Vitamin D - the vitamin we don't get enough of

What causes vitamin D deficiency?

Vitamin D deficiency in many Russian residents is due to:

• location in the northern temperate zone (above 42 degrees north latitude)
• limited exposure to the sun (office work, driving cars)
• eating meat from animals that have not been exposed to the sun (farm)
• use of sunscreens
• chronic diseases (obesity, intestinal pathology, taking a large number of medications)

You can determine the level of vitamin D in your body by taking the following test:

25-OH vitamin D (25-hydroxycalciferol) (amount)

Is Multiple Sclerosis Associated with Vitamin D Deficiency?

Scientists at McGill University in Canada conducted a study that showed that the development of multiple sclerosis is associated with vitamin D deficiency. Medical News Today reports this. Multiple sclerosis is characterized by multiple lesions of nerve tissue. According to the Multiple Sclerosis Foundation, 400 thousand people in the United States suffer from this disease. The disease is believed to be autoimmune, but there is no precise explanation of its causes or ways to predict its rate of development. Today, multiple sclerosis is one of the most common severe neurological pathologies affecting middle-aged people. Susceptibility to multiple sclerosis depends on a number of genetic and environmental factors. These factors may also influence the severity of the disease. A study by Canadian scientists showed that a lack of vitamin D in the blood is one of these factors. According to study leader Dr. Brent Richards, "Previous studies have shown that low vitamin D levels are associated with multiple sclerosis, but have not been able to prove that vitamin D deficiency causes multiple sclerosis." Previous studies have shown, in particular, a higher prevalence of multiple sclerosis at high latitudes, where there is less sunlight.

A team of researchers from McGill University examined the link between genetically low vitamin D levels and susceptibility to multiple sclerosis. The study used a method called Mendelian randomization, which helps better understand the influence of environmental factors on the occurrence of chronic diseases. Scientists analyzed data from 2,347 people who participated in the International Multiple Sclerosis Genetics Consortium study, the largest study of genetic factors in the development of multiple sclerosis to date, with a total of 14,498 patients with multiple sclerosis and 24,091 healthy people. The results found that “among participants of European ancestry, genetically lower vitamin D levels were directly associated with increased incidence of multiple sclerosis.”

Currently, there are no effective treatments for multiple sclerosis, and many drugs used for symptomatic treatment have serious side effects. “We are currently conducting randomized controlled trials to evaluate the effectiveness of vitamin D supplementation as a means of preventing and treating multiple sclerosis,” says Dr. Richards.

For the curious

Vitamin D

combines a group of vitamins (D1, D2, D3, D4, D5), of which only two forms (D2 and D3) have important biological significance.

The main biological role of calcitriol

(1,25-OH-vitamin D) is to maintain a constant level of calcium in the blood (vitamin D enhances the absorption of calcium in the intestines and, if there is not enough calcium in the blood, ensures the flow of calcium from the bones into the blood).

Over time, receptors for calcitriol, in addition to the intestines and bones, were found in the kidneys, genitals, pancreas, muscles, cells of the immune and nervous systems. Thus, it became clear that vitamin D performs a large number of different functions in the human body:

• regulates the expression of 3% of the human genome (several thousand genes)
• increases the sensitivity of the insulin receptor (prevention of insulin resistance, obesity, diabetes)
• strengthens the skeletal system
• reduces the level of parathyroid hormone in the blood
• promotes the synthesis of sex hormones (testosterone, estrogens, progesterone)
• improves reproductive function
• affects innate and acquired immunity
• prevents the development of tumors, depression, Parkinson's disease

Vitamin D (D) and the body's immune defense

Vitamin D (D) is a fat-soluble vitamin necessary for every person.
It enters the body with food, and can also be formed under the influence of enzymes from precursors in various organs (liver, kidneys, lungs, skin, prostate gland, brain, etc.) A blood test for vitamin D (D) is prescribed at the most different symptoms, because this vitamin plays an important role in stimulating the immune system. It activates the immune system's T cells (T lymphocytes) in the body, which are responsible for searching for and destroying foreign agents (bacteria and viruses). As a result of activation by vitamin D, inactive T cells turn into killer T cells (killer cells), whose purpose is to detect and destroy bacteria and viruses that cause infection in the human body.

In the case of vitamin D deficiency (insufficiency), the activation of T cells decreases, the number of killer T cells operating in tissues decreases, which leads to a weakening of the body’s protective “barrier”. Therefore, maintaining normal levels of vitamin D is necessary for an adequate protective response to the invasion of foreign agents that contribute to the development of infectious diseases in the body.

