Vitamin B12 and Multiple Sclerosis

By Julie Stachowiak, PhD

Updated on January 18, 2024

Medically reviewed by Huma Sheikh, MD

Fact checked by Sarah Scott

A vitamin B12 deficiency can cause neurological symptoms that mimic those of multiple sclerosis (MS). Symptoms of both conditions include muscle weakness, difficulty walking, cognitive dysfunction, and sensory disturbances.12

Vitamin B12, clinically known as cobalamin or, sometimes, cyanocobalamin, is a water-soluble micronutrient that, among other things, is important to the normal function of the nervous system. Because of this role, it’s been hypothesized that in some cases a deficiency of vitamin B12 may be linked to MS, although this theory is controversial.3

Researchers are looking into whether there is a definitive link between B12 deficiency and multiple sclerosis. Regardless of these findings, low levels of B12 are associated with symptoms and health issues, so it’s important to understand how it supports the brain and spinal cord.4 It’s also a good reason to make sure you’re getting enough of the vitamin in your diet.

This article discusses how vitamin B12 can affect your nervous system and whether it can help manage MS. It also covers the symptoms of vitamin B12 deficiency and what can cause it.

Vitamin B12 Deficiency and the Nervous System

Vitamin B12 plays a key role in helping to maintain myelin—the sheath, or layer, of protein and fatty material that surrounds nerves, including those in the brain and spinal cord. It’s the myelin sheath around individual nerve cells that insulates them and makes it possible for electrical signals to be transmitted quickly and efficiently.5


Vitamin B12 Deficiency and the Nervous System

MS is also a disease that affects the myelin sheath of the nerves in the brain and spinal cord. It’s easy to see, then, why a deficiency of B12 can cause MS-like symptoms such as:

  • Muscle weakness
  • Difficulty walking
  • Cognitive dysfunction
  • Sensory disturbances like Lhermitte’s sign6

Despite this similarity, vitamin B12 deficiency and multiple sclerosis differ in significant ways.

B12 Deficiency

  • Affects central and peripheral nervous systems
  • Early symptoms (numbness, tingling) that may progress to muscle weakness and gait unsteadiness
  • More likely affects legs rather than arms
  • Affects both sides of the body equally
  • More common in middle-age or elderly individuals
  • Can be diagnosed with simple blood test
  • On an MRI, the brain or spinal cord appear normal
  • May cause other problems, such as anemia and glossitis (in which the tongue becomes swollen and painful)

Multiple Sclerosis

  • Affects mostly the central nervous system
  • Early symptoms manifest and progress in a variety of ways that are unpredictable
  • Doesn’t impair one body part more than another
  • May be unilateral (affect only one side of the body)
  • More common in people in their 20s or 30s
  • Difficult to diagnose; requires multiple exams and tests
  • In most cases, an MRI will show lesions on brain or spinal cord
  • Not associated with any co-existing conditions

Even though vitamin B12 deficiency and multiple sclerosis are different conditions, they can co-exist. In fact, there has been research to suggest that people with MS are more likely to have a deficiency of B12 than are those who are otherwise healthy.7

Can B12 Help Manage MS?

This doesn’t mean, however, that there’s a link between B12 deficiency and multiple sclerosis. In fact, in a 2020 meta-analysis published in International Journal of Medical Sciences, researchers were not able to find such a connection.8

Can B12 Help Manage MS?

However, some research has found evidence that supplementation of vitamin B12, often along with another B vitamin, folate (B9), may help to alleviate some symptoms of the disease.

In a 2019 study published in Clinical Nutrition Research, for example, researchers looked at how B12 and folate supplements might affect quality of life for a group of participants with relapsing-remitting multiple sclerosis (RRMS), a form of the disease in which periods of normal health are punctuated by relapses of symptoms.9

The scientists first tested the blood of each subject to find out if any had significant deficiencies (no one did). The participants were then divided into two groups: One group received a 5-milligram (mg) tablet of folic acid and three 1,000-micrograms (mcg) doses of B12 by injection each day. The other subjects got a daily placebo tablet and shot.

After two months, blood samples were taken from all participants; each person also completed a questionnaire designed to measure quality of life in people living with MS.9

The members of the supplementation group were found to have lower levels of an amino acid called homocysteine that normally is broken down by vitamins B12, B6, and folic acid. (When levels of homocysteine are high, it may be a sign of a vitamin deficiency.)

