Heavy coffee drinking may increase kidney disease risk in these people

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Scientists from the University of Toronto and other institutions have found a link between heavy coffee consumption and kidney disease in individuals with a common genetic variant.

The findings were published in the journal JAMA Network Open.

The study revealed that markers of kidney disease were nearly three times higher in heavy coffee drinkers who had a variant of the CYP1A2 gene.

This gene variant makes these individuals slower at metabolizing caffeine compared to other heavy coffee drinkers with a different variant of the same gene that allows for faster caffeine metabolism.

The researchers suggest that faster metabolizers can eliminate caffeine more efficiently from their systems, preventing harmful caffeine build-ups.

Previous Findings and Recommendations

Previous studies have shown conflicting results, with some suggesting that caffeine impairs kidney function and causes kidney failure, while others have indicated that coffee could protect against kidney disease.

The current study found the risk of kidney dysfunction was only significant in people who drank three or more cups of coffee per day, approximately equivalent to 300 mg of Italian espresso.

Current guidelines in Canada and the U.S. recommend no more than 400 mg per day for healthy adults.

Prevalence of CYP1A2 Variant

Interestingly, the researchers found the prevalence of the CYP1A2 gene variant associated with slower caffeine metabolism was similar in both the study group and the general population—around 50%.

This gene variant is included in personalized genetic tests offered by many companies and clinics, as it can affect the risk for several conditions related to caffeine consumption.

Markers of Kidney Dysfunction

The study examined three markers of kidney dysfunction: albuminuria (an excess amount of the protein albumin in urine), hyperfiltration (a high glomerular filtration rate in the kidney), and high blood pressure.


The researchers hope their findings will raise awareness about the importance of personalized nutrition recommendations based on individual genetic makeup, particularly for those concerned about kidney health.

They suggested that further studies could provide more information about protecting kidneys from diabetes and the effects of common cholesterol-lowering statin drugs on kidney health.

If you care about kidney health, please read studies about pesticides linked to chronic kidney disease, and this drug may prevent kidney failure in people with diabetes.

For more information about kidney health, please see recent studies about drug duo that may treat kidney failure, and results showing these vegetables may protect against kidney damage.

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