Home > Encyclopedia of Nursing & Allied Health > Riboflavin

Description

Riboflavin, also known as Vitamin B₂, has many functions in common with the other members of the B complex family. These include support of the immune and nervous systems, and formation of healthy red blood cells. Riboflavin provides essential factors for the production of cellular enzymes that turn proteins, fats, and carbohydrates into energy. It also participates in cell reproduction, and keeps skin, hair, nails, eyes, and mucous membranes healthy. Folic acid (vitamin B₉) and pyridoxine (vitamin B₆) are activated by riboflavin.

General use

The RDA of riboflavin for infants under six months is 0.4 milligrams (mg). It goes up incrementally with age and caloric intake. Babies from six months to one year of age require 0.5 mg. Children need 0.8 mg at one to three years of age, 1.1 mg at four to six years, and 1.2 mg at seven to ten years. Women need 1.3 mg from 11-50 years, and 1.2 mg thereafter. Slightly more is required during pregnancy (1.6 mg) and lactation (1.7-1.8 mg). Men require 1.5 mg from 11-14 years of age, 1.8 mg from 15-18 years, 1.7 mg from 19-50 years, and 1.4 mg at 51 years and older. Riboflavin is water-soluble, and is not stored in significant quantities in the body.

High doses of riboflavin, as much as 400 mg per day, have been shown to reduce the frequency of migraine headaches by half in susceptible people. The severity of the events was also reportedly decreased. This may be an effect of improved use of cellular energy in the brain. It is theorized that riboflavin may help decrease the odds of getting cataracts, but the evidence for this protection is not definitive. One large study had a group taking both niacin (vitamin B₃) and riboflavin, and while the group had a significantly lower total incidence of cataracts, they had a somewhat higher than average incidence of a specific cataract subtype. Memory may be improved by these supplements, according to some research done on older people. Riboflavin and vitamin C both help boost the body's level of glutathione, which is an antioxidant with many beneficial effects. There is not enough evidence to support the effectiveness of riboflavin for sickle-cell anemia, canker sores, or as an athletic performance aid.

Preparations

Natural sources

Beef liver is a very rich source of riboflavin, but dairy products also supply ample amounts. Higher-fat sources contain less than those with low fat. Many processed grain products are fortified with riboflavin, as well as other B vitamins. Good vegetable choices include avocados, mushrooms, spinach, and other dark green, leafy vegetables. Nuts, legumes, nutritional yeast, and brewer's yeast contain riboflavin as well. Cooked foods provide as much of this vitamin as raw ones do, since the substance is heat stable. Light, however, does break down riboflavin. To preserve it, be sure to either store dairy and grain products in something opaque or keep them away from light.

Supplemental sources

Riboflavin is available as an oral single vitamin product. Consider taking a balanced B complex supplement rather than high doses of an individual vitamin unless there is a specific indication to do so. Store supplements in a cool, dry place, away from light, and out of the reach of children.

Deficiency

Ariboflavinosis is the term for the condition of vitamin B₂ deficiency. Since small amounts can be stored in the liver and kidneys, a dietary inadequacy may not become apparent for several months. Insufficient levels of riboflavin have noticeable effects on several areas of the skin. Commonly the corners of the mouth are cracked. Facial skin and scalp tend to itch and scale, as does the scrotal skin. The eyes fatigue easily and are sensitive to light, and may also become watery, sore, or bloodshot. Trembling, neuropathy, dizziness, insomnia, poor digestion, slow growth, and sore throat and tongue have also been reported. Anemia may develop if the deficiency is severe. People who are deficient in riboflavin are likely to be lacking in other B vitamins, and possibly additional nutrients as well.

Risk factors for deficiency

Riboflavin deficiency is uncommon, but some populations may need more than the RDA in order to maintain good health. Vegans, and others who do not use dairy products, would do well to take a balanced B vitamin supplement. Those with increased need for riboflavin and other B vitamins may include people under high stress, including those experiencing surgery, chronic illnesses, liver disease, or poor nutritional status. Diabetics may have a tendency to be low on riboflavin as a result of increased urinary excretion. Athletes and anyone else with a high-energy output will need additional vitamin B₂. This includes anyone who exercises with some regularity. The elderly are more likely to suffer from nutritional inadequacy as well as problems with absorption.

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KEY TERMS

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Antioxidant—Any one of a group of substances that function to destroy cell-damaging free radicals in the body.

Migraine—A very severe headache, often accompanied by nausea and vomiting. It is usually experienced on one side of the head, and may be preceded by visual symptoms.

Neuropathy—Abnormality of the nerves, which may be manifested as numbness, tingling, or weakness of the affected area.

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Smokers and alcoholics are at higher risk for deficiency, as tobacco and alcohol suppress absorption. Birth control pills may possibly reduce riboflavin levels, as can phenothiazine tranquilizers, tricyclic antidepressants, and probenecid. Consult a health care professional to determine if supplementation is appropriate.

Precautions

Riboflavin should not be taken by anyone with a B vitamin allergy or chronic renal disease. Other populations are unlikely to experience any difficulty from taking supplemental B₂.

Side effects

Taking supplemental riboflavin causes a harmless intense orange or yellow discoloration of the urine.

Interactions

Probenecid (a drug treating gout) impairs riboflavin absorption, and propantheline bromide (a drug treating peptic ulcers) reportedly both delays and increases absorption. Phenothiazines (antipsychotic drugs) increase the excretion of riboflavin, thus lowering serum levels; and oral contraceptives may also decrease serum levels. Supplementation should be discussed with a health care provider if these medications are being used. Absorption of riboflavin is improved when taken together with other B vitamins and vitamin C.

Judith Turner