B vitamins are needed for the proper functioning of almost every process in the body. They are needed to change the carbohydrates we eat into glucose and then convert that glucose into energy and deficiency can result in fatigue and lethargy. They are important for healthy function of both the nervous system and adrenals and low B vitamin levels can cause an impaired stress response, anxiety and depression. They are important in healthy digestion, helping the GI track absorb other important nutrients. They are also involved in skin, hair and nail health and low levels are associated with dry, grey skin, hair loss and split or weak nails. Birth control pills are known to deplete B vitamins. I use B vitamins in my treatment of PMS and I recommend a B supplement for all my patients with persistent HPV infections and/or cervical dysplasia.