Women, Calcium and Kidney Stones


Women, Calcium and Kidney Stones

Reference: Curhan GC, Willett WC, Speizer FE, et al. Comparison of dietary calcium with supplemental calcium and other nutrients as factors affecting the risk for kidney stones in women. Ann Intern Med 1997; 126:497-504.

Summary: This study utilized data from the Nurses' Health Study ranging over a 12 year period. Data from a total of 91,731 women were available for interpretation. A total of 864 instances of kidney stones were documented in this sample. Those women consuming the highest level of dietary calcium, even after adjustment for age and caloric intake, had a significantly lower risk of kidney stones than women at any other level of dietary calcium intake. The risk was approximately one-half in women with the highest dietary calcium intake. Dairy products were the main source of dietary calcium in this study. On the other hand, use of calcium supplements increased risk by about 1.2. There was no dose-dependent effect seen above intakes of 100 mg each day. Higher sucrose and sodium intake were associated with higher risk of developing kidney stones, while higher potassium and fluid intake were associated with lower risk. This study did not confirm a link between higher animal protein intake and increased risk or higher magnesium and phosophorus intake being linked to a lower risk of kidney stone formation. The results presented here largely confirm those found in men except as noted above. The authors note that taking supplemental calcium with meals may help reduce their lithogenic effect as this appears to reduce oxalate absorption. The only exception is breakfast, a time of low oxalate consumption generally.

Natural Product Research Consultants, Inc.


By E. Yarnell

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