Vitamin B2 is also called riboflavin. Throughout this article, the two terms are used interchangeably. It is one of the eight vitamins that make up the vitamin B complex group. These vitamins are chemically different but are usually found in the same foods. The vitamin is an important part of special enzymes that are needed for the production of energy from the carbohydrate foods we eat.


Other metabolic functions of riboflavin include:

  • Fat metabolism
  • Supports various cellular functions
  • Helps in the conversion of an amino acid called tryptophan into vitamin B3 (niacin)
  • Helps in the breakdown of medicines
  • Helps to breakdown steroids
  • Helps in the body’s management of homocysteine. This is an amino acid that if not controlled to a healthy level, will cause damage to the inner lining of the blood vessels which can in turn develop fatty plaque formations and narrowing (atherosclerosis) and an increased risk of heart problems.


The main sources of vitamin B2 are plant or animal-based. Plant-based sources include:

  • Mushrooms
  • Almonds
  • Sesame seeds
  • Spinach
  • Whole-meal bread
  • Unpeeled apples
  • Zucchini
  • Spirulina
  • Brown rice
  • Peas
  • Tomatoes
  • Kidney bean sprouts

Some processed foods are also fortified with the vitamin. Another convenient way of getting enough riboflavin is through nutritional supplements. This may be a supplement containing only riboflavin or as a combination supplement containing other vitamins in the B complex with or without some minerals. Beneficial bacteria inhabiting the large intestine are capable of synthesizing riboflavin which is subsequently absorbed in the same large gut. A vegetable diet supports this process better than a non-vegetable one. Cooking can lead to almost all the riboflavin in a vegetable to be lost through cooking water. Steaming and microwaving are cooking options that may reduce this problem.


These are very rare in the U.S and other developed countries. When deficiency occurs, the symptoms may include:

  • Generalized tiredness
  • Poor growth
  • Skin lesions
  • Hair loss
  • Throat problems
  • Itchy and red eyes
  • Symptoms of liver functions disorders
  • Neurological symptoms
  • Cataracts
  • Edema
  • Corners of the mouth lesions and cracking skin
  • Swollen tongue
  • Magenta tongue coloration
  • Light sensitivity
  • Anemia where the deficiency is chronic


  1. Athletes
    The American Journal of Clinical Nutrition of August 2000 published a study where the authors concluded that there is an increased utilization of riboflavin when a person is engaging in physical exercises. Athletes who do not take this into account and supplement the vitamin accordingly, may end-up having relative riboflavin deficiency. Since vegan athletes do not take animal sourced vitamin B2, they are at a higher risk of exercise—induced riboflavin deficiency. The American College of Sports Medicine has clear guidelines for athletes in this position and any other who for various reasons eliminate certain groups of food from their dietary needs. A report in the Medicine and Science in Sports and Exercise of March 2009 has some details about this. As a vegan athlete, a good place to start is by talking to a qualified sports dietician who will guide you on how to prevent deficiency problems.
  2. Breastfeeding or pregnant mothers
    Women in poor resource countries are more likely to develop this deficiency because they may not be getting enough riboflavin from their diet. In the U.S, vegetarians and vegans who are not well-informed on how to practice this lifestyle are also at a higher risk of the vitamin’s deficiency. For pregnant mothers, the deficiency is thought to increase the risk of developing preeclampsia.
  3. People with the rare genetic disorder called infantile Brown-Vialetto Laere syndrome
    People with this disorder have problem of taking up riboflavin from their intestines. Only supplementation with the vitamin can save them from respiratory complications associated with the disorder.


  1. It supports the functions of the mitochondria
    Dysfunction of the mitochondria has been associated with migraine headaches. These are types of headaches that affect some people. They are debilitating when they strike and grossly affect a person’s quality of life. Studies show that riboflavin supplements reduce the severity and the frequency of the migraines. Research is ongoing to find out whether these supplements can be used to treat and prevent the attacks.
  2. Lowers the risk of cancer development
    Scientists think that riboflavin reduces the risk of DNA damage. Such damage forms the basis of cancer development. Different studies have shown a lowered risk of cancers like lung cancer and cancer of the colon with the use of riboflavin in the diet and in supplements.


These include:

  • Supports healthy pregnancy
  • Helps very low birthweight infants to develop normally
  • Can play an important adjunct role in the management of psychiatry patients. One study found that the vitamin to be a good marker of the thyroxine status in psychiatry female patients.
  • Reduces exercise induced neuro-muscular irritability


Vitamin B2 appears to be safe even in high doses. However, it is prudent to follow the recommended dosages suggested by the manufacturer of the supplements you are using or as advised by your doctor. Do not use riboflavin for treating particular health conditions without your health care provider’s guidance.


There is no data available about any adverse interactions with other supplements or medications. All the same, if you are on any medications consult your doctor before using riboflavin supplements.


Institute of Medicine (US) Standing Committee on the Scientific Evaluation of Dietary Reference Intakes and its Panel on Folate, Other B Vitamins, and Choline. Dietary Reference Intakes for Thiamin, Riboflavin, Niacin, Vitamin B6, Folate, Vitamin B12, Pantothenic Acid, Biotin, and Choline. Washington (DC): National Academies Press (US); 1998. 5, Riboflavin. Available from: Soares MJ, Satyanarayana K, Bamji MS, Jacob CM, Ramana YV, Rao SS. The effect of exercise on the riboflavin status of adult men. Br J Nutr 1993;69:541–51 Bruijn J, Duivenvoorden H, Passchier J, Locher H, Dijkstra N, Arts WF. Medium-dose riboflavin as a prophylactic agent in children with migraine: a preliminary placebo-controlled, randomised, double-blind, cross-over trial. Cephalalgia 2010;30:1426-34 Zschabitz S, Cheng TY, Neuhouser ML, Zheng Y, Ray RM, Miller JW, et al. B vitamin intakes and incidence of colorectal cancer: results from the Women’s Health Initiative Observational Study cohort. Am J Clin Nutr 2013;97:332-43

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