Metabolismo da vitamina D no organismo

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Existem duas formas básicas de vitamina D: colecalciferol (vitamina D3) e ergocalciferol (vitamina D2). Ambas podem ser obtidas através de alimentos ou suplementos vitamínicos. A vitamina D3, porém, pode também ser produzida pelo nosso corpo. Através do colesterol que é consumido nos alimentos, conseguimos obter uma substância chamada 7-dehidrocolesterol. Este colesterol se deposita nas células da pele e, quando exposto à luz solar (raios UV-B), se transforma colecalciferol (vitamina D3).

Vitamina D

Tanto o colecalciferol (vitamina D3) quanto o ergocalciferol (vitamina D2) são formas inativas da vitamina D. Para que a vitamina D possa exercer seus efeitos no organismo, mais duas metabolizações são necessárias.

O processo se dá da seguinte maneira: as vitaminas D3 e D2 obtidas na alimentação e/ou exposição solar são transportadas para o fígado, onde serão transformadas em calcidiol (25-hidroxivitamina D). O calcidiol é a forma que o corpo usa para armazenar a vitamina D. Por isso, quando queremos saber se o paciente tem níveis adequados de vitamina D no corpo, dosamos no sangue os níveis de 25-hidroxivitamina D (25OH vit D).

Quando o organismo sente necessidade de agir sobre os níveis de cálcio do sangue e dos ossos, uma parte desta 25-hidroxivitamina D é transportada até o rins, onde sofrerá o último processo de metabolização, transformando-se em calcitriol (1,25-hidroxivitamina D), esta sim a forma ativa da vitamina D.

Portanto, resumindo, a obtenção e ativação da vitamina D podem seguir dois caminhos:

Fonte: http://www.mdsaude.com/2013/01/vitamina-d.html?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+mdsaude+(MD.Saude)

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Diversos depoimentos médicos – Vitamin D prevents breast cancer

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(NaturalNews) You’ve heard the good news about vitamin D for years: It’s a “miracle” medicine that reduces cancer rates by 77% according to previous research

breast_cancer_survivor_pree1

(http://www.naturalnews.com/021892_cancer_Vitamin_D_cancer_industry.ht…). It also happens to be a powerful anti-cancer medicine that can both prevent and help reverse breast cancer.

Yet, bewilderingly, the cancer industry still refuses to teach women about vitamin D. Ever wonder why?

Today, we bring you a compilation of expert quotations on vitamin D and breast cancer, cited from some of the most authoritative books and authors in the world. Feel free to share what you learn here with others who may also be suffering from breast cancer.

Vitamin D and breast cancer

Sunlight triggers the formation of vitamin D in the skin, which can be activated in the liver and kidneys into a hormone with great activity. This activated form of vitamin D causes “cellular differentiation” – essentially the opposite of cancer. The following evidence indicates that vitamin D might have a protective role against breast cancer: Synthetic vitamin D-like molecules have prevented the equivalent of breast cancer in animals.
– The Natural Pharmacy: Complete A-Z Reference to Natural Treatments for Common Health Conditions by Alan R. Gaby, M.D., Jonathan V. Wright, M.D., Forrest Batz, Pharm.D. Rick Chester, RPh., N.D., DipLAc. George Constantine, R.Ph., Ph.D. Linnea D. Thompson, Pharm.D., N.D.

Two equally effective sources of vitamin D in humans are derived from plant ergosterol, which is converted to ergocalciferol (vitamin D2) and cholecalciferol (vitamin D3) by the action of sunlight on the skin. The body uses vitamin D3 for normal immune system function, to control cellular growth, and to absorb calcium from the digestive tract. Vitamin D3 can inhibit the growth of malignant melanoma, breast cancer, leukemia, and mammary tumors in laboratory animals. Vitamin D3 can also inhibit angiogenesis, the growth of new blood vessels that permit the spread of cancer cells through the body.
– Permanent Remissions by Robert Hass, M.S.

