Level 2 1: What is folic acid? Folic acid is a B vitamin, also known as vitamin B9, which is essential for human health. Folic acid helps the body build new cells, especially red blood cells and DNA. In addition, folic acid can promote nerve development and function. Level 2: Why is extra folic acid intake required during pregnancy? During pregnancy, the fetal nerves are developing and therefore require a large amount of nutrients to support them.