Oct 25, 2008

Health - Binge drinking weakens bones

Researchers have uncovered how alcohol disturbs genes necessary for upkeep of bones, potentially opening up new ways of targeting bone loss in alcohol abusers or those at risk of osteoporosis.

"Of course, the best way to prevent alcohol-induced bone loss is to not drink or to drink moderately," said bone biologist John Callaci, Loyola University Stritch School of Medicine. "But when prevention doesn't work, we need other strategies to limit the damage."

Callaci is a co-author of the study. His other co-authors are Frederick Wezeman, a professor and Ryan Himes, a research assistant in the Burn and Shock Trauma Institute of the university.

The National Osteoporosis Foundation says that many people who abuse alcohol do not get enough calcium. Alcohol also can affect the body's calcium supply. And drinking too much can increase the risk of falls and broken bones. The foundation advises people to have no more than two drinks per day.

Loyola's Alcohol Research Program was among the first centres to demonstrate that rats given an amount of alcohol equivalent to binge drinking show significant decreases in bone mineral density and bone strength. In humans, binge drinking is defined as a woman having at least four drinks or a man having at least five drinks in two hours. But surprisingly little was known about the mechanisms responsible for these effects.

In the new study, researchers injected rats with an amount of alcohol equivalent to binge drinking for three days or to chronic alcohol abuse for four weeks. Control groups received injections of saline.

Researchers focussed on genes responsible for bone health. They found that alcohol affected the amounts of RNA associated with these genes. (RNA serves as the template for making proteins, the building blocks of bones and other tissue.)

With some genes, alcohol increased the amount of RNA. With other genes, alcohol decreased the RNA, according to a press release of Loyola University. These findings were published recently in Alcoholism: Clinical and Experimental Research.

Changing the amounts of RNA disrupted two molecular pathways responsible for normal bone metabolism and maintenance of bone mass.

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