How much coffee to drink to prevent kidney stones?

Kidney stones are crystallized deposits that form in the kidneys when urine becomes too concentrated with minerals and other chemicals, according to research published in the journal Advances in Nutrition. However, drinking certain fluids that increase urine output may help prevent kidney stones from forming.

Coffee is a diuretic, which certainly qualifies as such. But too much caffeine has also been linked to increased urinary calcium excretion, which can make people more susceptible to kidney stones.

An analysis published in Frontiers in Nutrition looked at the relationship between caffeine consumption and kidney stone risk in more than 30,000 people with a history of kidney stones. The study found a link between caffeine consumption and a reduced risk of developing kidney stones.

The link was strongest in women and people who were not overweight. In particular, coffee was found to have a greater effect on reducing the risk of kidney stones than other caffeinated foods and drinks.

A previous study published in the American Journal of Clinical Nutrition also yielded similar results. In it, the authors identified a link between caffeine consumption and a reduced risk of kidney stones. The team analyzed data from three other studies. Accordingly, those who consumed the most caffeine had a 26% lower risk of developing kidney stones.

Although scientists have found a stronger correlation between caffeinated coffee and a reduced risk of kidney stones, caffeine may not be the only influencing factor. Other contributing factors include coffee's antioxidant and anti-inflammatory properties, as well as its high magnesium content. However, evidence for a potential link between magnesium and kidney stone risk is limited.

According to the US Food and Drug Administration (FDA), if you want to add coffee to your daily diet for the purpose of improving your urinary system, you should remember not to consume more than 400mg of caffeine per day (equivalent to 4 cups of coffee). Maintaining a healthy weight and drinking plenty of water are other ways to reduce the risk of developing kidney stones.

Some dietary changes may also be helpful, such as reducing the amount of meat, salt, or peanuts. According to the National Institute of Diabetes and Digestive and Kidney Diseases, the DASH diet is more likely to reduce the risk of kidney stones. DASH emphasizes whole grains, fruits, vegetables, low-fat dairy, nuts, fish, lean meats, and unsaturated fats. It is high in calcium, fiber, potassium, and magnesium, and low in total fat, saturated fat, cholesterol, and sodium.