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Vitamin B2 (Riboflavin) - Benefits, Deficiency Symptoms And Food Sources

The isolation of thiamine from natural sources as a heat-labile component left a heat-stable component which was originally known as vitamin B2. It was later discovered that the heat-stable component was not a single factor but contained, besides riboflavin, other vitamins such as pyridoxine, niacin, and pantothenic acid.

Riboflavin derives its name from its yellow color (favus = yellow) and is found in many substances. The suffix 'flavin' was added to the name of the source from which it was obtained, e.g., lactoflavin from milk, ovoflavin from egg, hepatoflavin from liver, and uroflavin from urine. When it was discovered that the molecule contained a group similar to the sugar ribose, the name 'riboflavin' was coined.

Benefits and functions of vitamin B2

Vitamin B2 is required by the body to use oxygen and the metabolism of amino acids, fatty acids, and carbohydrates. Riboflavin is further needed to activate vitamin B6 (pyridoxine), helps to create niacin and assists the adrenal gland.

Vitamin B2 acts as an enzyme that takes part in cell respiration. There are several flavoproteins, each one having its own specific activity.

Recommended dosage of vitamin B2

The daily requirement is 1-1.5 mg. A reserve of riboflavin cannot be maintained on an intake below 1.1 mg per day. A well-balanced diet supplies 1-2 mg of vitamin b2 daily.

Deficiency symptoms of vitamin B2

Riboflavin deficiency is usually associated with deficiency of other factors of the vitamin B group. Deficiency can be precipitated by:

1. Inadequate intake, particularly of milk which is a good source of vitamin b2
2. Poor absorption, as in diseases associated with chronic diarrhea
3. Excessive demand, as with the raised metabolic rate in thyrotoxicosis, fever or pregnancy. During lactation, 30 micrograms per 100 ml is secreted in milk.

Deficiency of vitamin b2 also occurs with hypothyroidism and drugs such as phenothiazine, boric acid, and oral contraceptives. Infants with hemolytic hyperbilirubinemia subjected to phototherapy are likely to be vitamin b2 deficient.

Deficiency symptoms of this vitamin may manifest itself as cracks and sores at the corners of the mouth, eye disorders, inflammation of the mouth and tongue, and skin lesions.

Food sources of vitamin B2

Vitamin b2 is found in milk, meat, cereals and pulses. There is little Vitamin b2 in fruits, vegetables, nuts fish, legumes, whole grains, and yogurt. Human intestinal bacterial flora probably synthesize riboflavin.

Toxicity

Toxicity has not been noted following the therapeutic use of riboflavin, because of its rapid excretion by the kidneys.