As coffee is a major source of caffeine, people often wonder; when it comes to a healthy diet, should I drink coffee or not?
There is no unanimous recommendation on daily coffee intake, as over the years studies have been controversial and conflicting. However, in 2015, the US Dietary Guidelines, which previously had no position on coffee, were updated, indicating that drinking three to five cups of coffee per day “can be incorporated into healthy eating patterns” – essentially giving ‘moderate’ coffee consumption the thumbs up. This is because more recent studies have shown that adults who drink coffee are, on average, no worse off when it comes to their health.
And some of us in fact are better off.
It seems how ‘good’ coffee is for you depends in part on your genetic makeup. Caffeine is broken down (i.e. metabolized) in the liver by an enzyme called CYP1A2. The activity of this enzyme varies from person to person, which comes down to a slight variation in the CYP1A2 gene.
Scientists have revealed there is a ‘rapid’ variant of the gene associated with processing caffeine quickly. And a ‘slow’ variant of the gene associated with processing caffeine slowly. People with two copies of the ‘rapid’ variant (one from each parent) are called rapid caffeine metabolizers. And people with one or two copies of the ‘slow’ variant are called slow caffeine metabolizers. Studies have shown that young people (under 59) who are rapid metabolizers break down caffeine four times faster than slow metabolizers.
But what does this mean for our health? In 2007, a team of researchers from the University of Toronto found that how we metabolize caffeine seems to play a role in how good or bad drinking coffee is for our heart.
They studied 4000 adults (2000 who had previously suffered a heart attack) and found that drinking more than four cups of coffee a day was linked to an increased risk for heart attack. However, when they looked closer, this increased risk was seen only in the slow metabolizers. And surprisingly, rapid metabolizers who drank one to three cups of coffee per day had a much lower risk for heart attack. That is, the rapid metabolizers seem to gain some heart protection from drinking coffee.
How can this be? Researchers speculate that the lingering caffeine in slow metabolizers contributes to the triggers of heart attack. Whereas for rapid metabolizers, clearing the caffeine out of their system quickly allows their body to make use of the healthy compounds in coffee, like polyphenols (micronutrients with antioxidant properties that are thought to reduce the risk for cancer and heart disease).
A genetic test can tell you which kind of caffeine metabolizer you are, rapid or slow. Although in either case, it seems that drinking anywhere from one to three cups of coffee a day is a safe bet. And as a coffee lover, and a rapid metabolizer, that’s good news, and makes my daily cup of joe just a little more satisfying.