What Does Vitamin D3 Do?

Vitamin D3 is in fact not a vitamin but a potent immunodulatory seco-steroid, which means it’s a steroid-like molecule that’s capable of controlling the activity of the immune system. There are several forms of vitamin D. The type we get from food and exposure to the sun is called D3. The liver converts D3 to 25-D which functions as a steroid. 1,25-D is the activated form and functions as both a steroid and a hormone. It’s produced inside cells, which include the immune system and the kidneys, and in cells as a response to sunlight. The kidneys of healthy individuals convert 25-D to 1,25-D. Under hormonal control mechanisms, the enzyme 1-alpha-hydroxylase further hydroxylates 25-D into the main active seco-steroid 1,25-dihydroxyvitamin-D. Both 25-D and 1,25-D serve as endogenous ligands, a ligand being defined as an ion, a molecule or a molecular group that binds to another chemical entity to form a larger complex, for the Vitamin D Receptor, a nuclear receptor found in immune and other cell types. The VDR is responsible for transcribing 913 genes or more. Vitamin D directly or indirectly regulates 3% of the human genome. One such gene it regulates is cathelicidin, which is a naturally occurring broad-spectrum antibiotic.

Humans living in sun-rich environments have vitamin D levels between 40-70 ng/ml.The skin has the natural ability to produce vitamin D when it’s struck by ultraviolet sun rays. Dark-skinned people and those living in northern climates make less vitamin D than other people. The amount a person makes depends not only on skin pigment and where they live, but also on age and other factors. Studies show children, the elderly and woman have very low levels. One study suggested African American woman and women of child-bearing age might be deficient. Very few people get enough vitamin D from their diets.

It’s been recently suggested that vitamin D3 can be implicated in most diseases that effect man. There are two schools of thought in regards to supplementation with vitamin D. Paul J. Albert et al. in a paper titled Vitamin D: the alternative hypothesis suggests that the now popular belief that vitamin D should be supplemented is a black box epidemiology, which is a focus on risk factors related to disease outcome without satisfactorily understanding pathogenesis. They compare it to the use of HRT in menopausal women and the use of phentermine and fenfluramine for weight loss. Both seemed great in the beginning until more was learned and they were found to be harmful.

Many researchers believe that supplemental vitamin D alleviates autoimmune disease because it decreases inflammation and autoimmune symptoms. They call this view the deficiency/disease model. The other view they call the alternative model. This being the low 25-D levels could be the result of the disease and the drop in inflammation could be due to the vitamin D’s ability to slow immune function. They examined how 25-D affects the VDR to determine which model is correct.

In the deficiency/disease model autoimmune diagnoses is explained by the immune system and the VDR being overactive. The researchers state that giving vitamin D calms down the immune response by deactivating the VDR. Cancer, arteriosclerosis and other inflammatory diseases are illnesses where the immune system doesn’t function adequately which would suggest decreased VDR activity. The researchers theorize that supplementing vitamin D activates the VDR after being converted to 1,25-D. As it is possible for a person to have both cancer and an autoimmune disease it isn’t possible to activate the VDR for one disease state and slow it down for the other. Thus the deficiency/disease model isn’t a clear model as to how vitamin D works.

There are about 9 of 10 non-human cells, which persist in man, that very little is known about them. The genomes of only a fraction of these microbes have been sequenced. Some of these bacteria contribute to our well-being, but some may be pathogenic. Persistent and unique communities of microbes have been detected in people with diseases ranging from autism to obesity. The alternative model states a true recovery from autoimmune disease involves an activated immune response and a corresponding spike in symptoms due to bacterial die-off. This is known as immunopathology. The patient feels better then later worse after supplementing with vitamin D. It depends on how much the VDR is already blocked by bacterial ligands and is seen over the course of 20 years or more. Payne et al. found long-term vitamin D use was associated with increased brain lesions in the elderly. Hypponen et al. found atopy and allergic rhinitis was higher in 31 year old subjects whose parents gave them vitamin D as children.

It’s assumed that by giving vitamin D supplements 1,25-D production will be stimulated and that by raising 1,25-D to high levels the autoimmune disease won’t be exacerbated. The problem with this assumption is that 1,25-D is already above normal range because of the inability to break down the metabolite. Because most researchers only test 25-D this elevation is missed. If the levels of 1,25-D could be increased by supplementation they wouldn’t be able to bind to the VDR because the sites are already blocked by bacterial ligands. This has been supported by research data which is stated in the above mentioned article by Albert et al.

