Bowl of yogurt with berries and oats

Can Probiotics Help Multiple Sclerosis? A Q&A with Ahna Crum, R.D.N.

By Kerry Weiss
Reviewed by Dana Cooper, M.D.
December 15, 2023

This article is part of a Q&A series in which a healthcare professional in our community answers your frequently asked questions.

Probiotics are a popular way to improve digestive health, or gut health. Often called good bacteria, probiotics have caught on as a potential remedy for many other conditions that seemingly have nothing to do with digestion.

But what kind of an effect can probiotics have on multiple sclerosis, a neurological disorder that affects the brain and spinal cord? We asked Ahna Crum, a registered dietitian nutritionist, MS community expert, and fellow MS warrior, to give us the lowdown on probiotics and MS.

Is there a link between gut health and multiple sclerosis?

Ahna Crum, R.D.N.: In the gastrointestinal tract, known as the gut, is a part of the body’s nervous system known as the enteric nervous system. Through bidirectional communication via a network of nerves and neurotransmitters, your gut communicates with your brain and your brain communicates with your gut. Within the past decade, research has been uncovering just how important this cross-talk between the brain and gut truly is.

The bacteria and other microbes that live in your digestive tract not only help to improve overall digestive health but also play a role in keeping your immune system healthy. That’s because the microbiota (bacteria) in the digestive system help stimulate the immune system and help the body absorb and use the vitamins in your food.

Research has shown that the microbiome of a person with MS differs from the microbiome of a healthy individual without MS in that the former contains more pro-inflammatory bacteria. This type of bacteria has been linked with increased levels of Th17 cells—which are a key driver behind the development of MS.

Since the bacteria in your gut have such a critical role with the immune system, research suggests the gut plays an integral role in MS disease activity.

What are probiotics?

A.C.: Probiotics are defined by the World Health Organization as living microorganisms that may provide health benefits when consumed or taken in adequate amounts. While probiotics are available in many food sources, as well as in supplements, only specific strains that have been researched and tested qualify as probiotics under the official definition.

Probiotics may help with overall digestion and absorption of nutrients. By increasing the amount of beneficial bacteria in your gut, probiotics can help support the production of enzymes that defend you from harmful bacteria and protect your immune system.

Could probiotics help with MS symptoms?

A.C.: Consuming probiotics in food or supplement form may help balance the ratio of anti-inflammatory bacteria to pro-inflammatory bacteria in the gut. When the pro-inflammatory bacteria get out of balance, this is what can provoke the immune system, resulting in increased inflammation.

Several studies suggest that there may be excessive amounts of inflammatory bacteria in some people with MS, and therefore probiotics are being investigated for treatment of MS as a way to modulate the body’s immune response. Emerging research involving people with MS suggests that probiotic supplementation may:

  • Decrease systemic inflammation
  • Improve disease progression
  • Ease disability
  • Improve mental health symptoms like depression and anxiety

What are the best sources of probiotics?

A.C.: In addition to supplements, probiotics are also found in several fermented foods and beverages. Common foods that either contain natural probiotics or have probiotic strains added include:

  • Yogurt
  • Cheese
  • Kefir (a fermented milk drink)
  • Cultured milk
  • Buttermilk
  • Kombucha
  • Miso
  • Tempeh
  • Sauerkraut
  • Sourdough bread
  • Kimchi
  • Olives
  • Pickles

It’s important to note that not all fermented foods contain live bacteria—some processing methods, such as pasteurization, filtering, canning, or baking, can destroy the live bacteria.

There are debates on whether it’s better to get probiotics from taking supplements or eating food. Consuming probiotic foods can support beneficial bacteria and provide other important nutrients, and taking supplements can be a way to get a relatively consistent amount of specific strains of bacteria for specific health outcomes. Because both approaches have advantages, the best approach may be to do both: eat healthy probiotic foods and take supplements.

What should you look for in a probiotic supplement?

A.C.: When purchasing probiotic supplements, it’s important to look for three things on the product label: genus, species, and strain (usually denoted with capital letters and numbers).

There are many different types of bacteria that exert strain-specific effects. For example, many probiotic products list the genus and species (like Lactobacillus acidophilus), but not the strain (like Lactobacillus acidophilus CL1285), so it’s very hard to gauge how that’s impacting the body.

What’s more, the U.S. government does not regulate probiotic supplements. This means that many over-the-counter products may not contain what the label claims.

Therefore, it is very important to do the following:

  1. Make sure your probiotic supplement label includes specific strains.
  2. Choose brand-name products that have available research to back their health claims.

Several of the most-studied strains for MS include:

  • Lactobacillus paracasei DSM 24733
  • Lactobacillus plantarum DSM 24730
  • Lactobacillus acidophilus DSM 24735
  • Lactobacillus delbrueckii subspecies bulgaricus DSM 24734
  • Bifidobacterium longum DSM 24736
  • Bifidobacterium infantis DSM 24737
  • Bifidobacterium breve DSM 24732
  • Streptococcus thermophilus DSM 24731

Can probiotics cause side effects?

A.C.: In those who are immunocompromised or are taking immunosuppressants, the immune system may not be able to appropriately respond to microbes and may allow them to cross the gut barrier. This can lead to infection.

Everyone should talk to their doctor before taking a probiotic—and this is especially important if you’re currently taking immunosuppressants or are immunocompromised.

What about prebiotics?

A.C.: Prebiotics are nondigestible food components (usually plant fibers) that can feed gut bacteria. Like probiotics, prebiotics are also beneficial for increasing the amount of ‘good’ bacteria in the gut.

If you’re consuming the recommended amounts of daily fiber (which is between 25 and 38 grams) then you may already be receiving a healthy amount of prebiotics. If not, quality food sources of prebiotics include:

  • Asparagus
  • Fennel
  • Garlic
  • Artichokes
  • Legumes
  • Beans
  • Peas
  • Oats
  • Nuts
  • Flaxseeds
  • Onions
  • Scallions
  • Bananas
  • Apples

Prebiotic supplements are also available in health food stores and online. These include options like inulin, galacto-oligosaccharides, oligofructose, partially hydrogenated guar gum, or psyllium.

These can be very beneficial but aren’t always well tolerated. In some people, prebiotic supplements can cause abdominal cramping, gas, and bloating. If you experience these side effects yet still want to try prebiotics, it might be a good idea to try cutting your dose in half and slowly working your way up to the full dose recommended by your doctor or on the packaging.

What does the research say about probiotics and MS?

A.C.: It’s important to remember that most of the available research is from studies involving animals and not humans. So far, there have only been a few clinical trials conducted on people with MS. As these trials are very small in sample size and short in duration, there is not enough data to conclude how probiotics can benefit MS symptoms.

However, the limited amount of research we have is promising, and it seems very hopeful that managing gut health may help people manage their MS. Currently, research encourages using probiotics not as a replacement or stand-alone therapy, but rather in conjunction with other disease-modifying medications and treatment regimens for MS.

This area of study is still in its infancy—stay on the lookout for more fascinating research as the amount of data continues to grow.

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