Vitamin D
Vitamin D is directly related to the sun, and is not called sunlight. The vitamin is made inside the body in sufficient quantities when exposed to the sun with the help of cholesterol. Therefore, eating this vitamin is not necessary in case of exposure to sunlight. Exposure to the sun on sunny days for 10 to 15 minutes a day, two to three times a week, is enough to get vitamin D in the majority, but people with darker skin need to be exposed to the sun for longer periods to get their vitamin requirements.
Although the body’s needs are easily accessible through the sun, many people avoid sun exposure, or use sunscreen – which inhibits the manufacture of vitamin D in the skin – to protect the skin from damage caused by the sun, such as wrinkles and skin cancer. , And for the benefit of exposure to sunlight and avoid damage at the same time, the best possible exercise is to use the sunscreen after exposure for a period sufficient to get the needs of vitamin D.
The Truth About Vitamin D
Vitamin D, although called vitamin, is actually not a vitamin but a hormone produced in the body as a result of exposure to sunlight. The active form of this hormone is 1.25-dihydroxy-cholecalciferol (Calcium), called calcitriol (Calcitriol). This hormone starts in the skin and is then activated in two steps, the first in the liver, And the second in kidneys.
People living in the Arctic can not get their vitamin D needs through sun exposure, especially in the winter, as well as people who do not leave the house or whose lives are limited to indoor places and buildings, people living in crowded places where the level of Air pollution, which prevents the arrival of ultraviolet light, and dark-skinned people, as dense skin pigments can prevent up to 95% of ultraviolet rays from reaching the deep layers of skin where the manufacture of vitamin D3, and the use of protective Sun protection factor 15 or more also reduces the ability of the skin to manufacture vitamin D for up to 99%.
Functions of vitamin D hormone
When talking about the importance of vitamin D and its functions in the body, the first thing that comes to mind is the importance of absorption of calcium and phosphorus and bone health, but science is still discovering other important functions and roles of vitamin D, and include the following functions:
- To maintain the balance of calcium and phosphorus in the body by stimulating the absorption of calcium and phosphorus, and re-absorption in the kidneys, and works with thyroid gland hormone to stimulate the release of calcium from the bones and put phosphorus in the urine if the level of calcium in the blood, Calcium and phosphorus in the blood to allow bone deposition, and ensure access to sufficient amounts of vitamin D and calcium to maintain the level of calcium in the blood, and thus maintain the health of bones.
- Maintaining the normal growth, differentiation and reproduction of many cells of the body’s tissues, such as muscle tissue, skin, immune system, thyroid gland, nervous system, brain, genital organs, cartilage, pancreas, breast and colon, and its ability to prevent abnormal proliferation of cells in cancer prevention.
- Participation in metabolic processes of muscles and influence the strength and constriction, in contrast the increased risk of exposure to people who do not have vitamin D enough to weaken the muscles, which includes weakness of the heart muscle.
- Some studies have found that the level of vitamin D (calcitriol) in the blood is inversely proportional to insulin resistance and reduces the risk of type 2 diabetes.
- Vitamin D contributes to the control of immune system responses that cause certain autoimmune diseases, such as type 1 diabetes, scleroderma, inflammatory bowel disease, and rheumatism caused by autoimmune disorders.
Daily needs of vitamin d
The following table shows the daily requirements and maximum daily intake of vitamin D by age group:
| Age group | Daily needs (microgram / day) | Upper limit (microgram / day) |
|---|---|---|
| Infants 0-6 months | 10 | 25 |
| Infants 6-12 months | 10 | 38 |
| Children 1-3 years | 15 | 63 |
| Children 4-8 years | 15 | 75 |
| 5-50 years | 15 | 100 |
| 51-70 years | 20 | 100 |
| 71 years and over | 15 | 100 |
| Pregnant and nursing | 15 | 100 |
Vitamin D deficiency
Vitamin D deficiency leads to a decrease in the absorption of calcium from food. As a result, calcium is released from the bones in order to maintain a constant calcium level in the blood, causing rickets in children, and osteoporosis in adults, preventing adolescents from reaching the largest bone mass they can to get it. Where these diseases are the main results of vitamin D deficiency, but found to lack other effects include the following:
- Increased asthma risk, and was found to be associated with severe asthma in children.
