Folic acid is required for DNA synthesis and cell growth and is important for red blood cell formation, energy production as well as the forming of amino acids. Folic acid is essential for creating heme, the iron containing substance in hemoglobin, crucial for oxygen transport. 

It is important for healthy cell division and replication, since its involvement as coenzyme for RNA and DNA synthesis. It is also required for protein metabolism and in treating folic acid anemia. Folic acid also assists in digestion, and the nervous system, and works at improving mental as well as emotional health. This nutrient may be effective in treating depression and anxiety.

Shortage of folic acid may be indicated with diarrhea, heartburn and constipation.

Folic acid is very important in the development of the nervous system of a developing fetus.

Deficiency of vitamin B9

A deficiency of folic acid on an unborn baby may increase the risk of the baby being born with spina bifida and other serious defects of the nervous system.

When deficient of folic acid, you might suffer from fatigue, acne, a sore tongue, cracking at the corners of your mouth (same as deficiency of vitamin B2, vitamin B6 as well as iron). Long term deficiency may result in anemia and later in osteoporosis, as well as cancer of the bowel and cervix.