Calcium prevents kidney stones – New Research

Calcium is a common component of kidney stones. Therefore, consuming low-calcium foods was long advised to those affected. A diet like that is bad for the bones. Recently, it has also been demonstrated that a low-calcium diet actually encourages the development of (new) kidney stones.

Calcium prevents kidney stones

For their study, Api Chewcharat and his team at the Mayo Clinic in Rochester examined detailed dietary data from 411 patients who had kidney stones.

Risky: little water, little calcium

The two main risk factors for stone formation were low calcium intake and insufficient water consumption. The participants’ risk of developing a kidney stone was lowest when they consumed 1200 mg of calcium daily and about 3400 ml of liquid from food and drink. Increasing potassium intake and drinking a lot of coffee also lower the risk of developing stones.

After around four years, 73 of the participants had gotten kidney stones again . Here, the researchers only found a risk connection with a low calcium intake.

Sinister Compound: Oxalate and Calcium

In the intestine, calcium binds to the plant chemical oxalate to form insoluble calcium oxalate. Basically a harmless substance, oxalate is eliminated through the urine or stool. More oxalate enters the body and is eliminated by the kidneys if there is insufficient calcium in the intestine. But over time, it can also combine with calcium to create so-called calcium oxalate stones, which make up about 80% of all kidney stones.

Drinking plenty of fluids can also prevent stone formation in the kidneys. The liquid dilutes the concentration of calcium or uric acid salts in the urine. If this is too high, the salts form crystals that can form stones.

However, soft drinks may not be suitable for dilution. They contain phosphoric acid, which studies have shown could promote stone formation.

Higher dietary calcium levels are also associated with higher levels of urinary citrate and pH. Both can slow down the formation of calcium oxalate stones.

Bananas, mineral water, broccoli

The researchers advise those who have kidney stones to increase their calcium intake in addition to drinking more. Calcium-rich foods include milk, cheese, broccoli, spinach, and mineral water. Fruit, particularly bananas, and vegetables like mushrooms, potatoes, and zucchini are the main sources of potassium.

“Nierensteine: Kalzium Als Vorsorge.” NetDoktor, 20 Oct. 2022,