The doctor talked about the importance of vitamin D and the rules of intake

Residents of Russia, especially those living in conditions of limited sunlight in winter, have increasingly begun to buy vitamin D. The popularity of this vitamin is understandable — studies confirm its effect on the prevention of a number of chronic diseases. How to maintain optimal vitamin D levels — in the Izvestia article.

In everyone's house

In the first nine months of 2025, Russia has seen a 2% increase in sales of vitamin D in dosage form compared to last year, amounting to 14.4 million packages, the Honest Sign told Izvestia. The average cost of packaging for the same period increased by 22%, from 375 to 460 rubles. The largest sales growth per 10,000 people is observed in the Republic of Ingushetia and the Vologda Oblast (13% each), as well as in the Kabardino-Balkarian Republic and the Belgorod Region (11% each).

An increase in consumption with medical use and preferential prescription was recorded in the Chukotka Autonomous Okrug (+17%) and the Republic of Ingushetia with the Tyumen Region (+13%). During this period, 1,730,000 packages of vitamin D were purchased in Moscow, which is 0.8% more than last year, and sales in the Moscow Region increased by 2.1%, amounting to 1,112,000 packages.

An essential element for strengthening bones and the immune system

Elena Kosenko, the chief physician of Medline, told Izvestia that vitamin D is much more than just a vitamin, it is a prohormone that plays a key role in the work of almost all organs and systems of the human body.

— Its main and most studied function is to maintain bone health by regulating the absorption of calcium and phosphorus in the intestine. However, its receptors are found throughout the body, which explains its effect on immunity, mood, muscle strength and the state of the cardiovascular system," the expert shared.

According to her, numerous studies have confirmed the critical importance of vitamin D for bone mineralization and prevention of osteoporosis. There is also strong evidence for its role in modulating immunity — adequate vitamin D levels are associated with a lower risk of developing autoimmune diseases such as multiple sclerosis and respiratory infections. It affects the production of insulin, and its deficiency has been associated with muscle weakness, fatigue, and symptoms of depression.

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Elena Kosenko added that the correction of vitamin D deficiency brings the most tangible clinical benefits to several groups of patients. First of all, these are people with diseases of the bone system, such as patients with osteoporosis and osteopenia, for whom taking vitamin D objectively reduces the risk of fractures. Secondly, these are elderly people who have a combination of age-related decrease in vitamin synthesis in the skin, reduced sun exposure and increased bone fragility. Thirdly, deficiency correction is vital for children to prevent rickets.

"Overweight people are also at risk, as the vitamin is deposited in adipose tissue, with inflammatory bowel diseases that disrupt absorption, with dark skin, as well as residents of regions with low sunlight, which include most of Russia," Kosenko said.

How to take vitamin D correctly

As Seda Grigoryan, an endocrinologist at the Remedi clinic, shared with Izvestia, modern clinical guidelines suggest a very simple logic: do not prescribe vitamin D "just in case", but act according to the indications.

— If there are symptoms, risk factors, or a confirmed deficiency, we perform an analysis, select a dose, and monitor the condition. If there are no indications, a normal diet and reasonable sun exposure are sufficient. Daily physiological doses are preferable to any "shock" regimens. For most people, vitamin D levels above 20 ng/ml are already a physiological norm, and the goal of therapy is not records in tests, but bone health and risk reduction," Grigoryan said.

She noted that against the background of the growing popularity of self-administration, the number of cases of hypervitaminosis D has increased. Toxicity occurs with prolonged use of excessive doses of supplements, which is accompanied by hypercalcemia, deterioration of kidney function, and cardiac arrhythmias.

— This is not something that happens accidentally from sunny walks — it's almost always a matter of "shock" schemes and high doses without monitoring the analyzes. The upper safe limit for adults is about 4,000 IU per day, and it should not be exceeded without medical indications. Large bolus doses are especially undesirable, for example, 50-60 thousand mg. IU once a month: large studies have shown a lack of preventive benefits and even an increased risk of falls in the elderly," the expert emphasized.

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In turn, Elena Kosenko noted that the risk of hypervitaminosis D for the general population who take preventive doses on their own is often exaggerated. According to her, the main danger lies in the uncontrolled intake of therapeutic doses without a doctor's appointment and laboratory control. A much more common problem in Russia is precisely the shortage, which can reach 100% in the autumn-winter period among some groups of the population.

— To effectively and safely replenish the proven deficiency, an individually calculated therapeutic dose is required, which can be ten times higher than the preventive dose. This approach allows you to get the most out of this vital nutrient, avoiding unnecessary risks," the expert concluded.