Biologists consider vitamin H or biotin to be one of the vitamins of the B group. The reason for this is the functions it performs in metabolism. Thus, vitamin H is often also referred to as vitamin B7 or vitamin B8. The compound is soluble in water and heat stable. Biotin is also insensitive to the presence of oxygen, so oxidative degradation processes cannot occur. Vitamin H can be of animal or plant origin. The intestinal flora is also capable of synthesizing biotin.
Biotin takes the position of a coenzyme in biochemical processes and is involved in metabolic conversions as a “prosthetic group” in conjunction with enzymes. Vitamin H plays an important role in fat metabolism and in the metabolism (breakdown) of carbohydrates. Biotin probably also performs crucial tasks in gene regulation.
The deficiency symptoms that occur in hypovitaminosis of biotin are very diverse. Fatigue and low blood pressure, nausea and lack of appetite, anemia, depression, and cardiac complications have been observed in vitamin H deficiency. With such broad and nonspecific symptoms, only a urine and blood analysis will provide final certainty that hypovitaminosis is present.
The recommended daily intake of biotin for an adult is about 50 µg (µg: micrograms, which is 1 millionth of a gram). Adolescents need somewhat less, and in pregnant women and weakened adults the requirement is somewhat higher and can be ensured by dietary supplements. The same applies to people who suffer from a genetically determined absorption disorder of the small intestine. Regular consumption of raw eggs or corresponding products can also interfere with the absorption of biotin. The reason for this is the substance avidin present in eggs, which binds the biotin and prevents its absorption. In cooked eggs, however, avidin is harmless. Vitamin H should be a regular part of the diet because the liver does not store the water-soluble vitamin. Excesses are excreted by the kidneys.
The highest amounts of biotin are found in beef and pork liver with 50 – 100 µg/100 g fresh weight. In addition, nuts and whole grains are good sources of vitamin H. For example, the biotin content of peanuts is about 30 µg/100 g. Vegetable oils and dried yeast are also excellent sources of the vitamin. Biotin can also be taken therapeutically by the doctor or as self-medication in the form of capsules or tablets.