Riboflavin is also known as vitamin B2 and is one of the water-soluble B vitamins. Like thiamine, riboflavin is essential in the production of energy in the body on the cellular level. It attaches to protein enzymes so oxygen-based energy can be produced. Oxygen is very important in the body but is very reactive and can cause damage to cell membranes, joint tissues and the linings of blood vessels. B2 helps prevent this damage by assisting in the necessary recycling of glutathione, which is the molecule that prevents oxygen from causing damage.
Cardiovascular disease is often the result of increased levels of homocysteine. Riboflavin is an important factor in the homocystiene breakdown metabolism. A person who isn’t getting enough B2 can be at higher risk for cardiovascular disease. Prevention of migraine, anemia, cataracts, carpal tunnel syndrome, vaginitis and rosacea are also roles thatriboflavin plays. It is also often used in the treatment of these conditions.
Other B vitamins, particularly B3, depend on B2 to maintain adequate supplies. Riboflavin helps maintain B3, also called niacin, by helping the enzyme kynurenine mono-oxygenase convert an amino acid called tryptophan into niacin.
Since the 1940s, wheat flour has been fortified with riboflavin because the refinement process removes most of it. This has resulted in products made with processed flour being the primary source of riboflavin. However, there are other foods that provide significant amounts of B2. Two of the best sources are crimini mushrooms and spinach. Other good sources include summer squash, shitake mushrooms, asparagus, turnip, mustard and collard greens, Swiss chard, cow’s milk, yogurt, green beans, venison, calf’s liver, eggs and broccoli.
In storing and cooking foods, air and heat do little to diminish the amount of riboflavin in food. Exposure to light for long periods should be avoided, however, as that will cause riboflavin to decrease. Food should be stored in opaque containers and cooked in lidded pots whenever possible to prevent the loss of riboflavin in the food.
The early signs of B2 deficiency are often related to the eyes. There can be itching, burning and tearing as well as excessive light sensitivity. Other symptoms include sore tongue, lips and mouth and the skin in the corners of the mouth cracking open. Skin peeling also can indicate deficiency, especially if it is around the scrotum in men or the nose in anyone. Factors that contribute to riboflavin deficiency include severe alcoholism, though not to the extent it impacts B1 deficiency, and heavy exercise, especially for women. Diets that severely restrict carbohydrates can put people at risk to become deficient in B2.
As of 1998, toxic levels of riboflavin have not been established and there is not an upper limit of tolerance set by the National Academy of Sciences’ Institute of Medicine.
Vitamins B1 and B2 seems to need a balance. The right amount of B1 can ensure increased levels of B2 but excessive amounts of B1 can cause the loss of B2 through urination to increase. Without enough riboflavin, full availability of vitamins B3 and B12, folate, zinc and iron cannot be maintained.