Ask the Health Expert: Vitamin D – The Sunshine Vitamin

Vitamin D, despite its name, is not technically a vitamin. By definition a vitamin is an organic compound that must be obtained from dietary sources as they are not produced by the body. Vitamin D is not one chemical but many. It is naturally produced by the skin from a form of cholesterol in the presence of sunlight, specifically the ultraviolet B energy (UBV) into vitamin D3. Most dietary supplements of vitamin D are manufactured by exposing a plant sterol to ultraviolet energy and so producing Vitamin D2. Vitamin D can also be obtained from foods such as pink salmon, mushrooms, liver and egg yolks. As mushroom D2 is much more stable than D2 supplements you would do better to slice mushrooms and place them in direct sunlight for 20 to 60 minutes before eating them!

As the function of vitamin D3 and D2 are almost identical they are both known as vitamin D. Neither of these two forms are biologically active and will only perform their functions after further processing in the body. Firstly, in the liver vitamin D attaches to oxygen and hydrogen molecules to become 25-hydroxyvitamin D which is actually the marker used to measure vitamin D levels, but it is still not biologically active in this form. The compound then travels to the kidney where it is converted by an enzyme to the active form 1,25-dihydroxyvitamin D, known as calcitriol.

Vitamin D is considered a fat soluble vitamin but it also has properties of a hormone. It is best known for its job of keeping our bones healthy by increasing our absorption of calcium in the gut without which we absorb only 10% to 15% of the calcium we consume. However, it has many more functions. It is important in prevention and treatment of breast cancer and colon cancer, it is necessary for thyroid function and normal blood clotting, it is involved in the regulation of heartbeat and protects against muscle weakness. People living in the upper third of the northern hemisphere cannot produce adequate amounts of vitamin D during the winter and in times of limited sunlight, and the fact that people are spending more time indoors than any other time in human history has led to the fact that about 40% of people are deficient in this important vitamin.

Present day researchers are discovering a much wider range of functions than was previously thought. In fact, there are vitamin D receptors in many organs and body tissues including the prostate, heart, blood vessels and endocrine glands. it also controls the expression of over 200 genes and the proteins that those genes regulate. It has been proven crucial for regulating parts of our immune system. Our ability to regulate our responses to infection is very dependent on sufficient levels of vitamin D. There is increasing evidence linking vitamin D deficiency with immune disorders such as multiple sclerosis, type 1 diabetes and Crohn’s disease.

It has been shown that cells from the immune system contain all the apparatus needed to convert the precursor to calcitriol produced by the liver i.e. 25-hydroxyvitamin D, to its active form, without having to pass through the kidneys. This is extremely important for promoting antimicrobial responses to pathogens and triggering the immune response of the infection fighting white blood cells. This is possibly the way vitamin D controls T-cell function.

Increasing numbers of studies are discovering that vitamin D inhibits inflammation. At National Jewish Health a leading respiratory hospital, in fact the only one in the world dedicated exclusively to groundbreaking medical research and treatment of patients with respiratory, cardiac, immune related disorders, reported a recent study in March 1, 2012 Issue of The Journal of Immunology. Their research identified a new location at which the vitamin D receptor can bind directly to DNA and activate a gene (MKP-1) which interferes with the inflammatory cascade.

The system that integrates vitamin D has an ancestral origin involved with the primordial defense system. The vitamin D receptors were present in earlier organisms which did not have skin, bones, a cardiovascular system, kidneys or lungs which tells us that its purpose is other than that which conventional medicine knows. Vitamin D has other actions which include inhibiting of cell growth, secretion of other hormones, preventing T-cell overgrowth, and modulation of cytokines. Cytokines raise immune activity, but when they become too abundant the system goes into overload. It can cause a cytokine storm in which the lungs fill up with fluid affecting blood vessels and causing leakage; blood clots also form throughout the body. This is present in severe covid-19 cases. Vitamin D modulates many of the inflammatory pathways that are triggered during covid-19 and suppresses the actions of the body system involved in the inflammatory responses related to covid-19. The cells lining the lungs are rich in the enzyme used to convert vitamin D to its active form which inhibits the production of cytokines.

An increasing number of papers and systematic reviews have confirmed the link between low vitamin D levels and severe covid-19 infections. It appears that it could prove to be an effective tool for defense against the SARS-CoV-2 virus without adverse effects. A possible dose to obtain an effective increase in vitamin D levels would range between 5,000iu up to 10,000iu per day. This may help to improve the health of patients so they can better fight the virus and boost their defense against infection.


Author: LivingSpaces

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