How Vitamin B2 Works


Like many scientific discoveries, vitamin B2 was discovered almost accidentally. In the 1920s and 1930s, nutritionists were searching for a growth-promoting factor in food. Their search kept turning up yellow substances. Meanwhile, biochemists who were busy trying to solve the mysteries of metabolism kept encountering a yellow enzyme. The yellow substances in food and the enzyme that the researchers kept encountering were all riboflavin. In this article, we'll learn why vitamin B2, or riboflavin, is important and how to get enough of it in your diet. Here's a preview.
  • What Is Vitamin B2?

    Vitamin B2, or riboflavin, works together with the family of B-complex vitamins to provide the body with energy by metabolizing carbohydrates, fats, and proteins. It also helps in the regeneration of glutathione, an enzyme that rids the body of free radicals.

  • Benefits of Vitamin B2

    Riboflavin may be able to decrease the number of migraine headaches a person has. It might also help to prevent cataracts. Riboflavin has helped to increase iron levels for those suffering from iron-deficiency anemia.

  • Foods That Contain Vitamin B2

    Dairy products, such as milk, cheese, and yogurt, are excellent sources of riboflavin. Some meats and leafy green vegetables are also rich in this nutrient. "Enriched" breads and cereals have had riboflavin added to them.

  • Vitamin B2 Deficiency

    Hypersensitivity to light can be a sign of a riboflavin deficiency, which causes the skin to become greasy, scaly, and dry. A riboflavin deficiency might contribute to cataracts, so those who have suffered from cataracts in the past should consider a riboflavin supplement.
Riboflavin is just one of the many vitamins you need to maintain overall health. Follow the links below to learn more about these essential vitamins.
  • Vitamin A, or retinol, plays a vital role in vision. Learn more in How Vitamin A Works.
  • A vitamin B1, or thiamin, deficiency results in the disease beriberi. Learn more in How Vitamin B1 Works.
  • Vitamin B3, or niacin, acts as a coenzyme, assisting other substances in the conversion of food into energy. Learn more in How Vitamin B3 Works.
  • Vitamin B5, or pantothenic acid, can be found in all living cells and in all foods. Learn about its importance to your diet in How Vitamin B5 Works.
  • Vitamin B6 is actually three substances, pyridoxine, pyridoxamine, and pyridoxal, that work to metabolize protein and amino acids. Read more in How Vitamin B6 Works.
  • To learn about the many vitamins in our diet, how much you should be eating, and where to find them, go to our general Vitamins page.
  • Find the best prices on vitamin B2 supplements.

This information is solely for informational purposes. IT IS NOT INTENDED TO PROVIDE MEDICAL ADVICE. Neither the Editors of Consumer Guide (R), Publications International, Ltd., the author nor publisher take responsibility for any possible consequences from any treatment, procedure, exercise, dietary modification, action or application of medication which results from reading or following the information contained in this information. The publication of this information does not constitute the practice of medicine, and this information does not replace the advice of your physician or other health care provider. Before undertaking any course of treatment, the reader must seek the advice of their physician or other health care provider.

What Is Vitamin B2?

Most nutritionists in the 1920s believed that there were only two unidentified essential nutrients -- a fat-soluble A and a water-soluble B. Soon, however, they found there was a second water-soluble B compound waiting to be identified.

Milk is a good source of vitamin B2, or riboflavin.
©2007 Publications International, Ltd.
Milk is a good source of vitamin B2,
or riboflavin.

Nutritionists gradually isolated growth-producing substances from liver, eggs, milk, and grass. In 1933, L. E. Booher obtained a yellow growth-promoting substance from milk whey, observing that the darker the yellow color, the greater its potency. Booher's observation led nutritionists to discover that all the yellow growth-producing substances in foods were one and the same -- riboflavin.

While nutritionists zeroed in on the yellow substance in food, biochemists studied a yellow enzyme found to be essential for the body's energy needs. Biochemists were eventually able to separate the enzyme into two parts: a colorless protein and a yellow organic compound that turned out to be the riboflavin itself. This was the first clue scientists had that there is more than one B vitamin.

