Regular coffee drinkers can sniff out even tiny amounts of coffee and are faster at recognising its aroma, compared to non-drinkers, a study has found.
Habitual coffee drinkers are not just more sensitive to the odour of coffee and faster to identify it, but the more they craved coffee, the better their ability to smell it became.
It is the first time evidence has been found to prove coffee addicts are more sensitive to the smell of coffee, said researchers from the University of Portsmouth in the UK.
The results, published in the journal Experimental and Clinical Psychopharmacology, could open the door to potential new ways of using aversion therapy to treat people addicted to substances with a distinct smell, such as tobacco and cannabis.
"We found the higher the caffeine use, the quicker a person recognised the odour of coffee," said Lorenzo Stafford, from the University of Portsmouth.
"We also found that those higher caffeine users were able to detect the odour of a heavily diluted coffee chemical at much lower concentrations, and this ability increased with their level of craving.
"So, the more they desired caffeine, the better their sense of smell for coffee," Stafford said.
Researchers said they have known for sometime that drug cues -- for example, the smell of alcohol—can trigger craving in users.
However, in the new study they show with a mildly addictive drug, that craving might be linked to an increased ability to detect that substance.
"Caffeine is the most widely consumed psychoactive drug and these findings suggest that changes in the ability to detect smells could be a useful index of drug dependency," Stafford said.
The team wanted to examine if there were any differences in the ability of people to smell and respond to the odour of coffee, depending on whether or not they were big coffee drinkers.
The results point firmly to a link, with heavy coffee drinkers being more sensitive to the smell of coffee, and the smell being linked to their cravings.
