Every once in a while, I try to start my day without my usual cup of coffee. Within a few hours, I realize this is a big mistake. I really need that shot of caffeine to get going in the morning so I am always bewildered by equally sleep-deprived friends of mine who swear they never touch the stuff. How come they don't need it and I do?
Science may have found the answer. Researchers at Harvard and the National Cancer Institute say they have identified two genes that are linked to the way we metabolize caffeine and may be responsible for the inherited differences in how people consume this very popular stimulant.
The researchers, whose work is published in the journal PLoS Genetics, point out that 90 percent of people around the world consume some form of caffeine. In this country, the vast majority of people get their caffeine from coffee.
After examining the genetic traits and caffeine intake of more than 47,000 Americans in five different studies, the scientists found that people who carried a certain combination of genes consumed an extra 40 milligrams of caffeine, about the amount found in a third of a cup of coffee, compared to those who drank the least caffeine.