Vitamin B2, riboflavin, is an important nutrient but one that actually has few clinical uses. Physicians have used it to treat migraine headaches, cataracts and sickle cell anemia. It has also been used for problems with the skin, eyes, and nervous system. It is a water-soluble vitamin and very safe. No side effects or toxicities have been reported with its use, although it does turn the urine a bright yellow color.

Some interactions with drugs have occurred. Psyllium (e.g. Metamucil), alcohol, oral contraceptives and some antibiotics slow the absorption of Vitamin B2 in the gut. Caffeine, theophylline, and saccharin may bind B2 in the gut and prevent its absorption. A vitamin B2 deficiency is most commonly seen in the elderly and in alcoholics. Signs include burning or itching eyes that are more sensitive to the light, and cracks around the corners of the mouth, with sore, burning lips, mouth and tongue. The tongue may also be red or purple and swollen. It may hurt to eat or drink. The skin may flake or peel especially around the nose, eyebrows, chin, cheeks, earlobes, or hairline. There may also be a rash in the genital area. Some behavioral changes include moodiness, nervousness, irritability and depression.

The Recommended Daily Allowance of vitamin B2 is 1.2 mg/day. However, 50-400 mg a day have been given. Riboflavin should be taken with meals and in divided doses to increase absorption. Exercise and dieting may increase the need for riboflavin. Stress, pregnancy, and lactation also increase the requirements. Milk, cheese, yogurt, eggs; liver, kidney, fish and beef are all good sources of riboflavin as are beans, spinach, avacados, currants, asparagus, broccoli, Brussels sprouts, and nuts.

Uses

Vitamin B2, riboflavin, is an important nutrient but one that actually has few clinical uses. Physicians have used it to treat migraine headaches, cataracts and sickle cell anemia. It has also been used for skin problems such as acne, seborrhea, athelete's foot, rosacea, and cracks in the corners of the mouth. It may be useful for eye problems including blurred vision and eyes that are sensitive to light, tire easily, are bloodshot or watery.

Some problems with nerves or the nervous system, including nerve damage resulting in numbness and tingling, stress, tiredness, anxiety, depression, Alzheimer's disease and epilepsy have been treated with Vitamin B2. Riboflavin is used to help the body detoxify environmental pollutants. It is needed for tissue repair and may be helpful in healing burns, injuries and wounds, including surgical incisions. Vitamin B2 is needed by the body to make red blood cells. It may also prevent the development of esophageal cancer.

Proposed Mechanism of Action

Riboflavin is needed to make two enzymes, FMN (flavin mononucleotide)and FAD (flavin adenine dinucleotide) which are involved in energy metabolism. It helps regenerate glutathione, an antioxidant needed by the liver for the metabolism of drugs and environmental pollutants. Riboflavin also increases iron binding capacity and therefore the ability of the body to make red blood cells.

Side Effects / Precautions

Riboflavin is a very safe water-soluble vitamin that is easily excreted in the urine. It does turn the urine a bright yellow color, but there is no cause for concern.

Interactions

Psyllium (e.g. Metamucil), alcohol, oral contraceptives and some antibiotics slow the absorption of Vitamin B2 in the gut. Caffeine, theophylline and saccharin may bind B2 in the gut and prevent its absorption.

Symptoms of Deficiency

A vitamin B2 deficiency is more commonly seen in the elderly and in alcoholics.
Signs include an increased sensitivity to light, tearing, tired, burning or itching eyes and fuzzy vision. Symptoms around the mouth include cracks in the corners of the mouth, sore or burning lips, mouth and tongue, a red/purple swollen tongue. It may hurt to eat or drink resulting in weight loss. The skin can be affected and there may be flaking or peeling skin around the nose, eyebrows, chin, cheeks, earlobes, or hairline. There may also be a rash in the genital area. Some beharioral changes may be seen and include moodiness, nervousness, irritability and depression.

Symptoms of Toxicity

There are no known toxicities to vitamin B2. It is a water-soluble vitamin that easily excreted in the urine. It turns the urine a bright yellow color but this is no cause for concern.

Dosage and Administration

Very little vitamin B2 is needed to prevent a deficiency. The Recommended Daily Allowance is 1.2 mg/day. Up to 50-400 mg a day have been given to treat deficiency or symptoms associated with vitamin B2 deficiency. As examples, 25 mg/day has been given to prevent cataracts while up to 400 mg per day has been used for migraine headaches. Riboflavin should be taken with meals to increase absorption. Because it is water-soluble and easily excreted in the urine, it should be taken in divided doses. Exercise and dieting may increase the need for riboflavin. Stress, pregnancy, and lactation also increase the requirements.

Food Sources

Milk, cheese, yogurt, eggs; liver, kidney, fish and beef are all good sources of riboflavin. Other food sources include beans, spinach, avacados, currants, asparagus, broccoli, Brussels sprouts, and nuts. Whole-grains or fortified breads are also good sources.
Vitamin B2 is easily destroyed by light. Milk stored in clear glass bottles can lose up to 75% of riboflavin in just a few hours. Alkaline substances such as sodium bicarbonate, which is used to preserve the bright color of fruits and vegetables, destroy riboflavin. Cooking also causes a partial loss of this vitamin.

Other Supplements to Consider

Vitamin B1 (thiamin)
Vitamin B3 (niacin/niacinamide)
Vitamin B5 (pantothenic acid)
Vitamin B6 (pyridoxine)
Vitamin B12 (cyanocobalamin, hydroxycobalamin)
Folic acid
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