True and myths about vitamin D

In autumn, the amount of sunny days is sharply reduced, accordingly, people seek to compensate for the lack of light by taking vitamin D, popularly called solar vitamin. It is believed that this substance is necessary for all residents of the northern regions of the planet, and that it can prevent many diseases. We decided to check that science is actually known about vitamin D.

It is necessary to regularly take the analysis to determine the content of vitamin D and with its lack - start taking vitamin

Many clinic And laboratories In his own list services List Analysis of vitamin D. Sites, dedicated Healthy image life, Recommend Regularly it hand over, and with reduced indicators, immediately start taking vitamin D. "Gazeta.ru" in the article "Russians called tests that need to be passed in the fall" With reference to the founder of Health-Tech projects, Olga Osokina also mentions an analysis for vitamin D.

Russian Association of Endocrinologists Accepted Such a classification of vitamin D:

• 30–100 ng/ml - adequate level;
• 20-30 ng/ml - vitamin D deficiency;
• 10–20 ng/ml - vitamin D deficiency;
• Below 10 ng/ml - a pronounced deficit.

Based on these calculations some Experts literally declare About the pandemia of the lack of vitamin D. They accuse of this both the climate of the country as a whole and changes in lifestyle - more and more people work in offices or other rooms, and not in the open air, move less on foot, and also meet in closed rooms, for example restaurants and bars. 

However, there is no unanimity among foreign specialists regarding the norms of the content of vitamin. In particular, scientists from the University of Boston's medical school drew attention to the different sensitivity of the reagents used for analysis and Recommended Consider a healthy content above 40 ng/ml, and for children - at least 60 ng/ml. But the other group of American scientists, having studied the data of a national survey of the state of health and nutrition in 2007-2010, came to the conclusion that the existing norm was overstated and recommended to establish a detachment threshold of 12.5 ng/ml. 

Moreover, the normative level of vitamin was established by a group of scientists as arbitrary value (Arbitry Value), recognizes In an interview with New York Times, the head of the study by Kliffard Rosen. At the time of the study, scientists were convinced that a decrease in vitamin D levels always leads to an increase in the content of parathormone (PTG), which acts on bone tissue extremely destructively. To prevent such a negative impact, scientists considered it permissible to choose a high value of the norm of vitamin D, as well as determine a high preventive dose of 600-800 IU. However, further studies have shown that the relationship between vitamin D and PTG levels is not so direct - moreover, the PTG was not so dangerous for bone tissue. However, the norms were not revised.

Thus, today, experts have no consensus on what is considered the normal content of vitamin, and what can already be considered as a pathology. Dr. Stephen Cummings, a researcher at the California Pacific Medical Center, says this: “Laboratory should stop screening at vitamin D level and no longer recommend Vitamin D additives, and people, in turn, should stop hope that Vitamin D additives will protect them from a number of diseases or extend their lives.” At the same time, Cummings stipulatesWhat is an exception to patients with celiac disease, Crohn's disease and those who live in harsh climatic conditions and are not able to consume vitamin D with food through grain and dairy products, vitamin is really shown.

Most of the untruth

Vitamin D reduces the risk of fractures and osteoporosis

Vitamin D. counts important substance For protection our bones from fractures, as well as for prevention The development of osteoporosis is a disease characterized by a decrease in the density and strength of bones.

One of the largest studies of vitamin D called Vital, it began to be held in the United States in 2010, but planned to be finished by 2025. Scientists are watching 25,871 participants. Volunteers are divided into four groups: the first accepts vitamin D and omega-3, the second-vitamin D and placebo instead of omega-3, the third-the real omega-3, but the placebo instead of vitamin D, the fourth-two placebo. Neither the participants in the study, nor the doctors who evaluate their state of health know who is in which group. The phase of medication lasts a little more than five years, the rest of the time the participants are under the control of specialists. In 2020, scientists published the first conclusions of the study. It turned outthat the reception of vitamin D and omega-3 Not prevented The risk of falls and fractures among the participants. In addition, scientists noted that the reception of these substances:

- Not reduced the risk of breast cancer, prostate cancer or colorectal cancer;

-did not reduce the risk of developing cardiovascular diseases;

- He did not contribute slowdown in a decrease in cognitive abilities;

-did not reduce the risk of a heart attack, stroke or death from cardiovascular diseases; 

- Not reduced frequency and intensity of migraines;

- I did not show influence on the weight of the participants, their BMI, bone density and obesity;

- did not reduce the risk of development age -related macular degeneration (the most common reason for the irreversible loss of central vision among the elderly);

- Not reduced The pain in the joints of the elderly participants.

In addition to Vital, other major studies were also conducted in the world to determine whether the preventive technique of vitamin D can protect against osteoporosis and reduce the risk of fractures. However, scientists did not come to a single conclusion. There are studies in which vitamin D is taking reduced the risk of falls and fractures, other studies demonstrated it Uselessness, and in some even a group taking placebo, fell Less and less often broke the bones. Therefore, it is unambiguous to talk about the unconditional benefit or at least the safety of taking large doses of vitamin D for the prevention of osteoporosis prematurely.

This is not for sure

Vitamin D reduces the likelihood of cancer

Vitamin D is also attributed to oncupressor properties. Reportedthat "it affects glucose metabolism in cancer cells, this is especially manifested with breast cancer in women." It is also argued that "the cancer of the colon (colorectal) and the liver are neutralized by increased doses of vitamin D and its compounds." Vitamin D. Included to the so -called anti -cancer menu, and "Moscow 24" Published The material called "Vitamin is named, preventing intestinal cancer."