There’s surprising new evidence that older women who skimp on foods rich in vitamin D are more likely to develop breast cancer, according to Frank Garland, Ph.D., of the Department of Community and Family Medicine at the University of California at San Diego. This may also help explain fish’s anticancer protection, because fatty fish is packed with vitamin D. Specifically, Dr. Garland finds that dietary vitamin D wards off postmenopausal breast cancer in women over fifty, but not in women who get cancer at younger ages.
– Food Your Miracle Medicine by Jean Carper

In animals fed a high fat diet, which normally would produce a higher incidence of colon cancer, supplements of calcium and vitamin D blocked this carcinogenic effect of the diet. Vitamin D inhibits the growth of breast cancer in culture, and also seems to subdue human breast cancer. Cells from human prostate cancer were put into a “…permanent nonproliferative state”, or shut down the cancer process, by the addition of vitamin D. Human cancer cells have been shown to have receptor sites, or stereo specific “parking spaces” for vitamin D.
– Beating Cancer with Nutrition by Patrick Quillin

Even though vitamin D is one of the most powerful healing chemicals in your body, your body makes it absolutely free. No prescription required. Diseases and conditions caused by vitamin D deficiency: Osteoporosis is commonly caused by a lack of vitamin D, which impairs calcium absorption. Sufficient vitamin D prevents prostate cancer, breast cancer, ovarian cancer, depression, colon cancer, and schizophrenia. “Rickets” is the name of a bone-wasting disease caused by vitamin D deficiency.
– Natural Health Solutions by Mike Adams

George’s Hospital Medical School in London finds local production of vitamin D in breast tissue reduces the risk for breast cancer. For women with low breast tissue levels of vitamin D the risk for breast cancer rose by 354%! This study suggests women sunbathe with breast tissue exposed to the sun to enhance local vitamin D production. The provision of 400 IU of vitamin D per day has been found to reduce the risk of pancreatic cancer by 43%.
– You Don’t Have to be Afraid of Cancer Anymore by Bill Sardi

Taken together, these facts suggest that vitamin D and its derivatives may play a role in regulating the expression of genes and protein products that prevent and inhibit breast cancer. The cancer-stopping power of vitamin D has been documented in osteosarcoma (bone cancer), melanoma, colon cancer, and breast cancer. These cancer cells contain vitamin-D receptors that make them susceptible to the anticancer effects of this vitamin-hormone made by the skin when it is exposed to sunlight. Vitamin D-rich foods include salmon, tuna, fish oils, and vitamin D-fortified milk and breakfast cereals.
– Permanent Remissions by Robert Hass, M.S.

Low levels of vitamin D may also increase the proliferation of white blood cells and may accelerate the arthritic process in rheumatoid arthritis. Vitamin D supplements are likely to be useful in retarding these adverse effects of alterations in metabolism. Low levels of vitamin D have been linked to several cancers including those of the colon, prostate and breast. Laboratory experiments show that vitamin D can inhibit the growth of human prostate cancer and breast cancer cells. Lung cancer and pancreatic cancer cells may also be susceptible to the effects of vitamin D.
– The New Encyclopedia of Vitamins, Minerals, Supplements and Herbs by Nicola Reavley

Laboratory experiments show that vitamin D can inhibit the growth of human prostate cancer and breast cancer cells. Lung cancer and pancreatic cancer cells may also be susceptible to the effects of vitamin D. Sunlight also seems to be protective against several types of cancer including ovarian, breast and prostate cancers; and this effect may be mediated by vitamin D levels. Synthetic vitamin D-type compounds are being investigated for their potential as anticancer drugs.
– The New Encyclopedia of Vitamins, Minerals, Supplements and Herbs by Nicola Reavley

If mutations aren’t corrected or if a cell has already undergone malignant transformation, activated vitamin D can team up with other proteins to stimulate programmed death of abnormal cells. This evidence, along with animal studies, suggest that a girl who lacks adequate vitamin D during puberty years will have abnormal breast development. This, in turn, may increase a woman’s susceptibility to risk factors such as alcohol for breast cancer development. In other words, the window of greatest opportunity for vitamin D to reduce breast cancer risk may be during childhood and puberty.
– The Vitamin D Cure by James Dowd and Diane Stafford

