Health Benefits of Riboflavin (Vitamin B2)

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Riboflavin (vitamin B2) is a water-soluble vitamin that plays a key role in several important functions of the body. Among other things, it helps metabolizes glucose—the form of sugar that the body uses for energy—and supports the production of healthy red blood cells. Riboflavin also serves as an antioxidant, preventing free radicals from damaging cells and increasing the risk of many aging-related diseases.

Vitamin B2 is found naturally in many different foods, most of which are common in the American diet. Because of this, riboflavin deficiency is infrequently seen in the United States. If it does occur, it is usually a result of severe malnutrition or conditions that impair vitamin absorption.

Health Benefits

Riboflavin, along with all other B vitamins, is important for maintaining optimal nutrition and health. It plays an important role in breaking down nutrients in food—including carbohydrates, proteins, and fats—to produce energy. Without it, we simply could not function.

But riboflavin also considered beneficial in preventing or treating certain medical conditions, including:

It appears to do so by maintaining the metabolic integrity of the body, while minimizing certain byproducts of metabolism, such as homocysteine, that are harmful to cells.

In addition to its role in metabolism and blood cell synthesis, vitamin B2 enables the conversion of vitamin B6 (pyridoxine) to its active coenzyme form and the conversion of tryptophan to niacin. Beyond these normal biochemical functions, there is evidence that vitamin B2 is beneficial to people with specific medical conditions.

Here is what some of the current research says:

Migraines

According to the National Institutes of Health, vitamin B2 is showing a lot of promise as a potential treatment for migraine headaches. Migraines are believed to be caused by changes in the brainstem or Imbalances in brain chemicals.

Riboflavin appears to help overcome these imbalances by improving respiration and energy production within the mitochondria of brain cells.

A 1998 study published in the journal Neurology found that migraine-prone adults who took 400 milligrams (mg) of riboflavin per day had two fewer migraine attacks per month than people who took a placebo.

A subsequent study reported similar results in children.

Cancer

There is also evidence that vitamin B2 be helpful in preventing cancer. The underlying theory is that riboflavin can protect cellular DNA from being damaged by cancer-causing agents like cigarette smoke.

At its heart, cancer is the breakdown of normal cellular function in which cells no longer undergo apoptosis (programmed cell death). If this happens, cells can suddenly reproduce out of control and form tumors.

By stabilizing the structure of cellular DNA, scientists believe that certain cancers, like esophageal cancer and cervical cancer, may be avoided.

Although riboflavin deficiency is known to be an independent risk factor for both of the conditions, it is unclear what, if any, amount of riboflavin would be needed to achieve a tangible reduction in risk.

Corneal Disorders

Cataracts are a common aging-related condition in which the lens of the eye begins to cloud over. People who have riboflavin in their diet appear to have a lower risk of developing cataracts.

A 2014 study from Tufts University suggested that as little as 2 micrograms (μg) of riboflavin can reduce the risk of cataracts in malnourished people.

Riboflavin is also important in the synthesis of niacin, with higher niacin levels corresponding to a reduction in cataract risk.

Riboflavin eye drops are sometimes used with ultraviolet (UV) light therapy to treat a degenerative eye disorder known as keratoconus. When used together, the eye drops and UV radiation reinforces the corneal collagen and stabilizes the lens.

Homocysteinemia

Homocysteine is a common amino acid found in the blood. High levels of homocysteine (referred to as homocysteinemia) are associated with an array of adverse medical conditions, including stroke, dementia, heart attacks.

Riboflavin supplements taken daily can reduce homocysteine levels by up to 40 percent in some people.

According to a study published in Circulation, a 25 percent reduction of homocysteine reduces the risk of coronary artery disease (CAD) by 11 to 16 percent and the risk of stroke by 19 to 24 percent.

Similarly, a reduction in homocysteine may reduce the risk of neurocognitive disorders, including Alzheimer's disease, Parkinson's disease, vascular dementia, and epilepsy, according to research from Northumbria University in England.

When prescribed with anticonvulsant drugs, riboflavin lowers homocysteine levels by 26 percent, ensuring better seizure control.

High homocysteine level can also increase the risk of preeclampsia, a potentially dangerous complication of pregnancy characterized by a sharp rise in blood pressure. Supplementation with riboflavin, folic acid, and vitamin B12 is commonly used to reduce the risk.

Possible Side Effects

If you are not getting enough vitamin B2 in your diet, your doctor may recommend either a daily multivitamin or a B-complex supplement. Always use supplements as prescribed. Most offer between 25 mg and 100 mg of riboflavin, only a small amount of which is absorbed in the intestines. The rest is quickly excreted in urine.

