Folic acid
Overview
Folic acid, also known as folate or vitamin B9, is a water-soluble vitamin that plays a crucial role in various bodily functions. It is essential for the synthesis and repair of DNA, the production of red blood cells (RBCs), and the prevention of anemia. Folic acid is also vital during periods of rapid growth such as pregnancy and infancy.
Biochemistry
Folic acid is a member of the B-vitamin family and is structurally composed of a pteridine ring, para-aminobenzoic acid, and a glutamate chain. The active form of folic acid, tetrahydrofolate (THF), acts as a coenzyme in single-carbon transfers in the synthesis of nucleic acids and amino acids.
Dietary Sources
Folic acid is naturally present in a wide variety of foods, including leafy green vegetables, fruits, nuts, beans, and seafood. Additionally, many countries fortify their grain products with folic acid to ensure adequate intake among the population.
Absorption and Metabolism
Folic acid is absorbed in the small intestine, specifically in the duodenum and upper jejunum. The absorption process involves a carrier-mediated active transport system. Once absorbed, folic acid is converted to its active form, tetrahydrofolate, in the liver.
Functions
Folic acid plays a vital role in cell growth and development through the synthesis of DNA and RNA. It is also essential for the production of red and white blood cells, the metabolism of proteins, and the formation of hemoglobin. Folic acid is particularly important during periods of rapid cell division and growth, such as pregnancy and infancy.
Deficiency
Folic acid deficiency can lead to a variety of health problems, the most notable being megaloblastic anemia. This condition is characterized by the production of abnormally large and immature red blood cells, leading to inefficient oxygen transport. Other symptoms of folic acid deficiency include fatigue, weakness, and irritability.
Supplementation
Folic acid supplementation is often recommended for certain populations, particularly pregnant women, to prevent neural tube defects in the developing fetus. It may also be beneficial for individuals with certain medical conditions, such as kidney disease or malabsorption disorders, that can lead to folic acid deficiency.
Toxicity
While folic acid is generally considered safe, excessive intake can mask the symptoms of vitamin B12 deficiency, potentially leading to irreversible neurological damage. Therefore, it is important to adhere to recommended intake levels.