How much coffee do you drink each day? Researchers from the National Cancer Institute and several American universities have discovered two human genes whose variations determine individual caffeine consumption . The study is published today in the journal PLoS Genetics .
These are the CYP1A2 genes, involved in caffeine metabolism, and AHR , which regulates the former. Subjects with the "high-intake" genotype for each gene take about 40 milligrams more caffeine each day than subjects with the "low-intake" genetic profile. This equates to a third of a cup of coffee or a can of cola .
Caffeine is involved in many medical and physiological processes: it affects sleep patterns, mood, energy levels, and physical and mental performance. The identification of the genes that affect daily consumption may allow us to understand the speed of caffeine metabolism, how long it circulates in the blood or how intense the effects of its consumption are in each person.