More importantly, the supplement group had an improvement in both physical and mental quality of life. (The placebo group also had significant improvement in mental quality of life.)

By no means does this study (and a few others with similar findings) prove taking B12 will help with the management of MS. However, it clearly is an indication that more research is needed.9

Can You Have Too Much B12?

Video: “Rehabilitation of the patients with Multiple Sclerosis”


For additional information about Rehabilitation of the patients with Multiple Sclerosis you can watch a video demonstrating exercises and rehabilitation recommendations.


Causes of Vitamin B12 Deficiency

Vitamin B12 is found in dairy products, eggs, meat, chicken, shellfish, and fortified foods. People who are vegan or who follow a very strict vegetarian diet can be at risk of developing a B12 deficiency simply because they don’t consume enough natural food sources of the vitamin.10

Other reasons for vitamin B12 deficiency include:

  • Taking certain medications known to affect vitamin B12 levels. Common examples include the diabetes medication metformin and medications used to treat heartburn known as proton pump inhibitors11
  • Conditions that interfere with the absorption of nutrients, such as celiac disease and Crohn’s disease12
  • Bariatric surgery (such as gastric sleeve surgery) for weight loss, which has been found to affect how nutrients are absorbed13
  • Pernicious anemia, a condition in which a person cannot properly absorb vitamin B12 from foods because they lack intrinsic factor, a protein produced in the stomach14


Diagnosis of B12 Deficiency

If you have symptoms that suggest you may have a deficiency of B12, your healthcare provider can confirm this suspicion simply by checking the levels of the vitamin in a sample of your blood.

If your vitamin B12 levels are on the low side of normal, your healthcare provider may order two more blood tests: homocysteine and methylmalonic acid. These metabolic substances are both elevated in vitamin B12 deficiency.10

Although this is the most typical way to diagnose B12 deficiency, other tests may be used, including magnetic resonance imaging (MRI) of the spinal cord (to look for a bright signal in the posterior part of the cord), or somatosensory or visual evoked potentials.



Treating B12 Deficiency

Since B12 is readily available in common foods, dietary changes may be enough to bring blood levels up to normal. A simple approach to turning around a deficiency would be to eat more B12-rich foods, such as clams, beef liver, certain varieties of fish, and fortified nutritional yeast or cereals.

Treating B12 Deficiency

The recommended dietary allowance of vitamin B12 for teens and adults 14 and up is 2.4 mcg. Women who are pregnant are advised to get 2.6 mcg of B12 each day, and those who are breastfeeding are advised to get even more—2.8 mcg.10

Someone who is found to be deficient in B12 may need to take oral supplements of the vitamin or receive it via intramuscular injections. It can take some time, and in many cases, lifelong supplementation, to bring blood levels of vitamin B12 to normal and keep them there.




The jury is still out about the association between vitamin B12 deficiency and multiple sclerosis, as well as whether B12 supplements can help alleviate MS symptoms.15

What cannot be disputed, however, is that eating a well-balanced diet that includes ample vitamin B12 is a smart move for anyone who’s dealing with any chronic health problem or who’s healthy overall and wants to do everything possible to stay that way.

And whichever category you fall into, if you develop symptoms that suggest either MS or a B12 deficiency, see your healthcare provider. Having your levels checked is easy.

By Julie Stachowiak, PhD
Julie Stachowiak, PhD, is the author of the Multiple Sclerosis Manifesto, the winner of the 2009 ForeWord Book of the Year Award, Health Category.


Check out the demo version of our sets of exercises for Multiple Sclerosis on YouTube

Check out the demo version of our sets of exercises for Multiple Sclerosis on YouTube

You can find more information about  Multiple Sclerosis in our Blog.

Our website presents the following sets of exercises for the rehabilitation of the patients with Multiple Sclerosis:



