Vitamin B12 Deficiency and Multiple Sclerosis

A controversial link but an easy fix

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Vitamin B12, also known as cobalamin, is a water-soluble vitamin that plays an important role in the production of red blood cells and in maintaining the normal functioning of our nervous system. 

Link Between Vitamin B12 Deficiency and MS

Vitamin B12 plays an important role in the functioning of our nervous systems by helping to maintain the myelin sheath. In fact, a severe vitamin B12 deficiency can cause neurological symptoms that mimic MS symptoms, like weakness and numbness and tingling, walking and thinking problems.

 Even when people have slight B12 deficiency, they may exhibit symptoms like fatiguedepression, and memory loss.

Some studies have reported a higher rate of vitamin B12 deficiency in people with MS than in people without MS. Another study found low B12 levels in the cerebrospinal fluid of people with MS, although their blood levels were normal. That being said, other studies have found no association between vitamin B12 deficiency and MS—it's still a controversial subject.

B12 Deficiency

The good news is that if your doctor suspects that your MS-like symptoms could be from low B12 levels (or because he simply wants to rule out this possibility—one that is much easier to fix than MS), there is a simple blood test that can be done. If there is a deficiency, supplementation with either oral Vitamin B12 or injected vitamin B12 into the muscle can be prescribed.

It's important to note that there is no scientific evidence to support taking vitamin B12 if your levels are within the normal range—meaning taking vitamin B12 (when your levels are normal) will not help your neurological symptoms nor will they make your MS better by preventing disease progression or relapses.

The causes of vitamin B12 deficiency are variable and include dietary restrictions like those who eat vegan or vegetarian diets. Some medications affect vitamin B12 levels in the body like the diabetes medication metformin or medications used to treat heartburn. Alcohol abuse, Crohn's disease, and pernicious anemia are other health conditions that may cause vitamin B12 deficiency.

Vitamin B12 deficiency is also more common in the elderly and people who have undergone Roux-en-y gastric bypass.

Taking Vitamin B12

Vitamin B12 is found in dairy products, eggs, meat, chicken, and shellfish. If a person is not found to be deficient, the recommended daily allowance is two to three mcg per day, or 2.4mcg to be precise. If a person is deficient, much higher daily doses are prescribed, followed by a maintenance daily dose with periodic vitamin B12 levels checked by your doctor. 

The idea of a link or association between having MS and being vitamin B12 deficient is still controversial, as scientific studies show conflicting results. Likewise, there are no guidelines stating that just because you have MS, you need your vitamin B12 levels checked. Still, don't be too surprised if your doctor does check your vitamin B12 level, and if it's low, don't be discouraged. In fact, it might be a sigh of relief—something easy to treat, unlike MS. 


Bowling AC. Summary of Evidence-Based Guideline: Complementary and Alternative Medicine in Multiple S​clerosis . Neurology. 2014; 82(12).

National MS Society. Vitamins, Minerals, & Herbs in MS.,-Minerals,-and-Herbs-in-MS_-An-Introduction.pdf.

Naiafi, M.R., Shaygannaiad, V, Mirpourian, M., & Gholamrezaei, A. Vitamin B12 Deficiency and Multiple Sclerosis; Is There Any Association? International Journal of Preventive Medicine. 2012; 3(4):286-89.