Vitamina D
Es una vitamina que hay que tener en cuenta, es muy comun tener deficiencia y tiene muchos sintomas, uno de ellos es que causa permeabilidad intestinal: intolerancias-alimenticias-f111/permeabilidad-intestinal-t1133.html
Pero no solo eso!
"Vitamin D refers to two biologically inactive precursors – D3, also known as cholecalciferol, and D2, also known as ergocalciferol.Both D3 and D2 precursors are transformed in the liver and kidneys into 25- hydroxyvitamin D (25(OH)D), the non-active ‘storage’ form, and 1,25-dihydroxyvitamin D (1,25(OH)2D), the biologically active form that is tightly controlled by the body.Vitamin D deficiency, which is defined as a status of less than 20 nanograms per milliliter (ng/mL) of 25-(OH)D, can cause a number of health issues, including rickets and other musculoskeletal diseases.Data suggests that vitamin D deficiency (<20 ng/mL) and vitamin D insufficiency (between 21-29 ng/mL) may be linked to cancer, autoimmune diseases, infectious diseases, type 2 diabetes and cardiovascular disease."
Lo mejor es hacerse un analisis de sangre y ver el nivel, la vitamina D se genera con la exposicion al sol y yo vivo en uno de los paises con mas sol del mundo… pero… solo es efectivo el sol en horas puntas, que es cuando la gente se oculta de el!
Yo tenia una ligera deficiencia de vitamina D y me tome unas buenas mega-dosis recetadas por el medico, asi que ojo a la Vitamina D ya que es peligroso tenerla baja.
Vitamin D. If you were to take just one immune-enhancing supplement to lower your long-term risk for cancer, vitamin D would be the one to choose. More than 60 studies have found that high levels of vitamin D offer broad protection against many types of cancer. A recent German study reported that people with low vitamin D levels were one-third more likely to die of any type of cancer. Advice: Take at least 1,000 international units (IU) of vitamin D-3 daily. Vitamin D-3, with its slightly different molecular structure than D-2, is a more bioactive form of the vitamin, which means that the body can use it more readily. Take 2,000 IU if you don’t get much sun or have a dark complexion. (Dark skin absorbs less of the rays necessary for conversion to vitamin D.) Best: Have your blood tested to determine how much vitamin D you need.
Mercola recomienda 8 mil para adultos, otros recomiendan 2 mil o 4 mil… interesante! Voy a incrementar mi exposicion al sol, ya que es autoregulatorio y no te pasas, ademas es gratis… lo malo es que te puedes quemar y envejece la piel.
Es curioso cómo ha evolucionado la vitamina D. Hace unos 10 años recuerdo haber leído que era la vitamina más peligrosa en cuanto a megadosis ya que sobrepasar 4 veces la dosis diaria recomendada era tóxico. Al ser una vitamina liposoluble (que se puede almacenar), y que 60 minutos de exposición solar facial era suficiente para llegar a la dosis diaria, hacían que no se la tuviese en cuenta en ninguna preparación. En verano nació mi sobrina y le recomendaron suministrarle vitamina D para evitar el riesgo de bronquitis (niña nacida 100% sana!).
Hay cinco variedades de la vitamina D: D1 ,D2, D3, D4 y D5. De ellas, sólo D2 y D3 encuentran en cantidades interesantes en la comida. Entre D2 y D3, parece que la más interesante es la D3: http://www.ncbi.nlm.nih.gov/pubmed/24001747
¿Dosis diarias?
Recomendada 600 IU (15 μg/día) y maxima 4000 IU (100 µg/día).
¿Alimentos?
Para D2:
Champiñones expuestos a UV, 100g en crudo: 450 IU. Si no estuvieron expuestos a UV, sobre 20 IU. Utilizarlos sólo para relleno.
Para D3:
Salmón cocinado o sardinas en lata (en aceite), 100g 300 IU (es aproximado, depende de la grasa que contenga el pescado).
Huevos enteros: 100g 35 IU.
