Riboflavin, also known as vitamin B2, is a water-soluble vitamin present in most animal and plant tissues. It gets its name from its color: “flavus” is a Latin word meaning “yellow.” If you take a supplement high in riboflavin, your urine becomes bright yellow.

Riboflavin is one of the essential B vitamins, a family of compounds that help support adrenal function, calm and maintain a healthy nervous system, and facilitate key metabolic processes, including the conversion of food into energy.

The highest concentrations of riboflavin in your body occur in:

• Your liver, which serves as a central metabolic processing point
• Your kidneys, which eliminates unneeded molecules
• Your heart, which depends on riboflavin’s assistance for aerobic (oxygen-based) energy production

Riboflavin has many functions, including:

1. Helping your body produce energy
2. Assisting with normal cell function and growth
3. Helping folate and vitamin B6 undergo the chemical changes that make them available for your body
4. Acting as an antioxidant, potentially helping to prevent cancer and slow cholesterol buildup by controlling the proliferation of harmful free radicals

Like thiamine, riboflavin plays a critical role in your body’s energy production. In your 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 your body, and particularly in locations where oxygen-based energy production is constantly needed such as your heart and skeletal muscle. 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 are associated with increased risk of cardiovascular disease.

Your 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 damage many structures in your 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 riboflavin allows this recycling to take place.

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

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 riboflavin.

There are no known toxic side-effects from supplemental intake of riboflavin. In 1998, the Institute of Medicine at the National Academy of Sciences decided not to set a Tolerable Upper Limit (UL) for riboflavin.

Heat and air do very little damage to riboflavin, but light is a primary damaging factor for this vitamin. 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%.

Although not as dramatic as its impact on thiamine, alcoholism decreases the availability of riboflavin in your body. Alcoholics may require 5-10 times the ordinary amount of riboflavin. Heavy exercise also increases your need for riboflavin by up to 10-15 times, especially in women training for athletic events.

Almost 70% of the riboflavin in whole wheat flour is removed during processing. For this reason, beginning in the 1940’s, the U.S. government began to require the “enrichment” of processed wheat flour with riboflavin. Wheat flour remains the primary source of riboflavin in the U.S. diet; however, people who avoid wheat breads, grains, and pastas may be at risk for riboflavin deficiency.

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

Riboflavin may play a role in the prevention or treatment of anemia, carpal tunnel syndrome, cataracts, migraine, rosacea, and vaginitis.

Excellent sources of riboflavin include nutritional (brewer’s) yeast, nori, crimini mushrooms, and spinach. Very good sources include summer squash, asparagus, chard, shiitake mushrooms, green beans, mustard greens, sunflower seeds, broccoli, collard greens, and turnip greens. Among whole grains, the best source is buckwheat.

Sources of Riboflavin 

Food	Serving	Calories	Amount	DV
Nutritional Yeast	2 Tablespoons	45	9.7	570%
Nori	100 grams	188	2.33	194%
Soybeans	1 cup cooked	297.6	0.49	28.8%
Crimini Mushrooms	1 cup	19.1	0.43	25.3%
Spinach	1 cup cooked	41.4	0.42	24.7%
Tempeh	4 oz-wt cooked	222.3	0.4	23.5%
Almonds	0.25 cup	206	0.3	17.6%
Green Peas	1 cup raw	115.7	0.21	12.4%
Collard Greens	1 cup cooked	49.4	0.2	11.8%
Asparagus	1 cup raw	26.8	0.19	11.2%
Shiitake Mushrooms	87 g	29.6	0.19	11.2%
Summer Squash	1 cup raw	18.1	0.16	9.4%
Chard	1 cup cooked	35	0.15	8.8%
Wild Rice	1 cup cooked	166	0.14	8.2%
Winter Squash	1 cup baked	75.8	0.14	8.2%
Sunflower Seeds	1/4 cup kernels, raw	205	0.12	7.3%
Broccoli	1 cup raw	30.9	0.11	6.5%
Turnip Greens	1 cup cooked	28.8	0.1	5.9%
Green Beans	1 cup raw	31	0.1	5.9%
Mustard Greens	1 cup cooked	21	0.09	5.3%
Kale	1 cup cooked	36.4	0.09	5.3%
Brussels Sprouts	1 cup raw	37.8	0.08	4.7%
Bell Peppers	1 cup raw	28.5	0.08	4.7%
Carrots	1 cup	50	0.07	4.1%
Strawberries	2 cups sliced	106	0.07	4.1%
Buckwheat groats, roasted	1 cup cooked	155	0.07	4.1%
Celery	1 cup	16.2	0.06	3.5%
Cauliflower	1 cup raw	26.8	0.06	3.5%
Romaine Lettuce	2 cups	16	0.06	3.5%

Recommended Dietary Allowances (RDAs) for riboflavin 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