Vitamin B9

The A-B-C's of Vitamin Supplements

Peer Reviewed

Blood cell illustrationVitamin B9 is also known as folic acid or folate. This vitamin is required for energy production, and formation of red and white blood cells (immunity). Normal red blood cell production prevents anemia. Vitamin B9 may assist in regulating mood (antidepressant) and sleep patterns, particularly in older persons.

It works as a coenzyme in DNA and RNA synthesis, meaning it is important to normal cell division/replication. This is one reason why intake of folic acid is so important during pregnancy—for embryonic and fetal nerve cell development. Inadequate folic acid levels have been linked to birth defects such as spina bifida and anencephaly.

Folic acid helps to eliminate homocysteine, a blood toxin known to affect heart muscle and influences cholesterol to deposit in heart muscle. It is used to prevent and treat low blood levels of folate, as well as its complications, including anemia and the inability of the bowel to absorb nutrients properly.

Folic acid is also used to treat conditions associated with folate deficiency, such as ulcerative colitis, liver disease and alcoholism. Some people use folic acid in an attempt to prevent colon cancer or cervical cancer. It is also used to prevent heart attack and stroke.

Dosage Guidelines
The recommended dietary allowance is age and sex dependent. Always include vitamin B12 with folic acid. The following information is a guideline.

  • Men and women age 11 to 14 years: 150-mcg
  • Men and women age 15 or more years: 400-mcg
  • Pregnant women: 400-mcg
  • Nursing mothers: 280-mcg
  • *Infants less than 6 months old: 25-mcg
  • *Infants 6 to 12 months old: 35-mcg
  • *Children age 1 to 3 years: 50-mcg
  • *Children age 4 to 6 years: 75-mcg
  • *Children age 7 to 10 years: 100-mcg

*Check with a medical professional before giving vitamin B9 to an infant or child.

Sources of Vitamin B9
Foods that contain significant quantities of folic acid include: liver, lentils, legumes, brown rice, poultry, pork, lamb, cheese, spinach, turnip greens, asparagus, and brewer's yeast. Fresh vegetables are better than cooked because heat destroys folic acid.

High doses of vitamin B9 (more than 15-mg) may cause stomach, sleep, and skin disorders, and can cause seizures in persons with convulsive disorders.

High doses of folic acid are known to reduce or interfere with the effectiveness of methotrexate (an anticancer drug). Zinc, estrogen, anticonvulsant drugs, barbiturates, and sulfasalazine may not be absorbed as effectively when combined with folic acid.

Always consult with the doctor who prescribes medication to help avoid any potential medication-related adverse reactions.

Disclaimer: Many people report feeling improvement in their condition and/or general well-being taking dietary, vitamin, mineral, and/or herbal supplements. The Editorial Board of, however, cannot endorse such products since most lack peer-reviewed scientific validation of their claims. In most cases an appropriate diet and a "multiple vitamin" will provide the necessary dietary supplements for most individuals. Prior to taking additional dietary, vitamin, mineral, and/or herbal supplements it is recommended that patients consult with their personal physician to discuss their specific supplement requirements.

Updated on: 03/08/16
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Thomas G. Lowe, MD
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