Riboflavin, or vitamin B2, is a member of the B complex family. It is a water-soluble nutrient, meaning it can be readily eliminated through your kidneys. Its bright yellow-green color accounts for the fluorescent hue acquired by your urine after you take a B complex supplement. Riboflavin is not stored in your tissues to any extent, so you must obtain it from your diet on a regular basis. A deficiency of riboflavin can lead to a variety of symptoms, including cracking and soreness at the corners of your mouth, a condition known as angular cheilitis. Ask your doctor if you need to take more riboflavin.
Functions
The Linus Pauling Institute at Oregon State University cites riboflavin's importance in the formation of two flavo-coenzymes in your cells, flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD). These two coenzymes participate in a variety of energy-producing reactions requiring the transfer of electrons from one molecule to another. Without FMN and FAD, you could not efficiently metabolize fats, carbohydrates and proteins. This same electron-transferring property allows FMN and FAD to participate in detoxification and antioxidant processes throughout your body.
Sources
Riboflavin is present in most foods that contain other B vitamins. Thus, riboflavin deficiency often occurs in concert with deficiencies of other B vitamins. Nutritionist Elson Haas, M.D., reports that brewer's yeast is among the richest sources of riboflavin. Other dietary sources include liver and other organ meats, oily fish, shellfish, dairy products, eggs, millet, wild rice, legumes and sunflower seeds. Supplements containing up to 100 mg are also available, but Haas believes this dose is excessive.
Deficiency
Angular cheilitis, an early sign of riboflavin deficiency, is a manifestation of impaired cellular energy metabolism and oxidative damage. As the deficiency worsens, redness and cracking spreads from the corners of your mouth to the entire lip margin. The mucous membranes of your mouth, tongue and throat become reddened and tender, and you develop an oily scaly rash on your face, eyelids, ears and groin area. According to "The Merck Manual of Diagnosis and Therapy," you may develop neovascularization, or growth of abnormal blood vessels, over the surface of your corneas, leading to visual problems. Anemia may occur as the result of reduced red blood cell formation.
Considerations and Recommendations
Riboflavin, as a precursor for two flavin-containing coenzymes, is essential for normal energy metabolism, detoxification and protection from cellular oxidative damage. Deficiency leads to widespread symptoms, the earliest and most prominent of which include angular cheilitis and other skin manifestations. Recommended daily dietary allowances for riboflavin vary from 300 mcg for infants to 1.6 mg for lactating females. Doses of 25 to 50 mg daily are well tolerated and safe. Your health care provider can guide you in a dosage that is appropriate for you.
References
- Linus Pauling Institute at Oregon State University: Riboflavin
- "Staying Healthy with Nutrition: Riboflavin"; Elson M. Haas, M.D.; 2006
- "The Merck Manual of Diagnosis and Therapy, 18th Edition: Riboflavin Deficiency"; Mark H. Beers, M.D., Editor-in-Chief; 2006
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