A key development for vitamin D was the appearance of increasing evidence that experts had detected a strong relationship between vitamin D and breast cancer risk. The important Nurses Health Study found a 30 percent lower risk of breast cancer in pre-menopausal women when comparing the highest to the lowest intakes of vitamin D, calcium, and low-fat dairy, especially skim milk.
– The Vitamin D Cure by James Dowd and Diane Stafford

Out of every 100 women who might get breast cancer, 50 of them can avoid breast cancer by simply getting adequate levels of vitamin D in their body, and that’s available free of charge through sensible exposure to natural sunlight, which produces vitamin D. This vitamin, all by itself, reduces relative cancer risk by 50 percent, which is better than any prescription drug that has ever been invented by any drug company in the world. Combine that with green tea, and your prevention of breast cancer gets even stronger.
 Natural Health Solutions by Mike Adams

There’s so much more to vitamin D than enhancing calcium absorption; its anticancer benefit is just one other possibility. Most of 63 recently reviewed studies found a protective effect between vitamin D status and cancer risk. A study presented at the 2006 American Association for Cancer Research meeting suggested that an increase in vitamin D lowered the risk of developing breast cancer by up to 50 percent. How might vitamin D help?
– Food Synergy: Unleash Hundreds of Powerful Healing Food Combinations to Fight Disease and Live Well by Elaine Magee

Place sunshine or vitamin D pills on your list of preventive or therapeutic measures. A daily intake of 2,600 units of vitamin D (65 mcg) is recommended to attain blood concentrations that will optimally protect against disease. There is no way the diet can provide this much vitamin D. Sun-starved females are at great risk for breast cancer, particularly women living in northern latitudes where wintertime sun exposure produces little vitamin D because of a decline in UV radiation in solar light.
– You Don’t Have to be Afraid of Cancer Anymore by Bill Sardi

Sunlight produces vitamin D in humans. A deficiency of vitamin D is linked with breast cancer. Was the increase in male breast cancer caused by magnetic fields or by lack of vitamin D? These are the types of questions that make it difficult to ascertain if there is a link between EMF exposure and cancer. To make matters worse, a cell biologist doing work on EMFs for the Department of Energy, faked data linking cancer to electromagnetic fields in order to gain $3.3 million worth of grants for scientific research.
– You Don’t Have to be Afraid of Cancer Anymore by Bill Sardi

The dosage of vitamin D required to inhibit the growth of prostate cancer may be much higher than the recommended daily allowance (RDA) of 400 international units per day. Since vitamin D can be toxic in doses that greatly exceed this value, researchers have developed synthetic analogues of vitamin D that retain the ability to inhibit cancer cell growth without the toxicity associated with high doses. These analogs have been successfully used in animal models of leukemia and breast cancer. Vitamin D may be related to other cancers.
– Permanent Remissions by Robert Hass, M.S.

Sunlight exposure, which leads to an increased level of vitamin D, correlates with a reduced risk of breast cancer. I usually recommend small amounts of vitamin D (400 to 1,000 IU) for those people without sunlight exposure, especially during the winter. I also occasionally recommend cod liver oil during the winter months as a source of vitamin D and omega-3 fatty acids. Vitamin D deficiency is very common in the elderly and in people who live in parts of the world with little sunlight; it is also one of the major contributing factors to osteoporosis.
– Herbal Medicine, Healing and Cancer: A Comprehensive Program for Prevention and Treatment by Donald R. Yance, j r.,C.N., M.H., A.H.G., with Arlene Valentine

But how does vitamin D actually work? For many years that was a mystery. The “revolution of information” on vitamin D began in 1968, when J.W. Blunt and colleagues discovered the form of vitamin D that actually circulates in the blood (25-OH-D3). This hormonal form of the vitamin, created in the kidneys, is ultimately responsible for the classical action of the vitamin. At the molecular level, some cancer cells appear to have receptors on their surfaces that are capable of receiving the vitamin D molecule. Scientists studied cancer cells from 136 patients with breast cancer.
– Cancer Therapy: The Independent Consumer’s Guide To Non-Toxic Treatment & Prevention by Ralph W. Moss, Ph.D.

