Both of these act as coenzymes in energy production pathways in the body. Riboflavin is phosphorylated in the intestines prior to absorption, and thus is absorbed as FMN or FAD.

Energy Production
All of our cells need vitamin B2 to to produce energy through cellular respiration, which is a set of chemical reactions that allow cells to use food to make energy. Vitamin B2 is a part of the flavin coenzymes (FAD, and FMN), which both increase the rate at which our cells can make energy from the food that we eat.  Thus, riboflavin also helps the body to digest fats, carbohydrates and proteins and to convert them into energy used for growth and repair.

Cell Replication and Red Blood Cell Production
Sufficient riboflavin is important for a number of different types of cell replication and growth. It is an important vitamin for the formation of red blood cells, which circulate oxygen to our tissues. Thus riboflavin can help to prevent anemia. It also aids the replication of immune cells and antibodies, to ensure the proper functioning of the immune system.  It can also be used to treat carpal tunnel syndrome, dandruff and deficient growth of hair and nails.  A lack of riboflavin can cause birth defects in a fetus even if a mother shows no signs of deficiency.

Antioxidant
Riboflavin is an antioxidant, meaning that it neutralizes damaging molecules called free radicals.  Because of this it is used to help prevent cataracts, which result from free radical damage in the eye.  In this way it can also help to reduce other oxidative damage that causes the physical signs of aging. For more information on antioxidants, please click here.

Food Fortification and Deficiency
Deficiency symptoms appear as anemia, mouth or lip sores (particularly cracks at the corners of the mouth), skin lesions, dizziness, insomnia, poor digestion, and swelling of mucous membranes. Often it can also appear as a sensation of burning in the soles of the feet, migraines, and muscle cramps. Most commercial breads and cereals are fortified with riboflavin, which means that vitamin B2 is directly added to these foods during the manufacturing process. Because of this, deficiency is rare in North America, although it is more frequently seen in the elderly and those with impaired digestion.

Co-Supplementation
Vitamin B2 is required for the proper absorption of iron in the gut, so deficiency can cause a resultant iron deficiency. Taking riboflavin with iron can help to prevent this effect. All of the B vitamins work together and are best used by the body in a B complex, which is why many B complex supplements include a small dose of riboflavin in them.  If further supplementation of riboflavin is needed it should be taken in addition to a good B complex.

How can I take riboflavin?
Because it is water soluble, excess B2 is easily flushed out of the body. As such, it is best to take a lower dosage of the B complex several times a day, rather than one large dose.  Spray or sublingual forms of B vitamins are easily absorbed, as are capsules - if your digestion is healthy, then the tablet form is usually suitable for most people. General supplementation of vitamin B2 can be quite low, with doses around 5-10mg per day helping to prevent deficiency. For medicinal effects, dosages are generally between 30 and 300mg daily. Taking riboflavin in its R5P absorbable form may help to increase uptake in the intestines for those with difficult digestion.

Important Information
B2 is depleted by the use of oral contraceptives, antibiotics and alcohol.  Heavy exercise decreases levels of riboflavin in the body.  Diets recommended for ulcers and diabetes are usually deficient in riboflavin.  This vitamin is easily destroyed by light.  High levels of riboflavin hinder the action of some anti-cancer medications. Excess B2 is excreted in the urine and can cause the urine to change to a harmless bright yellow or yellow-orange colour. Toxicity is rare, but very high doses over long periods of time may cause itching, numbness, cataracts or retinal disease.