May 8, 2017

A study by researchers at UNC’s Gillings School of Global Public Health examines whether a low ratio of dietary calcium to phosphorus has an impact upon bone health of older adults in the U.S.

Dr. John Anderson

Dr. John Anderson

The article, by John Anderson, PhD, adjunct professor of nutrition at the Gillings School, and colleagues in the School’s biostatistics department, was published online March 22 in the Journal of the Endocrine Society.

Anderson considered data from the 2005-2006 National Health and Nutrition Examination Survey (NHANES) for 1,228 men and women, ages 50 to 70 and older, testing dietary calcium to phosphorus ratios by their association with hip and lumbar bone mineral density.

The study subjects exhibited a wide range of calcium to phosphorous ratios. However, even among men and women who consumed large amounts of supplemental calcium, there appeared to be no adverse impact of high phosphorus or calcium intake — or low dietary ratios – upon bone mineral density at major fracture sites in older adults.

Women had greater estimated dietary calcium to phosphorus ratios than did men, likely because women tend to consume greater amounts of supplementary calcium – a finding that had been observed previously by Anderson and others.

“The results of our study do not support an earlier view that too much phosphorus as phosphates in usual diets contributes to bone loss and potentially to osteoporosis,” Anderson said.

The analyses confirm that the recommended dietary allowances (RDA) of calcium for older adults (1,000 to 1,200 mg per day), as set by the Institute of Medicine, are sufficient for bone maintenance by older adults.

Co-authors include doctoral student Reuben Adatorwovor, Kathy Roggenkamp, MA, research instructor, and Chirayath M. Suchindran, PhD, professor, all in the Gillings School’s Department of Biostatistics.


Gillings School of Global Public Health contact: David Pesci, director of communications, (919) 962-2600 or

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