Calcium oxalate kidney stones are the most common type of kidney stones, which are hardened masses of minerals that form in the small filters of your kidneys. But don't let the word "calcium" fool you -- a calcium-rich diet, high in foods like milk, is not linked with an increased incidence for kidney stones. While whole food sources like milk may not contribute to kidney stones, high doses of calcium supplements potentially can.
Formation
Kidney stones typically form because you have a blood or chemical imbalance that causes your body to form kidney stones. This imbalance creates an environment where minerals can clump together in your kidneys and create stones of varying sizes. Four chief types of kidney stones exist: calcium, struvite, uric acid and cystine. Calcium stones are formed due to an imbalance in chemicals like calcium, oxalate or urate. A lack of citrate in your urine also can contribute to kidney stone development.
Misconception
If you have kidney stones symptoms, like severe flank pain or blood in your urine, your physician may recommend that you use a paper strainer when you urinate to collect the stones. A laboratory can then analyze the stones for the presence of certain minerals. If your physician diagnoses you with calcium stones, the milk you drink is not the cause of this. Instead, factors like excess sodium in your diet can contribute to kidney stones because salt causes your kidneys to hold on to calcium in your urine. This increases the likelihood calcium kidney stones will form. Another cause can be your body's excess production of parathormone, which causes your body to hold on to calcium.
Calcium Supplementation
Although milk may not contribute to kidney stone formation, calcium supplementation is linked with an increased risk. Your total calcium intake should not exceed 2,500 mg per day if you are between the ages of 19 to 50 or 2,000 mg per day if you are older than age 50. This is considered the upper limit of calcium you can consume in a day. Having more calcium than this can increase your risk for developing kidney stones.
Solution
If you experience calcium kidney stones, your physician may recommend drinking more fluids because fluids dilute your urine and reduce the likelihood kidney stones will form. The standard advice is to drink between eight and 10 glasses of fluid per day. While at least half should be water, other sources can come from milk or other fluids. Your physician also may recommend reducing your salt consumption because this is linked to an increased risk for calcium stones.
