In a study published in the April edition of the American Journal of Clinical Nutrition, nutrition researchers discovered Caucasian girls lose more calcium in their urine than African-American girls, but both races lose calcium at an accelerated rate when they consume a high-salt diet.
"While we found a racial difference in calcium retention in adolescents, we also confirmed that blacks retain more sodium on a high-salt diet than whites," said Connie Weaver, distinguished professor and head of Purdue's Department of Foods and Nutrition. "This proves that salt is processed differently in the races, but too much salt in the diet reduces bone density in both races."
One out of four Caucasians will be diagnosed with osteoporosis, a bone-loss disease that costs Americans $14 billion a year in health care. The disease strikes one out of 10 African-Americans, but studies show they are more susceptible to hypertension, Weaver said.
"Sodium causes water retention, which leads to high blood pressure, and that could be related to the high prevalence of hypertension in adult blacks," Weaver said. "So even though salt intake is less critical to blacks with respect to building bones, we still have to be concerned about how sodium affects heart health."
The research results were based on figures from Purdue's Camp Calcium. The summer camp, funded by the National Institutes of Health since 1990, is designed to investigate various aspects of calcium metabolism in adolescent girls and boys.
Thirty-five campers were selected to participate in two, 20-day summer camps separated by two weeks. While housed on campus, the girls ate a controlled diet that provided certain amounts of calcium and other
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Contact: Maggie Morris
maggiemorris@purdue.edu
765-494-2432
Purdue University
10-May-2005