Gut Bacteria's Possible Role in Multiple Sclerosis

Microorganisms in your GI tract influence your immune health

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E. coli gut baceria.
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Research has examined the impact of intestinal bacteria—small microorganisms that aid in the digestion of food and help protect your gastrointestinal (GI) system from infection—on a number of diseases. While the link between gut bacteria and multiple sclerosis (MS) is tenuous at this time, researchers have found some evidence that the gut bacteria of people with MS may differ slightly from that of people who do not have the disease.

As this possible link continues to be explored, the scientific community is also working on unraveling the practical implications of this, such as whether it is possible to significantly change gut bacteria and whether that could be beneficial for people with MS.

Your Gut and Your Immune System

MS is a disease in which inflammation and demyelination (decrease in the protective covering around nerve fibers) in the brain, spine, and optic nerves produce neurological deficits. Most experts believe that the disease is caused by an autoimmune process in which the body's immune cells attack its own myelin.

A growing number of research studies have shown interactions between an individual’s gut bacteria and their immune cells, with imbalances in the types or numbers of bacteria influencing immune system activity.

Whether gut bacteria play a role in MS specifically is yet to be confirmed, but there are some interesting observations about the possible connections.

Differences in Those With MS

Researchers have found that people with MS do not always have the same gut flora (combination of bacteria) as those who do not have MS. However, while the flora may differ between these two groups, it is not always identical among everyone who has MS.

Among the aspects of gut flora being looked at in relation to disease are short-chain fatty acids (SCFAs)—products produced by bacteria in the gut. These fats can cross the blood-brain barrier, a lining that protects the nervous system from some harmful substances. SCFAs are believed to create an anti-inflammatory effect, which can "calm" your immune system.

The altered gut flora seen with MS does not necessarily correspond to changes in SCFAs, but their potential benefit for the disease is being examined. One study demonstrated that SCFAs can diminish the effects of experimental autoimmune encephalitis (inflammation of the brain) in animal models. But this effect has not been reproduced in humans or in MS.

Diet and Gut Bacteria

Dietary changes may modify the GI flora. For example, a vegetarian diet, a ketogenic diet, or a probiotic diet can all alter the gut flora in relatively predictable ways. Not only do the bacteria change to more efficiently break down the specific foods you eat, but foods also introduce bacteria into your GI system, directly changing the flora.

But there is no evidence that changing your GI flora can change MS symptoms, reduce relapses, or alter your disease course.

It isn't clear whether the changes in gut flora cause MS, are caused by MS, or are caused by a physical process that causes both MS and altered gut flora.

Relevance to MS Treatment

Research regarding the link between gut flora and MS may identify some more definitive relationships in the future. For now, there are no established guidelines about how to act on this potential link in a practical way.

Two options, however, have been considered—probiotic supplements and fecal transplantation.

Probiotic Pills

A small study in Iran evaluated the effects of taking a probiotic capsule for 12 weeks. The researchers reported an overall improvement in several aspects of MS among those who took the probiotic pills, including the expanded disability status scale (EDSS), a commonly used measure of MS severity in research studies.

Fecal Transplantation

Fecal transplantation is a procedure in which stool from another individual is transferred into your intestines to alter your gut flora. This has been suggested as a potential mechanism of altering gut flora in MS. But without definitive information about the precise role of GI bacteria in MS, it has not been proven useful and is not currently recommended.

A Word From Verywell

At this time, there are no strategies that can prevent MS from developing. Gut bacteria and the products they make, such as SCFAs, raise an interesting issue that may play a role in future MS treatment.

If you opt to consider any dietary modification or supplements for the management of your MS, be sure to discuss it with your doctor and/or a dietitian to make sure it's the right decision for you. Our Doctor Discussion Guide below can help you start that conversation.

Multiple Sclerosis Doctor Discussion Guide

Get our printable guide for your next doctor's appointment to help you ask the right questions.

Doctor Discussion Guide Woman
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