Coffee is one of the most widely consumed beverages. In a new study, scientists from the University of California, San Diego and others conducted a genome-wide association study (GWAS) of coffee intake among US-based 23andMe participants. They investigated genetic correlations and conducted a phenotype-wide association study across hundreds of biomarkers, health, and lifestyle traits, and compared their results with the largest GWAS of coffee intake from UK Biobank.
Coffee drinking is an inherited habit and carries a certain amount of genetic load. Image courtesy of Sci.News.
“To create the GWAS, we collected genetic data and self-reported coffee consumption,” said lead author Dr. Hayley Thorpe, a researcher at Western University and the University of Guelph.
“Our goal was to identify associations between genes known to be associated with coffee consumption and health-related traits and conditions.”
“We used these data to identify regions in the genome that are associated with a higher or lower likelihood of drinking coffee.”
“And then we identify the genetics and biology that underlie coffee consumption.”
“Many people are surprised that coffee consumption has genetic effects,” said co-author Abraham Palmer, PhD, a research scientist at the University of California, San Diego.
“From previous papers, we had good reason to suspect that there was a gene that influenced coffee intake.”
“So it wasn’t a surprise to us that in both cohorts we looked at, there was statistical evidence that this is a genetic trait.”
“In other words, the specific genetic variants we inherit from our parents influence how much coffee we drink.”
“The genetic influence on coffee consumption was the first of two questions we wanted to answer,” said Sandra Sanchez Loij, PhD, a research scientist at the University of California, San Diego and senior author of the paper.
“The second thing is what coffee lovers really want to know: Is drinking coffee good or bad? Does drinking coffee have positive health consequences or not?”
The group’s genome-wide association study of 130,153 US-based 23andMe study participants, compared with a similar UK Biobank database (334,649 British individuals), found consistent positive genetic associations between coffee consumption and adverse health outcomes such as obesity and drug use.
A positive genetic association is a link between a particular gene variant (genotype) and a particular condition (phenotype).
Conversely, a negative genetic association would be a clear protective trait that would thwart the onset of the disease.
When it comes to mental illness, the findings are more mixed.
“For example, if you look at the genetics of anxiety disorders, bipolar disorder and depression, in the 23andMe data, they tend to be positively correlated with the genetics of coffee consumption,” Dr. Thorpe said.
“However, in UK Biobank we see the opposite pattern of negative genetic correlation, which is not what we expected.”
“There were other instances where the 23andMe sets did not match the UK Biobank, but the biggest discrepancies were for psychiatric disorders.”
“It’s common in this field to combine similar datasets to increase research power. This information tells us pretty clearly that combining these two datasets was not a smart idea. And we ended up not doing so.”
“Mixing databases can mask effects, leading researchers to erroneous conclusions, or even cancel each other out.”
“There are a few ideas as to how the differences in results could have arisen. First, the studies were comparing apples with oranges,” Dr. Sánchez Loisi said.
“For example, the 23andMe survey asks, ‘How many 5-ounce (cup-sized) cups of caffeinated coffee do you drink per day?’ Compare this to UK Biobank’s, ‘How many cups of coffee do you drink per day (including decaffeinated coffee)?'”
“The study did not take into account the variety of ways coffee is presented, beyond serving size and whether it’s caffeinated or decaffeinated.”
“We know that in the UK instant coffee is generally preferred, whereas in the US ground coffee is more commonly preferred,” Dr Thorpe said.
“And then there’s the Frappuccino, the American fad of drinking coffee loaded with added sugar,” Dr. Sánchez Loij added.
“There are other caffeinated drinks out there and, particularly in the UK Biobank context, tea was not included in the GWAS that looked solely at coffee,” Dr Palmer said.
“GWAS shows that the genotype-phenotype relationship is more different than that between coffee and tea.”
“Genetics influences a lot of things. For example, it influences your height.”
“And these things would probably play out in the same way whether you lived in the US or the UK. But coffee is a decision people make.”
“Coffee comes in many forms, from instant to Frappuccino, and is consumed within different cultural norms in different places,” Dr Sánchez Loij said.
“Someone with one genotype may end up with a completely different phenotype if they live in the UK and the US.”
“And that’s exactly what the data tells us, because in the case of height, behavior doesn’t really matter, but behavior and selection in the environment affect it in different ways. So genotype-environment interactions complicate the picture.”
Team paper Published in the journal Neuropsychopharmacology.
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HHA Soap othersGenome-wide association study of coffee consumption in UK/US participants of European descent revealed cohort-specific genetic associations. NeuropsychopharmacologyPublished online April 17, 2024, doi: 10.1038/s41386-024-01870-x
Source: www.sci.news
