miércoles, diciembre 03, 2008

Estudios muestran que el selenio frena replicación del VIH e inhibe al cáncer de prostata

Interesantes estudios de varias fuentes demuestran el poderoso efecto del selenio para proteger al cuerpo, y es un mineral que se encuentra en el huevo, la avena, el pan integral y en varias nueces. Copio de NaturalNews.com :

(NaturalNews) After decades of attempting to fight AIDS with experimental vaccines and drugs, scientists have recently discovered how several natural substances could be powerful weapons against the disease. For example, in mid-November, UCLA AIDS researchers published research concluding that the herb astragalus contains a substance with the potential to possibly replace the side-effect plagued HAART (highly active antiretroviral therapy) currently used to treat AIDS patients. http://www.naturalnews.com/024799.html

Now Penn State immunologists say they've documented how a micronutrient could help battle AIDS. Their findings, just published in the Journal of Biological Chemistry, show how selenium could dramatically put the brakes on the replication of HIV, the virus that causes AIDS.

Selenium is needed by the body to maintain normal metabolism. It's also increasingly being studied for its anti-cancer properties. Although other nutrients usually bind to proteins, selenium actually becomes incorporated into proteins, forming what are called selenoproteins. These selenium-containing proteins are believed to slow the spread of infections. However, when HIV infects a person, the virus manages to degrade selenoproteins, probably due to a protein, dubbed Tat, produced by the HIV virus. In particular, Tat seems to target a selenoprotein known as TR1.

But there may be a way to get around this degradation of selenoproteins -- supplementation with selenium. "Since HIV targets the selenoproteins, we thought that the logical way to deal with the virus is to increase the expression of such proteins in the body," K. Sandeep Prabhu, assistant professor of immunology and molecular toxicology at Penn State, said in a statement to the press.

To test their idea, the scientists isolated blood cells from human volunteers who did not have HIV. Then they infected those cells with the virus and added a form of selenium called sodium selenite to the cell culture.

The result? The added selenium inhibited the replication of the HIV virus at least 10-fold, in comparison to cell cultures with no added selenium. The scientists also selectively reduced the production pf the selenoprotein TRI. When there was less selenium-containing protein, the HIV virus replication soared 3.5 times. Bottom line: The research confirms that an increase in selenium in cells zaps replication of HIV while a reduction in the amount of selenium-containing TR1 protein gives the virus a boost.

"We have found that increasing the expression of proteins that contain selenium negatively affects the replication of HIV. Once we fully understand the function of these selenium proteins, it will give us a handle to come up with more effective drugs," said Dr. Prabhu in the prepared statement for the media.

Two more new studies offer additional evidence that selenium may impact the immune system. German scientists from St. Josefs-Hospital in Wiesbaden recently published a study in the Swedish medical journal Acta Oncologica that suggests the micronutrient could help prevent prostate cancer and prostate enlargement. The researchers found that whole blood selenium levels were significantly lower in all men tested who had prostate cancer or benign prostate hypertrophy (which can cause difficulty with urination) and concluded, "our findings may support the recommendation of selenium supplementation" to help prostate health. What's more, a study just published in the journal Molecular Nutrition and Food Research suggests enzymes that contain selenium have anti-oxidative and anti-inflammatory effects that could make them important in preventing prostate and colorectal cancers.

Too much selenium in can cause a condition called selenosis, resulting in loss of hair, nail problems, nausea, irritability, fatigue, and mild nerve damage. However, selenium toxicity is extremely rare. A lack of selenium may, in fact, be far more common and potentially more dangerous to health. According to the National Institutes of Health, people age 14 and older should take in about 44 micrograms of selenium a day. Good sources of the micronutrient include Brazil nuts, eggs, brown rice, whole wheat bread and pasta, walnuts and oatmeal.

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