By: Dr. Gary Bellman on April 13, 2018
affect approximately 12% of the American population, and calcium oxalate stones
account for almost 90% of kidney stone incidences. Oxalates
are organic chemicals found in certain foods (such as spinach and beets) that may combine with calcium to form calcium oxalate, an insoluble chemical the human body cannot use.
Since 20-40% of recurrent kidney stones have been associated with elevated urinary calcium
, it was originally thought that consumption of high amounts of calcium might cause or contribute to that of stone formation. However, established studies have shown that calcium restriction may actually
increase the risk of kidney stones under certain conditions.
Because most kidney stones are made of calcium oxalate
, it might seem counterintuitive to consume more calcium and end up with less in your kidneys, but there is theory about why it works…the real culprit is oxalate, not calcium. Oxalate is found in many foods including fruits, vegetables, nuts and chocolate, and calcium binds to it avidly. The more calcium in the digestive tract, the more oxalate that can bind and take out of the body before the oxalate is absorbed and ends up in the kidneys.
Anyone who has had kidney stones
should try to prevent a recurrence
; Some general observations include: increased fluid intake
, restrict sodium
, and reduce animal protein intake
Higher potassium intake can also lower the risk for calcium stones.
A high-calcium diet does not appear to increase the risk for kidney stones as long as it also contains plenty of fluids, dietary potassium, and phosphate. (Increasing calcium alone may pose a modest risk for stones.)
Patients should try to correct any dietary habits that cause acidic or alkaline imbalances in the urine, which promote stone formation.
Because different kidney stone types may require specific dietary changes
, patients should work with their doctors to develop an individualized plan. Nutritional considerations are very important in preventing recurrences, and patients should comply with the proper diet.
Role of Calcium
Dietary calcium recommendations for kidney stone prevention need to be determined on an individual basis; Dr. Bellman
will suggest calcium guidelines based on a patient's age, gender, body size, and type of stone. Most studies indicate that those who eat the recommended amount of dietary calcium have a lower chance of recurrence of stones than those who eat a low calcium diet; A diet containing a normal amount of calcium, but reduced amounts of animal protein and salt, may protect against stones better than a low-calcium regimen.
Calcium citrate is considered the best formulation, if supplements are needed.
Calcium Restriction in Certain Cases
Some patients, such as those whose stones are caused by genetic defects in which the intestine absorbs too much calcium, may need to limit calcium intake. More studies are needed to define this group precisely.
If you currently suffer from kidney stones or are feeling symptoms of an occurrence, we recommend consulting with Dr. Bellman
to determine the best course of action for your specific situation.
Our office can be reached at 818. 912. 1899