Can drinking coffee help prevent acute kidney injury? Potentially, says Kalie Tommerdahl, MD.
Tommerdahl, assistant professor of pediatric endocrinology at the University of Colorado School of Medicine, is lead author of a recent study that analyzed data from the ARIC (Atherosclerosis Risk in Communities) study – a study of prospective cohort of 14,207 adults aged 45-64. — to see if coffee consumption had an effect on the incidence of acute renal failure (ARI).
“ARIC was a prospective cohort study that was done in multiple communities across the United States, and it started in the 1980s,” says Tommerdahl. “ARIC has followed these people for about 25 years and assessed a variety of risk factors for atherosclerosis – or hardening of the arteries. We performed a secondary analysis to assess the risk of ARI and its association with coffee consumption self-declared.”
In a population of more than 14,000 participants, Tommerdahl and his fellow researchers identified nearly 1,700 episodes of ARI, defined as a sudden episode of kidney failure or kidney damage requiring hospitalization. The data showed that people who reported drinking any amount of coffee had an 11% lower risk of an ARI incident – and the number fell even more with increasing coffee consumption.
“This particular study showed there was an association, but we can’t yet say why. Further evaluation of the underlying characteristics of coffee is needed,” says Tommerdahl. “There could be an association with 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 consumption and ARI risk requires further study.
Coffee and diabetes
More answers can be found following a related article on which Tommerdahl is also the lead author – this one examining the results of a pilot and feasibility study by the faculty member of the medical school of CU Petter Bjornstad, MD, an associate professor with a dual appointment in pediatric endocrinology and adult kidney disease and hypertension, who 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 assessed before and after starting the coffee diet.
“In a small cohort of 10 adolescents with type 1 diabetes, we assessed the effects of a single cold brew coffee once daily for 10 days on kidney function,” says Tommerdahl. “We looked at baseline measures of kidney function and then assessed how they changed over the course of 10 days of treatment. We found no changes in kidney function parameters during the study, but the study itself was well tolerated from an adolescent perspective. Future directions include studying a larger cohort of individuals and including longer treatment duration.
Next steps in research
Both studies show the need for further evaluation of coffee’s effects on the kidneys and its comparison with other caffeinated and non-caffeinated beverages. Tommerdahl and his fellow researchers are hopeful, as coffee has already been shown to reduce the incidence of chronic kidney disease.
“The optimal next step would be to give individuals different types of coffee substances, while directly controlling the type of coffee and the amount of caffeine, and comparing to people who do not have the same exposure with assessments of the kidney function,” Tommerdahl said. “We would also want to control how the coffee was brewed – was it cold brew? Was it hot coffee? All of these characteristics affect how coffee is metabolized and how it exerts its effects in the body.
Another possibility, says Tommerdahl, is to isolate the caffeine and study the purely chemical effects, without the water and biological compounds that come with consuming a cup of java.
“We are considering a future study involving the administration of a caffeine load with pre- and post-exposure kidney MRIs and kidney function tests to see how the kidney responds directly to caffeine,” she says.
Help for pediatric patients
Any positive results of coffee on kidney function are helpful in pediatrics, where 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 fairly early in their diagnosis of diabetes and who are in good health still see changes in their cardiovascular and kidney function,” says Tommerdahl. “Anything we can do to help them improve their long-term health outcomes can be really valuable.”
“In addition, many young people regularly drink coffee, energy drinks and tea, all of which contain caffeine, so it will be important to better understand how this affects their long-term health,” she continues. “Coffee is the most consumed beverage in the world, so having a better understanding of its effects on our renal and cardiovascular systems will be beneficial.”
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