When You Drink Coffee Every Day, This Is What Happens To Your Kidney Stone Risk

Daily coffee-drinkers seem to have a leg up when it comes to urinary health. In addition to potentially lowering our susceptibility to type 2 diabetes, heart disease, certain cancers, and more (via Harvard T.H. Chan), starting off each day with a cup of joe or two may reduce one's risk for developing kidney stones as well.

Most often made up of calcium oxalate and calcium phosphate, kidney stones are crystallized deposits that develop in the kidneys when our pee becomes overly concentrated with minerals and other chemicals, according to research from a 2018 scientific review published in Advances in Nutrition. However drinking certain liquids known to boost urine output may help protect against the formation of kidney stones. Acting as a diuretic, coffee certainly meets this qualification. But caffeine has also been linked with increased urinary calcium excretion, suggesting that caffeine consumption may oppositely make people more prone to kidney stones. At the same time, a growing body of research suggests there may be something unique about coffee that causes our kidney stone risk to fall.

Researchers from a 2022 study published in Frontiers in Nutrition analyzed the relationship between caffeine consumption and kidney stone risk in over 30,000 participants with a medical history of kidney stones. The study findings showed a connection between caffeine consumption and a reduced risk for developing kidney stones. However this link was only observed in white participants, and was more significant amongst women and people who were not classified as overweight. Coffee, specifically, was found to have a greater effect on kidney stone risk reduction than other caffeinated foods and beverages.

An earlier 2014 study published in The American Journal of Clinical Nutrition yielded similar results, in which researchers also identified a link between caffeine consumption and a reduced risk of kidney stones. The study team analyzed data from three different ongoing studies. Among participants in the Health Professionals Follow-Up Study (HPFS), people who consumed the greatest amounts of caffeine were 26% less likely to develop kidney stones. This statistic jumped to 29% among people in the Nurses' Health Studies (NHS) I, and climbed to 31% for individuals in the Nurses' Health Studies (NHS) II. While caffeine is thought to be the primary contributing factor in the association between coffee and kidney stones, the researchers noted that decaffeinated coffee has also produced similar results. While not nearly as much as caffeinated coffee, decaf coffee does have a small amount of caffeine.

Although researchers have found a stronger correlation between caffeinated coffee and reduced kidney stone risk compared to decaffeinated coffee, the presence of such a relationship suggests that caffeine may not be the only influencing factor. Other contributing factors proposed in the research include the antioxidant and anti-inflammatory properties of both beverages, as well as coffee's high magnesium content. However the evidence is limited regarding the potential relationship between magnesium and kidney stone risk.

If you want to add a daily coffee to your urinary health regimen, just remember not to exceed 400 milligrams of caffeine per day, as per the U.S. Food and Drug Administration (FDA). Maintaining a healthy weight, and drinking plenty of water are other ways to keep your chances of developing kidney stones low. Depending on what kind of kidney stones you have, certain dietary changes may also be helpful, such as lowering one's intake of meat, salt, or peanuts. The Dietary Approaches to Stop Hypertension diet, or DASH diet, can also benefit the body and potentially make one less vulnerable to kidney stones, according to the National Institute of Diabetes and Digestive and Kidney Diseases. 

Talk to your doctor if you're concerned about kidney stones. Your physician can help determine what kind of kidney stone you have, and develop a treatment plan that may involve medication, lifestyle changes, or surgical removal.