In the 15th century, an epidemic of rickets (children with a curved spine, arms and legs) began in England in large cities. This was due to lack of sunlight due to the close development of high houses, smoke and air.
In 1928 German scientist Vindaus received the Nobel Prize in Chemistry for studying the properties and structure of vitamin D.
Vitamin D deficiency in almost many residents of Russia is due to:
- located in the northern temperate zone (above 42 degrees north latitude)
- limited exposure to the sun (office work, traveling by car)
- eating meat from animals that were not in the sun (farms)
- use of sunscreen
- chronic diseases (obesity, bowel disease, taking a large number of drugs)
For very smart
Vitamin D combines a group of vitamins (D1, D2, D3, D4, D5), of which only two forms (D2 and D3) have important biological significance.
The precursor of vitamin D, forms its supply in the skin.
In the skin of cholesterol under the action of beta-UV rays form 80% of vitamin D3. Its 20% is ingested with food of animal origin (fish oil, liver, egg yolk).
Enters the body only with herbal products (bread, etc.)
Then in the liver from both forms as a result of hydroxylation (the addition of OH groups) is formed
25-OH-hydroxy-CHOLECALCIFEROL (calcidol). This form is depot and transport, it is determined in the blood to establish the level of vitamin D.
Further, in the kidneys with the participation of parathyroid hormone (parathyroid hormone), the second hydroxylation occurs and the formation of the active form –
1,25-OH-dihydroxy-CHOLECALCIFEROL (calcitriol). It is calcitriol that provides the main biological effects of vitamin D in the body.
The main biological role of calcitriol (1,25-OH-vitamin D) is to maintain a constant level of calcium in the blood (vitamin D enhances the absorption of calcium in the intestine and if it is not enough in the blood – ensures the flow of calcium from the bones into the blood).
Over time, calcitriol receptors, in addition to the intestines and bones, have been found in the kidneys, genitals, pancreas, muscles, cells of the immune and nervous systems. Thus, it became clear that in the human body vitamin D performs a large number of different functions:
- regulates the manifestation of 3% of the human genome (several thousand genes)
- increases the sensitivity of the insulin receptor (prevention of insulin resistance, obesity, diabetes)
- strengthens the bone system
- reduces the level of parathyroid hormone in the blood
- promotes the synthesis of sex hormones (testosterone, estrogen, progesterone)
- improves reproductive function
- affects congenital and acquired immunity
- prevents the development of tumors, depression, Parkinson’s disease
Lack of vitamin D
A lack of vitamin D in the body can lead to the development of:
- diseases of the cardiovascular system
- immunodeficiency, allergies, psoriasis, bronchial asthma, rheumatoid arthritis
- periodontal disease
- tumors of the large intestine, mammary glands, ovaries, prostate
- chronic fatigue, depression, insomnia
- reduced muscle strength leading to the risk of falls
- decrease in motility and morphologically normal sperm count (male infertility factor)
- risk factor for preterm labor, fetopathy (less than 20 ng / ml)
Reaching the level of vitamtin D 50 ng / ml (125 nmol / l)