Normalmente desayuno 4 huevos enteros (75 IU) más 150g de salmón por la noche (que se quedará en 125g al cocinarlo, tengo que pesarlo, serían 375 IU), así que tengo bastantes papeletas de estar en déficit. Lo cierto es que no es fácil obtener la vitamina D recomendada de productos naturales, habría que aumentar la ingesta de salmón a 200g diarios, que sumado a los cuatro huevos empieza a ser un monto de grasa considerable. Tomaré megadosis por unas semanas y después incluiré un multivitamínico que aporte el 100% de la dosis recomendada.
He leido que la vitamina D3 reduce en un 50% la mortalidad de todo tipo (enfermedades), la mejor forma de saber la cantidad de vitamina D que tenemos es un analisis de sangre, se suele decir que 50-70 ng es lo mas saludable, pero hay estudios contradictorios que hablan de 20-30 ng como cantidad optima (campana de gaus), lo que en muchos lugares se considera deficiencia.
Esto puede ser debido a que las vitaminas A, K2 y E tienen mucho que ver y regulan la toxicidad de esta, por lo tanto no es una vitamina que debemos de observar de forma aislada.
Una persona de piel clara puede obtener 10000 U.I. de Vitamina D con 15-20 de exposicion al sol, una persona morena puede necesitar 2 horas.
La ventaja de usar el sol para obetener Vitamina D es que el cuerpo regula la que necesita.
Articulo de Mercola:
When it comes to the benefits of optimizing your vitamin D levels, the evidence is simply overwhelming. Research shows you can drastically reduce your risk of cancer and countless other chronic diseases by getting safe sun exposure, using a safe tanning bed, or taking a high-quality supplement.
As a result of flawed assumptions about sun exposure, and the subsequent recommendations, a vast majority of people are deficient in vitamin D. It’s thought that over 95 percent of U.S. senior citizens may be deficient, along with 85 percent of the American public.
Additionally, a robust and growing body of research clearly shows that vitamin D is absolutely critical for good health and disease prevention. Vitamin D affects your DNA through vitamin D receptors (VDRs), which bind to specific locations of the human genome. Scientists have identified nearly 3,000 genes that are influenced by vitamin D levels, and vitamin D receptors have been found throughout the human body.
With Dr. Garland at the helm, The D*Action Project will be monitoring, for five years, the health outcomes of individuals who get their vitamin D levels to the levels of 40-60 ng/ml. I would highly recommend that you optimize your levels to the high end of this spectrum, as optimal vitamin D levels are 50-65 ng/ml, or 65-90 ng/ml if you are treating cancer.
Says Carole Baggerly, director of GrassrootsHealth:
"We will be tracking the incidence of many diseases, from cancer to diabetes and muscular function as well as pain levels to see what effect the higher vitamin D levels may have.
We expect to see a significant reduction in the incidence of breast cancer (and its recurrence), colon cancer, diabetes and myocardial infarction, compared with the general population. With the expansion of the project by individuals, we could substantially reduce this epidemic in a few years!”
Algunos de los trabajos más interesantes han demostrado que la pro-hormona puede reducir el riesgo asociado con ciertas formas de cáncer por 78 por ciento.
Vitamina D inhibe un mecanismo de proteína utilizado por las células tumorales para impulsar el crecimiento de cáncer
Los investigadores trabajaron para obtener una mejor comprensión de cómo la vitamina D detiene la actividad de la proteína cMYC para detener el crecimiento tumoral y progresión metastásica. Autor principal del estudio, Dr. John White comentó "hemos descubierto que la vitamina D controla la tasa de producción y la degradación de cMYC. Más importante aún, encontramos que la vitamina D fuertemente estimula la producción de un antagonista natural de cMYC llamado MXD1, esencialmente eliminando la función de cMYC." Trabajando con una variedad especial de ratones que presentan similitudes metabólicas relacionadas con los seres humanos, el equipo aplicó vitamina D en la piel para evaluar la actividad de cMYC.
Summer sun is at its maximum in June and July but vitamin D, generated in the skin by sunlight, takes two or three months to get into the general circulation. So we reach our maximum level of vitamin D in about September. Babies born in October or November have the best chance of a relatively high level of vitamin D during their final months in the womb. And this, the birthday evidence suggests, can protect them from MS, while the risk is higher for babies born at the end of winter.
