Understanding Vitamin B2 – Riboflavin


Riboflavin was discovered in milk in 1879. Nobody realized it was a vitamin, mostly because back then nobody knew what a vitamin was. The discoverers just saw it as an interesting yellow-green pigment in the milk. The name riboflavin is a combination of two words: ribose, a type of sugar found in milk, and flavin, from the Latin word flavus, which means yellow.

Our cells need riboflavin to make energy, so we need to be sure we’re getting enough of this vital member of the B family.

Riboflavin does lots of other good things for us as well, mostly by working with the other B’s to keep our body’s systems, like the immune system, running smoothly. Riboflavin works especially closely with niacin and pyridoxine – in fact, without riboflavin, these two B siblings can’t do their main jobs at all.

The Role It Plays

Riboflavin gives us energy at the most basic level – inside our cells. We need it to make two of the enzymes that are absolutely vital for releasing energy from the fats, carbohydrates, and proteins we eat. To make a complicated story short, riboflavin keeps us alive.

Aside from that little chore, riboflavin also does a bunch of other little things in our body, either by itself or along with the other members of the B team (especially pyridoxine and niacin). Riboflavin regulates cell growth and reproduction and helps us make healthy red blood cells. It helps our immune system by keeping the mucous membranes that line the respiratory and digestive systems in good shape. If invading germs still sneak in, riboflavin helps make antibodies for fighting them off. Our eyes, nerves, skin, nails, and hair all need riboflavin to stay healthy. It might even help with memory – older people with high levels of riboflavin do better in memory tests.

By itself, riboflavin’s most important role is in cell respiration. Just as you breathe in oxygen and exhale the waste product carbon dioxide from your lungs, so does each and every cell in your body. Molecules of oxygen and food enter a cell and are carried into the mitochondria, tiny structures within the cell that act like little power plants. Enzymes in the mitochondria release the energy from the oxygen and food. Two of those enzymes must work together as part of the process. These enzymes contain riboflavin and if there’s not enough riboflavin then there’s not enough enzymes and therefore not enough energy.

The faster you use up energy, the more riboflavin you need. Most people have enough to meet their energy needs, but most people don’t really exercise very much. Anyone who exercises even moderately on a regular basis probably needs some extra riboflavin beyond the RDA. Women seem to need the riboflavin boost more than men.

Types Of Riboflavin

Riboflavin like all the B vitamins is water soluble. But riboflavin is an exception to the water-soluble rule. You store small amounts of it in your kidneys and liver. Riboflavin supplements come as tablets or capsules. They usually contain 50 mg or 100 mg – either amount is well over the RDA. You absorb about 15% of the riboflavin from supplements, especially if you take them on an empty stomach. To get the most from your riboflavin, take the supplements with meals.




1-3 years

0.8 mg

4-6 years

1.1 mg

7-10 years

1.2 mg

Men 11-14 years

1.5 mg

Men 15-18 years

1.8 mg

Men 19-50 years

1.7 mg

Men 50+

1.4 mg

Women 11-50 years

1.3 mg

Women 50+

1.2 mg

Pregnant Women

1.6 mg

Nursing Women

1.8 mg


Safe Dosage

The RDA for riboflavin is based on your calorie intake – the more you eat, the more you need. Important as riboflavin is, you really don’t need a lot of it for good health – just under 2 mg a day is enough.

You can’t really overdose on riboflavin, because even very large doses (over 1,000 mg) are safe. There is one side effect from large doses though: Your urine will turn a bright fluorescent yellow. It may be a little startling, but it’s harmless.

Make It Work Better

Most people get all the riboflavin they need from their food. Riboflavin is added to so many common foods, like bread and pasta, that even someone with lousy eating habits will probably get enough.

Most daily multivitamins contain the full RDA for riboflavin. If you think you need more, consider taking a complete B supplement. You need all the B vitamins for riboflavin to work well – and vice versa.

Good Sources

Riboflavin is found naturally in many foods, especially meat, milk products, and dark-green leafy vegetables. It’s also added to flour, bread, and most breakfast cereals.

Good choices include Broccoli, chick peas, cottage cheese, kidney beans, mushrooms, peas, spinach, sweet potato (with skin on), wheat germ and yogurt.



If you’re s strict vegetarian or if you exercise a lot (or both), you might need extra riboflavin.

Because small amounts of riboflavin are stored in the kidney and liver, a deficiency can take as long as three or four months to show up.

True riboflavin deficiency is rare. Most people get plenty of riboflavin in their food. When deficiency symptoms do occur, they’re usually related to a shortage of all the B’s. You need riboflavin to help niacin and pyridoxine work right. In fact, if you’re short on riboflavin you might have deficiency symptoms for one of the other vitamins. Usually, though, riboflavin deficiency shows up as problems with the mucous membranes, skin, eyes, and blood. An early and clear sign is sores and cracks on the lips, especially at the corners. Scaly skin, reddened eyes, and anemia are other deficiency signs.

Some people are at risk for riboflavin deficiency:

Athletes. You need extra riboflavin if you exercise a lot.

Diabetics, You may be excreting a lot of your riboflavin in your urine. Talk to your doctor about vitamin supplements before you use them.

Pregnant and Nursing women. You’re passing a lot of your riboflavin on to your baby, so you need about 0.5 mg more a day.

Elderly people. About a third of all elderly people have a riboflavin deficiency, mostly from poor absorption or poor diet.

People who can’t digest milk. Milk and dairy products such as cottage cheese are important sources of riboflavin. If you can’t digest these foods, you might not be getting enough riboflavin.

People who take tricyclic antidepressants. Drugs such as amitriptyline (Elavil) can interfere with riboflavin. Talk to your doctor about supplements before you take them.

Did you find this information helpful. Send a comment and let me know.


One Response to “Understanding Vitamin B2 – Riboflavin”
  1. Deborah says:

    Very helpful, thank you.

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