Coffee and Kidney Stones

Kidney function is affected by excessive coffee or caffeine intake. It may cause several complications such as diuresis, detrusor instability and kidney stones.

Caffeine intake must be limited or it could lead to the painful medical situation of kidney stones. In a recent study, participants with a history of kidney stones were given a dose of caffeine equivalent to that found in two cups of coffee. Following tests revealed more calcium in the urine of the subjects. The increased amount of calcium in the urine is a clear indication of increased susceptibility towards kidney stone development.


Following the study it is recommended that people prone to kidney stones should limit their intake of coffee to less than two cups or 16 ounces per day. Caffeine is also found in other beverages like soda which must be restricted to a similar amount.

In the same study, researchers examined the effects of coffee or caffeine on people prone to kidney stones. After 14 hours of fasting, 48 subjects were given caffeinated water to drink. Out of these, 39 were high-risk participants and nine without a history of stones. Urine tests conducted on these 48 subjects showed great dissimilarity from the tests that were conducted two hours prior to their drinking caffeinated water.

Furthermore, all research participants showed almost similar results regardless of whether they were susceptible to kidney stone formation or not. An increase in calcium and sodium in the urine was noted, which indicates a higher risk of developing kidney stones. In addition, both groups displayed an increase of magnesium and citrate in their urine after drinking the caffeinated water. Those elements are thought to prevent stones. However, after calculating the levels of each, researchers concluded that the levels or magnesium and citrate created by the caffeine were not enough to combat the increased amount of calcium.


Research has further also revealed an opposite association between small amounts of coffee consumption and a history of kidney stones. A study conducted on 45,289 men in the United States revealed 753 new cases of kidney stones. It was further discovered that the risk of developing kidney stones had fallen by 10% in response to 240 ml/day of caffeinated or decaffeinated coffee. In a similar study conducted on 81,093 women in the United States, the number of new kidney stones was found to be 719 and the risk of developing kidney stones fell by 10% in response to 240 ml caffeinated and 9% in response to 240 ml decaffeinated coffee. The above evidence refutes all claims that coffee may cause kidney stone formation.

Rather, the studies amply demonstrate that coffee works to lower the risk of kidney stones.

I have tried to present the two opposite views on the influence of coffee that have been substantiated by research. It remains to be clarified how much intake of coffee would prove beneficial and what quantity would be detrimental to healthy kidneys and a healthy life