Functions of Vitamin B2

Riboflavin acts as a coenzyme -- the nonprotein, active portion of an enzyme -- helping to metabolize carbohydrates, fats, and proteins in order to provide the body with energy. Riboflavin doesn't act alone, however; it works in concert with its B-complex relatives, particularly
B6 (pyridoxine). Riboflavin also has a role in the metabolism of other vitamins.

Riboflavin has a connection to glutathione, one of the enzymes that rids the body of free radicals. It helps in the regeneration of this beneficial compound.

Riboflavin has many health benefits -- it is thought to decrease migraines, help prevent
cataracts, and even alleviate sickle-cell disease. Keep reading to learn more about riboflavin's therapeutic value.

Riboflavin is just one of many vital nutrients your body needs for overall health. Visit the links below to learn more about these essential vitamins.
  • In How Biotin Works, learn how biotin acts as a coenzyme in several metabolic reactions, such as the metabolism of fats and carbohydrates.
  • Read How Folate Works to learn about folacin, folic acid, and folate and how a folate deficiency can cause megaloblastic anemia.
  • Vitamin B12, also called cyanocobalamin or cobalamin, is essential because it assists folate in making DNA and RNA. Read more in How Vitamin B12 Works.
  • Vitamin C, or ascorbic acid, is good for more than just easing the common cold. Learn more in How Vitamin C Works.
  • Vitamin D is necessary to hold of rickets, but if you get enough sunshine, your body can make its own vitamin D supply. Learn more in How Vitamin D Works.
  • To learn about the many vitamins in our diet, how much you should be eating, and where to find them, go to our general Vitamins page.
  • To find the best prices on vitamin B2 supplements, click here.
This information is solely for informational purposes. IT IS NOT INTENDED TO PROVIDE MEDICAL ADVICE. Neither the Editors of Consumer Guide (R), Publications International, Ltd., the author nor publisher take responsibility for any possible consequences from any treatment, procedure, exercise, dietary modification, action or application of medication which results from reading or following the information contained in this information. The publication of this information does not constitute the practice of medicine, and this information does not replace the advice of your physician or other health care provider. Before undertaking any course of treatment, the reader must seek the advice of their physician or other health care provider.

Benefits of Vitamin B2

As an energy releaser, riboflavin promotes the production of energy in the brain's blood vessels. There is speculation, after some research, that supplements of riboflavin may be able to help reduce the number of migraine headaches a person gets.

Riboflavin can help prevent cataracts, probably because of its close relationship with glutathione, an antioxidant. In a study of 408 Boston-area women, those who had the highest intake of riboflavin had the lowest level of cataract formation and lens opacity.

Riboflavin supplements might help reduce the number of migraines a person gets.
©2007 Publications International, Ltd.
Riboflavin supplements might help reduce the number of migraines a person gets.

Riboflavin may be helpful to people with sickle-cell disease; 5 mg given two times a day increased the amount of glutathione and iron in patients' blood. In a different blood condition, iron-deficiency anemia, riboflavin helped improve iron levels when given along with an iron supplement.

Older adult women who exercise have higher riboflavin needs than their sedentary counterparts. This makes sense because of riboflavin's role in coaxing energy out of food. Supplementing helped prevent low blood levels, but didn't seem to alter endurance capacity in the women studied.

Large doses of riboflavin are not toxic. For general health purposes, 5 to 10 mg per day is adequate. The body may only be able to absorb 20 mg at any one time. Because of its fluorescent yellow quality, large doses will turn the urine bright yellow for several hours after ingesting it.

Dairy products are an excellent source of riboflavin, as are some meats and leafy green vegetables. Go to the next page to find out more about foods that contain riboflavin.

