Alcoholics' brains adjust to heavy drinking by turning the alcohol into an energy source, suggests a new study. However, the brain becomes dependent on that alcohol-derived energy source and makes alcohol withdrawal that much worse.

After alcohol consumption, the liver begins quickly converting the ethanol alcohol into acetate, a chemical most commonly found in vinegar. The acetate then circulates throughout the body in blood.

Ethanol consumption can cause rapid drops in blood glucose levels, and since glucose (sugar) is the body's main source of cellular energy, acetate can compensate for low glucose by providing replacement fuel for the brain and other organs.

A team of researchers led by Lihong Jiang of Yale University found that long-term, heavy drinking increases the metabolism and speed of acetate uptake, which means that alcoholics comes to rely on acetate for energy after prolonged alcohol use. Without the acetate, the body goes into alcohol withdrawal. The study was published in the latest issue of the Journal of Clinical Investigation.

Jiang and his colleagues used a brain imaging technique called magnetic resonance spectroscopy to track acetate uptake and metabolism in the brains of heavy drinkers who consumed at least eight alcohol drinks per week, and compared them to light drinkers who had less than two drinks per week.

They found that heavy drinkers had twice as much circulating acetate, showing that acetate transport is much faster after prolonged heavy drinking.

"People who drink heavily have twice the ability to burn acetate as fuel," Dr. Graeme F. Mason of Yale to Medscape. "We find not only that the acetate is being burned faster [in heavy drinkers] but there is more of the acetate itself."

"Acetate as fuel for the brain may sound like a good thing," but heavy drinking can make alcoholics' brains adapt to acetate as a source of energy and make it more difficult to cut down on their alcohol intake

The higher levels of acetate cause inflammation in the liver, which breaks down alcohol, and the findings suggest that prolonged acetate exposure also inflames and damages the brain over time - even as it provides a metabolic boost.

In addition to the metabolic boost that comes from acetate after heavy drinking, they found that breaking down acetate produces adenosine, a chemical with a sedating effect that can also make it difficult for alcoholics to stop drinking.

The findings were surprising, since scientists used to think that glucose was the brain's only possible energy source.

"I jumped out of my chair and threw my fist in the air," Mason told Science News. Though the research team had hypothesized that acetate could provide brain fuel, "the effect was way bigger than I thought."

The research team wants to find out next whether acetate or adenosine supplements could ease the alcohol withdrawal symptoms of alcoholics, and help detoxification after heavy drinking. The idea is that providing acetate could make it less tempting for the body to turn alcohol into an energy source.