Vitamin B2 (Riboflavin), is part of the group of essential nutrients known as the B Complex. B Complex vitamins, including Vitamin B2, work to support and promote energy metabolism in the body. Vitamin B2 is necessary for normal cell function and helps to maintain a healthy nervous system, vision, skin and hair. It helps the body convert carbohydrates, fats and proteins into energy and supports the body during the stress of daily living. Symptoms of deficiency of Vitamin B2 include sores at the corners of the mouth, sore tongue, dermatitis numbness of the hands or decreased sensitivity to touch, temperature and vibration and visual changes. Alcohol decreases the bioavailability and absorption of riboflavin.