Pregnancy Home > Folic Acid Safety
There are numerous folic acid safety warnings and precautions to be aware of before taking the vitamin. For example, you should talk to your healthcare provider before using folic acid if you have heart disease, pernicious anemia, or any allergies. It is also important to know that high folic acid doses may increase the risk of cancer and seizures (in people with cancer or epilepsy).
- Epilepsy or seizures
- Heart disease
- Pernicious anemia (vitamin B12 deficiency anemia)
- Cancer (or a history of cancer)
- Any allergies, including allergies to foods, dyes, or preservatives.
- Pregnant or thinking of becoming pregnant
- Folic acid can "mask" a vitamin B12 deficiency. Although folic acid can correct anemia due to vitamin B12 deficiency (making the deficiency more difficult to detect and diagnose), folic acid does not prevent the nerve damage that a vitamin B12 deficiency can cause.
- High doses of folic acid may increase the risk of seizures in people with epilepsy. Do not take high doses of folic acid without your healthcare provider's approval.
- Although there is much interest in folic acid for preventing (and even treating) heart disease, some studies have shown that high doses of folic acid may actually increase the risk of heart attacks in people with heart disease. If you have heart disease, do not take any more than the usual recommended folic acid dose (400 mcg a day for most adults) without your healthcare provider's approval.
- Early research suggests that high doses of folic acid may increase the risk of cancer. If you have cancer (or a history of cancer), do not take more than the usual recommended folic acid dosage (400 mcg a day for most adults) without your healthcare provider's approval.
- Folic acid can interact with some medications (see Folic Acid Drug Interactions for more information).
- It is very important that pregnant or breastfeeding women get enough folic acid (see Folic Acid and Pregnancy and Folic Acid and Breastfeeding). Folic acid should be started before conception occurs.
- Some people may be allergic to folic acid, even though folic acid is added to many different foods in the United States.