We asked the doctor-endocrinologist of the expert clinic for evidence-based medicine "Dawn", PhD Marina Sviridonova, to tell the most important about vitamin D: how it works, what it is for, who needs it and how to get it, and also what its excess can turn out to be (yes, this also happens).
- Vitamin D is a fat-soluble compound that is present in a fairly limited amount of foods. There is a lot of it in seafood and fish oil and much less in dairy products. Vitamin D can be independently synthesized in the skin, however, this requires exposure to ultraviolet radiation.
At the same time, both vitamin D coming from food and vitamin D formed in the skin are inactive.
In order for it to become active and begin to show its properties, certain reactions must occur in the liver and kidneys. (So the state of these organs for the full functioning of vitamin D is also important.)
Vitamin D promotes the absorption of calcium in the intestine and maintains the necessary level of calcium and phosphorus in the blood (which allows to provide the necessary bone density). It is also involved in bone growth (lack of vitamin D in childhood leads to the development of rickets). In addition, recent studies have shown the participation of this vitamin in many processes in the body.
Vitamin plays a significant role in the prevention of cancer, autoimmune, infectious diseases, as well as some diseases of the nervous system. Vitamin D is involved in most metabolic processes, contributes to the normal functioning of the reproductive system.
There is evidence that, against the background of a deficiency of vitamin D, the risk of developing cancer of the breast, gastrointestinal tract, prostate, uterus, ovaries, bladder and kidneys increases. However, it is too early to draw conclusions - the effect of vitamin D on human health will be studied for a long time to come.
Recent studies have shown that in Russia a huge number of people suffer from both a lack of vitamin D and its deficiency. This is primarily due to climatic conditions and our geographical location. From November to March in our country, the angle of incidence of sunlight is such that the vitamin D in the blood under their influence simply is not produced. Yes, and in the spring and summer, we also do not have many sunny and warm days. Thus, the only source of vitamin D is food products, in which its content is also, alas, small.
So everyone needs vitamin D: in prophylactic doses, they really recommend it to everyone. According to epidemiological data, almost 90% of older women suffer from a lack of vitamin D. Moreover, among young people this problem is also widespread.
Most often, the basis for the study of vitamin D levels already identified risk factors in the body: bone tissue diseases, osteoporosis, fractures, obesity, chronic diseases of the liver, kidneys, gastrointestinal tract, pregnancy, dark skin tone. Symptoms of vitamin D deficiency do not appear in everyone, but attention should be paid to bone pain, muscle weakness and a tendency to fall.
In the laboratory, it’s enough to say that you want to get tested for vitamin D levels, and you’ll be assigned the appropriate one.
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In Russia, registered as medicines only solutions of vitamin D. The most common are Aquadetrim and Vigantol, aqueous and oily solutions of vitamin D, respectively. These drugs are taken in drops with a small amount of liquid.
Vitamin D in capsules and tablets, which can be found in our pharmacies, is usually a dietary supplement. There was no significant difference in the effectiveness of solutions and BA supplements of vitamin D, so everyone can choose the most convenient option for themselves.
As mentioned above, it is enough to add a drop of vitamin D to drink a little liquid. For children, you can add vitamin D to the milk mixture. Vitamin capsules are often recommended to be taken with meals.
However, it’s okay if you take them at any other time - it’s better than nothing.
A prophylactic dose of vitamin D is about 800 IU on average (1-2 drops of a solution per day). During pregnancy and in old age, the dose rises to 1,000-1,500 IU (2-3 drops of the solution per day).
It is necessary to take into account body weight - people who are overweight and obese sometimes require higher doses to maintain a normal level of vitamin A in the blood (6,000-10,000 IU or 12-20 drops per day). The category of people who may require a higher dose includes patients with digestive disorders, diabetes mellitus, and many other chronic diseases.
In case of vitamin D deficiency, the required dose of the drug increases significantly. Therefore, if during the examination you found a lack of vitamin, then the doctor should choose and prescribe the dose. For the first two months, as a rule, "saturating" doses of vitamin D are recommended, after which its level in the blood is measured and, if normal values are reached, they are transferred to preventive dosages.
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Since vitamin D is directly related to calcium metabolism, then a sufficient intake of this trace element is necessary to realize its potential.
If for one reason or another (this is often observed in old age), calcium intake or absorption is affected, it is advisable to take vitamin D and calcium at the same time.
In recent years, there has been increasing attention to omega-3 fatty acids. Due to the fact that vitamin D is fat-soluble, it combines well with them. There are special complexes that contain both vitamin D and omega-3 fatty acids.
First of all, vitamin D is found in seafood.
However, their cost and availability are limited - not everyone can include sea fish in their diet on a daily basis. It is worth noting that the vitamin D content in fish grown under artificial conditions is significantly lower than in wild varieties. There is no need to talk about the amount of vitamin D in other products, including dairy products - it is not enough there.
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Unfortunately, since the growing popularity of vitamin D is increasingly confronted with hypervitaminosis D.
Many rushed to solve the problem of deficiency on their own and sometimes take really high doses.
Caution patients: long-term use of high (other than preventive) doses of vitamin D without medical supervision is unsafe. An excess of vitamin D leads to an increase in the level of calcium in the blood and the deposition of its salts in the internal organs. Most often the kidneys suffer - urolithiasis can develop. Therefore, when taking high doses of vitamin D, special attention should be paid to clouding of urine.
In addition, hypervitaminosis D can be manifested by sleep disorders, decreased appetite, vomiting, joint pain, impaired renal and heart function.