You’re a coffee lover, requiring nothing more than a strong, bitter, dark-roasted coffee in the morning. Likewise you’re a beer drinker, with a great liking for the bitter hoppiness of an India pale ale, and no understanding of those who profess to enjoy sugary sweet drinks. It’s all a matter of taste, right?
Wrong.
When a team of researchers set out to study individual beverage tastes, aiming to understand how such preferences could be used to intervene in people’s diets, they began by searching for variations in genes that govern taste.
To their surprise, they found that the taste preferences for bitter or sweet beverages aren’t based on variations in those particular genes, but rather in genes concerned with psychoactive response.
“People like the way coffee and alcohol make them feel – that’s why they drink it – it’s not the taste,” says Marilyn Cornelis, one of the study’s lead researchers, from the department of preventive medicine at Northwestern University, in Illinois, US.
“The genetics underlying our preferences are related to the psychoactive components of these drinks.”
Their report, published in the journal Human Molecular Genetics, is based on data from the UK Biobank, an international health resource, in which about 370,000 “adults of European ancestry” responded to surveys and questionnaires about their beverage intake over a 24-hour period.
That last point bears emphasis; the researchers warn “one should be cautious in generalising our results to other populations of non-European ancestry”. {%recommended 6341%}
Bitter beverages included coffee, tea – both sources of caffeine – grapefruit juice, red wine, beer and other alcoholic liquors. Sweet beverages included artificially and sugar-sweetened beverages, pure non-grapefruit juices, flavoured milk and hot chocolate.
The scientists counted the number of servings of bitter and sweet beverages consumed by the respondents, then did a genome-wide association study.
They also tried to replicate their key findings in three US survey groups, in order to enhance their ability to generalise, and reduce false positive results.
“To our knowledge, this is the first genome-wide association study of beverage consumption based on taste perspective,” says co-author Victor Zhong, also from Northwestern University.
“It’s also the most comprehensive genome-wide association study of beverage consumption to date.”
In 1931, chemist Arthur Fox, while researching artificial sweeteners for the DuPont chemical company in the US, accidently discovered that for some people the compound phenylthiocarbamide (PTC) tasted intensely bitter, while he himself found it tasteless.
Further research led him to believe that the ability, or inability, to taste PTC was a genetic trait. The gene for the PTC taste receptor, TAS2R38, was identified in 2003.
Cornelis and colleagues note that given the widespread consumption of beverages and their substantial health implications, “understanding environmental and genetic factors contributing to beverage choice and consumption level has important nutritional and broader public health implications”.
The researchers did find one variant in a gene called FTO which linked to sugar-sweetened drinks. People who had a variant in the gene – the same variant previously found to correlate with obesity risk – surprisingly preferred sugar-sweetened beverages.
“It’s counterintuitive,” Cornelis says. “FTO has been something of a mystery gene, and we don’t know exactly how it’s linked to obesity. It likely plays a role in behaviour, which would be linked to weight management.”
