Folic acid is a synthetic form of vitamin B9, a water-soluble nutrient. It plays an important role in various bodily functions. Folic acid is commonly found in dietary supplements and fortified foods, distinguishing it from naturally occurring folate.
Understanding Folic Acid’s Importance
Folic acid is important for cell division and the synthesis of DNA and RNA. This function is particularly significant during periods of rapid cell growth, such as infancy and pregnancy.
A primary role of folic acid is in preventing neural tube defects (NTDs) in developing fetuses. NTDs, such as spina bifida and anencephaly, are severe birth defects that occur early in pregnancy, often before a woman knows she is pregnant. Folic acid helps ensure the proper closure of the neural tube, significantly reducing the risk of these conditions.
Folic acid also plays a role in the formation of healthy red blood cells. A deficiency in folate can lead to a type of anemia known as megaloblastic anemia, characterized by abnormally large, immature, and dysfunctional red blood cells. Symptoms of this anemia can include fatigue, weakness, and shortness of breath.
Beyond its role in cell production, folic acid contributes to heart health by helping regulate homocysteine levels. High levels of homocysteine can damage artery linings and increase cardiovascular risk. Folic acid assists in converting homocysteine to methionine, thereby maintaining normal levels of this amino acid.
Folic acid is also involved in brain health and mood regulation. It contributes to the metabolism of neurotransmitters, which are chemicals that transmit signals in the brain.
Where to Find Folic Acid
Folate, the naturally occurring form of vitamin B9, is found in many foods. Natural sources include dark green leafy vegetables like spinach, kale, and collard greens. Legumes such as beans, lentils, and peas also provide significant amounts of folate. Citrus fruits, including oranges and grapefruits, are good sources as well.
Folic acid, the synthetic form, is commonly added to staple foods through fortification programs. In the United States, enriched breads, cereals, flours, pastas, and rice have been fortified with folic acid since 1998. This fortification has substantially increased the average daily folic acid intake in the population.
Dietary supplements are another common way to ensure adequate folic acid intake, particularly for specific populations with increased needs. While naturally occurring folate from food is beneficial, folic acid from fortified foods and supplements is more bioavailable, meaning the body can absorb and utilize it more efficiently. About 85% of folic acid from supplements taken with food is bioavailable, compared to around 50% for naturally occurring food folate.
The body processes naturally occurring folate and synthetic folic acid differently. Folate found in foods is converted into its active form within the digestive system. In contrast, supplemental folic acid requires conversion in the liver to become active.
Guidance for Supplementation
The recommended daily allowance (RDA) for folic acid varies depending on age and life stage. For most adults, the recommended intake is 400 micrograms (mcg) of dietary folate equivalents (DFEs) daily. Women of childbearing age and those who could become pregnant are advised to consume 400 mcg of folic acid daily from fortified foods or supplements, in addition to dietary folate. During pregnancy, the recommendation increases to 600 mcg DFE daily, and for breastfeeding individuals, it is 500 mcg DFE daily.
Folic acid is considered safe at typical dosages, with side effects being uncommon. When they do occur, they may include mild gastrointestinal upset such as nausea or bloating, or skin reactions. However, doses exceeding 1 milligram (mg) daily may lead to side effects like stomach upset, diarrhea, irritability, or confusion.
Folic acid can interact with certain medications, potentially affecting their effectiveness. For example, some anti-seizure drugs, such as phenytoin, may have their action antagonized by folic acid, possibly requiring increased doses of the medication. Methotrexate, a drug used for various conditions, can also be impacted, and folic acid is sometimes prescribed to reduce its side effects.
It is important to consult a healthcare provider before starting any new supplement, especially for individuals with existing health conditions or those who are pregnant. A healthcare professional can provide personalized guidance on appropriate dosage and potential interactions with other medications. This consultation is especially important because high doses of folic acid can mask a vitamin B12 deficiency. While folic acid may alleviate the hematological symptoms of B12 deficiency, it does not address the underlying neurological complications, which can progress undetected and lead to severe nervous system damage.