Vitamin B2 (Riboflavin)

Dietary Sources

The best sources of riboflavin include brewer's yeast, almonds, organ meats, whole grains, wheat germ, wild rice, mushrooms, soybeans, milk, yogurt, eggs, broccoli, Brussels sprouts, and spinach. Flours and cereals are often fortified with riboflavin.

Riboflavin is destroyed by light, so food should be stored away from light to protect its riboflavin content. While riboflavin is not destroyed by heat, it can be lost in water when foods are boiled or soaked. During cooking, roasting and steaming preserves more riboflavin than frying or scalding.

Available Forms

Riboflavin is generally included in multivitamins and B-complex vitamins, and comes individually in 25-, 50-, and 100-mg tablets.

How to Take It

As with all medicines, check with a health care provider before giving riboflavin supplements to a child.

Daily recommendations for dietary riboflavin are listed below.

Pediatric

• Infants birth - 6 months: 0.3 mg (adequate intake)
• Infants 7 - 12 months: 0.4 mg (adequate intake)
• Children 1 - 3 years: 0.5 mg (RDA)
• Children 4 - 8 years: 0.6 mg (RDA)
• Children 9 - 13 years: 0.9 mg (RDA)
• Males 14 - 18 years: 1.3 mg (RDA)
• Females 14 - 18 years: 1 mg (RDA)

Adult

• Males 19 years and older: 1.3 mg (RDA)
• Females 19 years and older: 1.1 mg (RDA)
• Pregnant females: 1.4 mg (RDA)
• Breastfeeding females: 1.6 mg (RDA)

Riboflavin is best absorbed when taken between meals.

People who do not eat a balanced diet every day may benefit from taking a multivitamin and mineral complex. A good rule of thumb when selecting a multivitamin is to look for one that includes 100 - 300% of the daily value for all essential vitamins and minerals. You should also look for supplements that are designed to be taken 2 - 4 times daily to get these amounts, as opposed to one-a-day varieties. Check with a knowledgeable health care provider if you are considering supplement doses higher than twice the daily value.

Supporting Research

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Alternative Names

Precautions

Because of the potential for side effects and interactions with medications, you should take dietary supplements only under the supervision of a knowledgeable health care provider.

Riboflavin is generally considered safe, even at high doses. However, because doses above 10 mg per day may cause eye damage from the sun, people who take high doses should wear sunglasses that protect their eyes from ultraviolet light.

Riboflavin does not appear to cause any serious side effects. Very high doses may cause itching, numbness, burning or prickling sensations, yellow or orange urine, and sensitivity to light.

Taking any one of the B complex vitamins individually for a long period of time can result in an imbalance of the other B vitamins. For this reason, it is generally important to take a B complex vitamin with any single B vitamin.

Possible Interactions

If you are currently being treated with any of the following medications, you should not use vitamin B2 supplements without first talking to your health care provider.

Anticholinergic Drugs -- Used to treat a variety of conditions, including gastrointestinal spasms, asthma, depression, and motion sickness, these drugs may inhibit the body's ability to absorb riboflavin.

Tetracycline -- Riboflavin interferes with the absorption and effectiveness of tetracycline, an antibiotic. (All vitamin B complex supplements act in this way.) You should take riboflavin at a different time during the day from when you take tetracycline.

Tricyclic Antidepressants -- Tricyclic antidepressants may reduce levels of riboflavin in the body. In addition to raising levels of the vitamin in the body, taking riboflavin may also improve the effects of these antidepressants. They include:

• Imipramine (Tofranil)
• Desimpramine (Norpramin)
• Amitriptyline (Elavil)
• Nortriptyline (Pamelor)

Antipsychotic Medications -- Antipsychotic medications called phenothiazines (such as chlorpromazine or Thorazine) may lower riboflavin levels.

Doxorubicin -- Riboflavin may deactivate doxorubicin, a medication used for the treatment of certain cancers. In addition, doxorubicin may deplete levels of riboflavin in the body. Your doctor will let you know whether you need to take a riboflavin supplement or not.

Methotrexate -- Methotrexate, a medication used to treat cancer and autoimmune diseases such as rheumatoid arthritis, can inhibit the body from using riboflavin.

Phenytoin -- Phenytoin (Dilantin), a medication used to control epileptic seizures, may affect riboflavin levels in the body.

Probenecid -- This medication used for gout may decrease the absorption of riboflavin from the digestive tract and increase the excretion in the urine.

Thiazide Diuretics -- Diuretics (water pills) that belong to a class known as thiazides, such as hydrochlorothiazide, may cause you to excrete more riboflavin in your urine.

Introduction

Overview

Vitamin B2, also called riboflavin, is one of 8 B vitamins. All B vitamins help the body to convert food (carbohydrates) into fuel (glucose), which is "burned" to produce energy. These B vitamins, often referred to as B complex vitamins, also help the body metabolize fats and protein. B complex vitamins are necessary for healthy skin, hair, eyes, and liver. They also help the nervous system function properly.

All the B vitamins are water-soluble, meaning that the body does not store them.

In addition to producing energy for the body, riboflavin also works as an antioxidant by scavenging damaging particles in the body known as free radicals. Free radicals occur naturally in the body but can damage cells and DNA, and may contribute to the aging process, as well as the development of a number of health conditions, such as heart disease and cancer. Antioxidants such as riboflavin can neutralize free radicals and may reduce or help prevent some of the damage they cause.

Riboflavin is also needed to help the body convert vitamin B6 and folate into active forms. It is also important for body growth and red blood cell production.

Most healthy people who eat a well-balanced diet get enough riboflavin. However, elderly people and alcoholics may be at risk for riboflavin deficiency because of poor diet. Symptoms of riboflavin deficiency include fatigue; slowed growth; digestive problems; cracks and sores around the corners of the mouth; swollen magenta tongue; eye fatigue; swelling and soreness of the throat; and sensitivity to light. Riboflavin is an important nutrient in the prevention of headache and some visual disturbances, particularly cataracts.

Anemia

Children with sickle-cell anemia (a blood disorder characterized by abnormally shaped red blood cells) tend to have lower levels of certain antioxidants, including riboflavin. The same is also true of people with iron deficiency anemia, and studies suggest that taking riboflavin supplements may improve the response to iron therapy.

Cataracts

Vitamin B2, along with other nutrients, is important for normal vision, and preliminary evidence shows that riboflavin might help prevent cataracts (damage to the lens of the eye, which can lead to cloudy vision). In one double-blind, placebo-controlled study, people who took a niacin-riboflavin supplement had significantly less cataracts. However, researchers don't know whether that was due to riboflavin, niacin, or the combination of the two. And levels above 10 mg per day of riboflavin can actually promote damage to the eye from the sun. More research is needed to see if riboflavin has any real benefit in preventing cataracts.

Migraine Headache

Several studies indicate that people who get migraines may decrease the frequency and duration of the headache by taking riboflavin. One double-blind, placebo-controlled study showed that taking 400 mg of riboflavin a day cut the number of migraine attacks in half. The study did not compare riboflavin to conventional medications used to prevent migraines, however, so more research is needed.