Folic acid is essential nutrient because it cannot be made by the human body. It is required by the body for essential processes. Folic acid helps the body to create and maintain DNA and RNA, which is the building blocks of all life. We require folic acid to properly form red blood cells and for our bodies to metabolize protein for energy. Folic acid and other B vitamins have been shown to fight cardiovascular disease to help prevent osteoporosis, cancer and it helps to stabilize mental health.
Folic acid along with other B vitamins is an important part of the DNA and RNA replication process. Every now and then there can be a mistake in the replecation of a DNA strand, which can lead to a mutation such as cancer. Folic acid and the other B vitamins work to catch those mistakes and even prevent them so that you have healthy cells from the very beginning. In fact this is part of why folic acid is so important to take just before and during pregnancy to help prevent birth defects.
If our red blood cells don't form properly we can develop a condition known as anemia. Anemia is caused by a number of illnesses and while folic acid won't cure a potentially serious condition your doctor may prescribe folic acid for the symptom of anemia which it can fix.