riboflavin-B2

What can foods high in vitamin B2 do for you?

• Help protect cells from oxygen damage
• Support cellular energy production
• Maintain your supply of other B vitamins

What events can indicate a need for more foods high in vitamin B2?

• Sensitivity to light
• Tearing, burning and itching in and around the eyes
• Soreness around the lips, mouth, and tongue
• Cracking of the skin at the corners of the mouth
• Peeling of the skin, particularly around the nose

Excellent sources of vitamin B2 include mushrooms, calf's liver, and spinach.

For serving size for specific foods, see Nutrient Rating Chart below at the bottom of this page.

Description Function Deficiency Symptoms Toxicity Symptoms Cooking, storage and processing Factors that affect function

Drug-nutrient interaction Nutrient interaction Health conditions Supplements Food Sources Public Recommendations References

Description

What is vitamin B2?

Vitamin B2, also commonly called riboflavin, gets its name from its color. The root of this word is the Latin word "flavus" meaning "yellow." (One of the naturally-occurring coloring agents in milk, called lactoflavin, is also a usable form of this vitamin.) When a person's urine becomes bright yellow following high level supplementation with B-complex vitamins, excess riboflavin excreted in the urine is often responsible for this change in color.

Interestingly, the highest concentrations of riboflavin in the body occur in the liver, kidneys, and heart. These high liver and kidney concentrations reflect the prominent role of vitamin B2 in metabolic activity, with the liver serving as a central metabolic processing point, and the kidneys providing for elimination of unneeded molecules. The high concentration of vitamin B2 in the heart results from the heart's unusual dependence on aerobic (oxygen-based) energy production, and the key role of vitamin B2 in allowing that energy production to occur.

How it Functions

What is the function of vitamin B2?

Energy Production

Like vitamin B1, vitamin B2 plays a critical role in the body's energy production. When active in the body's energy production pathways, riboflavin typically takes the form of flavin adenine dinucleotide (FAD) or flavin mononucleotide (FMN). When riboflavin is converted into these FAD and FMN forms, it can attach to protein enzymes and allow oxygen-based energy production to occur.

Proteins with FAD or FMN attached to them are often referred to as flavoproteins. Flavoproteins are found throughout the body, and particularly in locations where oxygen-based energy production is constantly needed. These locations include the heart and skeletal muscle.

Cofactor for Homocysteine Metabolism

One of FAD's many important roles is to serve as a cofactor for an enzyme (MTHFR) that is involved in the breakdown metabolism of homocysteine (high levels of homocysteine have been found to be associated with increased risk of cardiovascular disease.) Certain individuals have MTHFR enzyme that don't function optimally, owing to a genetic mutation, and are therefore more at risk for having high homocysteine levels. Researchers have suggested that among these individuals, those who have inadequte riboflavin status are more likely to have elevated homocysteine levels than those whose riboflavin status is adequate.

Glutathione Recycling

The body's use of oxygen, while critical for energy production and overall metabolic activity, brings with it a constant risk. Oxygen-containing molecules can be highly reactive, and can inadvertently damage many structures in the body, including cell membranes, blood vessel linings, and joint tissue.

Glutathione is a small, protein-like molecule that is responsible for helping prevent this oxygen-based damage. Like many "antioxidant" molecules, glutathione must be constantly recycled, and it is vitamin B2 that allows this recycling to take place. (Technically, vitamin B2 is a cofactor for the enzyme glutathione reductase that reduces the oxidized form of glutathione back to its reduced version.)

Maintaining Supplies of Vitamin B3

Vitamin B2 plays an important role in maintaining supplies of its fellow B vitamins. One of the pathways used in the body to create vitamin B3 (niacin) is by conversion of the amino acid tryptophan. This conversion process is accomplished with the help of an enzyme called kynurenine mono-oxygenase, and vitamin B2 (in its FAD form) is required for this enzyme to function.

Deficiency Symptoms

What are deficiency symptoms for vitamin B2?

Many of the early-stage deficiency symptoms for riboflavin involve eye-related problems. These problems include excessive sensitivity to light, tearing, burning and itching in and around the eyes, and loss of clear vision. Soreness around the lips, mouth, and tongue, and cracking of the skin at the corners of the mouth are symptoms that can also be characteristic of riboflavin deficiency. Peeling of the skin, particularly around the nose, or in men around the scrotum, can also indicate lack of vitamin B2.

Toxicity Symptoms

What are toxicity symptoms for vitamin B2?

Toxic side-effects from supplemental intake of vitamin B2 have not been documented in the research literature. In 1998, the Institute of Medicine at the National Academy of Sciences decided not to set a Tolerable Upper Limit (UL) for vitamin B2.

Impact of Cooking, Storage and Processing

How do cooking, storage, or processing affect vitamin B2?

Heat and air do very little damage to vitamin B2, but light is a primary damaging factor for this vitamin. In studies involving the boiling of macaroni noodles, for example, the impact of water and temperature never determined the loss of vitamin B2 from the noodles. In each instance, prolonged exposure to light was the critical factor.

