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The impact on the human body of ultraviolet radiation is the main factor in the natural production of vitamin D. Under modern living conditions, not many can boast of having time for sunbathing. Therefore, a balanced diet has a significant place in saturating the body with active substances necessary to maintain health.
Substance functions
Two forms of vitamin D, cholecalciferol and ergocalciferol, are hormone-like substances. Entering the body, the compound undergoes a number of transformations until it becomes active and can have a direct effect on physiological processes. The role of vitamin D for the human body is difficult to overestimate:
- provides calcium-phosphorus metabolism, responsible for the strength of the bones;
- regulates the level of free calcium in the blood;
- stimulates the immune system;
- participates in the formation of cell structures;
- part of the membranes of nerve cells;
- ensures the normal functioning of the nervous system;
- necessary for the proper functioning of the parathyroid gland.
The Importance of Tanning
Some people mistakenly believe that the list of products containing vitamin D is irrelevant for them, since the whole body's need for this substance is blocked by sunlight.
Indeed, there is an opinion that it is enough to substitute the hands and face under open sunlight for 20 minutes and calciferol in excess will flow along with the blood through the veins, and also accumulate in the adipose tissue in reserve. This is actually not the case.
Sun baths are the main stimulant of endogenous synthesis of cholecalciferol. But the synthesized substance is not always enough. Therefore, the prevention of hypovitaminosis by the sun implies regular, but careful exposure to ultraviolet light about five times a week. Safe tanning rules state that irradiation in the morning sunlight will be the least harmful. The power of the morning sun is insufficient, therefore, for the synthesis of the required amount of cholecalciferol, you need to sunbathe for 30 minutes.
The area of the irradiated surface is important. You can quickly get the right dose of cholecalciferol by irradiating the whole body, and not just your hands and face. The lighter the skin, the more vitamin D will be synthesized under the influence of ultraviolet radiation. If the skin already has a tan, the exposure time to the sun will have to be increased.
But no one pinpoints exactly the time spent in the open sun. Under moderate climatic conditions, in the cold season, the duration of sunbathing is minimized. Residents of cities are particularly affected by a lack of sunlight.Therefore, it is impossible to get an excess for the body of naturally produced calciferol. But you can make a diet in such a way as to prevent a possible deficiency, because a lack of vitamin D leads to the following conditions:
- rickets in children;
- adult osteomalacia ending in osteoporosis;
- metabolic disease;
- increased risk of cancer;
- decreased activity of the body's defenses.
Given the wide selection of dietary supplements, it can be assumed that it is quite simple to take drugs with ergocalciferol. But synthetic D2 must undergo a number of transformations in the body in order to turn into an active form.
Individual needs
Using scientific studies, the recommended concentrations of calciferol in the blood were found to be 20-32 ng / ml. To achieve stable indicators, it is necessary to observe the recommended doses of the vitamin preparation:
- children under one year old - 300-400 IU or 7.5-10 mcg;
- children under five years old - 400 IU or 10 mcg;
- for children from five to 13 years old - 100 IU or 2.5 mcg;
- persons over 15 years old - 100-200 IU or 2.5-5 mcg;
- women during pregnancy - 400 IU or 10 mcg;
- breastfeeding women - 400 IU or 10 mcg;
- older people (from 60 years) - 400-600 IU or 10-15 mcg.
Even foods containing large amounts of vitamin D cannot completely block the daily requirement of the human body. For example, in order to provide yourself with the right amount of calciferol, you need to eat five quality chicken eggs, 900 g of cod or about a kilogram of beef liver per day. Naturally, no person can eat such an amount of food, and even more so - do it every day. Therefore, the main source of vitamin D is sunlight. Walking on a sunny day is the best prevention of vitamin deficiency. What if vitamin D is still lacking, what methods are used to make up for it?
What foods contain vitamin D
When discussing which foods have vitamin D, we focus on its maximum concentrations. It is recommended to include such food in your daily diet. The presence of animal products is mandatory for children's menus, the elderly and people with heavy physical labor. Products with the highest vitamin D content include:
- fish.
- meat;
- milk products;
- mushrooms.
The most fortified foods include cod liver oil. The daily requirement of calciferol can be blocked with just one tablespoon of the product. A high vitamin content is also observed in fatty herring, chum salmon, mackerel and pink salmon, salmon, black caviar, and seafood. 100 g of red caviar will block the body's need by only 29%. And what to look for in other food groups?
- Meat. Vitamin D is found in meat in smaller quantities - about 2 micrograms per 100 grams of tenderloin of any kind, as well as about 1.5 micrograms in beef or mutton liver.
- Milk. The leaders in the content of the compound among dairy products are ghee and butter. 100 g of product contains about 1.5 micrograms of vitamin. 50% Cheddar or Swiss Hard Cheese contains 1 μg of calciferol per 100 g of product. Fat homemade cottage cheese - 0.56 mcg.
- The eggs. To compensate for the deficiency of calciferol, it is recommended to use eggs.With a reduced calorie content, 100 g of quail eggs cover the daily requirement of vitamin D by 14%, chicken - by 22%.
- Mushrooms. Among mushrooms, the leading positions in the content of calciferol are occupied by morels and chanterelles. 100 g contain 5.4 mcg of substance - 50% of the increased daily requirement. Oyster mushroom calciferol contains much less - only 0.7 micrograms per 100 g of product.
To organize a healthy vegetarian diet, it’s important to know where vitamin D is found in plant foods. The concentration of ergocalciferol in them is small and has only prophylactic significance.
- Greenery. Nettle, parsley, celery, dill, basil, cilantro - all greens contain a small amount of vitamin, but it is absorbed completely.
- Vegetable oil. The richest in vitamin D is corn oil, but in the modern food industry, even refined sunflower oil is artificially enriched with it. He should be preferred for the prevention of hypovitaminosis D.
- Soya. In its pure form, as well as its processed products (tofu, soy milk) can be an excellent plant source of vitamin D.
- Nuts. They contain a small amount of ergocalciferol, compared with fish, but are rich in substances necessary for its full assimilation.
Signs of deficiency
Doctors' reviews say that it is hard to satisfy the body's daily need for vitamin D with food alone. If there are signs of deficiency, you need to contact a specialist to select the appropriate drug. Symptoms of a lack of calciferol:
- unreasonable weight loss;
- sore throat;
- loss of appetite;
- visual impairment;
- groundless concern;
- sweating
- sleep disturbances.
Vitamin D in plant foods is found in very small quantities. The ideal food for filling the deficit and preventing hypovitaminosis of calciferol is oily fish, seafood. The main way that a substance enters the human body is considered to be in direct sunlight.