TORONTO - The myriad of differences between the sexes might extend to how men and women react to a cup of joe in the morning.
Research being conducted at the University of Toronto suggests caffeine's effect on women contrasts significantly with its effect on men - a reaction based on which version of a gene binds to dopamine, a chemical in the brain known to affect mood.
"We know from animal studies that males and females respond differently to caffeine," said Ahmed El-Sohemy, a nutritional sciences professor at the University of Toronto.
"Here we are showing it in humans, and also relating it to an actual behavioural response."
The early stages of the research, being led by El-Sohemy, suggests 22 per cent of men with a particular form of the dopamine receptor gene experience an elevated mood after consuming a caffeinated beverage.
More than 60 per cent of men with a different form of this gene reported the same kind of mood elevation.
"That's a fairly big effect," said El-Sohemy.
In women, however, approximately 50 per cent reported experiencing an elevated mood after consuming caffeine, regardless of the version of the gene they had.
The research suggests the effect caffeine has on people, from inducing a headache to making them high-strung, could also be linked to genetic makeup.
"Some people avoid caffeine, some people seek it daily, and some people who don't get their daily fix suffer various withdrawal symptoms and seek caffeine to alleviate those symptoms," El-Sohemy said.
"What we're trying to understand is what the genetics behind these different responses might be."
El-Sohemy says he believes the results may also provide a genetic explanation as to why some people are more vulnerable to becoming dependent on caffeine.
"Further down the road one could predict whether or not you would be better off lowering your intake or perhaps maintaining what you consume," he said.
El-Sohemy said the caffeine project is just one among many exploring how genes can affect the kinds of food we eat, and how our bodies respond to those foods.
"What we are really interested in is being able to tailor individual dietary recommendations based on an individual's unique genetic profile," he said.
El-Sohemy, recently presented these preliminary findings at the Advanced Foods and Materials Network Scientific Conference in Quebec City. He said the final results of the caffeine study are expected to be published later this year.
