Genes that determine coffee drinking

in medicine, biology, omics

How many cups of coffee do you drink every day? Did you know that coffee consumption is a model for addictive behavior? Researchers say they have identified genes that play a role in influencing how much coffee people drink.

Dr Enda Byrne from Queensland Institute of Medical Research (QIMR) and a co-author said that coffee is the most popular beverage in the world and the study has shown there is a small genetic variant in the population that determines how people react to coffee and therefore explains why some people will consume coffee at higher levels and why others won’t drink it at all.

The paper was published in the journal Molecular Psychiatry.

They performed a complex analysis of genome-wide association studies on coffee intake from 8 Caucasian groups and tested the findings in a further 7929 individuals. They also performed a gene expression analysis treating different cell lines with caffeine.  They found a gene segment that lie in the 23-kb long commonly shared 5′ flanking region between CYP1A1 and CYP1A2 genes.

In humans, CYP1A1 encodes the protein Cytochrome P450, family 1, subfamily A, polypeptide 1 and CYP1A2 encodes Cytochrome P450 1A2. According to the paper, "CYP1A1 is known to metabolize polycyclic aromatic hydrocarbons, which are important constituents of coffee, whereas CYP1A2 is involved in the primary metabolism of caffeine."

"Our study found coffee consumption is not only influenced by genes, but caffeine can also affect the expression of genes,” Dr Byrne said.

“With caffeine impacting gene expression, we believe that caffeine then influences chemical pathways in the body.

“We also found a link between caffeine genes and other complex conditions, such as hypertension and Parkinson’s disease.

“Our study showed there were changes in the expression of genes previously linked to Parkinson’s disease after exposure to caffeine. This follows previous studies that have shown caffeine to be protective against Parkinson’s disease.

“While this finding relates directly to coffee consumption, it provides another small piece of the puzzle and could lead to further discoveries around the affect of caffeine on a range of complex disorders.”

QIMR worked closely with researchers from the Erasmus University Medical Centre in the Netherlands and looked at genes across the entire human genome of over 18,000 participants.

Though coffee intake has also been associated with increased risk of some cancers, blood pressure and myocardial infarction, coffee is not all that bad. Coffee drinking has been associated with a decreased risk of  Alzheimer's disease, Parkinson's disease and type II diabetes.

“In the Genetic Epidemiology Lab at QIMR, we are constantly looking at small genetic changes that increase disease risk. We often find interesting genetic variants, such as this coffee consumption gene, during our investigations,” Dr Byrne said.

“This study would not have been possible without the information collected from thousands of identical and non-identical twins taking part in the QTwin study.

“By comparing data from identical and non-identical twins we can establish how much of who we are is determined by our genes and how much is influenced by environment.

“Twins help us understand how small genetic changes can have large impacts on our health.”

Source article: Genome-wide association analysis of coffee drinking suggests association with CYP1A1/CYP1A2 and NRCAM. N Amin, E Byrne, J Johnson et al.  Molecular Psychiatry advance online publication 30 August 2011; doi: 10.1038/mp.2011.101. Photo credit: MedlinePlus, nih.gov.

Additional source: Queensland Institute of Medical Research

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