Alcohol amps up hunger signals in the brain

Alcohol amps up hunger signals in the brain

Alcohol intake associates with overeating in humans. This overeating is a clinical concern, but its causes are puzzling, because alcohol (ethanol) is a calorie-dense nutrient, and calorie intake usually suppresses brain appetite signals. The biological factors necessary for ethanol-induced overeating remain unclear, and societal causes have been proposed.

Researchers shown that brain cells (Agrp neurons) that regulate appetite and feeding are activated by alcohol, offering a possible explanation for why drinking can lead to overeating.

They exposed mice to alcohol for three days and found that the animals’ food intake increased during that period. An analysis of mouse brain tissue showed that alcohol boosts the activity of Agrp neurons, which trigger feelings of intense hunger when stimulated. The activity level was similar to that caused by fasting or hunger hormones.

Authors show that core elements of the brain’s feeding circuits—the hypothalamic Agrp neurons that are normally activated by starvation and evoke intense hunger—display electrical and biochemical hyperactivity on exposure to dietary doses of ethanol in brain slices.

When the team silenced these cells in mice and then gave them alcohol, the animals did not increase their eating.