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Vitamin B12 and Multiple Sclerosis

People with MS May Have Low Levels of Vitamin B12


Updated July 14, 2014

When I dabbled in vegetarianism (I even was a pretty strict vegan for almost a year), I was able to tell you that vegetarians need to supplement with vitamin B12 (or seek out fortified foods). I really couldn’t tell you why. I also didn’t ever take a supplement. Now that I have multiple sclerosis (MS), I am pretty shocked to learn that vitamin B12 deficiency is higher in people with MS than in those that don’t have MS. I also found out that if I am deficient, it can make many of my symptoms feel worse.

Why Should We Care About Vitamin B12?

Studies have reported a significantly higher rate of vitamin B12 deficiency in people with MS than in people without MS, which is suspected to be due to problems with binding and transport of vitamin B12 (meaning that the body does not process vitamin B12 efficiently, which makes it difficult to maintain normal levels without supplementation). One study found low B12 levels in the cerebrospinal fluid of people with MS, although their blood levels were normal.

What Is It For?

People with vitamin B12 deficiency have destruction of both the myelin and the underlying axon. If the deficiency is severe, there can be serious brain damage, causing MS-like symptoms. Even when people have slight B12 deficiency, they may exhibit symptoms like fatigue, depression and memory loss.

How Does It Work?

Vitamin B12 helps maintain the myelin sheath by playing a crucial role in the metabolism of fatty acids essential for the maintenance of myelin.

How Effective Is It?

There are no large studies using vitamin B12 in people with MS. One study used high dosages in 6 severely disabled patients. The study showed no clinical benefit, but did improve their results on evoked potential testing. Another placebo-controlled study of injected vitamin B12 (combined with lofepramine and l-phenylalanine) showed small (but statistically insignificant) beneficial effects in the treatment group.

Usual Dosage/How Taken

If a person is found to be deficient in vitamin B12, the following regimen is recommended:
  • Oral: Initial dosage of 1,000 to 2,000 mcg per day for one or two weeks, followed by a maintenance dose of 1,000 mcg per day for life
  • Intramuscular: 100 to 1,000 mcg every day or every other day for one to two weeks, followed by a maintenance course of 100 to 1,000 mcg every one to three months
  • If a person is not found to be deficient, the recommended daily allowance is 2 to 3 mcg per day.

    Note: Dosages are in micrograms (mcg), not milligrams (mg). One milligram contains 1000 micrograms.

    The only reliable unfortified sources of vitamin B12 are meat, dairy products and eggs. Different foods fortified with vitamin B12 are available and include breakfast cereals, some margarines and soy milk.

    Side Effects

    Vitamin B12 is usually fairly well-tolerated, but can cause:
    • Itching
    • Rashes
    • Diarrhea

    Prices of Supplements

    Oral vitamin B12 is very inexpensive, even the amounts needed to treat vitamin B12 deficiency cost less than $20 for a year’s supply of high-dose (1,000 mcg) supplements. Prices for vitamin B12 injections vary, as they include doctor/clinic fees.

    Additional Information/Points

    Talk to Your Doctor About Getting Tested: B12 deficiency is not very common in people with MS, but occasionally does occur. B12 deficiencies not only look like MS symptoms, but can make MS symptoms worse (and MS symptoms aggravate B12 deficiency symptoms). Some experts say that all people with MS should be screened for vitamin B12 deficiency.

    Steroids Can Contribute to the Problem: Vitamin B12 levels are reduced right after treatment with Solu-Medrol.

    Vegans and Vegetarians: If you do not consume much meat, and especially if you also avoid dairy products and eggs, it is important that you consider taking a vitamin B12 supplement, or at least seeking B12-fortified vegetarian products.

    Other Things to Watch Out For: Vitamin B12 absorption can be reduced by:

  • H2-blockers, including: cimetidine (Tagamet), famotidine (Pepcid), nizatidine (Axid), and ranitidine (Zantac)
  • Nicotine
  • Excessive alcohol intake lasting longer than two weeks
  • My Bottom Line

    I’m going to get tested. I’m not a huge meat eater and don’t really get much dairy or eggs. I certainly haven’t been seeking out vitamin B-12 fortified products. Anyway, wouldn’t it be lovely to think that even a little fraction of the terrible MS fatigue that plagues many of us could be alleviated by a supplement? Of course, I am not holding out for miracles, just plowing ahead in my constant efforts to improve how I feel. Having said that, I don’t think I would feel comfortable taking the high-dosage supplements without consulting with a doctor and knowing there was a concrete reason to do so.


    Schwarz S, Leweling H. Multiple sclerosis and nutrition. Mult Scler. 2005 Feb;11(1):24-32.

    Bowling, Allen C. Complementary and Alternative Medicine and Multiple Sclerosis. 2nd ed. Demos Publishing: New York. 2007.

    Reynolds EH, Bottiglieri T, Laundy M, Crellin RF, Kirker SG. Vitamin B12 metabolism in multiple sclerosis. Arch Neurol. 1992 Jun;49(6):649-52.

    Oh, RC and Brown, DL. Vitamin B12 Deficiency. Am Fam Physician. 2003;67:979-86,993-4.

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