Vitamin D deficiency

A lack of vitamin D in the body can lead to the development of:

• diseases of the cardiovascular system
• immunodeficiency, allergies, psoriasis, bronchial asthma, rheumatoid arthritis
• periodontal disease
• tumors of the large intestine, mammary glands, ovaries, prostate
• chronic fatigue, depression, insomnia
• decreased muscle strength leading to a risk of falls
• decreased motility and number of morphologically normal sperm (male factor infertility)
• risk factor for premature birth, fetopathies (less than 20 ng/ml)

Achieving a vitamin D level of 50 ng/ml (125 nmol/l) reduces the risk of developing:

Vitamin D is important during pregnancy.

Its deficiency is associated with the risk of developing gestational diabetes mellitus, premature birth, preeclampsia, and various intrauterine developmental defects.

There is not a single case of teratogenic (leading to the development of tumors) effect of vitamin D in the world.

Causes of vitamin D deficiency in Russia

1. Lack of sunny days, low temperatures due to long winters in most regions, when it is not possible to receive ultraviolet rays in the amount necessary for the skin.
2. Excess body weight, in which vitamin D accumulates in subcutaneous fat.
3. Various diseases of the gastrointestinal tract, when the digestion and absorption of fats is impaired.
4. The effect of certain medications (antiretrovirals, glucocorticoids) on the metabolism of vitamin D in the body.

Vitamin D standards

Considering the different units of measurement, the recommended level is:

60 - 100 ng/ml

150 – 250 nmol/l

To convert from ng/ml to nmol/l you need ng/ml * 2.5 = nmol/l

Example: 30 ng/ml * 2.5 = 75 nmol/l

Russian Association of Endocrinologists

considers
the optimal concentration
of vitamin D in the blood of an adult to be 30-100 ng/ml,
deficiency is
20-30 ng/ml,
deficiency
is less than 20 ng/ml.

According to data presented at the 10th European Congress on Menopause and Andropause (Madrid, 2015), vitamin D levels in obese patients in Russia:

less than 20 ng/ml - 35%

20-30 ng/ml - 30%

more than 30 ng/ml - 35%

Daily Values ​​for Vitamin D

according to the recommendation of the American Society of Endocrinology (2011).

Prophylactic dose

vitamin D (when you can not detect it in the blood and take it calmly) is considered to be 4,000 IU per day.

Without medical supervision, it is not recommended to take vitamin D at a dose of 10,000 IU for more than 6 months. (Russian Association of Endocrinologists)

It is almost impossible to overdose on vitamin D. For example, in Holland, an elderly couple (90 and 95 years old) accidentally took a single dose of cholecalciferol 2,000,000 IU each.

Doctors monitored them for 2 months and did not identify any symptoms of overdose or toxicity. The maximum blood concentration of its form of 25-OH-vitamin D on day 8 was 210 and 170 ng/ml, respectively, which is slightly higher than its target values.

Vitamin D - the vitamin we don't get enough of

Not just fish oil

Officially, vitamin D belongs to the group of fat-soluble vitamins.
It enters our body with food (see Table 1). The food set is so specific that it is unfortunately impossible to provide more than 20–30% of the daily requirement with food alone. With milk protein allergies, lactose intolerance, ovo-vegetarianism and strict vegetarianism, the development of deficiency is almost inevitable.

Table 1. Sources of vitamin D in food1

Main source of vitamin

The human body is designed very wisely, therefore, in addition to all exotic foods, we also have another wonderful source of this vitamin.

Of course it's sunlight! To synthesize vitamin D in physiological quantities, it is necessary to be in the sun with your limbs exposed to sunlight (from 10 a.m. to 3 p.m.) at least twice a week. In tanned skin, vitamin D synthesis is weakened.

By the way, it’s interesting that you won’t be able to achieve an overdose of vitamin D by tanning. If the skin suddenly synthesizes excess amounts of cholecalciferol (vitamin D3), ultraviolet rays will destroy all excess.

Geographical problem

According to Harvard University, in territories located above the 37th parallel (which is the entire territory of our country), the characteristics of solar radiation due to the more acute angle of incidence of solar rays and their dispersion in the atmosphere from November to March are such that the skin practically does not produce vitamin D, regardless of the time a person spends in the sun.