Binge drinking's metabolic whack starts in the head

Long after the buzz has gone, and even after the resulting hangover has cleared, a bout of binge drinking will leave your metabolism in a deeply disturbed state, which may be why binge drinkers -- even occasional ones -- are at greater risk of developing Type 2 diabetes (or its precursor, metabolic syndrome) than nondrinkers or those who drink more moderately.

A new study, conducted on rats, suggests that binge drinking disrupts metabolism not by poisoning the liver but by inflaming the brain's hypothalamus, which conducts the symphony of signals necessary for proper metabolic function. The research was published this week in the journal Science Translational Medicine.

Binge drinking -- defined as reaching a blood alcohol level of .08% in a period of two hours or less -- is a widespread practice among teens and young adults. But it's not uncommon in older people too. A recent survey of elderly and middle-aged adults found that 20% of men and 6% of women engage in this form of heavy drinking.

Calculate here how many drinks would constitute binge drinking for you.

While the metabolic disturbance that comes with this kind of alcohol consumption occurs in both men and women, the study found that even at alcohol consumption levels that were lower, female rats exhibited higher levels of insulin resistance. That's bad news for adolescent and young adult female humans, who are engaging in binge drinking at an accelerating rate.

The researchers simulated binge drinking by plying male and female rats with heavy doses of alcohol for three consecutive days, and then measured their levels of circulating insulin and conducted a glucose tolerance test. Eight hours after their last "drink," when alcohol was no longer measurable in the rats' blood, the binging rats showed impaired glucose tolerance as well as insulin resistance. And those metabolic disturbances persisted for 30 hours after their last dose of alcohol.

Researchers at Mount Sinai School of Medicine in New York noticed the livers of bingeing rats were failing to respond to signals that should have prompted a decrease in insulin production and the release of fatty acids. So, they focused on the quality of the regulatory signals being sent forth from the brain's hypothalamus. In rats exposed to high levels of alcohol, they saw evidence of increased inflammation there, which disrupted signals meant to regulate insulin production.

But it wasn't all bad news: The researchers found that when they inhibited a protein called protein tyrosine phosphatase 1B while rats were being plied with alcohol, the metabolic disturbance of binge drinking was reduced. That finding holds out the promise that if a drug could be found that inhibits PTP1B, insulin resistance that is the consequence of heavy drinking -- or perhaps, of aging or obesity-- might be averted.


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