Riboflavin, also known as vitamin B2, was once called “yellow enzyme” it has a distinctive yellow-green fluorescence. In fact, its name comes from its color (flavin means yellow in Latin). Riboflavin contains 3 linked 6-membered rings, with a sugar alcohol attached to the middle ring.

RIBOFLAVIN IN FOODS

Almost one quarter of the riboflavin in out diets comes from milk products. The rest typically is supplied by enriched white bread, rolls, and crackers, as well as eggs and meat, depending on regulations.

Foods rich in riboflavin are liver, mushrooms, spinach and other green leafy vegetables, broccoli, asparagus, milk, and cottage cheese. Exposure to light (ultraviolet radiation) causes riboflavin to break down rapidly. To prevent this light-induced breakdown, paper and plastic containers-not glass-should be used as packaging for riboflavin-rich foods, such as milk, milk products, and cereals.

FUNCTIONS OF RIBOFLAVIN

Riboflavin is a component of 2 coenzymes that play key roles in energy metabolism: flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD). These coenzymes, also referred to as flavins, have oxidized form of the coenzyme. When it is reduces (gains 2 hydrogens, equivalent to 2 hydrogen ions and 2 electrons), it is known as FADH2.

The riboflavin coenzymes are involved in many reactions in various metabolic pathways. They are critical for energy metabolism and are involved in the formation of other compounds, including other B-vitamins and antioxidants.

RIBOFLAVIN NEEDS AND UPPER LEVEL

The RDAs for riboflavin for an adult men and women are 1.3 and 1.1 mg/day, respectively. The Daily Value on food and supplement labels is 1.7 mg/day. There appears to be no adverse effects from consuming large amounts of riboflavin because of its limited absorption and rapid excretion via the urine, so no Upper Level has been set.

RIBOFLAVIN DEFICIENCY

Riboflavin deficiency, called ariboflavinosis, primarily affects the mouth, skin, and red blood cells. The symptoms include inflammation of the throat, mouth (stomatitis), and tongue (glossitis); cracking of the tissue around the corners of the mouth and red, scaly skin may occur.

Some of the symptoms of the ariboflavinosis may result from deficiencies of other B-vitamins because they work in the same metabolic pathways as riboflavin and are often supplied by the same foods.