Vitamin D or ergocalciferol refers to a group of fat-soluble vitamins, formed by ultraviolet rays in the tissues of plants and animals from sterols. Vitamin soluble in organic compounds and fats, but has no ability to dissolve in water.
To vitamin D group include:
- Vitamin D2 - ergocalciferol derived from yeast; it is a provitamin ergosterol;
- Vitamin D3 - cholecalciferol isolated from animal tissue; it is considered to be the provitamin 7-dehydrocholesterol;
- Vitamin D4 - 22, 23-dihydro-ergocalciferol;
- Vitamin D5, oils derived from wheat; sitokaltsiferol (24 etilholekaltsiferol);
- Vitamin D6 - stigma, calciferol (22 digidroetilkaltsiferol).
Today vitamin D are considered two compounds - cholecalciferol and ergocalciferol (D2 and D3). Active drug based on vitamin is expressed in IU - International Units.
1 IU contains 0, 025 micrograms of vitamin D in a chemically pure form.
Sources of vitamin D
The production of vitamin D in the body is made of pro-vitamins entering the body in the form of finished products or resulting from holesterinapod ultraviolet rays.
If human skin is getting enough ultraviolet radiation, its need for vitamin D is compensated with a vengeance. However, vitamin D contained in the products: yolk, fish oil, milk products, however, the consumption of dietary sources alone can not guarantee complete coverage of our needs for vitamin D.
Vitamin D in the product:
- Herring (400-1500 IU / 100 g.);
- Pork liver (40-50 IU / 100 g.);
- Beef liver (40-50 IU / 100 g.);
- Butter (10-150 IU / 100 g.);
- Egg yolk (50-400 IU / 100 g.).
The action of vitamin D
The main function performed by a vitamin - ensuring full absorption of phosphorus, calcium and magnesium, necessary for the normal development of the skeletal system. This substance promotes adequate calcium deposits in the bones and dentine, implementing prevention of osteoporosis and rickets, preventing softening (osteomalacia) bones.
The role of vitamin D is not limited to the protection of bones: it boosts the immune system, prevents muscle weakness, provides normal blood clotting and thyroid function. Improving mineral metabolism, vitamin D is involved in the restoration of protective membranes surrounding nerves, thereby including in complex therapy and prophylaxis of multiple sclerosis.
In addition, vitamin D effectively regulates the heart beat and blood pressure, including pregnant, inhibits the growth of cancer cells. For external use of vitamin D3 can reduce the characteristic scaly skin of psoriasis expressed.
The need for vitamin D
The main source of vitamin D is the sun. To fully meet the need for vitamin D is enough for 15-20 minutes a day to be under the influence of solar ultrafioleta- especially in the morning and sunset hours. However, winter time and smokiness atmosphere pronounced tan can reduce the production of vitamin A in the body. The same can be said of the elderly, whose body loses the ability to synthesize vitamin D from pro-vitamins and half of those who prefer to stick to different diets and eats a small amount of fat.
The need for vitamin D are as follows:
- Newborn term infants - 500-700 IU / day;
- In newborns weighing less than 2500 g - 1000-1400 IU / day;
- Children from 5-12 years - 400-500 IU / day;
- Adolescents - 500-600 IU / day;
- In adults from 20-50 years - 300-400 IU / day;
- Pregnant and lactating women - 600-800 IU / day;
- Older people - 600-800 IU / day.
Symptoms of hypovitaminosis
Lack of vitamin D causes osteomalacia and rickets appearance - bone disease, characterized by impaired bone formation. In milder forms, symptoms of vitamin D deficiency include:
- Burning sensation in the throat and mouth;
- Weight loss, loss of appetite;
- Blurred vision;
- Lack of vitamin D (vitamin deficiency);
- Hypophosphatemia, hypocalcemia;
- Renal osteodystrophy genesis;
- Hypoparathyroidism, including - complicated by osteomalacia;
- Lupus erythematosus;
- Chronic gastritis;
- Chronic enteritis;
- Chronic pancreatitis;
- Enterocolitis complicated by osteoporosis;
Indications to receive vitamin D
Vitamin D is appropriate at caries and tooth developmental disorders, psoriasis, spazmofilii, hay fever, hemorrhagic diathesis, in postmenopausal women, as well as to enhance the immune properties of the organism. Vitamin D during pregnancy is appropriate flowing in the autumn-winter period and the treatment of glucocorticoid drugs.
In addition, the prophylactic use of vitamin may be required for people living and working in the Arctic Circle, Metro employees, miners.
Symptoms of hypervitaminosis
The use of inadequate doses of vitamin D can lead to the following conditions:
- Sharp headaches, muscle pain, joint pain;
- Increased blood pressure;
- Loss of appetite, nausea, vomiting, weakness, disorders of the chair;
- Fever, shortness of breath, increased heart rate.
Chronic poisoning vitamin D can cause symptoms such as:
- The appearance of osteoporosis, bone demineralization, resorption of the stroma;
- Calcification of blood vessels and heart valves;
- The deposition of calcium in the intestines, lungs, kidneys, resulting in improper operation of these bodies.
Vitamin D simultaneously hyperlipidemic agents should stop because drugs that lower blood cholesterol levels can disrupt its absorption.
Hinder the absorption of vitamin D and mineral laxatives, steroids, antacids, phenytoin and barbiturates.
Vitamin D decreases the activity of the cardiac glycosides, but significant dose of vitamin can lead to iron deficiency in the body.
Complete vitamin D metabolism in the liver is not possible with a deficiency of vitamin E.