For this reason, high-riboflavin foods should be cooked in covered pots whenever possible and stored in opaque containers. Without prolonged exposure to light, loss of riboflavin from cooking and storing is typically less than 25%.

Factors that Affect Function

What factors might contribute to a deficiency of vitamin B2?

Although not as dramatic as its impact on vitamin B1, alcoholism clearly decreases the availability of vitamin B2 in the body. In chronic alcohol abuse, 5-10 times the ordinary amount of vitamin B2 may be required.

Heavy exercise has also been shown to increase the need for vitamin B2. Particularly in women training for athletic events, up to 10-15 times the ordinary amount of vitamin B2 may be needed to sustain optimal health.

Almost 70% of the vitamin B2 in whole wheat flour is removed during processing. For this reason, beginning in the 1940's, the U.S. government began to require enrichment of processed wheat flour with riboflavin. Due to enrichment, wheat flour remains the primary source of vitamin B2 in the U.S. diet. However, individuals on specialty diets where carbohydrates like breads, grains, and pastas are avoided may be at special risk for riboflavin deficiency.

Drug-Nutrient Interactions

What medications affect vitamin B2?

Birth control pills (oral contraceptives); the antibiotic drug tetracycline; tricyclic antidepressant drugs like amitryptyline (Elavil) or doxepin (Sinequan); alcohol; anti-malarial drugs like primaquine; and the anti-gout drug probenecid have all been shown to decrease vitamin B2 availability in the body.

Nutrient Interactions

How do other nutrients interact with vitamin B2?

Vitamin B2 status is strongly affected by intake of vitamin B1. Adequate supplies of vitamin B1 can help increase levels of vitamin B2. However, very high levels of vitamin B1 intake can increase the loss of vitamin B2 in the urine. Other nutrients, especially iron, zinc, folate, vitamin B3 and vitamin B12 are not fully available in the body without adequate supplies of riboflavin.

Health Conditions

What health conditions require special emphasis on vitamin B2?

Vitamin B2 may play a role in the prevention and/or treatment of the following health conditions:

• Anemia
• Carpal tunnel syndrome
• Cataracts
• Migraine
• Rosacea
• Vaginitis

Form in Dietary Supplements

What forms of vitamin B2 are found in dietary supplements?

Riboflavin is found in its simplest chemical form in most dietary supplements. However, when active in the body's metabolic pathways, this vitamin usually takes the form of flavinadenine dinucleotide (FAD) or flavin mononucleotide (FMN). Both of these forms of vitamin B2 are water-soluble. One fat-soluble version of the vitamin, called riboflavin tetrabutyrate, has also been the subject of experimentation in treatment of riboflavin-related disorders, but is not widely available as a dietary supplement.

Food Sources

What foods provide vitamin B2?

Excellent sources of vitamin B2 include mushrooms, and calf liver, spinach.

Very good sources include romaine lettuce, asparagus, chard, mustard greens, broccoli, collard greens venison, turnip greens, chicken eggs, yogurt and cow's milk.

 

Introduction to Nutrient Rating System Chart

In order to better help you identify foods that feature a high concentration of nutrients for the calories they contain, we created a Food Rating System. This system allows us to highlight the foods that are especially rich in particular nutrients. The following chart shows the World's Healthiest Foods that are either an excellent, very good, or good source of vitamin B2 (riboflavin). Next to each food name, you'll find the serving size we used to calculate the food's nutrient composition, the calories contained in the serving, the amount of vitamin B2 (riboflavin) contained in one serving size of the food, the percent Daily Value (DV%) that this amount represents, the nutrient density that we calculated for this food and nutrient, and the rating we established in our rating system. For most of our nutrient ratings, we adopted the government standards for food labeling that are found in the U.S. Food and Drug Administration's "Reference Values for Nutrition Labeling." Read more background information and details of our rating system.

