Medically reviewed by Qasim Butt, MD, Susan Kerrigan, MD and Marianne Madsen on February 19, 2022
It’s hard to ignore all the good news about coffee. Numerous studies have connected coffee consumption to everything from improving mental acuity to reducing the risk of type 2 diabetes. Coffee may also be beneficial for kidney health. However, a new study suggests that drinking America’s number one beverage may also harm those organs. Here’s what the research reveals.
Coffee’s Contributions
Coffee doesn’t just contain caffeine. The bold brew is also rich in antioxidants including caffeic, chlorogenic, and n-coumaric acids along with brown pigments called melanoidins. These are known fighters of the free radicals in our cells which can among other things drive the DNA damage that leads to cancer. Coffee can also reduce the risk for Parkinson’s syndrome and reduce depression.
However, the jury is still out on whether or not a cup of Jane or Joe is good for your kidneys. Part of the problem is that caffeine is a mild diuretic. That means it doesn’t just make you go in the morning, it can really make you go in the morning. For someone with healthy, active kidneys that isn’t a big issue––although you’ll want to drink water with your coffee to reduce any dehydrating risk. However, anything that activates your kidneys isn’t a good idea if you have later stage chronic kidney disease.
Think of your kidneys as your body’s waste treatment facility. These fist-sized organs occupy territory on either side of your spine. The tiny wonders remove excess fluid from your blood along with acid and waste products. They work to keep you in balance by maintaining the optimal amount of minerals, water, and salts while also regulating high blood pressure and creating red blood cells. When they start to fail, it’s as unpleasant and dangerous as if the neighborhood waste treatment plant went kaput. Failing kidneys means waste products are allowed to accumulate while proteins and other vital nutrients are expelled in the urine rather than utilized by your body.
Kidney disease is a leading cause of death in the United States with the Centers for Disease Control and Prevention estimating that not only do 37 million adults suffer from chronic kidney disease but that some 40% of people with severely reduced kidney function are not aware of it. That’s because in the early stages the disease often lacks symptoms. That means if you have a family history of kidney disease or have risk factors including diabetes, high blood pressure, or being over the age of 65 then you should be cautious about caffeine and other things that can tax those organs.
However, moderate consumption of coffee has long been considered acceptable for people with early stages of the disease. In later stages of the disease, the risk is as much from the potassium in milk and creamers as the potassium in coffee. Generally, people fighting the disease have to be careful about their intake of the mineral. However, the common coffee advice that it’s not risky for people with kidney issues has been questioned in a new study at the Johns Hopkins Bloomberg School of Public Health.
The Study
Examining the some 372 blood metabolites in almost 4,000 people who took part in the Atherosclerosis Risk in Communities study, researchers linked 41 of them to coffee consumption. The byproduct of a metabolic process, metabolites linked to coffee were also found in the Bogalusa Heart Study of over 1,000 adults. Examining these metabolites, the researchers linked three of them that are connected to both kidney disease and coffee: glycochenodeoxycholate, O-methylcatechol sulfate, and 3-methyl catechol sulfate. However, some studies suggest that the lipid glycochenodeoxycholate can actually contribute to healthy kidneys. The other two metabolites (O-methylcatechol sulfate and 3-methyl catechol sulfate) metabolize benzoate, a process that can damage the kidneys.
As study author, Casey M. Rebholz, PhD, MS, MNSP, MPH, explains, although there is significant research supporting the idea that “… consuming a moderate amount of coffee is consistent with a healthy diet. We were able to identify one metabolite that supports this theory,” while two others “…surprisingly were associated with a higher risk of incidents of chronic kidney disease. These compounds were also associated with cigarette smoking, which may in part explain why these compounds were associated with higher risk of kidney disease.”
It will require further study before a link between those two metabolites and kidney disease is proven, although for heavy coffee drinkers who are also smokers it could be more dangerous. However, you don’t need to put the cup down just yet.
Written by John Bankston
References
- Nine Reasons Why (the Right Amount of) Coffee Is Good for You
- Antioxidant and Antiradical Activity of Coffee
- Effect of caffeine on bladder function in patients with overactive bladder symptoms
- Your Kidneys & How They Work
- Chronic Kidney Disease Basics
- Chronic kidney disease: Risks and Causes
- Coffee and Kidney Disease: Is it Safe?
- Metabolites Associated with Coffee Consumption and Incident Chronic Kidney Disease
