Vitamin B2, also called riboflavin, is one of 8 B vitamins. All B vitamins help the body to convert food (carbohydrates) into fuel (glucose), which is used to produce energy. These B vitamins, often referred to as B-complex vitamins, also help the body metabolize fats and protein. B complex vitamins are necessary for a healthy liver, skin, hair, and eyes. They also help the nervous system function properly.