Study finds genes and environment influence coffee drinking

Greek Coffee is consumed all day long- in the morning, lunchtime and evening!

The coffee culture in Greece is a daily ritual for most, that is enjoyed alone while reading the newspaper, or when catching up with the parea at a busy cafe (before the coronavirus pandemic).

New research suggests that one's coffee intake is affected by a positive feedback loop between genetics and the environment.

The study, published in the journal Behavioral Genetics, noted that this phenomenon, known as “quantile-specific heritability,” is also associated with cholesterol levels and body weight, and is thought to play a role in other human physiological and behavioural traits that defy simple explanation.

“It appears that environmental factors sort of set the groundwork in which your genes start to have an effect,” said Paul Williams, a statistician at Lawrence Berkeley National Laboratory (Berkeley Lab).

“So, if your surroundings predispose you to drinking more coffee – like your coworkers or spouse drink a lot, or you live in an area with a lot of cafes – then the genes you possess that predispose you to like coffee will have a bigger impact. These two effects are synergistic.”

As part of the study, Williams assessed 4,788 child–parent pairs and 2,380 siblings from the Framingham Study – a famous, ongoing study launched by the National Institutes of Health in 1948 to investigate how lifestyle and genetics affect rates of cardiovascular disease. Based on this data, Williams used statistical methods to calculate what proportion of the participants' coffee drinking could be explained by genetics and what must be influenced by external factors.

“When we started to decode the human genome, we thought we’d be able to read the DNA and understand how genes translate into behaviour, medical conditions, and such. But that’s not the way it’s worked out,” said Williams. “For many traits, like coffee drinking, we know that they have a strong genetic component – we’ve known coffee drinking runs in families since the 1960s. But, when we actually start looking at the DNA itself, we usually find a very small percentage of the traits’ variation can be attributed to genes alone.”

The study noted that the situation is more complex, adding that the methods used to arrive at the findings may help explain the diversity of traits we see in the real world. "This is a whole new area of exploration that is just now opening up. I think it will change, in a very fundamental way, how we think genes influence a person's traits," Williams said.

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