Vitamin B2

Vitamin B2 (riboflavin)Discovery of vitamin B2 in 1920 during isolation from eggs. Riboflavin or lactoflavin is the chemical/medical name for vitamin B2. "Growth vitamin". Riboflavin, also known as lactoflavin or vitamin B2, is a water-soluble vitamin that is yellow in color and can be easily destroyed by light when dissolved. Riboflavin can only be absorbed (taken up by the body) in free form. In food, it is usually present in the form of various phosphorus compounds. This compound must first be released before it can be absorbed. In the organs (liver, kidneys, heart) it is stored again in bound form. The storage period does not last longer than 2 - 6 weeks.

Task/function

Riboflavin serves as a coenzyme and plays a role above all in growth processes. It is also often used to control cleaning processes (surfaces, hands, etc.) in the pharmaceutical industry, as it glows in UV light even in low concentrations and is therefore highly visible. Riboflavin is involved in a number of reactions that are responsible for the breakdown of fatty acids and purines. It is often involved in the production of energy from nutrients in the respiratory chain. It also activates the vitamins B6 (pyridoxine).

Occurrence

The daily requirement is around 1.2 mg and is usually covered by normal food intake. It is often used as a colorant and declared as E 101. Although riboflavin is very sensitive to light, it is very heat-stable so that it is not destroyed during cooking. Its decomposition by heat only starts at 240°C. Because it is found in milk, it is also known as lactoflavin. Riboflavin is found in all living cells of the animal and plant kingdoms. Large quantities are found in milk, dairy products, whole grain cereals, liver, kidney and heart, but also in vegetables such as broccoli, asparagus and spinach. However, not in free form, but as compounds of phosphate with a coenzymatic character. Sprouting cereals increases the riboflavin content. Salads with fresh cereal sprouts or muesli with rye or oat sprouts are therefore not just a culinary delight. Due to riboflavin's high sensitivity to light, sun-dried foods only contain small amounts of the vitamin. No significant losses are to be expected during cooking due to the high heat stability. Only when cooking in liquid does the food leach out. To prevent a high loss of leaching, it is best to process the food using gentle cooking methods such as steaming or blanching.

Deficiency symptoms (hypovitaminosis)

No deficiency symptoms occur with a normal diet. However, pregnant women and alcoholics may experience deficiency symptoms, which manifest themselves in exanthema, skin cracks and hypersensitivity to light. A vitamin B2 deficiency also manifests itself as:

• Skin changes, such as redness or scales in the corners of the eyes,
• brittle and dull fingernails,
• clouding of the lens of the eye (cataract) and
• changes in the nervous system.

The classic deficiency disease, in which a deficiency of vitamins B3, B6 and B9 is also involved in addition to B2, is called pellagra. It used to be the disease of the poor rural population. The name comes from the Latin and means "rough skin", as the disease always begins with typical changes to areas of skin that are exposed to the sun. At that time, the disease could be cured with yeast, as it contains a lot of vitamin B2.

Consequences of an overdose (hypervitaminosis)

An excess of vitamin B2 is excreted with normal kidney function. High doses can cause nausea and vomiting. The toxicity of B2 is very low.

Requirements

As with thiamine, riboflavin requirements are closely related to energy intake. Intake recommendations are therefore linked to the daily energy intake. The DGE recommends a daily intake of 1.7 mg for men and 1.5 mg for women. The basic value is: 0.6 mg of riboflavin should be consumed for every 1000 kcal consumed. The need for riboflavin increases with the intake of certain medications.

Requirements in sport

10-100 mg per day, taken several times with meals.