Vitamin B2 (Riboflavin)

Wednesday July 6, 2022 8 minutes to read

Note — The article was checked and updated February 2024.

What is Vitamin B2?

Vitamin B2, also known as riboflavin, is a water-soluble vitamin that is used by the body to help metabolize carbohydrates, protein and fats.

Riboflavin also functions as an antioxidant to help maintain the immune system and healthy skin and hair.^[¹^]

In 1872, Alexander Wynter Blyth, a British chemist was the first to isolate riboflavin from cow’s milk. He named it “lactochrome” (lacto from milk and chrome due to its yellowish color).^[²^]

However, Blyth was unable to define the chemical properties of lacto-chrome until 1934 when Paul Karrer, a Swiss chemist, and Richard Johann Kuhn, an Austrian-German biochemist, independently observed and described the structure of riboflavin.^[²^]

A few years later, in 1939, a study by William Henry Sebrell and Roy Edwin Butler reported that riboflavin is an essential nutrient for human health and was advised that it should be included in the diet.^[³^]

Vitamin B2 deficiency

An acute deficiency of vitamin B2 is called ariboflavinosis, which rarely occurs by itself and is most often accompanied by other nutrient deficits.

Riboflavin is required in many oxidation-reduction reactions and deficiency may affect many processes in the body.^[³^]

Vitamin B2 deficiency is usually caused by poor diet or malabsorption

Cases of deficiency mostly occur in low-income or developing countries where the intake of meat and dairy products is low.

Riboflavin is easily absorbed from food, but oral supplementation of riboflavin alone is poorly absorbed, with only 15% of bioavailability.^[⁴^]

Who is most at risk of Vitamin B2 deficiency?

Low vitamin B2 levels in vegans and vegetarians

Vegetarians and vegans are at risk of riboflavin deficiency because of excluding animal products such as dairy and eggs, which tend to be good sources of riboflavin.^[⁵^]

A Danish study on vegans reported that 29 out of 70 participants did not reach their recommended amount of riboflavin in their diets. The major food sources of vitamin B2 in Nordic diets are dairy and meat products.^[⁶^]

Elderly people and vitamin B2

A study observed that approximately 60% of elderly people were at risk for riboflavin deficiency. This is because their intake of food and nutrients is lower on average than that of younger adults.^[⁷^]

Alcoholic abuse and absorption of vitamin B2

Excessive amounts of alcohol can cause vitamin B2 deficiency because of limited dietary intake and diminished absorption.

A study by Subramanian et al. found that chronic exposure to alcohol reduced the number of riboflavin uptake across the small intestine.^[⁸^]

Vitamin B2 in pregnant and lactating women

Pregnant or lactating women who rarely consume dairy and meat products are at risk of riboflavin deficiency, which can affect their health and the health of their infants.

Riboflavin deficiency during pregnancy might lead to preeclampsia

Currently, there is limited evidence on the benefits of riboflavin supplements during pregnancy.^[⁵^] In saying that, riboflavin intake during pregnancy had a positive association with infant birth weight and length.

Infants of mothers with riboflavin deficiency or low dietary intakes (<1.2 mg/day) during pregnancy have a higher risk of deficiency and of certain birth defects (e.g., outflow tract defects of the heart).^[⁵^]

Different types of Vitamin B2

Vitamin B2 comes in two different forms

Riboflavin
Riboflavin-5′-phosphate sodium

Riboflavin

Riboflavin naturally occurs in some foods (e.g., dairy milk, eggs, lean meat) and is fortified in some food products (e.g., cereal or bread).^[⁵^]

The dietary riboflavin comes in the form of flavin mononucleotide (FMN; also known as riboflavin-5’-phosphate) and flavin adenine dinucleotide (FAD) which have an important role in the Krebs cycle.

Most of the riboflavin is absorbed nearer to the centre of the small intestine.^[⁵^]

Riboflavin-5′-phosphate sodium

Riboflavin-5′-phosphate sodium is an active pharmaceutical ingredient usually used in vitamin B2 supplements or research using vitamin B2.

Riboflavin-5′-phosphate sodium is absorbed by a specific transport mechanism from the upper gastrointestinal tract.^[⁹^]

Between these two forms it is better to obtain riboflavin from food sources because it is easier to absorb than those in supplement form. Eating healthy and balanced food could give more advantages than taking supplements and eating poorly.

