The bittersweet brain chemical clue that could help women stop binge drinking

Scientists at The Florey have discovered a chemical in the brain that may explain the different drinking habits of men and women. 

It comes down to how our brains detect bitter tastes, and could be harnessed to help women stop binge drinking.

Dr Leigh Walker led a study that showed that when a certain chemical is removed from the brain, males drink more and females drink less. But when the alcoholic drinks are sweetened, female consumption goes up. 

Dr Walker, an expert in the neurobiology of anxiety and alcohol use disorders, said the findings could pave the way for treatments designed to help women stop binge drinking. 

“The taste of alcohol is an important and often overlooked factor that drives alcohol preference, intake and use,” Dr Walker said. 

“We have identified a chemical in the brain that makes alcohol taste bitter to females, unless the drink is sweetened.” 

Dr Walker said science has primarily focused on examining how male brains work. Her study, published in Neuropsychopharmacology, looked at how female brains might differ from male brains and identified differences in response to taste. The research centered on ‘CART’, a neuropeptide present in all species and associated with energy balance, depression, anxiety, and reward-related behaviour, including those around drinking alcohol. 

Dr Walker, working closely with graduate researcher Xavier Maddern and other Florey researchers, studied the effect of inhibiting CART in mice that were trained to drink alcohol. 

“Alcohol has an underlying bitter taste,” Dr Walker said. “When we inhibited CART in male mice their drinking increased. And when we knocked out the same brain chemical in female mice, they drank less. But when the alcohol was sweetened, the female mice drank more. This tells us that without CART, alcohol is unpalatable to females.” 

Alcohol use contributes to about 3 million global deaths each year with alcohol misuse accounting for 5.1 per cent of the global disease burden, while rates of risky drinking and alcohol use disorders are rising in women much faster than in men.* 

“If we can find a way in future research to target the CART neuropeptide system, we may be able to create treatments to help women curb excessive alcohol use. And if we can work out how male and female brains differ it will open unprecedented opportunity to treat disorders of the brain in women, including alcohol use disorders,” Dr Walker said. 

* Global status report on alcohol and health 2018, World Health Organization; and Jama Psychiatry.