Hunger makes alcohol more appealing, study finds

Scientists have found that being hungry can make alcohol appear more rewarding, causing some organisms to feel the desire to want it. This is because of a single brain cell that becomes more active as hunger builds, leading the subject to be attracted to alcohol. Even though the study was carried out on fruit flies, the findings offer a starting point for understanding how internal states like hunger, stress, or environmental cues can heighten alcohol cravings and contribute to addiction and relapse risks in humans.

The study was carried out by Kavin Nuñez and Lewis Sherer at Brown University‘s Carney Institute for Brain Science, along with another researcher at Montana State University. They worked at Karla Kaun’s lab to decode how memories of alcohol as a reward drive cravings.

Karla said if you are hungry, you are more likely to feel pulled towards that bar on the way home. "But maybe today you’re hungry after skipping lunch. You’re more likely to notice that cute sign and feel like stopping to have a drink," she said. She stated that the bar sign normally wouldn't entice you when you weren't hungry, but you start craving alcohol if you have skipped a meal.

How fruit flies were trained on alcohol

For the study, the team trained fruit flies in vials of 30 to connect a smell with alcohol. They were given three doses of an intoxicating alcohol vapour for 10 minutes within a 50-minute interval, each paired with the same smell. The second odour wasn't paired with anything. The flies had to choose between the two smells.

Initially, they did not like the smell of alcohol. But as the day progressed, they were attracted to it. The flies that were given no food switched to alcohol three hours before the flies that were well fed. This happened because of the chemical called octopamine. Several neurons come together to make it. They were silenced in groups before the team found that the effect was happened because of one cell, named VUMa3.

The cell tracked hunger, which the team saw happening using a fluorescent sensor that lit up when the neuron was activated. After three hours of food deprivation, the cell's baseline activity began to climb, matching the exact timeframe in which the flies showed a behaviour change. The neuron responded to the alcohol-paired smell only in hungry flies, which meant that it was retrieving the memory.