Folic Acid and RA

Quick quiz: what do pregnancy and chemotherapy treatment have in common? If you guessed “folic acid supplements,” then you and I probably have some similar life experiences. I have been prescribed folic acid during four stretches of time in my life; once for each of my two pregnancies, and again during the two times rheumatologists put me on methotrexate.

What is folic acid?

Folic acid is a B vitamin that assists the body in making new cells.1 Folate occurs naturally in foods such as lentils, beans, asparagus, spinach, turnip greens, and broccoli.2 Folic acid is the synthetic version of folate that is available in supplement form. As folic acid has been shown to decrease neural birth defects such as spina bifida, it is not only recommended that pregnant women take the supplement, but it is mandated by the U.S. Food and Drug Administration that folic acid be added to enriched cereal products (cold cereals, pastas, breads, etc.).3

Dose recommendation for folic acid

Health practitioners recommend that women attempting to get pregnant take 400 mcg (0.4 mg) of folic acid daily.4 The dose recommended for individuals taking methotrexate is generally higher, as many people with RA are prescribed 1 mg of folic acid daily or 5 mg once a week. To understand why doctors recommend folic acid be taken while on methotrexate treatment, it’s important to understand how methotrexate works.

Why is methotrexate used for RA treatment?

Methotrexate is often called a chemotherapy drug, as it is used to treat cancer, although generally it is prescribed in much higher dosages for cancer than for rheumatoid arthritis. Methotrexate inhibits the metabolism of folic acid, which is needed for the production of certain immune system cells.

Less immune systems cells for a decrease in RA symptoms

Rheumatoid arthritis is an autoimmune condition, meaning that the immune system is confused and fights healthy joints, tissues, and organs rather than solely killing germs. Therefore, most medical treatments for RA target components of the immune system. In the case of methotrexate, it keeps certain immune system cells from being created, which in turn can cause a reduction in RA symptoms.

Folic acid, methotrexate, and RA

Unfortunately, methotrexate can also cause a wide variety of problematic side effects. As our bodies need folate for healthy cell growth, preventing the body from metabolizing folate often leads to folate deficiency. Symptoms of folate deficiency include gastrointestinal disorders, hair loss, tongue inflammation, and feeling sluggish.5 In addition, methotrexate can also impact liver function.6

Positive effects of methotrexate on RA symptoms do not disappear with folic acid

Taking a folic acid supplement can decrease or eliminate all of these side effects, and is therefore routinely prescribed for people taking methotrexate. 7 Interestingly, although methotrexate works by inhibiting the metabolism of folic acid, the positive benefits of methotrexate on rheumatoid arthritis symptoms do not disappear when taking a folic acid supplement.8 (However, folic acid supplements can impact the benefits of methotrexate treatment for cancer, and therefore may not be recommended for cancer patients.9)

Personally, I continued to experience side effects while taking methotrexate in spite of taking folic acid. However, many people in our online community have shared that it did indeed help with their side effects.

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This article represents the opinions, thoughts, and experiences of the author; none of this content has been paid for by any advertiser. The team does not recommend or endorse any products or treatments discussed herein. Learn more about how we maintain editorial integrity here.

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