How much coffee you can drink depends on the degree to which your liver can metabolize caffeine. This breaking down process appears to be determined by your genes.
Addiction to coffee also appears to have a genetic cause. These are the conclusions made by a group of international researchers led by Erasmus MC. The results of their research not only help understand the differences in coffee consumption among people but the genes found also appear to affect disorders such as hypertension and Parkinson’s disease. The study has been published in Molecular Psychiatry.
Coffee addiction is considered to be a benign addiction. Coffee drinkers have a craving for coffee and get withdrawal symptoms when they abstain from drinking coffee, for example, headaches. Caffeine addiction has become a model for serious addictions. The liver sees coffee as a potentially toxic substance and after consumption it produces several proteins to process, among other, the caffeine. These proteins determine the amount of coffee you can handle and thus drink. The researchers looked for genetic variations that have an effect on drinking coffee. They found that particularly variations in the CYPIA1 gene determine to what extent the liver can metabolize the caffeine. In addition, they found that coffee consumption is determined by the NRCAM gene, a gene known to play a role in other addictions, such as addictions to morphine, amphetamine and cocaine.
An important aspect of drinking coffee is that the consumption has an effect on a wide range of diseases. This new study shows that the genes involved in the metabolism of the coffee are also related to the onset of Parkinson’s disease. This result explains the phenomenon that drinking coffee appears to protect against Parkinson’s disease. Professor Cornelia van Duijn, chief researcher and genetic epidemiologist at Erasmus MC: “Patients with Parkinson’s disease appear to drink less coffee. Our research shows that this result can be partly explained by a common genetic origin. An important question raised by the study is whether drinking coffee does actually protect against Parkinson’s disease or whether the genes that determine that one doesn’t drink much coffee also by chance happen to be the genes that play a role in the processes in the body that ultimately result in Parkinson’s disease. This will require further investigation. “
Researchers from VU Medical Center Amsterdam, UMC Groningen and UMC St. Radboud in Nijmegen also participated in this large-scale international study. The results have been based on more than 18,000 study subjects who participated in eight different international subjects.