World's Healthiest Foods ranked as quality sources of: vitamin B2 (riboflavin)
Food	Serving Size	Cals	Amount (mg)	DV (%)	Nutrient Density	World's Healthiest Foods Rating
Crimini mushrooms, raw	5 oz-wt	31.2	0.69	40.6	23.4	excellent
Calf's liver, braised	4 oz-wt	187.1	2.20	129.4	12.4	excellent
Spinach, boiled	1 cup	41.4	0.42	24.7	10.7	excellent
Romaine lettuce	2 cup	15.7	0.11	6.5	7.4	very good
Asparagus, boiled	1 cup	43.2	0.23	13.5	5.6	very good
Swiss chard, boiled	1 cup	35.0	0.15	8.8	4.5	very good
Mustard greens, boiled	1 cup	21.0	0.09	5.3	4.5	very good
Broccoli, steamed	1 cup	43.7	0.18	10.6	4.4	very good
Collard greens, boiled	1 cup	49.4	0.20	11.8	4.3	very good
Venison	4 oz-wt	179.2	0.68	40.0	4.0	very good
Turnip greens, cooked	1 cup	28.8	0.10	5.9	3.7	very good
Egg, whole, boiled	1 each	68.2	0.23	13.5	3.6	very good
Yogurt, low-fat	1 cup	155.1	0.52	30.6	3.6	very good
Cow's milk, 2%	1 cup	121.2	0.40	23.5	3.5	very good
Green beans, boiled	1 cup	43.8	0.12	7.1	2.9	good
Celery, raw	1 cup	19.2	0.05	2.9	2.8	good
Kale, boiled	1 cup	36.4	0.09	5.3	2.6	good
Cabbage, shredded, boiled	1 cup	33.0	0.08	4.7	2.6	good
Tomato, ripe	1 cup	37.8	0.09	5.3	2.5	good
Strawberries	1 cup	43.2	0.10	5.9	2.5	good
Cauliflower, boiled	1 cup	28.5	0.06	3.5	2.2	good
Goat's milk	1 cup	167.9	0.34	20.0	2.1	good
Raspberries	1 cup	60.3	0.12	7.1	2.1	good
Brussel sprouts, boiled	1 cup	60.8	0.12	7.1	2.1	good
Summer squash, cooked, slices	1 cup	36.0	0.07	4.1	2.1	good
Tempeh, cooked	4 oz-wt	223.4	0.40	23.5	1.9	good
Green peas, boiled	1 cup	134.4	0.24	14.1	1.9	good
Plum	1 each	36.3	0.06	3.5	1.8	good
Soybeans, cooked	1 cup	297.6	0.49	28.8	1.7	good
Almonds, dry roasted	0.25 cup	206.0	0.30	17.6	1.5	good
Beef tenderloin, lean, broiled	4 oz-wt	240.4	0.35	20.6	1.5	good
Cane juice, evaporated	1 oz-wt	111.4	0.16	9.4	1.5	good

World's Healthiest Foods Rating	Rule
excellent	DV>=75%	OR	Density>=7.6	AND	DV>=10%
very good	DV>=50%	OR	Density>=3.4	AND	DV>=5%
good	DV>=25%	OR	Density>=1.5	AND	DV>=2.5%

Public Health Recommendations

What are current public health recommendations for vitamin B2?

Recommended Dietary Allowances (RDAs) for vitamin B2 were set in 1998 by Institute of Medicine at the National Academy of Sciences for all individuals 1 year and older. Adequate Intake (AI) levels were set for infants under 1 year of age. These recommendations are as follows:

• 0-6 months: 300 micrograms
• 6-12 months: 400 micrograms
• 1-3 years: 500 micrograms
• 4-8 years: 600 micrograms
• Males 9-13 years: 900 micrograms
• Males 14 years and older: 1.3 milligrams
• Females 9-13 years: 900 micrograms
• Females 14-18 years: 1.0 milligram
• Females 19 years and older: 1.1 milligrams
• Pregnant females of any age: 1.4 milligrams
• Lactating females of any age: 1.6 milligrams

References

• Belko AZ. Effects of exercise on riboflavin requirements of young women. Am J Clin Nutr 1983;37:509-517 1983.
• Bender DA. Nutritional biochemistry of the vitamins. Cambridge University Press, New York, 1992 1992.
• Beutler E. Nutritional and metabolic aspects of glutathione. Ann Rev Nutr 1989;9:287-302 1989.
• Feinman L, Lieber CS. Nutrition and liver disease. Hosp Med 1990 Apr:150-166 1990.
• Groff JL, Gropper SS, Hunt SM. Advanced Nutrition and Human Metabolism. West Publishing Company, New York, 1995 1995.
• Guerrant NB, O'Hara MB. Vitamin retention in peas and lima beans after blanching, freezing, and processing in tin and in glass, after storage and after cooking. Food Technol 1953;7:473-477 1953.
• Inoue K, Katsura E, Kariyone S. Secondary riboflavin deficiency. Vitamin 1956;10:69 1956.
• Jacques PF, Kalmbach R, Bagley PJ et al. The relationship between riboflavin and plasma total homocysteine in the Framingham Offspring cohort is influenced by folate status and the C677T transition in the methylenetetrahydrofolate reductase. J Nutr 2002 Feb;132(2):283-8 2002.
• McNulty H, McKinley MC, Wilson B et al. Impaired functioning of thermolabile methylenetetrahydrofolate reductase is dependent on riboflavin status: implications for riboflavin requirements. Am J Clin Nutr 2002 Aug;76(2):436-41 2002.
• Merrill AH, Lambeth JD, Edmonson DE, et al. Formation and mode of flavoproteins. Ann Rev Nutr 1981;1:281-317 1981.
• Woodcock EA, Warthesen JJ, Labuza TP. Riboflavin photochemical degradation in pasta measured by high performance liquid chromatography. J Food Sci 1982;47:545-555 1982.

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