Vitamin B2 - Riboflavin Benefits
Vitamin B2, also known as riboflavin, is a water-soluble B-vitamin that belongs to the group of micronutrients and vitamins. Additionally, when exposed to ultraviolet light, vitamin B2 emits a yellow fluorescence 1. Due to its yellow color, riboflavin is also used as a food coloring. It is labeled as a food additive with the E number E101 on corresponding products.
Riboflavin is very light-sensitive. Vitamin B2 is rapidly lost in the corresponding food due to light exposure (sunlight). Additionally, a large portion of riboflavin is degraded during food storage 2. Therefore, foods containing vitamin B2 should be stored in a dark place and for a short duration. It is advisable to consume foods rich in vitamin B2 quickly.
In the body, vitamin B2 is stored only in very small amounts in the liver, heart, and kidneys 3.
Functions and Benefits
The B-vitamin riboflavin is necessary for energy-generating processes, i.e., the conversion of food into energy in the body 4. Thus, vitamin B2, as part of the respiratory chain, supports carbohydrate metabolism and fat burning.
Vitamin B2 is essential for the formation of two coenzymes (required for enzyme function). Coenzymes formed from riboflavin are referred to as flavocoenzymes. Flavin adenine dinucleotide (FAD) and flavin mononucleotide (FMN; also known as riboflavin-5'-phosphate) are the key flavocoenzymes into which vitamin B2 is incorporated. Enzymes that utilize flavocoenzymes are called flavoproteins.
The coenzymes FAD and FMN are essential for energy production from fats (β-oxidation of fatty acids; degradation of fatty acids), carbohydrates (glucose), alcohol (glycerin), and proteins (including all heme proteins) 5 6. They function as catalysts for the redox reactions 7.
Vitamin B2, in the form of FMN, is involved in the conversion of vitamin B6 into its bioactive form (pyridoxal-5-phosphate; functional coenzyme) 8.
In the form of FAD, B2 is required for the conversion of the amino acid tryptophan into two coenzymes that contain niacin (Vitamin B3) 9.
In addition, they also play a role in the metabolism of vitamin D and vitamin K 10. Nucleotides also perform other important functions in amino acid metabolism, the production of steroid hormones, and electron transport in mitochondria 11. From a chemical perspective, nucleotides are involved in redox reactions and the citric acid cycle.
FAD is also involved in the conversion of methylenetetrahydrofolate (MTHF) to methyltetrahydrofolate through the enzyme methylenetetrahydrofolate reductase (MTHFR) 12. Methyltetrahydrofolate, in turn, is required for the vitamin B12-dependent formation of methionine from homocysteine 13. Thus, riboflavin helps maintain the level of the sulfur-containing amino acid homocysteine in the blood 14. Elevated homocysteine levels are often mentioned as a risk factor for cardiovascular diseases 15. However, the results often vary, so homocysteine is seen more as a marker for cardiovascular diseases 16.
Another FAD-dependent enzyme (xanthine oxidase) catalyzes the oxidation of hypoxanthine and xanthine to uric acid 17. Uric acid is needed in the blood as one of the most important antioxidants.
Vitamin B2, in the form of FAD, is involved in the metabolism of glutathione (glutathione reductase), which has an antioxidant benefit in the body. 18 19 20. The glutathione redox cycle plays an important role in protecting the body from reactive oxygen species (harmful forms of oxygen). Findings from a 2014 study indicate that vitamin B2 can protect the body against oxidative stress, particularly lipid peroxidation and oxidative damage from reperfusion. 21.
Riboflavin is also important for body growth, development, and cell functioning. 22. Flavoproteins are also required as co-factors for the metabolism of essential fatty acids in brain lipids and for the regulation of thyroid hormones. 23. In addition, riboflavin is involved in the formation of red blood cells. 24. These cells carry oxygen to the cells for energy production.
Riboflavin may also contribute to eye health by reducing the risk of cataracts (clouding of the lens) when combined with vitamin A, niacin (vitamin B3), thiamin (vitamin B1), and proteins. 25.
Vitamin B2 against colon cancer and breast cancer?
The results of a summary of studies from 2015 indicate that there is a connection between vitamin B2 and colon cancer 26. The scientists associate vitamin B2 intake inversely with the risk of colon cancer. However, further and larger investigations are needed to properly interpret the results.
According to the results of a study from 2016, high plasma concentrations of riboflavin and vitamin B6 are associated with a significantly lower risk (-55%) of breast cancer in premenopausal women 27. According to scientists, further investigations are necessary to explore this association.
Does Vitamin B2 help with migraines?
According to several studies in adults, riboflavin could reduce the frequency of migraine headaches 28. In this regard, a study summary demonstrates that vitamin B2 supplements reduce the frequency and duration of migraine attacks in adults without significant side effects 29. According to scientists, riboflavin appears to be a well-tolerated option for preventing migraine symptoms in adults. However, there is still insufficient evidence to establish corresponding intake recommendations.
According to some scientists, riboflavin appears to be a well-tolerated, effective, and cost-efficient prophylactic treatment for children and adolescents suffering from migraines. 30 On the other hand, other scientists consider the results regarding migraine prevention in children to be inconclusive. 31 Nevertheless, if a decision is made to proceed with riboflavin treatment, the recommended dosage should be between 50 and 400 mg per day for at least 4 months.
Vitamin B2 has a similar ebenfit to valproic acid in reducing migraine attacks. 32 However, according to scientists, vitamin B2 has fewer complications and side effects.
Vitamin B2 and Fitness
Riboflavin is of great importance for fitness and training. Vitamin B2 supports the transport of electrons in energy metabolism. Thus, vitamin B2 assists in electron transport, which is necessary for the formation of ATP. 33.
Vitamin B2 can be easily absorbed by the body. Approximately 95% can be absorbed 35. However, the maximum amount that can be absorbed in the small intestine is limited 36. Therefore, with the administration of an oral dose (40 and 60 mg), a maximum of 27 mg of riboflavin is absorbed by the body 37.
Approximately 90% of the vitamin B2 present in the corresponding foods is in the form of easily digestible flavoenzymes, primarily flavin adenine dinucleotide, and to a lesser extent, flavin mononucleotide 38. The remaining 10% is present as free vitamin B2, as well as in the form of glycosides or esters 39.
Bacteria in the colon can synthesize free vitamin B2, which is also absorbed by the body depending on the diet 40 41. Consuming vegetables results in higher vitamin B2 production compared to consuming meat products.
Considerations for Vegans
Vegans need to pay attention not only to vitamin B12 but also to sufficient intake of vitamin B2 42 43. A Danish study from 2015 found that vegans had lower intake levels of riboflavin compared to the general population 44. On average, men consumed 1.2 mg and women consumed 1.0 mg of riboflavin per day. These amounts are below the recommended daily intake of B2.
In a small Swedish study from 2002, 30 vegans were examined (15 men and 15 women) 45. Five study participants had insufficient intake of vitamin B2. According to an Australian study, over 30% of vegan participants also showed a deficiency in riboflavin 46.
Published study results from the UK in 2002 show only slightly different values for different dietary patterns, including vegan diet 47. Vegans consumed 2.26 mg of vitamin B2, only 0.04 mg less than meat eaters at 2.30 mg. Thus, the intake levels even exceeded the recommended daily allowance of vitamin B2.