Vitamin B2 (Riboflavin): Benefits and Functions

Vitamin B2 belongs to the so-called vitamin B complex and is also known as riboflavin or lactoflavin. The water-soluble vitamin is indispensable for many functions of the metabolism. Since it is contained in numerous foods, you can usually cover your daily requirement well with your diet. A lack of riboflavin is usually caused by health problems, and vitamin B2 supplements are used to treat the deficiency.

Vitamin B2 at a glance

• Vitamin B2 or riboflavin is one of the water-soluble vitamins and is very important for the metabolism.
• The daily riboflavin requirement of adults is 1 to 1.4 milligrams.
• Good B2 suppliers are e.g. meat, fish, green leafy vegetables and legumes.
• The typical symptoms of a deficiency include problems with the skin and mucous membranes.
• A high-dose dietary supplement helps to remedy the deficiency.

What do you need vitamin B2 for?

Also known as riboflavin, the vitamin is involved in many metabolic processes in the body. Among other things, it is important for the preservation of the skin, mucous membranes and eyesight.

Otherwise, the water-soluble vitamin supports e.g. with:

• a normal formation of red blood cells,
• a normal iron and energy metabolism,
• cell protection against oxidative stress,
• the reduction of tiredness and fatigue and
• normal mental function.

Vitamin B2 supports other vitamins

In addition to the functions mentioned, vitamin B2 is also involved in the metabolism of some other vitamins. These include, for example, vitamin B6 (pyridoxine), vitamin B3 (niacin), vitamin B9 (folate) and vitamin K.

What is the daily dosage of vitamin B2?

How much vitamin B2 you need depends mainly on age and gender. The DGE (German Nutrition Society) has set the following reference values for the daily intake:

• 1 to 1.1 mg for adult women 19 years of age and older,
• 1.3 to 1.4 mg for adult men 19 years of age and older,
• 0.7 to 1.6 mg for children and adolescents between 1 and 19 years of age,
• 0.3 to 0.4 mg for infants.

Daily requirement during pregnancy

Pregnant and breastfeeding women have an increased need. From the second trimester, the DGE recommends 1.3 mg and from the third trimester and during breastfeeding even 1.4 mg riboflavin per day.

How can the demand be met?

The body can neither produce vitamin B2 itself nor store it properly. Therefore, a regular supply through nutrition is indispensable. Since riboflavin is contained in many animal and plant foods, this is usually not a problem, regardless of the exact diet.

Which foods are rich in vitamin B2?

Animal foods with a very high B2 content include meat and offal, many fish and seafood, as well as milk and dairy products. If you eat a vegan diet, you can mainly use legumes and mushrooms as vitamin B2-rich plant foods.

Examples of foods high in riboflavin (mg per 100 g)

Which fruits and vegetables contain vitamin B2?

Fruit contains very little vitamin B2. 100 grams of bananas, for example, have just 0.06 milligrams. Most other fruits do not even reach this value. Fruit therefore does not play a significant role in a needs-based supply. The situation is different with vegetables. Green leafy vegetables such as spinach and kale in particular are a good source of riboflavin at 0.2 milligrams per 100 grams.

What are the causes of riboflavin deficiency?

Healthy people can usually cover their needs with a balanced diet without any problems. This is also confirmed, for example, by the National Consumption Study II published in 2008. According to this, the median intake of riboflavin in men and women is significantly above the respective reference values. If a deficiency does occur, in the majority of cases it can be traced back to a health problem.

Possible triggers of riboflavin deficiency include:

• eating disorders,
• long-term alcoholism,
• chronic diseases of the liver,
• Crohn’s disease and other chronic intestinal diseases,
• dialysis in people with kidney disease and
• the use of certain medications.

How does vitamin B2 deficiency manifest itself?

The possible consequences of a persistent riboflavin deficiency include anemia and various skin and mucous membrane problems. The inadequate supply can manifest itself with a variety of symptoms.

Typical deficiency symptoms are, for example:

• pale skin,
• inflammation of the skin,
• cracked lips and corners of the mouth,
• a sore mouth and a sore tongue,
• inflamed oral mucous membranes and
• the formation of eczema.

How is a riboflavin deficiency treated?

To treat the deficiency and the symptoms associated with it, high-dose vitamin B2 preparations are used. These must be taken orally until the symptoms subside. Sometimes the riboflavin is also administered as an infusion. In addition to riboflavin, other B vitamins are often missing. If this is the case, they may also have to be taken as dietary supplements.

Can you overdose on vitamin B2?

If you take in too much vitamin B2, the body simply excretes the excess with the urine. If the intake is limited to the diet, an overdose is almost impossible anyway. Even if you take larger quantities with a vitamin supplement, this does not cause any side effects according to current knowledge.

Are there any recommendations for the maximum daily dose?

Due to a lack of data, the EFSA, the authority responsible for food safety in the EU, has so far refrained from setting a maximum daily dose. This also applies to the German Federal Institute for Risk Assessment (BfR), which has developed recommendations for maximum levels in food supplements and fortified foods for various other B vitamins.

When to take riboflavin as a dietary supplement?

Riboflavin is considered harmless even in high doses. However, most people already consume enough with their normal diet to cover their daily requirement. For them, reaching for a vitamin B2 supplement would have no advantages.

For members of risk groups, however, the situation is different. The additional intake can help them to meet an increased need or to compensate for an already existing deficiency.

Important to know

Are you not a specialist and have complaints, certain diseases or suspect deficiency symptoms? Then please be sure to consult a doctor to discuss this.