Q: Does a lack of vitamins B12, B6 or folic acid have an effect on arthritis?

A: A lack of B vitamins, including folic acid, B6 and B12, is not known to have an effect on arthritis. Low vitamin levels are not a recognized cause or trigger for arthritis. Taking extra B vitamins is not known to be an effective arthritis treatment. However, with more than 100 types of arthritis, there could be important effects of B vitamins on arthritis that we do not yet understand.

In addition, there are some important connections between these vitamins and arthritis:

  • People with rheumatoid arthritis tend to have lower blood levels of B vitamins (especially B6 and B12) than people without this disease.

  • People with rheumatoid arthritis and lupus have a greater risk of heart disease. An elevated level of homocysteine may be a contributor to this risk. B vitamin therapy (especially folic acid) can reduce homocysteine levels.

  • Rheumatoid arthritis is often treated with methotrexate, a drug that blocks the action of folic acid. That's why doctors often recommend folic acid supplements for people taking methotrexate.

  • People with one autoimmune disease, such as rheumatoid arthritis or lupus, may be more likely to have another. Pernicious anemia is an autoimmune illness caused by an inability to absorb B12 from the diet. Although there is no clear association between the two, there are occasional reports of people with both an autoimmune form of arthritis and pernicious anemia.

Although B vitamins are not thought to be involved in causing arthritis and are not effective treatments, future research could find more direct links to a number of forms of arthritis and other inflammatory conditions.

Although not directly related to joint problems, I routinely recommend folic acid supplements for my patients taking methotrexate. Taking folic acid decreases some of the side effects of methotrexate.

Until we know more, it's probably not a bad idea for arthritis patients to take a multivitamin daily, just to be certain that they are getting sufficient B vitamins as well as other micronutrients.