The Benefits of Riboflavin

How to Get Enough of This B Vitamin in Your Daily Diet

close up on a variety of dry beans
Dry beans are rich in riboflavin. Sanja Gjenero

Riboflavin (vitamin B2) is a water-soluble nutrient that plays a key role in several important functions in the body. For one thing, it's important for metabolizing glucose—the form of sugar that's converted from carbohydrates into energy. Riboflavin supports the production of healthy red blood cells as well.

Riboflavin also serves as an antioxidant to help prevent free-radical damage to cells. This damage can come from smoking or exposure to smoke or other pollutants, and also happens as a result of normal metabolism.

Vitamin B2 occurs naturally in many different types of foods, most of which are common in the American diet, so it's rare for someone to get too little vitamin B2 or to need to take supplements of it. This doesn't mean riboflavin deficiency (medically known as ariboflavinosis) never occurs, however. Besides simply not getting enough B2 in the diet, there are certain conditions that can cause a deficiency. The most common sources of B2 in developed countries are milk and dairy products but it's plentiful in lean meats, eggs, green leafy vegetables, nuts, and legumes as well.

Since it's abundant in so many common foods, it's rare for someone Here's a look at what riboflavin does in the body, how much of the vitamin is needed for health, what can happen if a deficiency occurs, and the best sources.

Recommended Amounts of Riboflavin

The dietary reference intakes (RDIs) for riboflavin that follow were set by the Health and Medicine Division of the National Academies of Sciences, Engineering, and Medicine. They refer to the optimum amount of B2 a healthy person should get each day and are based on age and sex.

Children ages 1 to 3: 0.5 milligrams
Children ages 4 to 8: 0.6 milligrams
Children ages 9 to 13: 0.9 milligrams
Girls 14 to 18: 1.0 milligrams

Boys 14 to 18: 1.3 milligrams

Women 19 and older: 1.1 milligrams

Men 19 and older: 1.3 milligrams
Pregnant women: 1.4 milligrams
Women who are breastfeeding: 1.6 milligrams

Riboflavin Deficiency

Although ariboflavinosis (vitamin B2 deficiency) is uncommon, it usually occurs along with deficiencies of other water-soluble vitamins. The symptoms include:

  • Sore throat
  • Redness and swelling of the lining of the mouth and throat
  • Cracks or sores on the lips (cheilosis)
  • Cracked corners of the mouth (angular stomatitis)
  • Inflammation of the tongue (magenta tongue)
  • Seborrheic dermatitis, a condition in which skin becomes moist and scaly
  • Blood vessels in the cornea of the eye
  • Decreased red blood cell count

If riboflavin deficiency becomes severe it can affect the conversion of vitamin B6 to its coenzyme form as well as the conversion of tryptophan to niacin. It also has been linked to an increased risk of preeclampsia and eclampsia during pregnancy—conditions that are characterized by high blood pressure, protein in the urine of the mom-to-be, and swelling (edema).

Most healthy people are unlikely to develop a riboflavin deficiency but there are certain ones who are at an increased risk. They include:

  • People who are dependent on alcohol. Folks who are addicted to drinking are likely to get too little B2 in their diets and their bodies may not adequately absorb or use what they do get.
  • People with anorexia. Because they cut calories so dramatically, they don't eat enough to take in adequate nutrients in general.
  • People who are lactose intolerant. Given that dairy products are a primary source of riboflavin, it's not surprising that folks who don't drink milk or eat milk-based foods may not get enough of the vitamin in their daily diet.
  • People with hypothyroidism and adrenal insufficiency. These conditions impair the conversion of riboflavin to forms that the body can use.
  • Athletes. Highly active people may need to take in more riboflavin than folks who are more sedentary but fail to increase their intake. This may be especially true for highly active people who also are vegetarian.
  • People being treated with light therapy. Riboflavin breaks down when exposed to ultraviolet light, which is used to treat skin conditions such as psoriasis as well as jaundice in infants. If exposure to UV rays is lengthy, it may contribute to a B2 deficiency.

    Vitamin B2 Sources and Supplements

    Riboflavin is found in many different foods, so unless you're an extremely picky eater or have a condition that puts you at risk of a riboflavin deficiency you're unlikely to develop one. Here's a look at some of the best natural sources of dietary B2.

    • 1 ounce Cheddar cheese = 0.11 milligrams
    • 3 ounces cooked salmon = 0.13 milligrams
    • 6 spears cooked asparagus = 0.15 milligrams
    • 3 ounces cooked ground beef = 0.15 milligrams
    • 3 ounces roasted chicken (dark meat) = 0.16 milligrams
    • 1/2 cup cooked spinach = 0.21 milligrams
    • 1 cup skim milk = 0.22 milligrams
    • 1 large hard-boiled egg = 0.26 milligrams
    • 1 ounce almonds = 0.29 milligrams

    If you don't eat dairy, are a vegetarian, hate vegetables, or all three, you can get vitamin B2 from fortified cereals and grains to which certain nutrients (such as thiamin, niacin, and iron) have been added. For example, a cup of puffed wheat cereal has 0.22 milligrams of riboflavin, while two slices of whole-wheat bread have 0.12 milligrams.

    As noted above, vitamin B2 breaks down if it's exposed to light, so when you store foods that are rich in riboflavin you should put them in opaque rather than clear containers. This is why milk is sold in opaque containers. However, cooking doesn't destroy riboflavin, so you won't lose any of the vitamins when you roast chicken legs, say, or steam spinach.

    If you think you may not be getting enough vitamin B2 in your diet, see a nutritionist who can look at your overall diet to confirm that this really is the case. If it is, she may suggest you take a daily supplement and prescribe how much. Riboflavin supplements don't seem to cause any serious side effects, although even small doses may turn your urine bright yellow—a side effect known as flavinuria.

    However, more than 10 milligrams of supplemental riboflavin per day have been associated with itching, numbness, a burning sensation on the skin, and sensitivity to light. There also has been some concern that high doses of vitamin B2 may bring about a risk of eye damage from the sun. And taking any one B vitamin as a supplement for a long period can result in an imbalance of other important B vitamins. For this reason, you may want to take a B-complex vitamin, which includes all the B vitamins. Again, a nutritionist can evaluate your overall diet and nutrient intake to determine if you would benefit from taking any supplements.

    Riboflavin for Disease Prevention and Treatment

    Riboflavin clearly is important for maintaining nutritional balance and overall health, but the vitamin also is being looked at as being beneficial for preventing and treating certain diseases. In particular, according to the National Institutes of Health (NIH), B2 is showing a lot of promise as a potential treatment for migraine headaches. A 1998 study published in the journal Neurology found that migraine-prone adults who took 400 milligrams of riboflavin per day had two fewer migraine attacks per month than people who took a placebo. A subsequent study found similar promising results in children.

    There's some evidence that vitamin B6 also may be helpful in preventing cancer. The theory is that the nutrient may help protect DNA in the cells from being damaged by carcinogens (cancer-causing agents such as cigarette smoke). Scientific findings have been promising, but mixed, so it's much too early to view riboflavin as being able to lower the risk of cancer, but the research is ongoing.

    Meanwhile, the most important thing to remember about riboflavin is that if you eat a variety of foods each day and you don't have a disease or condition that puts you at risk of a vitamin deficiency, you shouldn't have to worry about tracking your B6 intake. Your healthy and balanced diet will have you covered.

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