Researcher CU School of Medicine sets up research into the effects of coffee on acute kidney injury

Can Drinking Coffee Help Prevent Acute Kidney Injury? Potentially, says Kalie Tommerdahl, MD.

Tommerdahl, an assistant professor of pediatric endocrinology at the University of Colorado School of Medicine, is the lead author of a recent study that analyzed data from the Atherosclerosis Risk in Communities (ARIC) Study — a prospective cohort study of 14,207 adults ages 45 to 64. years — to see if coffee consumption had any effect on the incidence of acute kidney injury (AKI).

“ARIC was a prospective cohort study conducted in multiple communities in the United States and began in the 1980s,” Tommerdahl says. “ARIC followed these individuals for approximately 25 years and evaluated several risk factors for atherosclerosis – or hardening of the arteries. We conducted a secondary analysis to evaluate the risk of AKI and how that relates to self-reported coffee intake.”

In a population of more than 14,000 participants, Tommerdahl and her fellow researchers identified nearly 1,700 episodes of AKI — defined as a sudden episode of kidney failure or kidney damage requiring hospitalization. The data showed that people who self-reported drinking any amount of coffee had an 11% lower incident risk of AKI — and the number dropped even more as coffee consumption increased.

“This particular study showed that there was a connection, but we can’t say why yet. Further evaluation of the underlying characteristics of coffee is necessary,” says Tommerdahl. “There could be a link to caffeine or the bioactive compounds in coffee, or it could be due to water intake and how that interacts with your kidneys. The association between coffee intake and risk of AKI needs further investigation. ”

Coffee and diabetes

More answers can be found as the result of a related paper on which Tommerdahl is also lead author – this one looks at the results of a pilot and feasibility study by CU School of Medicine faculty member Petter Bjornstad, MD, an associate professor with a dual appointment in pediatric endocrinology and adult kidney disease and hypertension, which evaluated the effects of coffee on adolescents with type I diabetes.

Study participants were given a 10-day course of caffeine with cold brew coffee, and their kidney function was evaluated before and after starting the coffee regimen.

“In a small cohort of 10 adolescents with type 1 diabetes, we evaluated the effects of a single cold brew coffee once daily for 10 days on kidney function,” Tommerdahl says. “We looked at gold standard measures of renal function and then evaluated how they changed over the 10-day course of treatment. We found no change in renal function statistics over the course of the study, but the study itself was well tolerated from an adolescent perspective. Future directions include studying a larger cohort of individuals and incorporating a longer duration of treatment.”

Next steps in the research

Both studies demonstrate the need to further evaluate the effects of coffee on the kidneys and compare it to other beverages that contain and do not contain caffeine. Tommerdahl and her fellow researchers are hopeful, as coffee has previously been shown to lower the incidence of chronic kidney disease.

“The optimal next step would be to give individuals different types of coffee substances, while controlling directly for coffee type and amount of caffeine, and comparing people who don’t have the same exposure with renal function assessments,” Tommerdahl says. “We would also like to check how the coffee was brewed – was it brewed cold? Was it hot coffee? All those characteristics influence how the coffee is metabolized and how it exerts its effects in the body.

Another option, Tommerdahl says, is to isolate caffeine and study its effects purely from the chemical, without the water and biological compounds associated with drinking a cup of java.

“We are considering a future study that involves administering caffeine with pre- and post-exposure MRIs of the kidneys and kidney function tests to see how the kidney responds directly to caffeine,” she says.

Help for Pediatric Patients

All the positive results of coffee on kidney function are useful in pediatrics, where health care providers are always looking for ways to prevent long-term kidney disease in children, especially those with diabetes.

“Our studies have shown that even children who are quite early in their diagnosis of diabetes and who are healthy still see changes in their cardiovascular and kidney function,” says Tommerdahl. “Anything we can do to help them improve their long-term health outcomes could be really valuable.”

“In addition, many young people today regularly drink coffee, energy drinks and tea, all of which contain caffeine, so it will be important to better understand how that affects their long-term health,” she continues. “Coffee is the most consumed beverage worldwide, so a better understanding of its effects on our kidneys and cardiovascular systems will be beneficial.”

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