Vitamin B-2 (Riboflavin): Vitamin B2 is one of eight water-soluble B vitamins. Like its close relative vitamin B1 (thiamine), riboflavin plays a crucial role in certain metabolic reactions, particularly the conversion of carbohydrates into sugar, which is "burned" to produce energy. Together, the eight B vitamins, often referred to as B complex vitamins, are also essential in the breakdown of fats and protein. In addition, B complex vitamins play an important role in maintaining muscle tone along the lining of the digestive tract and promoting the health of the nervous system, skin, hair, eyes, mouth, and liver.

In addition to producing energy for the body, riboflavin also works as an antioxidant by scavenging damaging particles in the body known as free radicals. These particles occur naturally in the body but can damage cell membranes, interact with genetic material, and possibly contribute to the aging process as well as the development of a number of health conditions such as heart disease and cancer. Antioxidants such as riboflavin can neutralize free radicals and may reduce or even help prevent some of the damage they cause.

Unlike other B vitamins, riboflavin is not found in many foods, so the most common cause of deficiency is lack of dietary intake, especially in the elderly. Symptoms of riboflavin deficiency include fatigue; slowed growth; digestive problems; cracks and sores around the corners of the mouth; swollen magenta tongue; eye fatigue; soreness of the lips, mouth and tongue; and sensitivity to light. Riboflavin is an important nutrient in the prevention of headache and some visual disturbances, particularly cataracts.

The best sources of riboflavin include brewer's yeast, almonds, organ meats, whole grains, wheat germ, wild rice, mushrooms, soybeans, milk, yogurt, eggs, broccoli, brussel sprouts, and spinach. Flours and cereals are often fortified with riboflavin.