Dr. Ilya Barsukov, an endocrinologist, points out that vitamin D plays an important role in supporting immunity, maintaining muscle health, and enhancing cognitive functions.
According to him, vitamin D studies have historically been associated with the prevention of rickets in children and osteoporosis in the elderly. However, current clinical guidelines recommend checking vitamin D levels in the elderly, patients with bone diseases, those with endocrine disorders, obesity, chronic kidney disease, as well as pregnant and breastfeeding women, people with dark skin, and those taking certain medications.
He says: “It later became clear that vitamin D has an effect that goes beyond bone health, as it plays a role in supporting immunity, muscle health, and cognitive functions. This data formed the basis for expanding the recommendations related to it, and the new guidelines aim to differentiate between cases in which the examination requires its inclusion in routine medical examinations, and those in which it is carried out at the patient’s request.”
According to the expert, the prevalence of vitamin D deficiency is linked to geographical location, since its primary source is synthesis in the skin under the influence of ultraviolet radiation. Therefore, residents of countries and regions that do not receive sufficient ultraviolet radiation throughout the year are more susceptible to this vitamin deficiency.
He says: “Ergocalciferol (D2) and cholecalciferol (D3) differ in their chemical structure, but cholecalciferol is more widely used in medical practice. Both forms regulate calcium metabolism. Preventive doses range between 1000 and 2000 IU daily, while therapeutic doses are higher and are determined based on test results.”
When the recommended doses are followed, the risk of side effects is minimal. However, toxic effects, such as hypercalcemia (high blood calcium levels), may occur if vitamin D concentrations exceed 150 nmol/L for an extended period. Therefore, high doses should be administered under medical supervision, taking into account any co-existing medical conditions, such as hyperparathyroidism, in which calcium levels are naturally elevated.
The doctor points out that vitamin D is necessary for calcium absorption, so the recommendations regarding it and calcium are related, but neither replaces the other.
