Quest Vitamins LTD,
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Aston Science Park,
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Riboflavin (B2)

DESCRIPTION

Riboflavin (vitamin B2) is a member of the B complex that is naturally a bright yellow colour. It was isolated from whey by Dr. Khun in 1933.

STABILITY

Riboflavin is relatively unaffected by cooking processes, but is destroyed by alkalis (e.g. bicarbonate of soda) and exposure to light.

FUNCTIONS

Riboflavin forms the essential coenzymes FAD (flavin adenine dinucleotide) and FMN (flavin mononucleotide). These two are essential for converting proteins, fats and carbohydrates into energy in the presence of oxygen.

DEFICIENCY

Typically, deficiency symptoms take the form of oral complaints such as sore, burning lips and tongue ailments. An oily-type Dermatitis is also often present down either side of the nose. Eyes can also be affected, with burning, itchiness and visual Fatigue present.

REQUIREMENTS

Upper safe level for daily supplementation = 200mg

Recommended Daily Allowance = 1.6mg

SUPPLEMENTAL USES

Riboflavin supplementation is necessary in those with a deficiency of this nutrient. Such a deficiency is not uncommon in people who have undergone total or partial gastrectomy, and in those being treated with chloramphenicol or other antibiotics.

In high amounts, riboflavin has been reported to be of use in eye conditions such as blepharitis (sore itchy eyelids) and keratitis (Inflammation of the cornea) (1). Riboflavin is also occasionally effective in the treatment of Migraines (2) and muscle Cramps, but there is no known rationale for this.

SAFETY

Intakes of more than 120 mg/day for ten months have not been associated with any adverse side effects. Absorption of riboflavin from the intestine is limited by poor solubility and so it is unlikely that enough could be absorbed to be harmful.

INTERACTIONS AND CONTRA-INDICATIONS

Diuretics:
Thiazide diuretics can increase the excretion of riboflavin.

Antibiotics:
Riboflavin is unstable in the presence of the antibiotics erythromycin and tetracycline. The vitamin should be taken apart from these drugs.

Methotrexate:
Riboflavin may affect the way cancer cells respond to the anti-cancer drug methotrexate.

N.B. Riboflavin supplements may cause a harmless yellow coloration of the urine.

It is usually recognised that B vitamins are best taken together for most general purposes. However there is no detriment in taking riboflavin singly for a specific reason.

FOOD SOURCES

Food (mg/100g)
Yeast extract 11.0
Lamb?s liver 4.64
Pig?s kidney 2.58
Fortified breakfast cereal 1.6
Wheatgerm 0.61
Cheese, cheddar 0.5
Eggs 0.47
Beef, stewing steak 0.23
Milk 0.17
Chicken 0.13

The main sources of riboflavin in the diet are milk, meat, fortified cereal products and eggs.

REFERENCES

1. "Handbook of Dietary Supplements", Pamela Mason, Blackwell Science, 1995.
2. Schoenen J, Lenaerts M, Bastings E. Cephalagia, 1994,14;5:328-329.