal inflammation.”
— Dr. Achillefs Ntranos, neurologist
The researchers next checked whether the same process occurred in people with MS.
They found that the subjects’ stools had higher levels of Lcn-2. This is a marker that is associated with intestinal inflammation. According to researchers, this marker was associated with fewer types of bacteria in the intestines.
In addition, the types of bacteria that tend to reduce inflammation in the intestines were less common in people with MS with higher levels of Lcn-2 in the stool.
According to the researchers, the amount of Lcn-2 in feces could be a good way to determine how healthy a person’s intestinal microbiota is. The study also suggests that a high-fiber diet, which can reduce inflammation in the intestines, may be helpful in treating MS
Dr. Sara Mesilhy, a gastroenterologist at the Royal College of Physicians in the UK, who was not involved in the study, emphasized the importance of fecal Lcn-2 as a biomarker.
“Lcn-2 in stool is a sensitive biological marker of intestinal dysbiosis in MS,” she explained. “In this study, levels of antimicrobial protein (Lcn-2) were higher in the stool of multiple sclerosis patients, which correlates with reduced microbial diversity in the intestine.”
“Other intestinal inflammatory mediators have been associated with reduced intestinal microbiota diversity in MS patients, [including] fecal Lcn-2, neutrophilic elastase, and calprotectin. Among these three mediators, fecal Lcn-2 levels were [the] significantly most sensitive marker. The study tracked the link between changes in intestinal bacteria and experimental autoimmune encephalomyelitis (EAE) in mice in order to better identify MS-related intestinal dysbiosis.”
— Dr. Sara Mesilhy, gastroenterologist
Dr. Mesilhy added that certain types of beneficial bacteria are depleted in MS. This includes SCFA-producing gut bacteria such as:
- Alistipes finegoldii
- Alistipes shahii
- Bifidobacterium adolescentis
Nancy Mitchell, RDN, a registered nurse and contributing author at the Assisted Living Center, who was also not involved in the study, emphasized to MNT that “inflammation is one of the main tactics of the immune system to ward off foreign substances and control bacterial growth in the intestines.”
“It is no surprise that reduced intestinal flora triggers an inflammatory response. The study shows that the population of intestinal bacteria needed to maintain a healthy digestive system is far lower in MS patients than in people without an autoimmune disease. These bacteria maintain balance in the intestines, and when there isn’t a significant population, the digestive tract is susceptible to infections, unwanted bacterial growth and, ultimately, inflammation.”
— Nancy Mitchell, registered nurse
Implications for people with MS
Dr. Ntranos noted that the findings suggest a possible link between intestinal dysbiosis and the development of MS and that intestinal inflammation could play a role in disease progression.
“This is important because it could potentially lead to [development] of new treatment strategies for MS aimed at improving the balance of microbes in the gut and reducing bowel inflammation,” he said.
“This could include the use of probiotics or prebiotics, i.e. substances that promote the growth of beneficial microbes in the intestines, or the use of specific antibiotics or other drugs against certain types of harmful bacteria.”
Areas for further study
Dr. Mesilhy explained that studies in mice increase the “probability of reproducibility and validation by allowing the removal of large tissues, testing of different parts of the GIT system, and the removal of brain tissue.”
She added that conducting similar research in humans is an important next step because people respond differently to DNA damage, vascular hemostasis responses, and immune responses.
“Environmental and dietary factors are included [and] the long-term effects are measured,” Dr. Mesilhy said.
“The link between MS and the gut will alert us to the benefits [of] diet and probiotics in improving and preventing MS. However, more studies are needed to
assess the benefits and side effects of this approach.”
Dr. Mesilhy further noted that it is important to “study the relationship between fecal Lcn-2 levels and clinical parameters, including MS relapse rate and disease progression.”
She concluded that further evidence that high-fiber diets or probiotics can help combat MS is an important area for future studies.
How much fiber should you consume daily?
According to the researchers, unhealthy eating habits, including low fiber intake and high fat consumption, may have contributed to the significant increase in MS in the United States.
The researchers also point out that countries with higher fiber intakes tend to have lower MS rates
According to the USDA Dietary Guidelines 2020—2025 for Americans, more than 90% of women and 97% of men do not meet the recommended fiber intake.
Dietary Guidelines note that men should consume between 28 and 34 grams of fiber per day, depending on age, while women should consume 22 to 28 grams. (Most older adults need less fiber).
Experts recommend increasing your fiber intake to reach the recommended daily intake. To increase daily fiber, people could do the following
- Consider: eating more sources of whole foods, eating more vegetables at mealtimes
- Choose whole grains over refined grains
- include plenty of legumes in your diet
- or add them to recipes
, eat nuts and seeds