Health benefits of Vitamin B2

Vitamin B2 and the body’s energy supply

Vitamin B2 is an essential component of two significant coenzymes called FMN and FAD.^[⁵^] These coenzymes have a role as a cofactor in the process in mitochondria to convert the energy stored to adenosine triphosphate (ATP) which is the universal energy donor in the cell.^[¹⁰^]

Any disturbance in riboflavin metabolism and absorption may have consequences on the energy supply, which may impair repair and recovery.^[¹¹^]

Vitamin B2 and digestion of protein and fats

FMN and FAD, the two flavoprotein coenzymes derived from riboflavin, are also cofactors in the metabolism of essential fatty acids in brain lipids.^[¹²^]

A study observed the effect of a diet deficient in riboflavin in rats and after 21-days

Myelin lipids
Cerebrosides
Sphingomyelin
Phosphatidylethanolamine

which are essential components of the myelin membrane, were decreased.

The myelin membrane is an insulation layer that is made up of protein and fatty substances. This membrane allows electrical impulses to transmit effectively along the nerve cells.

Any disturbance in it would slow down the impulses in the brain.^[¹³^]

If you are wondering how food impacts our brain, you might be interested in reading

Diet and the Brain — Fats

Diet and the Brain — Sugar

Diet and the Brain — Proteins

Role of vitamin B2 in conversion of carbohydrates into ATP

Vitamin B2 or riboflavin is a required ingredient as part of the Krebs cycle, which contributes to the production of adenosine triphosphate (ATP).

In the Krebs cycle, FAD is needed in the process of converting succinate to fumarate.

ATP is responsible for providing energy to many functions in the body, including nerve impulses and muscle contractions.^[¹⁴^]

Vitamin B2 and migraine prophylaxis effect

Several clinical trials resulted in the prophylactic effect of high-dose riboflavin supplementation on migraine attacks.

In an open-label study, a high dose of riboflavin supplementation (400 mg/day) for 6 months led to a reduction in migraine attack frequency.

Another study suggests that riboflavin supplementation (100 mg/day) is equally effective and better tolerated than 80 mg/day of propranolol (a gold standard prophylactic drug) for the reduction of headache frequency, duration, and severity.^[³^]

Prevention of cataracts and high dose of vitamin B2

A study reported that a high dose of riboflavin (400 mg/day) appears to have a preventive effect on the development of age-related cataracts.

Riboflavin concentration influences the glutathione (GSH) concentration in the lens, protecting the lens against oxidative damage.^[⁴^]

Vitamin B2 and autism

The analysis of urinary dicarboxylic acid (abnormal organic acid) is a very important tool used in the diagnosis of several metabolic disorders.

A study observed the level of dicarboxylic acid in the urine of autistic children after supplementation of vitamin B2, vitamin B6 and magnesium.

A daily dose of 20 mg riboflavin orally twice a day for 3 months, reduced the concentrations of dicarboxylic acid in the urine.

Furthermore, the parents of these children reported improvement in some autistic symptoms such as the ability to concentrate and eye contact. However, further study might be needed to investigate this effect.^[¹⁵^]

Health claims that still need more evidence and research

Vitamin B2 and tumor / cancer prevention

A few studies reported mixed results on the relationship between riboflavin intake and lung cancer risk.

A study on

Current
Former
Never smokers

reported a weak inverse association between dietary riboflavin intake and lung cancer risk in the current smokers after the intake of 2.5 mg of riboflavin per day.^[¹⁶^]

Source: Mikkelsen, K., Anti-Tumor Effects of Vitamin B2, B6 and B9 in Promonocytic Lymphoma Cells. International Journal of Molecular Sciences. (2019)

Another study observed that riboflavin showed a borderline positive interaction with lung cancer risk after an intake of 1.30 mg per day.^[¹⁷^]

Vitamin B2 and Parkinson’s disease

Parkinson’s disease (PD) is a neurodegenerative condition that mainly affects motor function in a chronic and progressive process.

Some evidence suggests that riboflavin may have a neuroprotective role in PD patients.

