Vitamin D is responsible for the functioning of many systems in our body. It supports bones, the circulatory system, improves mood and immunity. No one is surprised that it is called the vitamin of life. In principle, every person living in our latitude suffers from its deficiency, which has serious health consequences. In this category, you can find preparations with vitamin D for both adults and children, in the form of capsules, drops, gummies or syrups.
Vitamin D-functions in the body
The primary function of vitamin D in the body is to regulate calcium and phosphorus metabolism, although other properties have also been emphasized for years. Observational studies have found, among m.in, a relationship between low plasma vitamin D levels and an increased risk of developing certain diseases, m.in. autoimmune diseases, civilization diseases and some cancers. It should be added, however, that despite the observed relationship, no clear evidence has been obtained that deficiency of this vitamin affects the development and course of the above diseases.
It is emphasized that only a small part of the vitamin D requirement can be covered by dietary sources, while a significant amount of it is released in the skin under the influence of sunlight.
Vitamin D deficiency
Available research indicates that vitamin D deficiency is a common problem that affects the general population regardless of where they live, gender, age and race. There are also certain risk groups for its deficiency. These include, m.in, people with the following diseases:
- civilization (obesity, type 2 diabetes, lipid metabolism disorders, metabolic syndrome)
- cardiovascular system (hypertension, ischemic heart disease)
- autoimmune (Hashimoto’s disease, rheumatoid arthritis, type 1 diabetes)
- allergic (bronchial asthma, atopic dermatitis)
- liver and kidney disease (liver failure, non-alcoholic fatty liver disease, kidney failure, kidney stones)
Among the people at risk of vitamin D deficiency, there are also patients with digestive and absorption disorders, calcium-phosphate metabolism disorders and people chronically treated with steroids, ketoconazole, anticonagulants and antiretroviral drugs. Among the causes of vitamin D deficiency, the most common are its low intake and at the same time low exposure to the sun.
In addition to the above-mentioned diseases, the deficiency of this vitamin is also affected by rare malabsorption disorders and abnormalities interfering with the formation of its biologically active metabolites.
Vitamin D dosage in adolescents and adults
In healthy adolescents and healthy adults, cholecalciferol is the first choice in the prevention of vitamin D deficiency, and calcifediol is the second choice. In the case of this population, in people exposed to the sun with uncovered forearms and lower legs for 30-45 minutes from 10.00 to 15.00, not using sunscreen, from May to the end of September, cholecalciferol supplementation is not necessary, although still recommended and safe.
In people who do not meet the above conditions, supplementation with cholecalciferol at a dose of 1000–2000 IU/day is recommended, depending on body weight and vitamin D supply in the diet, throughout the year. If the above conditions are not met, alternative prophylaxis based on calcifediol in a daily dose of 10 μg (oral solution) throughout the year and a follow-up serum 25(OH)D determination is recommended 6–8 days after the start of supplementation.
Vitamin D dosage in people aged 65–75 years
In this age group, cholecalciferol is the first choice in the prevention of vitamin D deficiency, and calcifediol is the second choice. In people aged 65 to 75, due to the reduced effectiveness of skin synthesis, supplementation with cholecalciferol at a dose of 1000–2000 IU/day is recommended, depending on body weight and the supply of this vitamin in the diet, throughout the year.
If the above conditions are not met, it is recommended to perform alternative prophylaxis based on calcifediol at a daily dose of 10 μg (oral solution) throughout the year and to perform a follow-up serum 25(OH)D determination 6–8 days after the start of supplementation.
Vitamin D supplement or drug – what to choose?
There are both over-the-counter (OTC) drugs and vitamin D supplements available on the market. In the case of dietary supplements, manufacturers must declare the composition of the product.
This means that the quantitative and qualitative data and ingredients of the product are only the manufacturer’s declaration, and the introduction of the supplement to the market requires only the product label to be presented to the Chief Sanitary Inspectorate.