Vitamin B2 is also known as riboflavin.
It is one of the group of B vitamins.
See also an overview of the main vitamins.
Active Forms of Vitamin B2:
There are two active forms of vitamin B2:
- Flavin mononucleotide (FMN), and
- Flavin adenine dinucleotide (FAD)
Functions of Vitamin B2:
The main functions of vitamin B2 are:
- Helps with conversion of foods into energy via working with enzymes to metabolise fats, proteins and carbohydrates. Specifically, FAD and FMN are coenzymes for several oxidases and hydrogenases (this information is useful to people who also need to understand the chemical reactions within the body, i.e. details about metabolism)
- Promotion of healthy skin, hair and nails - hence the skin and hair problems listed as possible consequences of deficiency of vitamin B2.
- Supports healthy eyesight by protecting against cataracts and helping to ease eye strain.
- Production of acetylcholine, noradrenalin, serotonin (neurotransmitters essential to the brain), as well as synthesis of arachidonic acid, linoleic acid and linolenic acid (essential fatty acids)
- Antioxidant functions, e.g. boosting immune system via helping with the formation of antibodies
- Helps to convert vitamin B6 into its active forms
- Supporting female functions - often included in supplements taken to alleviate symptoms of premenstrual syndrome and/or menopausal effects
- Aids mental functioning e.g. in tasks that require concentration and alertness
A non-harmful side-effect of excessive intake of vitamin B2 is bright yellow-green colouration of urine.
Sources of Vitamin B2:
There are many different types of foods that include some vitamin B2.
Examples of sources of vitamin B2 follow below:
- Yeast extract
- Whole grains and pulses
- Breakfast cereals fortified with vitamin B2 (which is often listed as riboflavin)
- Green leafy vegetables e.g. cabbage, kale, etc.
Vitamin B2 dissolves in cooking liquids but is not destroyed by heat. However, it is destroyed by ultraviolet light incl. e.g. sunlight. For this reason foods that are rich in riboflavin should be stored in dark places, e.g. cupboards, to retain their nutritional value. Where relevant this advice is often printed on food packaging.
Problems due to insufficient or too much Vitamin B2:
Signs of Deficiencies of Vitamin B2
Signs of Excessive Intake of Vitamin B2
Vitamin B2 deficiency is unusual in the populations of most rich western countries. It is most likely to apply to elderly or alcoholic people.
Deficiency can lead to the following symptoms:
- Ariboflavinosis - sore throat / mouth (incl. skin probs mentioned below), moist scaly skin and decreased red blood count i.e. number of red blood cells.
- Skin problems around the mouth, e.g. inflammation at the sides of the mouth (angular stomatitis), fissures at the corners of the mouth (cheilosis), cracked lips, mouth ulcers inflamed tongue (glossitis).
- Oversensitivity to light / itchy eyes
- Hair loss / scaly scalp
Vitamin B2 is not generally considered toxic if consumed in excessive quantities. However, other components in foods that include riboflavin may lead to adverse symptoms if consumed in excessive amounts so a balanced diet is important.
People prone to cataracts are particularly advised not to take excessive does of riboflavin.
See also what is a balanced diet? .