Folate deficiency

Folate deficiency, also known as vitamin B₉ deficiency, is a low level of folate and derivatives in the body. This may result in a type of anemia in which red blood cells become abnormally large and is a late finding in folate deficiency and folate deficiency anemia is the term given for this medical condition. Signs of folate deficiency are often subtle. Symptoms may include feeling tired, heart palpitations, shortness of breath, feeling faint, open sores on the tongue, loss of appetite, changes in the color of the skin or hair, irritability, and behavioral changes. Temporary reversible infertility may occur. Folate deficiency anemia during pregnancy may give rise to the birth of low weight birth premature infants and infants with neural tube defects.

Not consuming enough folate can lead to folate deficiency within a few months. Otherwise, causes may include increased needs as with pregnancy, and in those with shortened red blood cell lifespan. Folate deficiency can be secondary to vitamin B₁₂ deficiency or a defect in homocysteine methyl transferase that leads to a "folate trap" in which is an inactive metabolite that cannot be recovered. Diagnosis is typically confirmed by blood tests, including a complete blood count, and serum folate levels. Increased homocysteine levels may suggest deficiency state, but it is also affected by other factors. Vitamin B₁₂ deficiency must be ruled out, if left untreated, may cause irreversible neurological damage.

Treatment may include dietary changes and folic acid supplements. Dietary changes including eating high foods in folate such as, fruits and green leafy vegetables can help. Prevention is recommended for pregnant women or those who are planning a pregnancy.

Folate deficiency is very rare in countries with folic acid fortification programs. Worldwide prevalence of anemia due to folic acid deficiency generally is very low.