How Gut Bacteria Affects Multiple Sclerosis

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Everyone has bacteria in their gut–billions of microorganisms that make up the “microbiome.” They help our bodies function properly by preventing the advancement of disease, assisting with nutrient absorption, producing vitamins, and promoting a healthy immune system. But some kinds of gut bacteria can cause problems, especially when they outnumber “good” bacteria.

When helpful bacteria are outweighed by harmful bacteria, called dysbiosis, this can affect MS symptoms, progression, and possibly even trigger its development. Studies suggest some kinds of gut bacteria may worsen inflammation in people with MS, while others can protect the brain from inflammation. A balanced microbiome can keep “bad” bacteria in check to keep MS more under control.

MS is a disease of the central nervous system, made up of your brain, optic nerves, and spinal cord. When you have MS, your immune system misfires, disrupting your central nervous system and sending cells to attack your nerves’ protective coating. This interferes with communication between the body and the brain and results in symptoms like numbness, tingling, and trouble walking. People with MS are more likely to experience constipation, fecal incontinence, and inflammatory bowel diseases, suggesting a direct connection between the digestive tract and the central nervous system.

Studies have shown that certain groups of gut bacteria change how the immune system works, impacting MS. One study found that levels of certain groups of bacteria are different in the guts of people living with MS than those who aren’t. For example, two bacterial strains, acinetobacter and akkermansia, were four times more likely to be found in people with MS than people without it.

Researchers found that these microbes increase the number of cells, called T helper cells, that activate an immune attack–and they decrease the number of cells, called regulatory T cells, that suppress an overactive immune response like that seen with MS. Additionally, a strain of bacteria called parabacteroides–known to reduce inflammation–was four times less likely to be found in people with MS than those without the condition.

This research has built a foundation for developing new MS treatments based around gut bacteria. Researchers are looking into the effect of balancing out this bacteria in people with MS so the harmful types are less able to thrive. Experts are also examining the possibility of introducing specific bacteria into the microbiome of people with MS in order to improve symptoms.

One bacteria called Prevotella histicola (P. histicola), for example, shows promise in reducing inflammation and nerve cell damage in people with MS. And one study found that certain brain cells may be directed by specific gut bacteria to suppress brain inflammation. Ask your doctor about clinical trials that may be on the horizon. There’s much more research to be done on this topic, but existing studies are revealing that gut bacteria does play a role in activating–or suppressing–the immune response and resulting inflammation.

Diet has a big impact on gut health. Many people see improvements when they move toward a Mediterranean diet and away from Western ways, which tend to be high in sugar, fat, and red meat. A Mediterranean diet emphasizes:

• fiber-packed whole grains
• fresh fruits and vegetables
• nuts and seeds
• olive oil

One study found that a Mediterranean diet changes gut bacteria in a positive way that reduces frailty in aging people and may be helpful for those with MS as well.

Adding probiotics through food or supplements has also been shown to help promote a healthy microbiome. Popular probiotic food choices include:

• yogurt
• soy
• kefir
• kimchi

Certain probiotic supplements can also perform specific duties like making the immune system stronger. Before you take supplements or make big changes to your diet, talk with your doctor with your overall MS treatment plan in mind.

Be especially careful of taking supplements, because it can be hard to choose the right dose on your own. Ask your doctor if a registered dietitian or nutritionist can be added to your team to help you plan appropriate meals and stay on track toward your goals.