The relationship between coffee consumption and the kidneys is… complicated. Some studies have found drinking coffee linked to kidney damage while others have found that coffee can actually have a beneficial effect on the body’s blooding cleaning organ (filter recognize filter, as it were). So which is it? Is coffee good or bad for your kidneys? According to a new study, it depends, and the answer is in your genes.
As reported by Medical News Today, the new study was published in the journal Nephrology and is the joint work of researchers from universities in Toronto, Canada and Padova, Italy. For the study, researchers examined 1,180 participants between the ages of 18 and 45, all with untreated stage 1 hypertension, who had elected to be part of the 16-year Hypertension and Ambulatory Recording Venetia Study. For their work, researchers homed in on the CYP1A2 gene, the one responsible for how the body metabolizes caffeine. In particular they were looking at a particular variant known as rs762551, which around half of the participants in the study possessed.
The rs762551 variant, per Medical News Today, causes the body to metabolize caffeine more slowly. When comparing the rs762551 group to the rest—“tracing three accepted markers of kidney disfunction: albuminuria, hyperfiltration, and hypertension”—they found a stark contrast in kindey health in the moderate coffee consumers from the group groups. Those with the metabolism-slowing variant who drank three or more cups of coffee daily were 2.7 times more likely to develop kidney dysfunction and 2.8 times more likely to develop hypertension. Those without the variant saw no adverse effect.
This, according to the researchers, suggests that caffeine is harmful to individuals who aren’t able to “quickly detoxify” it out of their system. They also note that, like the cohort in the study, about half the general population has the rs762551 variant.
So whether or not coffee is good for your kidneys, especially at more volumes or above, it may already be decided by your genetics.