Individuals who have a slower rate of caffeine metabolism as determined by their genetic constitution seem to have an increased risk for development of non-fatal heart attack, following increased intake of coffee.
Coffee is the most important source of caffeine and deserves the credit of being the most popular stimulant, consumed by millions, worldwide. Several studies have highlighted the possibility of cardiovascular disease as a consequence of coffee consumption. The data available, regarding the health benefits and risks of coffee consumption, is however, controversial and inadequate.
The enzyme cytochrome P450 1A2 (CYP1A2) is responsible for metabolism of caffeine. Genetic variation associated with this gene may either confer a quicker (CYP1A2*1A) or a slow caffeine metabolism (CYP1A2*1F). The researchers analyzed more than 2014 individuals for their genetic constitution with respect to the CYP1A1 gene.
Those who had the *1F allele and drank 2-3 cups of coffee had a 36% increased risk of heart attack. Young individuals with this polymorphism were particularly at increased risk. With increase in frequency of coffee consumption (4 cups or more), the risk rose to 64%. The risk of heart attack for similar levels of coffee consumption in *1A/*1A genotype individuals was 22% and 1% respectively.
More such studies, involving a large group of patients are needed to establish the risk Vs benefit of consuming coffee.