Has summer brought us enough of the powerful hormone and immunomodulator - vitamin D?

In my clinical practice, I recommend vitamin D almost every day, and with this text I would like to point out its numerous positive effects on the human body. It has been the focus of interest of the professional public in recent years. Much is known about him, but even more seems to be unknown. It is represented by a group of 5 different liposoluble prohormones. Among them, the most important are vitamin D2 and D3.

It is also called calciferol and is present in food in two forms: vitamin D2 - ergocalciferol (in mushrooms and some plants), and vitamin D3 - cholecalciferol, which is present in food of animal origin (eg, eggs, dairy products, fish oil (cod), blue fish (mackerel, herring, sardines, salmon...), etc.; it is also produced by the human body when exposed to sunlight, due to UVB rays. Upon resorption from the guts into the blood stream, this vitamin goes to liver and kidneys where it is transformed into calcitriol - biologically active form of vitamin D. Vitamin D3 is much easier to transform into active form - calcitriol than vitamin D2. Storage of vitamin D in adipose tissue and liver is done in the form of calcidiol.

So far, the known effects of this vitamin/hormone on the human body have been very well studied, and among them, the most significant are:
- maintaining normal metabolism of calcium and phosphate (helps the absorption of these minerals from food in the small intestine and their incorporation into bones and teeth),
- increase of phagocytic ability of macrophages, production of antimicrobial peptides, as well as interleukin Il-10 by stimulation of T-cells, antimicrobial peptides and cytokines, etc., thereby improving the function of the immune system,
- effect on cell division,
- controlling apoptosis....

Vitamin D deficiency causes the most intense changes in the bones. Among them, the most characteristic are:
- rickets (deformity of bones and skull),
- osteomalacia (muscle and bone weakness) and
- osteoporosis (loss of bone structure and mass).

However, recent studies also suggest that people with vitamin D deficiency are more likely to get:
- malignant diseases
- autoimmune diseases,
- high blood pressure and heart attack,
- infectious diseases,
- autism,
- diabetes,
- colds,
- eczema and / or psoriasis,
- osteoporosis,
- asthma,
- depression,
- obesity,
- inflammatory bowel disease, including Crohn's disease,
- eye yellow spot degeneration,
- Alzheimer's disease,
- multiple sclerosis,
- rheumatoid arthritis,
- hearing loss,
- infertility,
- migraine attacks,
- schizophrenia...

Regarding malignant diseases, there is a growing number of professional papers that explain the connection between vitamin D deficiency in the body and the occurrence of cancer of the colon, breast, and prostate. Today, its role in the prevention of uncontrolled growth of intestinal microflora and improving the function of the intestinal barrier is being investigated. This implies that vitamin D has a significant role as an adjunct in the treatment of inflammatory processes in the intestines, Crohn's disease. At least 11 studies have confirmed the finding that a higher incidence of miscarriages is more common in women with vitamin D deficiency. Because sleep is controlled by the hypothalamus and higher centers of the central nervous system, as well as neurotransmitters (some of which are involved in pain perception), some studies have linked vitamin D supplementation to the prevention and treatment of chronic pain.

People who are predisposed to develop vitamin D deficiency are those who are not exposed to the sun enough, who wear long clothes and cover most of their body, as well as people who live in the northern parts of the planet and have few sunny days during the year. The following categories of the population are also at risk of developing vitamin D deficiency:
- babies feeding by instant formulas (since 2008, American Academy of Pediatrics recommends that infants who are fed exclusively breast milk should take 400 IU of vitamin D per day, since breast milk is an insufficient source of of this vitamin),
- dark-skinned people (these people produce less vitamin D under the influence of UVB than light-skinned people),
- elderly people, and
- persons who have various (chronic) diseases (inflammatory bowel disease, obesity etc.).

Vitamin D intoxication can occur in those people who are supplemented with vitamin D supplements, as well as by eating foods enriched with vitamin D. Then, there is an accumulation of vitamin D in the liver and adipose tissue of people and signs of intoxication. The most significant signs of vitamin D intoxication are: increased calcium in the blood, slowed mental and physical development, decreased appetite, nausea, nausea and vomiting, kidney and heart disorders, increased blood pressure, fetal development disorders. To avoid vitamin D intoxication, people are advised not to take more than 4,000 IU per day. Studies have shown that a daily dose of 40,000 IU to 100,000 IU per day can lead to toxic effects after several months of use.

Studies focused on vitamin D and its health impact, proved that this vitamin is extremely important for the normal functioning of our organism and our defense system. The recent situation with the COVID-19 pandemic convinced us of this, when this vitamin was added to the treatment protocol for patients with COVID-19 infection. On the other hand, in medical practice, I think that insufficient importance is given to routine determination of vitamin D levels in the blood. Therefore, supplementation is lacking, because we do not know its current value. Dealing with integrative medicine and holistic treatment of the body, I noticed that we are almost all deficient in vitamin D; the only question is how big the deficit is and how long it lasts. A longer-term deficit will open the door to a bad process in the body (previously mentioned). Also, through practice, I notice that the dosage of this vitamin creates great doubts, both for patients and doctors. The recommended daily allowance of vitamin D (RDA), as well as the upper limit (UL), depends on the age of the subjects and ranges from 400IJ to 800IJ. This daily recommended dose is completely insufficient to raise the low value of this vitamin to its optimal value in the body. It can be considered a dose of maintaining a good value of this vitamin in the blood of the subjects (which I did not see in practice during the first examination of patients, but only at the controls of patients that I previously supplemented with this vitamin). Also, I have had in practice patients who determined the value of this vitamin in the blood after returning from the seaside and their values were below or near to recommended lower limit. This would indicate that they either did not sunbathe or used excessively strong factors to block UVB radiation. Therefore, the articles in popular magazines that speak in favor of sunbathing can make reserves of this vitamin for winter days, are not exactly true.

At the end, I would like to summarize - vitamin D is a vitamin-hormone that is extremely important for the entire human body, and not only for the bone and joint system, when it is the focus of rheumatologists and endocrinologists who deal with osteoporosis. For that reason, it should be routinely monitored along with other biochemical parameters and, if the findings indicate, supplementation of the organism is recommended, which would enable the optimal value of this vitamin in the blood throughout the year.