  1. University of Rochester Medical Center. Multiple Sclerosis.
  2. Harvard Health Publishing, Harvard Medical School. Vitamin B12 Deficiency Can Be Sneaky And Harmful.
  3. Nemazannikova N, Mikkelsen K, Stojanovska L, Blatch GL, Apostolopoulos V. Is there a link between vitamin b and multiple sclerosisMC. 2018;14(2). doi:10.2174/1573406413666170906123857
  4. The Johns Hopkins University, The Johns Hopkins Hospital, and Johns Hopkins Health System. Vitamin B12 Deficiency Anemia.
  5. Nemazannikova N, Mikkelsen K, Stojanovska L, Blatch GL, Apostolopoulos V. Is there a link between vitamin B and multiple sclerosisMedicinal Chemistry. 2018;14(2):170-180. doi:10.2174/1573406413666170906123857
  6. Pandey S, V Holla V, Rizvi I, Qavi A, Shukla R. Can vitamin B12 deficiency manifest with acute posterolateral or posterior cord syndrome? Spinal Cord Ser Cases. 2016;2(1):16006. doi:10.1038/scsandc.2016.6
  7. National MS Society. Vitamins, Minerals and Herbs in MS.
  8. Li X, Yuan J, Han J, Hu W. Serum levels of homocysteine, vitamin B12 and folate in patients with multiple sclerosis: an updated meta-analysisInt J Med Sci. 2020;17(6):751-761. doi:10.7150/ijms.42058
  9. Nozari E, Ghavamzadeh S, Razazian N. The effect of vitamin B12 and folic acid supplementation on serum homocysteine, anemia status and quality of life of patients with multiple sclerosisClin Nutr Res. 2019;8(1):36-45. doi:10.7762/cnr.2019.8.1.36
  10. National Institutes of Health, Office of Dietary Supplements. Vitamin B12 fact sheet for health professionals.
  11. Miller JW. Proton Pump Inhibitors, H2-Receptor Antagonists, Metformin, and Vitamin B-12 Deficiency: Clinical ImplicationsAdv Nutr. 2018 Jul 1;9(4):511S-518S. doi:10.1093/advances/nmy023
  12. National Library of Medicine. Malabsorption Syndromes.
  13. Lupoli R, Lembo E, Saldalamacchia G, Avola CK, Angrisani L, Capaldo B. Bariatric surgery and long-term nutritional issuesWorld J Diabetes. 2017 Nov 15;8(11):464-474. doi:10.4239/wjd.v8.i11.464
  14. The Trustees of the University of Maryland. Pernicious Anemia.
  15. Multiple Sclerosis Trust. Vitamin B12.

Additional Reading



1. What are usually the first signs of MS?

Early signs of MS include:

          1. Bladder issues
          2. Bowel problems
          3. Difficulty focusing/concentrating
          4. Dizziness/lack of coordination
          5. Fatigue
          6. Muscle spasms
          7. Pain throughout the body
          8. Sexual problems
          9. Speech problems
          10. Tingling and numbness
          11. Vision problems
          12. Weakness

2. What age does MS usually start?

People are typically diagnosed with MS between the ages of 20-40, though it can develop at any age. Late-onset MS can affect people aged 50 and older.

Learn More Multiple Sclerosis (MS): Prevalence and Incidence

3. What does MS do to a man?

Males with MS experience common symptoms such as issues with balance and mobility, pain, vision problems, numbness, and tingling. Research shows that some males with MS have higher rates of low testosterone ( hypogonadism), which may be associated with disease progression.17

4. Can you suddenly get MS?

MS generally starts with a vague symptom that goes away within a few days or weeks. Symptoms may appear suddenly and disappear after the first episode/attack. An attack is when MS symptoms suddenly show up. In order to be diagnosed with MS, you must have had two attacks at least one month apart.

5. What are the four stages of MS?

MS is a progressive disease, and most people with MS follow one of four identified disease courses, including:

      1. Clinically isolated syndrome. The first episode of neurological symptoms is caused by demyelination and inflammation in the central nervous system.
      2. Relapsing-remitting. Clearly defined attacks of new and increasing neurologic symptoms. Attacks are often followed by remission (period of partial or complete recovery) before the next relapse/attack.
      3. Secondary progressive. People with this form of MS may experience relapses of attacks, followed by partial recovery, but the disease does not disappear between attack cycles.
      4. Primary progressive. Characterized by worsening neurological function and disability from the onset of symptoms, with no relapses or remission.

Learn More What to Know About the Multiple Sclerosis Diagnostic Criteria

6. Is MS higher in men or women?

Females are two to three ties more likely to be diagnosed with MS than males. Sex hormones may play a role in why females develop the disease more often.

7. Does MS affect men differently than women?

Many MS symptoms are experienced by males and females alike, such as problems with balance and walking, vision problems, numbness/tingling, and bladder issues. Males have a higher risk of primary progressive MS and seem to have more neurodegeneration and worse cognitive symptoms (e.g., memory problems, difficulty focusing) than females.

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