- The high chance of infection in both respiratory and bacterial infections.
- Increase the chance of depression.
- High chance of getting overweight and obesity.
- Increase the chance of high blood pressure.
- Increased chance of cognitive retardation in older persons.
- High risk of death for any reason.
- High risk of death from cardiovascular disease.
- Increase the chance of high cholesterol.
- Increase the chance of cancer.
- High chance of type 2 diabetes.
- Increased risk of autoimmune diseases, such as type 1 diabetes, multiple sclerosis, and others.
Vitamin D poisoning
Vitamin D poisoning does not get much exposure to sunlight, nor has it been affected by the use of fortified foods, but vitamin D toxicity is obtained by taking over-the-counter dietary supplements. These supplements should be taken under medical supervision to prevent The incidence of any side effects, and the consumption of very large amounts rise in the level of calcium and phosphorus in the blood, which leads to the deposition of calcium in the soft tissues such as the heart, lungs, kidneys and membrane tympanic in the ear, which can result in deafness, kidney stones, calcium can also precipitate In the walls of Oo Which is considered serious if it occurs in major arteries, the risk of death may reach death, but in infants, vitamin D poisoning causes gastrointestinal infection, delayed growth and weak bones.
Vitamin D analysis
Vitamin D, which is taken or processed in the skin, turns into 25-hydroxyl-vitamin D (25). Therefore, the best analysis of vitamin D body inventory is the analysis of the 25-hydroxyl vitamin D level. To identify the definition of vitamin D deficiency and inadequate, according to the laboratories of the Mayo Clinic, a person is severely deficient vitamin D if the result of the analysis less than 10 ng / ml, while it is deficient if the result ranges from 10 to 24 ng / ml, If the result is between 25-80 ng / ml, it is normal and good, and if it is higher than 80 nano Grams / ml are considered at a level that may cause toxicity.
When should you take a vitamin D test?
Although vitamin D deficiency is common, its analysis is not routinely required by everyone because of its high cost, but it should be examined in people at high risk, such as:
- Do not get enough vitamin D because of insufficient intake, malnutrition, or insufficient exposure to sunlight.
- Such as short bowel syndrome, pancreatitis, inflammatory bowel disease, amyloidosis, (Celiac), and surgery for obesity, which results in malabsorptive bariatric surgery procedures.
- Some liver diseases, such as taking some antiepileptic drugs that increase the activity of 24-hydroxylase (24-hydroxylase), and in cases of severe liver disease or liver failure, which reduces the activity of 25-hydroxylase (25-hydroxylase) .
- Some renal conditions, such as aging and renal insufficiency, increase the activity of 1-alpha-hydroxylase, and Nephrotic syndrome, which has a low level of renal insufficiency, Protein Linkage to Vitamin D
Checking the level of vitamin d
Vitamin D levels should also be examined in people whose laboratory or radiation tests have shown vitamin D deficiency, such as:
- Low calcium level in full urine analysis (24-hour urine test) in cases of non-use of diuretic Thiazide.
- High level thyroid hormone thyroid gland.
- Elevated alkaline phosphatase (alkaline phosphatase).
- Low level of calcium or phosphorus in the blood.
- Low bone mineral density, osteoporosis, and osteopenia.
- Fractures not resulting from shocks or trauma (or high fracture).
- Skeletal pseudofractures.
It is also suggested that physicians request vitamin D analysis in all people with bone and muscular symptoms, such as bone pain, myalgias, and general weakness, as these symptoms are often misdiagnosed as chronic fatigue, In age, Fibromyalgia syndrome or depression, while these symptoms may result from vitamin D deficiency in many people, despite the absence of large scientific research supporting the association of vitamin deficiency with pain .