MILAN – A new study by Johns Hopkins Medicine researchers found that drinking at least one cup of coffee daily may lower the risk of acute kidney injury (AKI) as compared to those who don’t. The results, which were recently published in the journal Kidney International Reports, revealed that daily coffee consumption was associated with a 15 percent reduced risk of AKI, with the greatest decreases being seen in those who drank two to three cups (a 22 percent to 23 percent lower risk).
“We already know that drinking coffee on a regular basis has been associated with the prevention of chronic and degenerative diseases including type 2 diabetes, cardiovascular disease, and liver disease,” says study corresponding author Chirag Parikh, M.D., Ph.D., director of the Division of Nephrology and professor of medicine at the Johns Hopkins University School of Medicine.
“We can now add a possible reduction in AKI risk to the growing list of health benefits for caffeine.”
The National Kidney Foundation defines AKI as “a sudden episode of kidney failure or kidney damage that happens within a few hours or a few days.” The kidneys struggle to maintain the proper balance of fluids in the body as a result of the waste products that accumulate in the blood.
The signs and symptoms of AKI might vary depending on the underlying cause and can include: insufficient urine output; swelling in the legs, ankles, and eye area; weariness; shortness of breath; mental disorientation; nausea; chest pain; and, in more severe instances, seizures or coma. The condition is most often seen in hospitalized individuals whose kidneys have been stressed by medical and surgical procedures and complications.
Researchers examined 14,207 people with a median age of 54 who were recruited between 1987 and 1989 in the Atherosclerosis Risk in Communities Study, a continuing investigation of cardiovascular disease in four communities in the United States. Over the course of a 24-year period, participants were questioned seven times about how many 8-ounce cups of coffee they drank per day: 0, 1, 2 to 3, or more than 3. 1,694 instances of acute kidney injury were reported throughout the study period.
When accounting for demographic characteristics, socioeconomic status, lifestyle influences, and dietary factors, there was a 15% lower risk of AKI for participants who consumed any amount of coffee versus those who did not. When adjusting for additional comorbidities — such as blood pressure, body mass index (BMI), diabetes status, use of antihypertensive medication, and kidney function — individuals who drank coffee still had an 11% lower risk of developing AKI compared with those who did not.
“We suspect that the reason for coffee’s impact on AKI risk may be that either biologically active compounds combined with caffeine or just the caffeine itself improves perfusion and oxygen utilization within the kidneys,” says Parikh. “Good kidney function and tolerance to AKI — is dependent on a steady blood supply and oxygen.”
More studies are needed, Parikh says, to define the possible protective mechanisms of coffee consumption for kidneys, especially at the cellular level.
“Caffeine has been postulated to inhibit the production of molecules that cause chemical imbalances and the use of too much oxygen in the kidneys,” he explains. “Perhaps caffeine helps the kidneys maintain a more stable system.”
Parikh and his colleagues note that coffee additives such as milk, half-and-half, creamer, sugar, or sweeteners also could influence AKI risks and warrant further investigation. Additionally, the authors say that consumption of other types of caffeinated beverages, such as tea or soda, should be considered as a possible confounding factor.
Reference: “Coffee Consumption May Mitigate the Risk for Acute Kidney Injury: Results From the Atherosclerosis Risk in Communities Study” by Kalie L. Tommerdahl, Emily A. Hu, Elizabeth Selvin, Lyn M. Steffen, Josef Coresh, Morgan E. Grams, Petter Bjornstad, Casey M. Rebholz and Chirag R. Parikh, 5 May 2022, Kidney International Reports.