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Vitamin

Folic Acid

Folic acid is the synthetic form of vitamin B9 used in supplements and fortified foods. The body converts it into active forms of folate.

Also listed as Vitamin B9, Pteroyl L-glutamic acid

Women's HormonesEssential HealthFertilityCardiovascularCognition

What is the European upper limit?

EFSA retains an adult upper limit of 1,000 µg daily for the combined supplemental folate forms covered by its opinion, including folic acid and authorized 5-MTHF salts. This also applies in pregnancy and lactation; children have lower limits. It is a safety ceiling, not a target intake. 1

Why is vitamin B12 part of the safety discussion?

Large folate doses can correct the anemia caused by vitamin B12 deficiency without correcting its neurological damage. EFSA used progression of neurological symptoms in B12-deficient people as the critical concern for its upper limit. Treating an unexplained anemia with folic acid alone can therefore leave the underlying B12 problem unresolved. 1 2

Which medicines need a review?

Folate can interfere with methotrexate used for cancer, while prescribed folate may reduce gastrointestinal side effects of low-dose methotrexate for rheumatoid arthritis or psoriasis. Antiepileptic medicines can lower folate levels, and folate supplements may lower levels of some of these medicines. Sulfasalazine reduces intestinal folate absorption; NIH recommends discussing intake with the treating clinician in these situations. 2

For information, not individual medical advice. Ingredient studies do not establish the effectiveness of these products.

Sources

  2. Folate: Fact Sheet for Health Professionals NIH Office of Dietary Supplements