Vitamin D is the most important element in the complete life of a human being. It affects almost all systems of the body: first of all the formation and strengthening of the skeleton. Vitamin D supports the immune system and reduces susceptibility to various infections, prevents the growth of cancer cells, and strengthens the cardiovascular system. Some of its compounds form under sunlight, and other types of substances we can find in food.
Key functions of vitamin D
The history of vitamin D discovery goes back to the study of retinol, or vitamin A. At the beginning of the 20th century scientists found that fish oil was rich in retinol. As an experiment, reseachers gave fish oil to dogs. After a while scientists noticed that the animals stopped getting rickets, which was one of the main problems of pediatrics at the time.
Experts tried to connect rickets with vitamin A deficiency, but Elmer McCollum, who discovered retinol, disproved this hypothesis. He conducted his own experiments with dogs suffering from rickets: for some time McCollum gave them fish oil with neutralized retinol. This led the scientist to believe that the cure came from some other substance that also was present in the fish oil. This is how vitamin D was discovered in the early 20th century.
About a year later, scientists discovered that if food was under ultraviolet light, the amount of vitamin D in it increased. Thus the sun was the source of this valuable element.
The main functions of vitamin D are:
- promotes normal skeletal formation.
- provides for the metabolism of the
- promotes muscle tone.
- enhances immunity.
- necessary for the functioning of the thyroid gland and normal blood clotting.
- helps the body rebuild protective membranes surrounding nerves.
- participates in the regulation of blood pressure and heart rate.
What are the signs of vitamin D deficiency?
The vitamin is responsible for biological processes in almost all body systems. It is not by chance that some specialists consider it as a hormone-like substance. Signs and vitamin D deficiency can be weak muscle tone, brittle nails, dry skin. Some begin to lose hair and experience muscle and bone pain.
Vitamin D deficiency is one of the main causes of childhood rickets. Because of prolonged avitaminosis can develop cancer pathologies in patients of different ages. Old people often get osteoporosis – increased bone fragility. Some people may develop cardiovascular disease, including myocardial infarction. Immunity and thyroid function decrease, metabolic processes are disrupted, leading to the development of diabetes and obesity, and the risk of age-related dementia increases.
How to make up for vitamin D deficiency
Many people think that it is necessary to spend more time in the sun. Ultraviolet does synthesize vitamin D, but there are regions which are in a low insolation zone with low intensity of solar radiation, especially in the fall and winter. UV light does not penetrate through glass; its level depends, among other things, on the thickness of the cloud layer and atmospheric pollution.
The risk group includes inhabitants of large cities where the level of atmospheric pollution is higher, office workers, and people who stay indoors for a long time. This group also includes older people – over 60 years old, people with a darker skin tone, as well as those with chronic kidney disease, liver disease, obesity.
You should regularly – at least twice a week – stay in the sun: from 10-30 minutes in the morning hours. The sun’s rays should fall not only on the face, but also on the skin of the arms, legs and back.
Often vitamin D deficiency can only disappear by taking medication. The doctor should determine the dosage, guided by a blood test of the actual level of the vitamin.
If a patient is deficient in vitamin D, doctors prescribe vitamin complexes taking into account all contraindications – allergies, elevated blood calcium concentration, chronic GI pathologies, renal and hepatic insufficiency, phenylketonuria.
What foods contain large amounts of vitamin D
A lot of vitamin D we can discover in fish. The maximum concentration is in the salmon family – salmon, chum salmon, pink salmon and taimen. The daily dose of cholecalciferol, which is equal to 10 micrograms, is in 150 grams of salmon fillets or 850 grams of cod.
With vitamin D deficiency, children and adults should include fish oil, dairy products, egg yolk, salmon caviar, and mushrooms in their diets.
Keep in mind that meals do not meet the body’s daily requirement for vitamin D. A dose of 10 micrograms is in 18 to 20 egg yolks. For this reason, patients who are vitamin D deficient should visit a nutritionist to help them form a balanced diet.
The following is a list of foods that contain vitamin D. The amount of calciferol in 100 g of food in parentheses is given as a percentage of daily intake:
- Cod liver (1000 %).
- Fatty herring (300 %).
- Chum salmon (163 %).
- Atlantic salmon (110 %).
- Pink salmon (109%).
- Black caviar (80 %).
- Egg yolk (77 %).
- Tuna (57 %).
- Chanterelle mushrooms – (53 %).
As you can see, among the first ones are different types of fish. It has more vitamin D than eggs or mushrooms. That’s why housewives should cook fish dishes for their families more often. So both children and adults will get the necessary amount of calciferol.