Riboflavin
Overview
Riboflavin (REY-bo-FLAY-vin), commonly known as vitamin B2, is an orange-yellow crystalline solvent with a bitter taste. It is relatively stable when exposed to heat, but tends to decompose in the presence of light for extended periods of time. Riboflavin is used in the body for a variety of functions, including the metabolism of carbohydrates for the production of energy and the production of red blood cells.
Key Facts
Other Names:
Vitamin B2
Formula:
C17H20N4O6
Elements:
Carbon, hydrogen, nitrogen, oxygen
Compound Type:
Organic
State:
Solid
Molecular Weight:
376.36 g/mol
Melting Point:
280°C (536°F)
Boiling Point:
Not applicable; decomposes
Solubility:
Very slightly soluble in water and ethyl alcohol; very soluble in alkaline solvents, but resulting in decomposition
Riboflavin was first observed in 1879 by the English chemist Alexander Wynter Blyth (1844–1921) who noticed a compound in cow's milk that glowed with a yellow fluorescence when exposed to light. Blyth called the compound lachtochrome (lachto- = "milk" and -chrome = color), but was unable to determine its chemical composition or its chemical properties. In fact, it was not until the 1930s that the chemical nature of the compound was determined. The Swiss chemist Paul Karrer (1889–1971) and the Austrian-German chemist Richard Kuhn (1900–1967) independently determined the chemical structure of riboflavin and first synthesized the compound. The name riboflavin is derived from the fact that the vitamin was first found in association with the sugar ribose.
How It Is Made
Plants and microorganisms synthesize riboflavin naturally. Some foods rich in riboflavin are brewer's yeast, dark green vegetables, mushrooms, legumes, nuts, milk and other dairy products, sweet potatoes, and pumpkins. Bacteria that live in the human digestive tract are also able to synthesize some riboflavin, but not enough to meet the body's requirement for the vitamin.
Riboflavin is produced synthetically using either the genetically-modified bacterium Bacillus subtilis or a fungus called Ashbya gossifyii. The bacteria or fungus are cultured in a large vat that has been seeded with small amounts of riboflavin. Over time, the organisms generate large quantities of riboflavin until some desired amount of the compound has been produced. The vat is then heated to a temperature sufficient to kill the bacteria or fungi, leaving crystalline riboflavin behind. The riboflavin is then separated and purified.
Interesting Facts
- The human body cannot store riboflavin, so it is excreted in the urine. For this reason, it is not dangerous to consume large doses of riboflavin, although the consumption of large amounts of the vitamin serves no biological purpose.
- Since riboflavin does not dissolve in water, it must be converted to a water soluble form, such as riboflavin-5-phosphate, for use as a food additive.
- The recommended daily dose of riboflavin for adults is 1.6 milligrams for men, 1.2 milligrams for women, 0.6 milligrams for children age four to eight, 0.9 milligrams for children age nine to thirteen, and 1.3 milligrams for teenagers.
Common Uses and Potential Hazards
The human body needs riboflavin to use oxygen efficiently in the metabolism of amino acids, fatty acids, and carbohydrates. The vitamin is involved in the synthesis of niacin (another B vitamin), it activates vitamin B6, and it helps the adrenal gland to produce hormones. It helps the body make antibodies to fight disease and infection, regulates the thyroid gland, and is important in maintaining healthy hair, nails, and skin. Riboflavin is especially important during periods of rapid growth because it is involved in the formation and growth of cells, especially red blood cells.
In combination with vitamin A, riboflavin helps maintain the mucous membranes that line the digestive tract. Pregnant women need riboflavin to help the fetus grow and develop. The vitamin is also essential for eye health. Some medical professionals recommend riboflavin for the treatment of eye disorders, such as cataracts, sensitivity to bright light, and bloodshot, burning, or itching eyes. Doctors have begun experimenting with the use of riboflavin to treat migraine headaches.
In spite of its many important functions in the body, riboflavin deficiencies do not lead to serious medical problems or death. They may result in a delayed healing of wounds or relatively minor medical conditions such as cheilosis (a reddening and soreness in the corners of the lips), angular stomatitis (cracking of the skin at the corner of the lips), dermatitis (an oily skin disorder), glossitis (a swollen, reddened tongue), and cracking around the nose. In all such cases, however, a riboflavin deficiency by itself is almost never the cause of the problem; instead, deficiencies of other vitamins in the B group are also involved.
Words to Know
A group of sugars and starches produced by plants and used as food. A disease caused by malfunction of the liver in which the skin and eyes become yellow. A member of the pea family of plants, which includes peas and beans. The process that includes all of the chemical reactions that occur in cells by which fats, carbohydrates, and other compounds are broken down to produce energy and the compounds needed to build new cells and tissues. Tissues that line the moist inner lining of the digestive, respiratory, urinary and reproductive systems. A substance that is able to dissolve one or more other substances. A chemical reaction in which some desired chemical product is made from simple beginning chemicals, or reactants.Riboflavin deficiencies are very rarely seen in the United States because the vast majority of people consume a diet that contains adequate amounts of the vitamin. Individuals most likely to suffer from riboflavin deficiency problems are those with anorexia (a condition in which people refuse to eat adequate amounts of food), older people with poor diets, alcoholics (because alcohol impairs a person's ability to absorb and use the vitamin), and newborn babies being treated for jaundice by exposure to ultraviolet light (because light destroys riboflavin).
For Further Information
"Food Safety: From the Farm to the Fork." European Commission Web Site. http://europa.eu.int/comm/food/fs/sc/scf/out18_en.html (accessed on November 3, 2005).
"Riboflavin." Linus Pauling Institute, Micronutrient Information. http://lpi.oregonstate.edu/infocenter/vitamins/riboflavin/ (accessed on November 3, 2005).
"Riboflavin." MedlinePlus. http://www.nlm.nih.gov/medlineplus/ency/article/002411.htm (accessed on November 3, 2005).
"Vitamin B2 (Riboflavin)." Herb & Supplement Encyclopedia. http://www.florahealth.com/flora/home/canada/healthinformation/encyclopedias/VitaminB2.asp (accessed on November 3, 2005).
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