Science of beverage sipping: Is coffee good for you or bad for you?


By Dr. Tim Sandle

June 23, 2024

DIGITAL JOURNAL

Morning coffee. — Image © Tim Sandle

One scientific study about the benefits of drinking coffee tends to be counterbalanced by another that draws out neutral or ill-health effects. What is the right answer? When it comes to your genetics, the answer is complicated.

Of course, such an answer depends on how much coffee is consumed, with six cups of coffee a day were considered the upper limit of safe consumption. But is it more complicated than that and does the answer relate to the individual?

While the effects of coffee consumption on human health remains a knotty question, but one thing is certain: coffee is a psychoactive substance.

Researcher Dr. Sandra Sanchez-Roige, from the University of California San Diego School of Medicine Department of Psychiatry, has been leading a team examining coffee-consumption characteristics of people from a 23andMe database.

The research team collected genetic data as well as self-reported coffee-consumption numbers to assemble a genome-wide association study. The idea was to make connections between the genes that were known to be associated with coffee consumption and the traits or conditions related to health.

The researchers used these data to identify regions on the genome associated with whether somebody is more or less likely to consume coffee. From this they proceeded to identify the genes and biology that could underlie coffee intake.

The data suggests the particular gene variants that a person inherits from their parents influence how much coffee they are likely to consume.

Sanchez-Roige says the genetic influence on coffee consumption was the first of two questions the researchers wanted to address.

“The second is something that coffee lovers are really keen on learning,” she explains. “Is drinking coffee good or bad? Is it associated with positive health outcomes or not?”

The answer is not definitive. The group’s genome-wide association study of 130,153 U.S.-based 23andMe research participants was compared with a similar UK Biobank database of 334,649 Britons, revealing consistent positive genetic associations between coffee and harmful health outcomes such as obesity and substance use.

A positive genetic association is a connection between a specific gene variant (the genotype) and a specific condition (the phenotype).

Conversely, a negative genetic association is an apparent protective quality discouraging the development of a condition. The findings get more complicated when it comes to psychiatric conditions.

It was also found that the relationship between genotype and phenotype is more different than the relationship between coffee and tea.

One factor influencing the interpretation of the data is that coffee comes in a variety of forms, from instant to frappuccino, and is consumed amid cultural norms that differ from place to place.

The researchers conclude that to unravel the relationships between genetics and the environment, more research is needed, research focusing not only on coffee/caffeine intake but also other substance-use issues.

So, for the time being the question of coffee and the impact on health remains unanswered.

The research appears in the journal Neuropsychopharmacology, titled “Genome-wide association studies of coffee intake in UK/US participants of European ancestry uncover cohort-specific genetic association