These recommendations are based on the assumption that carriers of at least one C allele in the rs762551 CYP1A2  gene, which encodes a caffeine metabolizing enzyme, metabolize caffeine more slowly (classified as slow metabolizers), which leads to a prolonged physiological effect of caffeine and may increase the risk of adverse health outcomes associated with high caffeine intake, including a higher risk of nonfatal myocardial infarction (MI) [5]. The gene discussed is CYP1A2; the disease is myocardial infarction.