In summary popular theories of vitamin D aren’t precise and have contradictory understandings of vitamin D metabolism. 25-D is immunosuppressive. Supplementation temporarily alleviates symptoms of chronic disease but leads to long-term increase in morbidity. Molecular biology suggests low levels of 25-D is a result of autoimmune disease not a cause. Bacterial pathogens survive in the human body by secreting proteins that antagonize the VDR and disable the immune response. Elevated levels of 1,25-D exist at the site of disease and indicate the immune system is responding to an infection.

The other view on the benefits of vitamin D supplementation is described in the article Use of vitamin D in clinical practice from the Alternative Medicine Review, March 2008 by John J. Cannell and Bruce W. Hollis. They state the data comes from 18 randomized controlled trials. Those who adhere to this belief feel vitamin D deficiency is common and the majority of people are deficient. They believe that assessing serum levels of 25-hydroxy-vitamin D is the only way of determining a diagnosis of low vitamin D in an individual. There’s three treatments for such a deficiency; sunlight, artificial ultraviolet B (UVB) radiation, and vitamin D supplementation. Treatment of vitamin D deficiency in otherwise healthy patients with 2,000 to 7,000 IU vitamin D daily should be sufficient to maintain year-round 25(OH)D levels between 40-70 ng/mL. People with serious illness should be treated more aggressively to maintain levels between 55-70 ng/ mL.

While most people are aware of the importance of vitamin D in calcium absorption and bone metabolism, many doctors and patients aren’t aware of the recent research on vitamin D and the wide range of therapeutic applications it’s being used for. This is because of the discovery of vitamin D receptors in other tissues besides the bone and gut.

Based on research the authors of this article believe that assessment of vitamin D and the treatment of vitamin D deficiency with oral vitamin D supplements should become routine in clinical practice and preventative medicine. They believe Vitamin D supplementation with of 2,000 to 5,000 IU per day for adults is clinically safe and reasonable since such doses are less than that obtained by full-body sun exposure. But periodic assessment of serum 25-OH-vitamin D (25(OH)D) and serum calcium levels will help to ensure that vitamin D levels are safe and effective for maintaining health and the prevention of disease.

One of the top vitamin D researchers in the world states that the cancer rate in Iceland is 90 per 100,000 people per year, but people in the tropics have rates of 25 per 100,000. In the United States the majority of cancer is vitamin D sensitive. This is evidence that the farther away from the equator you live, the higher your risk of dying from cancer becomes.

The best way to raise vitamin D levels is exposure to the sun. But depending on where you live this isn’t always possible especially in the winter. Tanning lights are available with the proper type of light, which are different from those found in tanning salons. The only other way to raise levels is by oral supplementation. Caution should be taken to avoid overdosing. It is best to have your levels tested by a nutritionally inclined physician. There are two vitamin D tests; 1,25(OH)D and 25(OH)D. 25-hydroxyvitamin D is the better marker, because it’s strongly associated with overall health.

Although there are a number of different companies approved by the FDA to perform vitamin D testing the gold standard is DiaSorin. Their radioimmunoassay method is more accurate than others and is the one used in almost all major vitamin D studies. The DiaSorin RIA results are the results used to establish recommended levels of vitamin D. Vitamin D is measured by determining blood levels of 25(OH)D. There are three common methods. LC-MS/MS measures 25-hydroxyvitamin D2 and D3 separately. RIA (DiaSorin), which was developed in 1985, measures total 25-hydroxyvitamin D. Liaison (DiaSorin), which was developed more recently has mostly replaced RIA. The Mayo Clinic, ZRT, Esoterix use the LC-MS/MS method. LabCorp uses the Liaison method. If the lab doesn’t recalibrate against DiaSorin assays the results will be too low even as much as 40 per-cent.

On November 3, 2009 doctors Cedric Garland and Tracey O’ Connor held a seminar at the University of Toronto in Ontario, Canada. They talked on how vitamin D can be used to prevent breast and colon cancer, type 1 diabetes, hypertension and infectious diseases. Some of the best known vitamin D researchers and practitioners such as John White, Susan Whiting, Robert P. Heaney and Reinhold Vieth were presenters. The conference looked at current research and practice with vitamin D.

If buying Vitamin D make sure it doesn’t contain Vitamin A as you could get too much of this vitamin, which would be toxic.

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