jueves, 10 de enero de 2013

¿El vino tinto puede ser usado como dopaje por los deportistas?


¿EL VINO TINTO PUEDE SER USADO COMO DOPAJE POR LOS DEPORTISTAS?

El vino tinto puede aumentar el rendimiento de atletas y deportistas en el terreno de juego incrementando la cantidad de testosterona disponible, una hormona que mejora notablemente el rendimiento físico.

Es la conclusión a la que han llegado investigadores de la Escuela de Ciencias de la Vida de la Universidad de Kingston (Reino Unido) en un reciente estudio. Además, puesto que beber vino reduce la cantidad de testosterona excretada en la orina, los autores del estudio aseguran que podría distorsionar los resultados de controles de dopaje.

La testosterona es una hormona esteroide natural que poseen tanto hombres como mujeres. Puede aumentar la masa muscular, uno de los motivos por los que su consumo se considera como dopaje (mejora artificial de los resultados de pruebas físicas) y está prohibido a los deportistas por parte de la Agencia Mundial Antidopaje. Sin embargo, el vino tinto no es una sustancia incluida en los controles antidoping, a pesar de que, según acaban de demostrar Declan Naughton y sus colegas, tiene la capacidad de alterar los niveles corporales de testosterona. Concretamente sus efectos se deben la quercetina, una sustancia antioxidante (flavonoide) que bloquea parcialmente la acción de la enzima UGT2B17, que es la encargada de que los riñones expulsen la testosterona. Si se bloquea esta enzima, la cantidad de hormona que elimina el organismo es menor y la concentración en sangre aumenta, como exponen los investigadores en la revista Nutrition.

Naughton ya había observado previamente un efecto similar tras el consumo de té verde.

RED WINE COULD MASK TESTOSTERONE LEVELS, EXPERTS WARN

Red wine could give athletes and players a boost in the sports arena by increasing the amount of performance-enhancing hormone testosterone in their bodies, according to researchers from London's Kingston University.

However not only could the beverage help them to trophy success, it could also allow them to beat anti-doping tests. A team led by Professor Declan Naughton, from the University's School of Life Sciences, found that red wine might reduce the amount of testosterone excreted by the body, which could distort the findings of drug tests taken from urine samples.

Testosterone is a naturally-occurring steroid hormone present in both men and women. It can increase muscle mass, boost stamina and speed up recovery. Sportspeople, however, are prohibited from taking it, or a synthetic version of it, to try to gain a competitive edge.

Although red wine is not a banned substance away from the sports field, Professor Naughton's team has referred its findings to the World Anti-Doping Agency because of the newly-discovered side effect of potential change to the amount of testosterone in the body.

"Previous research has shown the effect over-the-counter anti-inflammatory drugs can have on enzymes," Professor Naughton explained. "Since many of these drugs are derived from plants, we decided to look at the effect particular foods and beverages can have on enzymes involved in testosterone excretion. We chose green tea and then red wine because both have a huge variety of natural molecules and we wanted to see if they affected the amount of testosterone excreted in urine."

The team found that a compound in red wine, known as quercetin, partially blocked the action of an enzyme called UGT2B17, which looks for testosterone and then sends a message to the kidneys to excrete it.

Professor Naughton stressed that the research had so far been conducted in test tube experiments and had yet to be trialled on humans. "A full clinical study would be needed to determine the effects on people but, if the same results were found, it would confirm that compounds in red wine can reduce the amount of testosterone in urine and give a boost to testosterone levels," he explained.

The effect of red wine on an individual would vary because of factors such as weight, fitness, health and diet, making it hard to estimate how much was needed to improve performance, Professor Naughton said.

Teetotallers are not exempt from the effects. In fact, the alcohol content of red wine has very little impact because non-alcoholic molecules are responsible for inhibiting testosterone excretion.

The team also found the results were the same for red wine extract in supplement form. The active compounds such as quercetin are found in many foodstuffs as well as supplements.

The findings have been published in leading international journal Nutrition. The research follows an earlier study from Professor Naughton's team which showed that green and white tea could also inhibit testosterone excretion.

Fuentes consultadas:
- (www.muyinteresante.e)¿El vino tinto puede ser usado como dopaje por los deportistas?
- (www.sciencedaily.com)Red Wine Could Mask Testosterone Levels, Experts Warn

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