Vitamin B2, or riboflavin, is essential for the body's energy supply. Vitamin B2 is primarily found in milk and dairy products, but also in meat, processed meats, vegetables, fruit, bread, and grain products. Vitamin B2 is sensitive to light and is water-soluble. Therefore, it's recommended to store products containing vitamin B2 in the dark and cook vegetables with a small amount of water. A vitamin B2 deficiency can cause skin conditions around the mouth and tongue, and inflammation around the nose.