Symptoms of vitamin D toxicity include anorexia, disorientation, dehydration, fatigue, weight loss, weakness, and vomiting. New analogues of vitamin D3 allow cancer victims to take high doses of the vitamin without fear of elevating calcium in the blood to dangerous levels. These new forms of vitamin D have very high potency in controlling cell proliferation and differentiation. One of these, calci-potriol, can be used topically to treat psoriasis and inhibit the growth of metastatic breast cancer in patients with whose tumors have vitamin D receptors.
– Permanent Remissions by Robert Hass, M.S.

In an investigation into the relationship of breast density as measured by mammography to serum-vitamin D levels, it was found that there was a strong inverse correlation; the higher the density, the lower the vitamin D levels. Does the blood level of vitamin D at the time of diagnosis of breast cancer make a difference in a woman’s time of survival? Yes, it does.
 The Clinician’s Handbook of Natural Healing by Gary Null, Ph.D.

Although not part of the study, outdoor exercise where you are getting some (but not too much) sun exposure also raises vitamin D levels. Low levels of vitamin D have been associated with a greater risk of cancer. Relaxation techniques such as writing, meditation, yoga, or massage therapy can aid in battling breast cancer. There is a clear link between alcohol consumption and an increased risk of breast cancer. A study reported in The New England journal of Medicine has stated that consuming as few as three alcoholic drinks a week increases the potential for breast cancer by 50 percent.
– Prescription for Nutritional Healing, 4th Edition: A Practical A-to-Z Reference to Drug-Free Remedies Using Vitamins, Minerals, Herbs & Food Supplements by Phyllis A. Balch, CNC

Learn more: http://www.naturalnews.com/027204_cancer_Vitamin_D_breast.html#ixzz2GCGrQrq6

Vitamin D: powerful cancer protection

English: Most common cancers in the United Sta...

English: Most common cancers in the United States 2008. See Epidemiology of cancer (Photo credit: Wikipedia)

Sobre este assunto, assista:

Vitamina D – Sem Censura – Dr. Cicero Galli Coimbra e Daniel Cunha

Vitamina D – Por uma outra terapia (Vitamin D – For an alternative therapy)

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Leia:

Vitamina D pode revolucionar o tratamento da esclerose múltipla

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“A protective effect of vitamin D against cancers was first proposed in 1980, based on an earlier observation that colon cancer mortality was the highest in geographical areas exposed to the least amounts of sunlight.2,3”

“Today, over 800 scientific papers have been published on the relationship between vitamin D and cancers. We now have ample evidence that maintaining adequate vitamin D levels is an effective strategy for protection against cancer.”

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Posted on July 26, 2012 by Joel Fuhrman, M.D.

Vitamin D insufficiency is common among Americans overall but more prevalent among African Americans. A recent review of the literature suggests that vitamin D insufficiency is a key contributor to cancer survival disparities that exist between African Americans and white Americans (darker skin is less efficient at producing vitamin D in response to UV rays).1 A striking part of this literature review is the comprehensive summary of the existing data on vitamin D status and cancer survival: the authors present a long list of studies reporting that vitamin D adequacy is associated with reduced risk of death in all cancers combined, breast, colorectal, lung, and prostate cancer, leukemia and lymphomas.1

Several more studies of geographical variations in cancers have found the same result: inverse relationships exist between sun exposure and 24 types of cancer, including the most common cancers – those of the breast, colon, rectum, and prostate.4, 5

Since 1980, evidence for the involvement of vitamin D in the relationship between sun exposure and decreased cancer risk has progressively accumulated, as associations were found between blood vitamin D levels and reduced risk of cancers.6, 7 Further support for the importance of vitamin D in cancer prevention was provided by randomized controlled trials of vitamin D supplementation that showed reduced cancer risk compared to placebo. There have also been many reports that vitamin D receptor gene mutations, which interfere with the normal biological actions of vitamin D, were associated with increased cancer risk.8-10

Additional studies confirmed that vitamin D has growth-inhibitory effects on cells derived from breast, colon, prostate, and skin cancers.11 Vitamin D can block cancer cell growth in a number of ways: Vitamin D alters the expression of genes that regulate inflammation, cell death and cell proliferation, and also interferes with the growth-promoting actions of IGF-1 and other growth factors. Additional anti-cancer effects of vitamin D include enhanced DNA repair and immune defenses, and angiogenesis inhibition.12

