Vitamin B1 (Thiamine/Thianin)

Vitamin B2 (riboflavin) – The vitamin deficiency to watch out for if you are a vegan or a vegetarian athlete.

Riboflavin (vitamin B2) is an essential nutrient that must be acquired from the diet. The riboflavin content of foods can be affected in several ways. Riboflavin is a yellow fluorescent molecule that can be inactivated by exposure to UV/visible light or an alkali environment. For this reason, milk which is rich in vitamin B2, is generally not stored in clear glass bottles. Riboflavin is a water-soluble vitamin. This means it can be lost when food is boiled. The vitamin will move into the water used to boil the food which is then discarded along with riboflavin. A better option would be to steam/bake food, preventing loss of this vitamin.

Vegans are at a greater risk of developing this deficiency because they do not consume any animal products. When we decide to become vegan, we must be careful to have a balanced diet that includes all vitamins and minerals required for normal body function. To meet the daily riboflavin needs of a vegan it can be quite complex and require the consumption of a variety of foods. For example to meet a daily requirements of 1.1 -1.3mg of riboflavin from wholefoods, you could have 2/3 cup of quinoa (0.2mg), 1 cup of crimini mushrooms (0.35mg), 1 cup of spinach (0.4mg) and 1 cup of beet greens (0.4mg). Vegetarian athletes are also at a higher risk of developing riboflavin deficiency because when they exercise it increases their need for this nutrient. These individuals need to make sure they have eggs and dairy products to meet their needs or the foods described above for vegans.

Deficiencies of riboflavin are also more common in individuals with endocrine abnormalities such as aldosterone and thyroid hormone insufficiency and in those that suffer from alcohol abuse because it may interfere with how riboflavin is used. The Australian Health Survey carried out in 2011-12 found that 20% of individuals aged 71 and over had inadequate riboflavin intake making the elderly a high-risk group for B2 deficiency. In addition, approximately 8% of individuals between the ages of 51 to 70 also had inadequate riboflavin intake.


  • Critical in the normal functioning of our in-built antioxidant system.
  • Involved in the production of other vitamins such as, pyridoxine (B6), niacin (B3), and folate (B9).
  • Involved in the generation of energy.


A small amount of riboflavin is stored in the liver, heart and kidneys.


Riboflavin is absorbed in the small intestine. Most the of the excess riboflavin consumed will not be absorbed. Instead it will be excreted within faeces. Excess B2 within the body will be excreted by the kidneys dissolved in the urine.   

Absorption can be decreased by psyllium gum and alcohol. Psyllium gum decreases the rate of riboflavin intestinal absorption and alcohol can interfere with digestion resulting also in decreased absorption.

Sources: Meat and dairy products have the highest content. Other foods that are good sources of B2 are eggs, organ meat (kidney and liver), green leafy vegetables, nuts and legumes.

Dietary requirements:

The recommended dietary allowance for riboflavin is 1.3mg for men

and 1.1mg for women.


Deficiency signs and symptoms:

  • swollen cracked lips (cheilosis),
  • fissuring at the corner of the mouth (angular stomatitis),
  • inflammation of the tongue and oral cavity,
  • seborrheic dermatitis (an inflammatory skin condition),
  • degeneration of the liver and nervous system (neuropathy),
  • anaemia (There is evidence to suggest that riboflavin deficiency can reduce iron absorption),
  • oedema of the mouth and throat,
  • hair loss and,
  • itchy and red eyes.

Most of these signs and symptoms can also be found in other vitamin deficiencies.


The tolerable upper intake has not been established.

Medicinal uses:

There is some evidence supporting riboflavin supplementation in reducing the frequency and duration of migraine attacks with no serious side effects.

All the information contain herein is for informational purposes only. The author expressly disclaim responsibility for any adverse effects that may result from the use or application of any material contained within this article.

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