- Properties of vitamin D
- The role of vitamin D in the body
- The effects of scarcity and excess
- Food products containing vitamin D
- When is the need for supplementation?
- Recommendations for vitamin D supplementation
Properties of vitamin D
The name vitamin D concerns two compounds. They are ergocalciferol (D2) and cholecalciferol (D3). They differ in their origin and absorption. Ergocalciferol is of plant origin and can be taken by vegans and vegetarians, while cholecalciferol is found in animal products. The bioavailability of vitamin D2 is up to two times lower than that of cholecalciferol. Vitamin D can be synthesized in the body during exposure to sunlight. The condition for the start and proper course of the synthesis is the right amount of cholesterol in the body, staying outside in the hours of intense sunshine (south) and giving up cosmetics with a high UV filter that blocks the penetration of sun rays through the skin.
The role of vitamin D in the body
As mentioned in the introduction, this vitamin has many important functions in the body. She is responsible for
– regulation of absorption of calcium and phosphorus in the small intestine,
– maintaining a constant level of calcium in the blood,
– proper course of bone and tooth mineralization,
– regulation of phosphorus levels in the kidneys,
– proper functioning of the parathyroid glands,
– neutralization of free radicals,
– protection and proper functioning of the nervous system,
– regulation of insulin secretion,
– muscle contractility,
– relieving inflammation, especially within the skin.
The right amount of vitamin D in the body is associated with a reduction in the risk of various diseases. Most of the discussed vitamin is associated with the prevention of osteoporosis and less frequently with the prevention of osteomalacia. Other conditions that can be prevented by taking care of the proper amount of vitamin D are hypertension, diabetes, depression, autoimmune diseases and cancers (prostate, breast, ovarian and colon). It has also been proven that seniors with normal levels of vitamin D have longer cognitive functions and are in better mental condition.
Effects of deficiency and excess of vitamin D
Deficiency of vitamin D is favored by a small amount of sunny days of the year (preventing proper skin synthesis of the vitamin), the use of cosmetics with a UV filter and the reduction or complete elimination of fish and eggs from the diet. Symptoms of vitamin D deficiency are often neglected and confused with fatigue. In the Polish population vitamin D deficiencies are common and they concern all age groups.
Symptoms of vitamin D deficiency
– sudden lack of appetite;
– bone and muscle pain;
– weakness and muscle cramps;
– periodontal disease;
– sight problems;
– disgust and burning in the mouth and throat;
Vitamin deficiencies are found in people with depression, schizophrenia, autism and neurodegenerative diseases (including Alzheimer, Parkinson, amyotrophic lateral sclerosis).
Excess vitamin D in the body is very rare. The body has mechanisms that regulate the production of vitamin D, so after reaching a certain level of vitamin accumulation in the body, skin synthesis is stopped. A properly balanced diet can not lead to excess vitamin D in the body. Symptoms associated with excessive supply of vitamin D are observed in people taking food supplements. This applies to people who independently, without consulting a doctor or pharmacist, increase the dose above the recommended values ??or otherwise do not follow the dosage specified by the doctor or given on the leaflet.
Symptoms of excess vitamin D
– constant thirst feeling;
– lack of appetite;
– repeated nausea and vomiting;
– eye pain;
– dementia, problems with concentration;
– pruritus of the skin;
– increased urination;
– excessive sweating;
– calcification of the blood vessels, heart, kidneys or lungs (hypercalcemia).
Food products containing vitamin D
– fish (eel, herring, salmon);
– eggs (egg yolk);
– milk and milk products;
– wholegrain flour;
– spread margarine;
The most valuable source of vitamin D is eel. On average, it contains up to 1200 IU per 100 g. Further products in terms of vitamin D content are herring and salmon. They contain 760 and 520 IU, respectively, in 100 g of fresh product.
Vitamin D is sensitive to high temperatures. For this reason, dishes with the addition of these products should be boiled (in water or steamed), stewed or baked. The shorter the treatment, the more vitamin D will remain in the product.
When is the need for vitamin D supplementation?
Recommendations for vitamin D supplementation vary depending on geographic location and the number of cases of deficiency. A high number of sunny days ensures an adequate level of skin synthesis, so there is no need for supplementation. The level of vitamin D in the population is also affected by environmental pollution and the type of work. Pollutants reduce the amount of sunlight reaching, which negatively affects the process of vitamin D synthesis. This type of work applies to people performing their duties in enclosed spaces, such as offices. Stress has a negative impact on both the absorption and production of vitamin D. Official recommendations on the Polish population suggest taking vitamin D supplementation from September to April. If there are other factors limiting the supply or synthesis of vitamin D, it is recommended to take supplementation throughout the year. Very often, year-round supplementation is also suggested for seniors.
Recommendations for vitamin D supplementation
There are many factors affecting the recommended dose of vitamin D. These are geographical location, age, physiological status and obesity. It has been found that people with excessive body weight have problems with the proper use of vitamin D, so in extreme cases the recommended dose may be three times higher than for people with normal body weight. I reports that a safe daily dose without the risk of side effects is 100 µg, and the toxic dose of vitamin D is 1.25 mg.
Recommended daily doses of vitamin D
– Newborns and infants 0-6 months 400 IU (10 µg);
– Infants 6-12 months, 400-600 IU (10-15 µg);
– Premature 400-800 IU (10-20 µg) until the corrected age of 40 weeks;
– Children and adolescents 600-1000 IU (15-25 µg);
– Children and adolescents over 1200-2000 IU (30-50 µg);
– Adults 800-2000 IU (20-50 µg);
– Adults overweight 1600-4000 IU / day, (40-100 µg / day);
– Pregnant and breastfeeding women 1500-2000 IU (37.5-50 µg).
Supplementation in such a dose should begin no later than the second trimester of pregnancy.
The exact dose is determined by the physician based on body weight and possibly occurring disorders (vitamin D is used during the treatment of psoriasis).
Daily doses were also established for people with dark complexion and for those working on shifts. High concentration of melanin in the skin significantly reduces the skin synthesis of vitamin D, which is why deficiencies are more often observed among these people. In turn, people working on night shifts during the most intense radiation usually sleep off the overworked night. The recommended daily doses for these people are 1000-2000 IU (25-50 µg), depending on body weight.
Supplementation of vitamin D in the autumn and winter is a good way to maintain its normal level in the body and avoid the unpleasant symptoms associated with its deficiency. Before choosing a supplement, we advise you to perform tests showing the current vitamin D concentration in the blood, and additionally consult your doctor or pharmacist. They will help you choose the right dose of vitamin D, so that your body gets the most benefit from the started supplementation. At the same time, they will inform you how long the supplementation should last.