MSD Manual

Please confirm that you are not located inside the Russian Federation

honeypot link

Folate Deficiency

(Folic Acid Deficiency)


Larry E. Johnson

, MD, PhD, University of Arkansas for Medical Sciences

Reviewed/Revised Nov 2022

Folate deficiency is common. Because the body stores only a small amount of folate, a diet lacking in folate leads to a deficiency within a few months.

  • Not eating enough raw leafy vegetables and citrus fruits can cause folate deficiency.

  • Anemia can develop, causing fatigue, paleness, irritability, shortness of breath, and dizziness.

  • A severe deficiency may result in a red and sore tongue, diarrhea, a reduced sense of taste, depression, confusion, and dementia.

  • If a pregnant woman has folate deficiency, the risk of having an infant with a birth defect of the spinal cord or brain is increased.

  • The diagnosis is based on blood tests.

  • Folate supplements taken by mouth usually correct the deficiency.

Good sources of folate include raw green leafy vegetables, asparagus, broccoli, fruits (especially citrus), liver, other organ meats, dried yeast, and enriched breads, pastas, and cereals. Extensive cooking destroys 50 to 95% of the folate in food.

In the United States and Canada, folate is added to enrich foods made from grains. Folate in supplements or in enriched foods is easier for the body to absorb than the folate that occurs naturally in food.

Women who are pregnant or who could become pregnant should take folate supplements to reduce the risk of having an infant with a birth defect, mainly neural tube defects Neural Tube Defects and Spina Bifida Neural tube defects are a certain type of birth defect of the brain, spine, and/or spinal cord. Neural tube defects can result in nerve damage, learning disabilities, paralysis, and death. The... read more . Women who have had a baby with a neural tube defect are often prescribed higher doses of folate.

Women who are taking both oral contraceptives and antiseizure drugs may need to take folate supplements. Antiseizure drugs can make oral contraceptives less effective. Folate supplements can help maintain the effectiveness of oral contraceptives.

Folate supplements do not protect against coronary artery disease or stroke. There is no evidence that folate supplements reduce or increase the risk of various cancers. Folate supplements do not seem to improve cognitive function in older adults.

Folate is generally not toxic.

Causes of Folate Deficiency

Folate deficiency may result from

Women who are pregnant or breastfeeding and people undergoing dialysis may develop this deficiency because their need for folate is increased.

Some drugs decrease the absorption of this vitamin. They include

Other drugs interfere with the metabolism of folate. They include

  • Methotrexate (used to treat cancer and rheumatoid arthritis)

  • Triamterene (used to treat high blood pressure)

  • Metformin (used to treat diabetes)

  • Trimethoprim-sulfamethoxazole (an antibiotic)

Symptoms of Folate Deficiency

In addition to the general symptoms of anemia (such as paleness, irritability, shortness of breath, and dizziness), folate deficiency, if severe, may result in a red and sore tongue, diarrhea, a reduced sense of taste, weight loss, and depression.

Did You Know...

  • If a pregnant woman has folate deficiency, her risk of having an infant with a birth defect of the brain or spinal cord is increased.

Diagnosis of Folate Deficiency

  • Blood tests

Doctors also measure the vitamin B12 level to rule out vitamin B12 deficiency Vitamin B12 Deficiency Vitamin B12 deficiency can occur in vegans who do not take supplements or as a result of an absorption disorder. Anemia develops, causing paleness, weakness, fatigue, and, if severe, shortness... read more because this deficiency can also result in anemia and large red blood cells. Doctors must rule out vitamin B12 deficiency before they treat folate deficiency in people with anemia. If people with vitamin B12 deficiency are treated with folate, the anemia may lessen. But folate supplementation does not relieve the nerve damage due to vitamin B12 deficiency and may even make it worse.

Prevention and Treatment of Folate Deficiency

  • Folate supplements

To help prevent folate deficiency, people who are taking drugs that interfere with the absorption or metabolism of folate should take a folate supplement.

Taking daily doses of a folate supplement by mouth effectively treats the deficiency.

quiz link

Test your knowledge

Take a Quiz!