Considering all of this evidence, achieving vitamin D sufficiency is so very important. Unfortunately, the Institute of Medicine is hesitant to significantly raise its vitamin D recommendations, so most multivitamins still do not contain nearly enough vitamin D (only 400 IU) to offer the security that a normal Vitamin D level will be achieved. This is an important reason why I designed my new Men’s and Women’s Daily Formula + D multivitamins to include 2000 IU of vitamin D3. In my experience, 2000 IU has been an appropriate dose to bring most people into the favorable blood 25(OH)D range of 30-50 ng/ml (I also recommend getting a blood test to confirm adequate levels). These are the only multivitamin supplements with a 2000 IU dose of D3 plus no folic acid, beta-carotene, copper, and vitamin A. This enables most people to get everything they need without needing to take multiple different products. For extra assurance, I’ve also utilized Vitamin D3 because of its highest biological value thus offering the most protection, which also is most effective for raising 25(OH)D levels.13 My goal is to make it as easy as possible to maintain healthy vitamin D levels, with plenty of D3 in a multivitamin which also gives you everything else that is worthy of supplementing, and carefully avoiding those supplemental ingredients that are potentially harmful; so additional supplements aren’t necessary to obtain the anti-cancer and bone-protective benefits of vitamin D and the other recommended nutrients.

References:

1. Grant WB, Peris AN. Differences in vitamin D status may account for unexplained disparities in cancer survival rates between African and White Americans. DermatoEndocrinology 2012;4.
2. Garland CF, Garland FC. Do sunlight and vitamin D reduce the likelihood of colon cancer? Int J Epidemiol 1980;9:227-231.
3. Apperly FL. The Relation of Solar Radiation to Cancer Mortality in North America. Cancer Res 1941;1:191-195.
4. Grant WB, Garland CF. The association of solar ultraviolet B (UVB) with reducing risk of cancer: multifactorial ecologic analysis of geographic variation in age-adjusted cancer mortality rates. Anticancer Res 2006;26:2687-2699.
5. Grant WB. Ecological studies of the UVB-vitamin D-cancer hypothesis. Anticancer Res 2012;32:223-236.
6. Gandini S, Boniol M, Haukka J, et al. Meta-analysis of observational studies of serum 25-hydroxyvitamin D levels and colorectal, breast and prostate cancer and colorectal adenoma. Int J Cancer 2011;128:1414-1424.
7. Grant WB. Relation between prediagnostic serum 25-hydroxyvitamin D level and incidence of breast, colorectal, and other cancers. J Photochem Photobiol B 2010;101:130-136.
8. Kostner K, Denzer N, Muller CS, et al. The relevance of vitamin D receptor (VDR) gene polymorphisms for cancer: a review of the literature. Anticancer Res 2009;29:3511-3536.
9. Lappe JM, Travers-Gustafson D, Davies KM, et al. Vitamin D and calcium supplementation reduces cancer risk: results of a randomized trial. Am J Clin Nutr 2007;85:1586-1591.
10. Bolland MJ, Grey A, Gamble GD, et al. Calcium and vitamin D supplements and health outcomes: a reanalysis of the Women’s Health Initiative (WHI) limited-access data set. Am J Clin Nutr 2011;94:1144-1149.
11. Fleet JC. Molecular actions of vitamin D contributing to cancer prevention. Mol Aspects Med 2008;29:388-396.
12. Fleet JC, DeSmet M, Johnson R, et al. Vitamin D and cancer: a review of molecular mechanisms. Biochem J 2012;441:61-76.
13. Tripkovic L, Lambert H, Hart K, et al. Comparison of vitamin D2 and vitamin D3 supplementation in raising serum 25-hydroxyvitamin D status: a systematic review and meta-analysis. Am J Clin Nutr 2012.

Fonte: http://www.diseaseproof.com/archives/vitamins-supplements-vitamin-d-powerful-cancer-protection.html

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