Dietary Calcium Intake Linked to Kidney Stone Risk

PORTLAND, MaineIndividuals who consume a diet rich in calcium from non-dairy or dairy sources may reduce their risk of developing kidney stones, according to a new study published in The Journal of Urology.

Because of high correlations between dairy intake and total dietary calcium, previously reported associations between lower calcium intake and increased kidney stone risk represent de facto associations between milk products and risk. Led by Eric Taylor, M.D., researchers at the Maine Medical Centre conducted a study to examine associations between dietary calcium from non-dairy and dairy sources and symptomatic nephrolithiasis.

They conducted a meta-analysis of three large studiesHealth Professionals Follow-up Study (HPFS), the Nurses Health Study I (NHS I) and the Nurses Health Study II (NHS II)that followed more than 1 million people for more than five decades. Food frequency questionnaires assessed calcium intake every four years. The researchers used Cox proportional hazards regression to adjust for age, BMI, supplemental calcium, diet and other factors.

During the 56-year follow-up, they 5,270 incident kidney stones were documented. Those who consumed calcium from both dairy and non-dairy sources had a 77% reduced risk compared to participants who consumed the least amount. Men and women who consumed more than 450 milligrams of calcium a day from non-dairy products had a 50% reduced risk of kidney stones. Those who consumed more than 800 milligrams of calcium daily from dairy products reduced their kidney stone risk by 30% compared to participants who consumed roughly 150 milligrams a day.

In 2010, a study led by Taylor and his research team found following a diet designed to prevent high blood pressure also can help ward off the formation of kidney stones. The findings suggested that the Dietary Approaches to Stop Hypertension (DASH) diet, which is high in fruits, vegetables, nuts and legumes, dairy products, and whole grains and low in sweetened beverages and red and processed meats, effectively lowers blood pressure.