This seasonal pattern in the risk of MS has now been found in eight different countries including Australia, winning over previously sceptical scientists. Less well known is the link between end of winter birthdays and an increased risk of several other diseases. Studies of thousands of birthdays in Europe, Canada and Australia over some 30 years have found that people born at this time are also at greater risk of type 1 diabetes, coeliac disease (gluten intolerance), schizophrenia and autism.
Writing in the peer-reviewed journal, BMC Medicine, in July 2012, Professor Ebers, working with Dr Sreeram Ramagopalan, has shown that the risk of rheumatoid arthritis, a digestive disease called ulcerative colitis and a distressing condition called systemic lupus erythematosus follows the same pattern of seasonal births. These are all autoimmune diseases, which occur when the body is attacked by its own immune system. Diabetes type 1 is also an autoimmune disease and in the case of coeliac disease the immune reaction is to wheat in the bowel. To date, at least 18 autoimmune diseases have been linked to low vitamin D levels – more than enough to demonstrate a pattern.
Certain types of T cells react against the body tissues and they may cause autoimmune disease later on if they persist. These unwanted T cells are normally removed from the body in the first year of life by a clever arrangement – they are deleted in the thymus gland, a process that requires vitamin D.
Some 15 or more different cancers have been consistently associated with low vitamin D levels in a way that accords with established criteria, according to epidemiologist Dr William B Grant, from the non-profit organisation the Sunlight Nutrition and Health Research Center in California. In his paper published in 2009, the link is most clearly seen in breast and bowel cancer. Insufficient vitamin D leads to loss of control of several genes which regulate proliferation of cancer cells and inhibit the cell cycle.
In fact there are more than 900 genes that Vitamin D is now known to switch on and off – and in doing so alters our vulnerability to disease. The large number of genes involved explains how so many quite different diseases can be caused by insufficient sunshine. In this way sunshine exposure directly alters the action of genes which may actually be passed on in their altered state – a newly understood process known as epigenetics. So it is possible to see how some diseases may emerge for the first time in one generation and be passed on to the next.
Amount of vitamin D in sample food sources:
1 Tbsp cod liver oil: 1,360 IU
3 oz. salmon: 800 IU
8 oz. fortified milk:100 IU
8 oz. fortified orange juice: 100 IU
3 oz. irradiated mushrooms: 400 IU
How Much Is Too Much?
Vitamin D is a fat-soluble vitamin. Fat-soluble vitamins can build up in the body and are not as easily excreted as water-soluble vitamins. The IOM committee set a level of 4,000 IU as the ‘tolerable upper limit’ or the maximum amount that is safe to consume daily.
In July 2011, the Endocrine Society Practice Guidelines published recommendations for the evaluation, treatment, and prevention of vitamin D recommending an upper limit of 10,000 IU/day.
"There is a potential to cause harm if you overdose on supplements above 4,000 IU/day but there is no fear of overdosing from the sun because your skin acts like a regulatory system, only allowing production of the amount of vitamin D you need"
Using vitamin D blood levels is the best estimate of adequacy that accounts for dietary intake and sunshine, yet experts differ on what that level should be.
"A 25(OH)D blood level of at least 20 nanograms/ml was used by the IOM committee to set the recommendations for vitamin D because this level showed adequacy for a wide variety of bone health indicators" says Brannon.
The Endocrine Society Practice Guidelines, as well as many laboratories and experts (including Baetti), recommend a minimum vitamin D blood level of 30 nanograms/ml as an acceptable level.
Studies link VD (bioactive vitamin D metabolite, 1,25-dihydroxyvitamin D3) signaling through the VDR directly to distinct molecular mechanisms of both HAT activity and the sirtuin class of HDACs (SIRT1) as well as the forkhead transcription factors thus contributing to elucidate complex epigenetic mechanisms for cancer preventive actions of VD.
Fuente: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3365599/
Vitamin D has a variety of actions in the body. It binds to the vitamin D receptor (VDR), which then binds to the retinoid X receptor (RXR) and activates the expression of numerous genes. Through this mechanism, vitamin D promotes calcium absorption in the gut and helps maintain calcium and phosphate levels to promote healthy bones. It also helps regulate genes involved in cell growth, neuromuscular and immune function, and reduction of inflammation. Accordingly, vitamin D deficiency has been linked with a wide range of diseases.
Fuente: http://www.the-scientist.com/?articles. … -on-Trial/