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. 

Symptoms of Vitamin B12 Deficiency

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

Anemia and glossitis (a condition in which the tongue becomes swollen and painful) are additional symptoms of vitamin B12 deficiency.

Link Between Vitamin B12 Deficiency and MS

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. Conversely, other studies have found no association between vitamin B12 deficiency and MS—in other words, whether or not a link exists is still a controversial subject.

Cause of Vitamin B12 Deficiency

The causes of vitamin B12 deficiency are variable and include:

  • Dietary restrictions like those who eat strictly vegan or vegetarian diets.
  • Certain medications may affect vitamin B12 levels in the body like the diabetes medication metformin or medications used to treat heartburn (called proton pump inhibitors)
  • Crohn's disease or other conditions that impair gut absorption like celiac disease, bacterial overgrowth, and post-bariatric surgery
  • Pernicious anemia: a condition in which a person cannot properly absorb vitamin B12 from foods because they lack a protein called intrinsic factor

Diagnosis of 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 are simple blood tests that can be done:

  • A complete blood count
  • A Vitamin B12 level

If there is a deficiency detected on the blood test, supplementation with either oral Vitamin B12 or injected vitamin B12 into the muscle can be prescribed.

If your vitamin B12 levels are low-normal, your doctor may order two more blood tests, homocysteine and methylmalonic acid. These metabolic substances are both elevated in vitamin B12 deficiency.

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.

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 (although, more is needed in pregnancy and less in children).

The good news is that many foods (fish, meats, fortified cereals) contain more than 2 mcg. In other words, vitamin B12 supplementation is generally unnecessary in people who eat a normal diet.

If a person is vitamin B12 deficient, much higher daily doses are prescribed, followed by a maintenance daily dose with periodic vitamin B12 levels checked by your doctor. Depending on the "why" behind a person's vitamin B12 deficiency, their doctor will decide the best route of vitamin administration, like by mouth or through an injection into the muscle.

A Word From Verywell

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. 

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