Researchers from the University of Copenhagen and Herlev and Gentofte Hospital have for the first time analyzed human genes and found regular coffee consumption neither increases nor decreases the risk of developing lifestyle diseases such as obesity and diabetes.
As Dr. Boerge Nordestgaard, senior physician in the Herlev and Gentofte Hospital’s Department of Clinical Biochemistry and a clinical professor at the University of Copenhagen, and his fellow authors explained in the latest edition of the International Journal of Epidemiology, an analysis of the DNA and coffee drinking habits of some 93,000 Danes found that the caffeinated beverage had no significant impact on a person’s risk of developing these conditions.
The study is said to be the first to examine the genetic impact of elevated levels of coffee consumption over a person’s lifetime – genes that are completely independent of other lifestyle factors. By investigating those genes which impact a person’s desire for coffee, the team was able to conclude that drinking the beverage was not linked to an increased or decreased risk of developing lifestyle diseases such as diabetes or obesity.
Coffee intake genes not associated with lifestyle diseases
“Previous studies have shown that coffee intake is associated with five different variations in the human genome, and that each of these variations might lead to a 0.2 cups/day higher coffee intake,” Dr. Nordestgaard told redOrbit via email. “To sum up the effect of these variations we genotyped 93,000 Danish individuals for all of the five genetic variations.”
“We saw that these variations combined lead to an increase in mean coffee intake of up to 50 percent from two to three cups/day for individuals with none of the genetic variations to individuals who had inherited all five variations from both of their parents. The biological explanation for this association is not clear, but it might be related to the metabolism of caffeine,” he added.
Dr. Nordestgaard explained that since genetic variations are inherited randomly and are thus not associated with lifestyle factors that could potentially interfere with the relationship between the risk of lifestyle diseases and a person’s coffee consumption. In their study, they compared people with none of the coffee-intake variations with those that possessed some or all of those genes.
By doing so, they were able to “estimate an unconfounded risk of type 2 diabetes and obesity not prone to reverse causation for an up to 50 percent increase in coffee intake in 93,000 individuals,” he told redOrbit. “We did not observe any change in risk of type 2 diabetes or obesity, and therefore, we concluded that coffee intake most likely is not associated causally with risk of type 2 diabetes or obesity.”
The study was based on the Copenhagen General Population Study, which includes more than 110,000 individuals and is one of the largest cohorts of its kind in the world, he added. By reviewing data on diagnosis and death from National Danish Patient registries, the authors were able to follow participants from 1977 until today with no losses to follow-up.