Water-soluble vitamin Biotin, also referred to as vitamin B7 or H7, helps the body metabolize protein, fats, and carbohydrates. Since the body does not store water-soluble vitamins, you must ingest them every day. Fortunately, bacteria in the body produce it, and certain foods contain vitamin B7. For example, great sources of Biotin include eggs, red meat, nuts, and seeds. In addition, many people use this vitamin to improve nail, hair, and skin health. Yet, evidence to support this use is lacking. Finally, if your body does not get enough vitamin B7, you might experience skin problems and hair loss, but this is rare.