Foto: BB.LV / Витамин D
Dr. Karin Amrain is a specialist in internal medicine, a board member of the Austrian Society for Bone and Mineral Metabolism and the Austrian Society for Endocrinology and Metabolism. In addition to her medical practice, she is involved in clinical research, [reports](https://www.activebeauty.hu/egeszseg/d-vitamin-egy-endokrinologus-valaszol-a-legfontosabb-kerdesekre/) Active Beauty. ### Why the body needs vitamin D Strictly speaking, vitamin D is not quite a vitamin. It is a prohormone, meaning a precursor to a hormone that is converted in the body into the active steroid hormone calcitriol. One of its most important functions is related to calcium metabolism. Vitamin D affects the absorption of calcium in the intestines and its excretion by the kidneys, making it especially important for bone health. Women during menopause should pay particular attention to this issue, as the risk of osteoporosis increases. In children, severe vitamin D deficiency can lead to rickets and deformation of growing bones. Vitamin D is also linked to the functioning of the immune system. According to the endocrinologist, this is of interest in the context of infections, autoimmune diseases, and cancer. ### Can vitamin D protect against cancer? It cannot be definitively stated that taking vitamin D prevents the development of cancer. As Amrain explains, there is currently insufficient data on the impact of vitamin D on cancer incidence. However, according to the specialist, there is data on patients who have already been diagnosed with cancer. According to the information she provided, in such patients, taking vitamin D is associated with a 10–15% reduction in the risk of death. However, this does not mean that vitamin D can be used instead of cancer treatment. ### What about diabetes? Vitamin D is involved in the metabolism of sugars and fats and is associated with the production, release, and use of insulin. The material notes that its deficiency may be linked to an increased risk of insulin resistance, type 1 and type 2 diabetes, as well as vascular damage. According to Amrain, existing data indicate a risk reduction of about 18% with vitamin D supplementation. Additionally, individuals with prediabetes may have increased chances of returning to normal glucose metabolism. However, the endocrinologist notes that there are currently not enough large studies on this issue. ### Where do we get vitamin D? The body is capable of producing most of its vitamin D on its own under the influence of sunlight, primarily UVB rays. This is why it is often referred to as the "sunshine vitamin." It can also be obtained from food. Sources include fatty sea fish, such as mackerel and sardines, sun-dried mushrooms, and eggs. However, according to the specialist, a typical diet provides only a small part of the body's needs. According to the endocrinologist, the recommended daily intake of vitamin D is about 600 IU for children and 800 IU for older adults. However, with a regular diet, a person typically receives only about 100 IU per day, and the rest must be produced by the body under the influence of sunlight. The rest should come from sunlight, but in winter in our latitudes, this may be insufficient. In cases of established deficiency, vitamin D supplements may be used. ### How to tell if you are lacking vitamin D The problem is that deficiency often does not manifest itself in any way. With very pronounced deficiency, nonspecific fatigue and muscle pain may occur; however, according to the endocrinologist, this is more of an exception. Therefore, it is not reliable to determine vitamin D levels solely based on how one feels. If deficiency is suspected, vitamin D levels can be checked through a blood test for calcidiol. A level in the range of 40–90 ng/ml is considered desirable. ### Who is at risk? Vitamin D can accumulate in the liver and adipose tissue. However, in countries where there is insufficient sunlight in winter, its deficiency remains a common problem. The endocrinologist identifies people working shifts, those who rarely spend time in the sun or cover a large part of their skin, as well as individuals with darker skin, as being at increased risk. Increased attention to vitamin D levels may also be required for pregnant women, older adults, and patients with prediabetes and diabetes. People with Crohn's disease and ulcerative colitis may be more susceptible to deficiency. Additionally, the absorption of vitamin D can be affected by certain medications. According to Amrain, a significant portion of people in at-risk groups should pay special attention to their vitamin D intake, at least in winter. ### How to take vitamin D properly The endocrinologist recommends preferring high-quality supplements. Since vitamin D is fat-soluble, some products already contain the fat component necessary for its absorption. Generally, small daily doses are preferable to infrequent intake of very high doses. However, the regimen may depend on the individual: for example, for those who frequently forget to take the supplement daily, the doctor may suggest a different schedule. The main thing is not to determine the dosage on your own. ### Can you overdose? Yes. Vitamin D can accumulate in adipose tissue, so theoretically, intoxication is possible. According to the endocrinologist, the likelihood of severe poisoning is very low, but it cannot be completely ruled out. With moderate overdose, symptoms may include nausea, loss of appetite, abdominal cramps, and vomiting. With extremely high doses, the consequences can be significantly more serious — up to confusion and coma. This is why the specialist does not recommend taking vitamin D uncontrollably without knowing its level in the body. ### Vitamins cannot replace a healthy lifestyle Vitamin D indeed plays an important role in maintaining bone health and the proper functioning of the immune system. However, it is not advisable to expect that taking supplements will compensate for an unhealthy lifestyle. The endocrinologist reminds us that the foundation of health remains a balanced and varied diet with minimal amounts of highly processed foods, physical activity, adequate sleep, and the ability to manage stress. Therefore, vitamin D should not be viewed as a universal remedy "for all ailments," but rather as an important component for the body, the deficiency of which should be corrected consciously and in appropriate dosages when necessary.