Riboflavin is just one piece in the puzzle when it comes to vital nutrients. Check out these links to learn more about the vitamins your body needs to maintain overall health.
  • Vitamin A, or retinol, plays a vital role in vision. Learn more in How Vitamin A Works.
  • A vitamin B1, or thiamin, deficiency results in the disease beriberi. Learn more in How Vitamin B1 Works.
  • Vitamin B3, or niacin, acts as a coenzyme, assisting other substances in the conversion of food into energy. Learn more in How Vitamin B3 Works.
  • In How Vitamin E Works, learn about this important antioxidant with far-reaching health benefits.
  • Vitamin K is important in allowing your blood to clot properly. Learn more in How Vitamin K Works.
  • To learn about the many vitamins in our diet, how much you should be eating, and where to find them, go to our general Vitamins page.
  • To find the best prices on vitamin B2 supplements, click here.
This information is solely for informational purposes. IT IS NOT INTENDED TO PROVIDE MEDICAL ADVICE. Neither the Editors of Consumer Guide (R), Publications International, Ltd., the author nor publisher take responsibility for any possible consequences from any treatment, procedure, exercise, dietary modification, action or application of medication which results from reading or following the information contained in this information. The publication of this information does not constitute the practice of medicine, and this information does not replace the advice of your physician or other health care provider. Before undertaking any course of treatment, the reader must seek the advice of their physician or other health care provider.

Foods That Contain Vitamin B2

Milk is the single best source of vitamin B2 in the American diet. A glass of milk provides one-quarter of the RDA of riboflavin for men and one third of the RDA for women. Other dairy products such as cheese, yogurt, and ice cream are also good sources of the vitamin. Meats, especially liver and kidney, and some green leafy vegetables are other rich sources. Enriched breads and cereals have riboflavin added to them.

Dairy products, such as milk, cheese, and yogurt, are excellent sources of riboflavin.
©2007 Publications International, Ltd.
Dairy products, such as milk, cheese, and yogurt, are excellent sources
of riboflavin.

Heat and oxygen do not easily destroy riboflavin, but light does. Milk can lose one-half or more of its riboflavin content when exposed to light for four to six hours. To prevent this from occurring, it's important not to store milk in clear glass or translucent plastic containers. It's better to buy and store milk in cardboard containers or colored plastic jugs.

Dietary Requirements of Vitamin B2

The RDA for riboflavin is 0.5 mg for every 1,000 calories. This works out to be 1.3 mg each day for the average adult man and 1.1 mg for the average adult woman. A pregnant woman needs an additional 0.3 mg. During a baby's first six months, a nursing mother needs an additional 0.5 mg daily; during the second six months, she needs only 0.4 mg more. Recommended levels decrease slightly to 1.4 mg for men and 1.2 mg for women over age 50 as energy needs decrease.

You can use this chart to find foods that are a good source of riboflavin.

Food Quantity
Riboflavin (mg)
Milk shake, thick 1 cup 0.5
Cottage cheese, low-fat 1 cup 0.41
Milk, whole 1 cup 0.39
Buttermilk, from whole milk 1 cup 0.38
Buttermilk, from skim milk 1 cup 0.37
Yogurt, low-fat frozen 1 cup 0.37
Pancakes 3 medium 0.36
Sweet potatoes 1 cup 0.33
Pretzels 1 cup 0.25
English muffin 1 medium 0.24

Hypersensitivity to light can be a sign of a riboflavin deficiency, which causes the skin to become greasy, scaly, and dry. Keep reading to learn more about the effects of a riboflavin deficiency.

