People who like to drink their coffee black also prefer dark chocolate, a new Northwestern Medicine study found. The reason is in their genes.
Scientists at Northwestern University have found coffee drinkers who have a genetic variant that reflects a faster metabolism of caffeine prefer bitter, black coffee. And the same genetic variant is found in people who prefer the more bitter dark chocolate over the more mellow milk chocolate.
The reason is not because they love the taste, but rather because they associate the bitter flavour with the boost in mental alertness they expect from caffeine.
The gene variants are related to the faster metabolism of caffeine rather than to taste. These individuals metabolise caffeine faster, so the stimulating effects wear off faster as well. Hence they need to drink more.
The scientists have interpretated the findings as these people equate caffeine’s natural bitterness with a psycho-stimulation effect. They learn to associate bitterness with caffeine and the boost they feel. This becomes a learned effect. When they think of caffeine, they think of a bitter taste, so they enjoy dark coffee and, likewise, dark chocolate.
The dark chocolate connection also may be related to the fact that dark chocolate contains a small amount of caffeine but predominantly theobromine, a caffeine-related compound, also a psychostimulant.
Why does this matter?
Coffee and dark chocolate consumption have been shown to lower the risk of certain diseases. Moderate coffee consumption ( two to three cups a day) lowers the risk of Parkinson’s disease, cardiovascular diseases, type 2 diabetes and several types of cancer. Dark chocolate appears to lower the risk of heart disease.
Currently, when scientists study the health benefits of coffee and dark chocolate, they must rely on epidemiological studies, which only confer an association with health benefits rather than a stronger causal link.
Cornelis’s new research shows these genetic variants can be used more precisely to study the relationship between coffee and health benefits. Previously, scientists were using the genetic markers for coffee drinkers in general. The new findings suggest they are stronger markers for particular types of coffee drinkers—black coffee drinkers. This impacts the interpretation of these genetic studies of coffee and health.
Drinking black coffee versus coffee with cream and sugar is very different for your health. The person who wants black coffee is different from a person who wants coffee with cream and sugar. Based on the findings, the person who drinks black coffee also prefers other bitter foods like dark chocolate. So these results are strating to help drill down into a more precise way to measure the actual health benefits of this beverage and other food.
REFERENCES:
M.C. Cornelis and R.M. van Dam
Genetic determinants of liking and intake of coffee and other bitter foods and beverages.
Sci Rep 11, 23845 (2021).
https://doi.org/10.1038/s41598-021-03153-7