Vital study, which has already been mentioned above, Not discovered Evidence that vitamin D intake reduces the risk of breast cancer, gland or colorectal cancer. In total of 12,927 participants taking vitamin D, oncological diseases were diagnosed in 793 (that is, 6.1%). There were 12,944 people in the placebo group, 824 of whom fell ill with oncological pathology (6.3%). As can be seen from these numbers, the difference was only two tenths of a percentage, which is not considered a statistically reliable change. At the same time, the intake of vitamin D reduced by 17% the death of cancer in this study. Scientists report that to determine the need to take high doses of vitamin D with already diagnosed cancer, additional studies are needed.

To the absolutely opposite conclusions Australian experts from the Quinskland Institute of Medical Research came. The experiment was attended by 21,315 people, 10,662 of whom received vitamin D, and 10,653 - a placebo. During the observation (average intervention time-five to seven years), 1,100 people died from various reasons, of which 538 took placebo, and 562-real vitamin, that is, the reception by 0.22% increased the risk of total mortality. At the same time, death from cancer was higher by 15% in a group taking real vitamin. 

Japanese scientists focused On the effects of vitamin D exclusively on already diagnosed cancer of the gastrointestinal tract. They selected 417 patients (esophagus cancer - 10%; stomach cancer - 42%; colorectal cancer - 48%) and for several years (the median surveillance period - three and a half years) gave them real vitamin or placebo. The statistically significant improvement in five -year survival (the main prognostic indicator for cancer) in the intervention group could not be detected. To the similar conclusions American doctors also came. They narrowed the research field to the same form of cancer-colorectal metastatic and focused on patients receiving chemotherapy. The addition of high doses of vitamin D during treatment did not lead to a reliable improvement in survival without the progression of the disease.

Thus, apparently, vitamin D does not affect the risk of developing cancer (one study shows a statistically insignificant increase in incidence, the other is a statistically slight decrease). Regarding whether vitamin D can extend the life of those who have already been diagnosed with cancer, scientists disagreed radically. Additional studies are needed. However, the progression of oncological diseases of the gastrointestinal tract vitamin D, judging by the research, does not affect.

This is not for sure

Vitamin D intake is needed for the prevention and treatment of coronavirus infection

During Pandemia new coronavirus infection vitamin D Entered To many recommendations. In different versions Offered start taking to prevent the disease or to reduce The risk of complications.

Separate research And Observations They showed this dependence: the lower the level of vitamin D in the patient before the disease, the more pronounced the symptoms were. Scientists suggested that the influence of vitamin D on the severity of the COVID-19 course is associated with its ability to stimulate the immune system to combat pathogenic viruses. However, further studies have refuted this hypothesis.

British doctors Selected More than 6,000 volunteers who have not regularly received vitamin additives before. Then they determined the level of vitamin in half the volunteers and asked them to take additives in different doses. It turned out that the vitamin group was sick at least and no easier for those who did not accept additives. Similar design research Spent also Norwegian doctors. It was attended by 34,000 volunteers, some of which received vitamin D, and part - placebo. They did not reveal a decrease in the frequency or severity of infections, including coronavirus, in the reception group. Kokrainovskaya library, one of the largest resources for evidence -based medicine, analyzing the Spanish and Brazilian experiments, also reportsthat the protective role of vitamin D in coronavirus has not been proven.

Not true

Vitamin D intake can cure depression

Additives With "solar vitamin" attributed Another Healing property - supposedly the replenishment of this substance in the body is capable of improve The mood of people and treat them from depression.

Vitamin D really Playing An important role in the work of nerve cells, and clinical depression Related With violation of their work. It would be natural to assume that the lack of vitamin will entail failures in work that will affect mental health. In 2018, Canadian scientists from the University of McMaster Spent metaanalysis of existing studies about the relationship of low levels of vitamin D and the risk of clinical depression. The low levels of the content of this substance really correlated with a higher prevalence of depression. However, the correlation is not yet a causal relationship. It is possible that people with depression can have a lower level of vitamin D, since, being in this psychological state, they eat worse and walk less. Moreover, the researchers noted that the analyzed experiments relied on a small sample, took a different level of its content as a lack of vitamin and used different questionnaires for self -reporting about the symptoms of depression, so their conclusions cannot be called accurate. 

The experiment more correct in methodology was conducted by American scientists. They Selected 18 353 volunteers, at the time of selection, none of them had symptoms of depression. For five years, some of them received high doses of vitamin D, and part - a placebo. The risk of depression in both groups turned out to be the same, the preventive method of vitamin did not reduce the incidence of depression. 

Vitamin did not show good results for the treatment of already diagnosed depression. Analyzing The data of six studies, including in the amount of 1203 patients with already diagnosed depression, scientists could not confirm that the additive with vitamin D would improve their psychological state more effectively than placebo. Thus, the intake of vitamin D is not able to protect against the occurrence of depression or help in its treatment.

Not true

Image on the cover: Maxpixel

What do our verdicts mean?

Read on the topic:

1. Is it true that vitamin C helps to cure colds?
2. Is it true that in the winter and spring months it is necessary to prevent vitaminosis?