Riboflavin is just one of the essential vitamins that should be a part of your diet. Follow the links below to learn more about the nutrients your body needs.
  • Vitamin B5, or pantothenic acid, can be found in all living cells and in all foods. Learn about its importance to your diet in How Vitamin B5 Works.
  • Vitamin B6 is actually three substances, pyridoxine, pyridoxamine, and pyridoxal, that work to metabolize protein and amino acids. Read more in How Vitamin B6 Works.
  • In How Biotin Works, learn how biotin acts as a coenzyme in several metabolic reactions, such as the metabolism of fats and carbohydrates.
  • Read How Folate Works to learn about folacin, folic acid, and folate and how a folate deficiency can cause megaloblastic anemia.
  • Vitamin B12, also called cyanocobalamin or cobalamin, is essential because it assists folate in making DNA and RNA. Read more in How Vitamin B12 Works.
  • To learn about the many vitamins in our diet, how much you should be eating, and where to find them, go to our general Vitamins page.
  • To find the best prices on vitamin B2 supplements, click here.
This information is solely for informational purposes. IT IS NOT INTENDED TO PROVIDE MEDICAL ADVICE. Neither the Editors of Consumer Guide (R), Publications International, Ltd., the author nor publisher take responsibility for any possible consequences from any treatment, procedure, exercise, dietary modification, action or application of medication which results from reading or following the information contained in this information. The publication of this information does not constitute the practice of medicine, and this information does not replace the advice of your physician or other health care provider. Before undertaking any course of treatment, the reader must seek the advice of their physician or other health care provider.

Vitamin B2 Deficiency

In vitamin B2 deficiency, the skin becomes greasy, scaly, and dry. There may be cracks, or fissures, at the corners of the mouth, inflammation and soreness of the lips, and a smooth, reddish-purple tongue.

Because prolonged deficiency of vitamin B2 causes severe eye damage in animals, some say eye problems in people, such as cataracts, might be due to a lack of this vitamin. Several studies have found people who develop cataract have lower levels of riboflavin in their blood than people who do not develop cataracts. Supplementation is justified if you have had cataracts and are trying to prevent a reoccurrence.

Some speculate that eye problems such as cataracts might be due to a riboflavin deficiency.
©2007 Publications International, Ltd.
Some speculate that eye problems such as cataracts might be due to a
riboflavin deficiency.

Hypersensitivity to light is a sign of riboflavin deficiency, but it is more likely due to a deficiency of several B vitamins. Since the B vitamins work together in a sequence of reactions, a deficiency of one vitamin affects the entire sequence.

As we've just learned, vitamin B2 is an essential part of the b-complex vitamins that help to provide the body with energy. Use the information in this article to make sure you're getting enough riboflavin in your diet.

Riboflavin is one of many vitamins we all need to maintain overall health. Visit the links below to learn more about these vital nutrients.
  • Vitamin B12, also called cyanocobalamin or cobalamin, is essential because it assists folate in making DNA and RNA. Read more in How Vitamin B12 Works.
  • Vitamin C, or ascorbic acid, is good for more than just easing the common cold. Learn more in How Vitamin C Works.
  • Vitamin D is necessary to hold of rickets, but if you get enough sunshine, your body can make its own vitamin D supply. Learn more in How Vitamin D Works.
  • In How Vitamin E Works, learn about this important antioxidant with far-reaching health benefits.
  • Vitamin K is important in allowing your blood to clot properly. Learn more in How Vitamin K Works.
  • To learn about the many vitamins in our diet, how much you should be eating, and where to find them, go to our general Vitamins page.
  • To find the best prices on vitamin B2 supplements, click here.
ABOUT THE AUTHOR:

Jennifer Brett, N.D. is director of the
Acupuncture Institute for the University of Bridgeport, where she also serves on the faculty for the College of Naturopathic Medicine. A recognized leader in her field with an extensive background in treating a wide variety of disorders utilizing nutritional and botanical remedies, Dr. Brett has appeared on WABC TV (NYC) and on Good Morning America to discuss utilizing herbs for health.


This information is solely for informational purposes. IT IS NOT INTENDED TO PROVIDE MEDICAL ADVICE. Neither the Editors of Consumer Guide (R), Publications International, Ltd., the author nor publisher take responsibility for any possible consequences from any treatment, procedure, exercise, dietary modification, action or application of medication which results from reading or following the information contained in this information. The publication of this information does not constitute the practice of medicine, and this information does not replace the advice of your physician or other health care provider. Before undertaking any course of treatment, the reader must seek the advice of their physician or other health care provider.