Riboflavin (vitamin B2)


The Birds and the B’s: It’s time to have the Talk*

*This is the second of eight articles in our series on B vitamins

The B-complex vitamins belong to the group of vitamins known as the water soluble vitamins. There are technically 8 B-complex vitamins. These include, vitamin B1 (thiamine), vitamin B2 (riboflavin), vitamin B3 (Niacin), vitamin B5 (pantothenic acid), vitamin B6 (pyridoxine), Biotin, vitamin B12, and Choline (the unofficial B vitamin).  

The specific function of each of the individual B-complex vitamins varies, yet they all play an important part in energy production. More specifically, all of the B-complex vitamins perform as cofactors for numerous major enzymes in the human body.  Without the presence of these vitamins, many of the enzymes necessary for the metabolism of fat, protein, and carbohydrate would not function properly.

Riboflavin (vitamin B2)

Riboflavin, which is also known as vitamin B2, is one of the water soluble vitamins. The water soluble vitamins include all of the B vitamins and vitamin C. The fat soluble vitamins include vitamins A, D, E, and K. Unlike the fat-soluble vitamins, the water soluble vitamins are not stored in the body and must be replenished daily.

The water soluble vitamins are also easily destroyed during cooking, especially when food is cooked in water, and during storage. However, Riboflavin is an exception because it is destroyed by being exposed to light and irradiation, but not by cooking.

Why do we need Riboflavin?

Riboflavin is very important for energy production as it functions in two very important coenzymes called flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD). These flavin coenzymes are manufactured from riboflavin and thus will not function without it.

Riboflavin deficiency

A deficiency will develop after several months of deprivation of Riboflavin. However, riboflavin deficiency does not usually occur in isolation, as it is typically accompanied by other nutrient deficiencies. Riboflavin deficiency is different than many other types of vitamin deficiencies because there is not a specific disease association with it. The principal result of a riboflavin deficiency is that the progression of growth is terminated. This is because energy production is decreased when adequate riboflavin levels are not present. 

 Symptoms of a riboflavin deficiency tend to show up first as cracking of the lips and corners of the mouth, visual disturbances, cataract formation, and burning and itching of mucous membranes such as the eyes, lips, mouth, and tongue.Riboflavin deficiency is uncommon among most groups in the United States. However, people who suffer from congenital heart disease, cancer, or excessive alcohol intake may be at greater risk for riboflavin deficiency as a result of limited dietary intake. Women who take oral contraceptives are at a greater risk of developing a riboflavin deficiency than women who do not take these kinds of drugs.

History of Riboflavin

Riboflavin (vitamin B2) was recognized in 1879 because of the fluorescent yellow-green pigment that it gave to milk. In 1933 it was recognized as belonging to the B-complex group of vitamins.

Vegan Raw Food Sources of Riboflavin

Brewer’s yeast (this food is not raw, but is used by some to add a cheesy flavor to food)


Wild Rice





Split peas


Pine nuts


Sunflower seeds

Beet greens

Mustard greens



Riboflavin is destroyed by irradiation

Riboflavin is damaged by exposure to light and irradiation. So, it is Important to choose foods that have not been irradiated. The FDA requires the labeling of all foods that have been irradiated. Organic food is less likely to have been irradiated.

Foods that have been irradiated must be labeled with this symbol which is called the "Radura":

Riboflavin toxicity

There is no known potential for toxicity from taking too much riboflavin. However, taking large dosages are not beneficial.

Written by: Angela Coate-Hermes

Copyright 2009 RawPeople.com All rights reserved

These statements have not been evaluated by the food and drug administration.  The preceding information and/or products are for educational purposes only and are not meant to diagnose, prescribe, or treat illness. Please consult your doctor before making any changes or before starting ANY exercise or nutritional supplement program or before using this information or any product during pregnancy or if you have a serious medical condition.  


Marz, Russell. Medical Nutrition from Marz. Portland, OR: Oni-press, 1999.

Murray, Michael and Joseph Pizzorno. The Encyclopedia of healing Foods. New York: Atria Books, 2005.