Even small doses of riboflavin can cause your urine to turn a bright yellow color (a side effect known as flavinuria). Doses greater than 100 mg may cause itchiness, diarrhea, stomach cramps, numbness, light sensitivity, blurriness, and a burning sensation on the skin.

While it is impossible to overdose on vitamin B2 (given the high rate of excretion and the low level of absorption) that shouldn't suggest that there will no adverse effects. While rare, induced light sensitivity can increase the risk of eye damage from direct sun exposure.

With that being said, there are no known toxic effects associated with high riboflavin intake, either by oral or injected use.

Dosage and Preparation

The dietary reference intake (RDI) for riboflavin is set by the National Academies of Sciences, Engineering, and Medicine in Washington, D.C. The RDI describes the optimum amount of nutrient a person should get each day based on age and sex.

For riboflavin, the RDIs for American children and adults are:

  • Children ages 1 to 3: 0.5 milligrams (mg)
  • Children ages 4 to 8: 0.6 mg
  • Children ages 9 to 13: 0.9 mg
  • Girls 14 to 18: 1.0 mg
  • Boys 14 to 18: 1.3 mg
  • Women 19 and older: 1.1 mg
  • Men 19 and older: 1.3 mg
  • Pregnant women: 1.4 mg
  • Breastfeeding women: 1.6 mg

Vitamin B2 supplements are available as tablets, capsule, effervescent, and liquids. Vitamin B2 injections delivered intramuscularly (into a muscle) are available from your doctor. There are also prescription eye drops used by ophthalmologists and injectable vitamin B2 formulations for eye injections.

What to Look For

Riboflavin is found in many different foods, most especially dairy and tree nuts. Here is a list of some of the best dietary sources of vitamin B2:

  • Cheddar cheese: 1 ounce = 0.11 mg
  • Salmon: 3 ounces = 0.13 mg
  • Asparagus: 6 spears = 0.15 mg
  • Ground beef: 3 ounces = 0.15 mg
  • Roasted chicken (dark meat): 3 ounces = 0.16 mg
  • Cooked spinach: 1/2 cup = 0.21 mg
  • Skim milk: 1 cup = 0.22 mg
  • Hard-boiled egg: 1 large egg = 0.26 mg
  • Almonds: 1 ounce = 0.29 mg

You can also get vitamin B2 from fortified cereals and grains. A cup of puffed wheat cereal, for example, delivers 0.22 mg of riboflavin, while two slices of whole wheat bread have 0.12 mg.

Cooking doesn't destroy riboflavin, so you won't lose any of the nutritional benefits whether a food is roasted, fried, boiled, or steamed. Since vitamin B breaks down when exposed to light, it is best to store dairy and other riboflavin-rich foods in opaque rather than clear containers.

Riboflavin supplements can be found at almost any drugstore, grocery store, or health food store. They can also be purchased online in tablet, capsule, and liquid formulations.

When shopping for a vitamin B2 supplement, always buy a brand tested and approved by a certifying body like the U.S. Pharmacopeia (USP), NSF International, or ConsumerLab to ensure the highest quality and safety.

Other Questions

Although vitamin B2 deficiency is uncommon in the United States, there are certain conditions that can increase a person's risk:

  • Alcohol abuse: People who are alcoholic are unlikely to get ample vitamin B2 in their diets and are less able to absorb what vitamins that do ingest.
  • Anorexia: Because calories are so dramatically reduced, people with anorexia are less able to attain adequate nutrition in general.
  • Lactose intolerance: Given that dairy products are a primary source of riboflavin, it's not surprising that people who don't drink milk or eat dairy are commonly deficient.
  • Birth control pills: Birth control pills interfere with the absorption of vitamin B2 and can also cause the depletion of vitamin B6, vitamin B12, folic acid, vitamin C, magnesium, and zinc as well.
  • Hypothyroidism and adrenal insufficiency: Both low thyroid function (hypothyroidism) and low adrenal function (adrenal insufficiency) impair the conversion of riboflavin to forms the body can use.
  • Overtraining: Athletes need more nutrition than other people and will often fall short of their dietary needs if their nutritional intake isn't increased. This is especially true for athletes who overtrain or are vegetarian.

    Symptoms of Deficiency

    Riboflavin deficiency doesn't usually occur on its own. More often than not, there will be a depletion of all key B vitamins, each of which causes similar symptoms, including

    • Sore throat
    • Fatigue and weakness
    • Cracks or sores on the lips (cheilosis)
    • Cracked corners of the mouth (angular stomatitis)
    • Inflammation of the tongue ("magenta tongue")
    • Scaly, red patches of (seborrheic dermatitis)
    • Swollen blood vessels in the eye
    • Hair loss (alopecia)
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