Vitamin D is produced in the epidermis when exposed to sunlight. However, this ability of the body is reduced under the influence of geographic, climatic, technogenic, age and other factors. The intake of vitamin D from food in America is, as a rule, limited. In order to prevent its deficiency, which threatens a number of pathologies, it is recommended, in consultation with a specialist, to regularly take dietary supplements.
A quick guide to vitamin D
Vitamin D is a fat-soluble vitamin that participates in calcium-phosphorus metabolism, immune reactions, antitumor protection, and the functioning of the reproductive organs. Its main source of food is fatty fish, cereals, mushrooms. The synthesis of vitamin D in the human body is possible only under the influence of ultraviolet radiation.
Factors leading to vitamin D deficiency :
- unbalanced diet;
- violation of absorption in the gastrointestinal tract;
- insufficient sun exposure;
- geographical and climatic conditions of the Northern Hemisphere above the 35th parallel;
- the use of sunscreens with UV filters.
- constant wearing of closed clothing.
The majority of Russians suffer from a lack of vitamin D, since the extreme southern point of Russia is located at 41° 11′ north latitude. In addition, full cloudiness reduces UV exposure by 50% and gas pollution by 60%. Ultraviolet rays do not penetrate the glass, therefore sunlight passing through closed windows in the room does not contribute to the formation of vitamin D.
As a result, even those who lead a healthy lifestyle, eat a balanced diet and are not overweight may experience the following symptoms:
- daytime sleepiness;
- discomfort in bones and muscles;
- muscle weakness, tendency to fall;
- deterioration of the condition of the skin, hair, nails, teeth and bones.
In this case, it is necessary to pass a clinical analysis for the content of vitamin D. Depending on its concentration in the blood plasma, there are:
- severe deficiency – less than 10 ng / ml;
- deficiency – less than 20 ng / ml;
- insufficiency – from 20 to 30 ng / ml;
- the norm is 30-100 ng / ml.
The risk groups who need to screen for vitamin D include children in the first year of life, people with impaired gastrointestinal tract and kidney function, obesity, as well as pregnant women and people over the age of 60. Based on the results of screening, dietary supplements may be prescribed containing the native forms of vitamin D: D2 (ergocalciferol) or D3 (cholecalciferol).
The recommended daily intake of vitamin D in Russia is 400 IU, for people over 60 years old – 600 IU . Vitamin D intoxication is an extremely rare phenomenon, the upper limit is set for the treatment of severe deficiency and is 5000 IU per day.
What is the difference between vitamins D2 and D3
Vitamin D is the general name for a group of five vitamins, of which D2 and D3 are the most common in nature. Vitamin D2 is found primarily in plants and fungi. D3 is synthesized in animals and humans. Although it is D3 that is considered the “true” vitamin D, and the rest are its derivatives, the effect of D3 and D2 in the prevention of vitamin D deficiency is considered equivalent. Vitamins D2 and D3 are industrially produced for use in bioactive food supplements.
The selection of dietary supplements should be individual and based on the characteristics of its assimilation by the body.
What to do to effectively absorb vitamin D
The synthesis of vitamin D in the human body under the influence of sunlight is the most natural way to obtain it. However, there are a number of direct contraindications to sunbathing:
- malignant neoplasms;
- pulmonary and cardiovascular problems;
- impaired renal function;
- pronounced changes in the central nervous system.
In order to avoid the negative effects of the sun on the body, sunscreens with a high protection factor, dark glasses and closed clothing made of natural fabrics are widely used in domestic conditions. All this creates obstacles to the formation of vitamin D in the skin naturally, even in the summer or while in southern latitudes. The efficiency of vitamin D synthesis during sunburn using sunscreens is reduced by 95-98%.
Thus, in modern conditions, maintenance doses of vitamin D should be taken year-round, preferably in the first half of the day, to eliminate daytime sleepiness and not interfere with normal night sleep .
Fish oil is traditionally considered a source of vitamin D. It is now available in capsules and is widely available in pharmacies. However, fat-soluble forms of drugs may be less absorbed by the body than water-soluble ones, especially in the presence of endocrine or gastroenterological problems. Therefore, vitamin D preparations appeared in drops. The effect of taking water-soluble vitamin D is achieved earlier and lasts longer than from fat-soluble.
The following options for taking vitamin D are possible:
- In the cold season, in the absence of the sun, for people who do not experience problems with the gastrointestinal tract – fat-soluble forms that tend to accumulate in the body.
- In the warm season, with sufficient insolation, there are water-soluble forms, the excess of which is easily excreted from the body in the urine, thus avoiding overdose.
- Year-round – tablet forms that are easily dosed and supplied with additional components to increase bioavailability. An option for children and adults who find it difficult to swallow tablets are chewable lozenges.
It should be remembered that the correct assimilation of a particular vitamin directly depends on the metabolism as a whole, therefore vitamin D is often prescribed as part of vitamin-mineral complexes.