Low riboflavin levels have been reported in Parkinson’s patients

This study showed that

supplementation of riboflavin (90 mg/day)
elimination of red meat from the diet for 6 months

improved motor function.^[¹⁸^]

However, further research comparing riboflavin status between PD patients and healthy control could provide stronger evidence for supporting the neuroprotective effects of riboflavin in Parkinson’s disease.^[³^]

Best sources of Vitamin B2

Riboflavin is present in high concentrations in

Nuts
Meats
Fatty fish
Dark-green vegetables
Eggs
Mushrooms
Milk and dairy products
Legumes^[²^]

*Food Sources*	*Concentration (mg/100g)*	*Daily Value (DV)*
Almonds	1.1mg	88%
Beef (skirt steak)	0.9mg	66%
Feta cheese	0.8mg	65%
Eggs	0.5mg	39%
Salmon	0.5mg	37%
Mushrooms	0.5mg	36%
Fortified tofu	0.4mg	34%
Bluefin tuna	0.3mg	24%
Lean pork chops	0.3mg	21%
Spinach	0.2mg	18%
Non-fat yogurt	0.2mg	18%
Soy milk	0.6mg	16%
Lean chicken breast	0.2mg	14%
Whole milk	0.2mg	13%
Avocado	0.1mg	10%

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Daily requirements and recommended intake

A study reported that vitamin B2 deficiency occurs with dietary intakes of less than 0.6 mg/day.

Age	Male	Female
Birth to 6 months	0.3mg	0.3mg
7-12 months	0.4mg	0.4mg
1-3 years	0.5mg	0.5mg
4-8 years	0.6mg	0.6mg
9-13 years	0.9mg	0.9mg
14-18 years	1.3mg	1.0mg
19-50 years	1.3mg	1.1mg
>51 years	1.3mg	1.1mg

Pregnant and lactating women should add additional 0.3 mg to 0.6 mg of vitamin B2 to their diet or supplementation.^[²^]

How to take Vitamin B2

It is suggested to consume good-quality and fresh food that make a balanced diet.

Some methods of food processing may alter the content of riboflavin

For example extruding, blanching, milling, fermenting, and sun-drying of fruits and vegetables significantly reduce the amount of riboflavin in food.^[²^]

Riboflavin can also be destroyed by exposure to light because it’s photosensitive. For example, milk stored in a glass bottle can usually have low quantities of riboflavin.^[⁴^]

Also, heating food, microwaving, or exposure to infrared radiation has an effect on reducing the amounts of riboflavin.^[²^]

Taking vitamin B2 supplements might be beneficial for people who can’t eat a balanced diet every day. It is suggested to take multivitamins between meals.

Common signs and symptoms of Vitamin B2 deficiency

Currently, no diseases related to riboflavin deficiency have been found. However, clinical symptoms of deficiency after 3-4 months of inadequate vitamin B2 intake include:^[⁴^]

Cheilosis and angular stomatitis
Painful lesions or fissures on the outside of the lips and corners of the mouth

Glossitis
The tongue may appear smooth and magenta in color

Hyperemia and edema of the oral cavity

Inflammatory skin condition
Seborrheic dermatitis, which is associated with the secretion of waxy substance found noticeably around the nose or nasolabial fold
Peripheral nerve dysfunction (neuropathy)

Anemia
Riboflavin contributes to blood cell formation, improves iron absorption and helps in the mobilization of ferritin from tissues. A significant association between riboflavin and iron intake in correspondence to the risk of anemia was detected.

Vitamin B2 risks and side effects

There are no toxicity reports associated with large oral doses of riboflavin. Also, no tolerable toxicity intake level for riboflavin has been determined.

When excess amounts are consumed, the body will excrete them in the urine.

Possible interactions with herbs and supplements

Blond psyllium

Blond psyllium is a herb used as a laxative and stool softener, and it also helps maintain cholesterol levels.

Blond psyllium is available in many different types of products including bread, cereals and snack bars. Blond psyllium may affect the absorption of riboflavin.^[¹⁹^]

Folic acid

Taking folic acid while having a methylenetetrahydrofolate reductase (MTHFR) deficiency, may worsen the riboflavin deficiency.

MTHFR is an enzyme that has a role in amino acid metabolism and is involved in the chemical reaction of folate or vitamin B9.

Folic acid could decrease riboflavin blood levels in people with this condition.^[¹⁹^]

Possible interactions with medications

Anticholinergic medications

Anticholinergic drugs are used to treat a variety of conditions including gastrointestinal spasms, asthma, depression and motion sickness. This type of medication could impair the body to absorb riboflavin.^[²⁰^]

Tetracycline

Riboflavin interferes with the absorption and effectiveness of this antibiotic.

It is advised to take riboflavin supplements at a different time during the day when taking tetracycline.^[²⁰^]

Summary

Key Takeaway – In this summary illustration we have outlined the most important information that you should know about Riboflavin (vitamin B2).

Bernadeth Atrinindarti

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