Author Interviews, Calcium, Kidney Disease, Kidney Stones, Supplements, Vitamin D / 20.10.2015
Calcium Supplements Linked To Increased Risk of Kidney Stones
MedicalResearch.com Interview with:
Christopher Loftus M.D. candidate
Cleveland Clinic Lerner College of Medicine
Medical Research: What is the background for this study? What are the main findings?
Response: Most kidney stones are made, at least partially, of calcium composite. In a prospective study of nurses in the post-menopausal age, it was found that diets that contained high amounts of calcium were beneficial in preventing kidney stones in this population. In the gut, calcium can bind to oxalate which prevents it from being absorbed into the body and decreases the concentration of calcium in the urine. However there has been debate as to whether supplemental calcium (calcium pills) has the same beneficial effects as calcium in the diet. Supplemental calcium enters the gut in large quantities all at once so it may enter the blood stream in higher concentrations over smaller amounts of time. By the same token, vitamin D plays a role in the management and balance of calcium in the body and could potentially have an effect on stone formation as well. It has also been debated whether vitamin D supplementation has major effect on patients who are known to be stone formers. So we reviewed CT scans of patients and 24 hour urine collections (both male and female of adult age) who were known to have kidney stones and measured the growth of stones over a period of time.
Our main findings were that supplementary calcium increased the rate of stone formation in these patients. We also found that vitamin D had a protective effect and patients taking only vitamin D had a slower rate of stone progression.
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