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ARS Home » Northeast Area » Boston, Massachusetts » Jean Mayer Human Nutrition Research Center On Aging » Research » Publications at this Location » Publication #161786
Title: EFFECT OF DIETARY PROTEIN SUPPLEMENTS ON CALCIUM EXCRETION IN HEALTHY OLDER MEN AND WOMEN

Author
item DAWSON-HUGHES, BESS - TUFTS-HNRCA
item HARRIS, SUSAN - NE RESEARCH INSTITUTE
item RASMUSSEN, HELEN - TUFTS-HNRCA
item SONG, LINGYI - TUFTS-HNRCA
item DALLAL, GERARD - TUFTS-HNRCA

Submitted to: Journal of Clinical Endocrinology and Metabolism
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/4/2003
Publication Date: 3/1/2004
Citation: DAWSON-HUGHES, B., HARRIS, S.S., RASMUSSEN, H.M., SONG, L., DALLAL, G.E. EFFECT OF DIETARY PROTEIN SUPPLEMENTS ON CALCIUM EXCRETION IN HEALTHY OLDER MEN AND WOMEN. JOURNAL OF CLINICAL ENDOCRINOLOGY AND METABOLISM. 2004;89(3):1169-73.

Interpretive Summary: It is known that the level of calcium intake is an important factor in good bone health but currently there is no consensus on the impact of dietary protein on calcium and bone metabolism. This study was conducted to examine the effect of increasing protein intake, from meat sources, on various biochemical markers of bone health. Some of these markers include urine calcium excretion, a measure of calcium absorption, serum insulin growth factor (IGF-1), a measurement of bone growth, and urinary N-telopeptide, a measurement of bone resorption or deterioration. Thirty-two men and women, age 50 and older, were randomly selected to consume either high or low protein food supplements for 9 weeks. Measurements were taken at days 0, 35, 49, and 63. Changes in urine calcium excretion in the 2 groups didn't differ significantly over the course of the study. The high protein group had significantly higher levels of serum IGF-1 and lower levels of urinary N-telopeptide over the period of day 35 to day 49 or 63. In conclusion, increasing protein intake with meat supplements did not alter urine calcium excretion but it was associated with higher circulating levels of IGF-1, a bone growth factor, and lowered levels of urinary N-telopeptide, a marker of bone resorption. Thus meat supplements may have a favorable impact on the bone health in older men and women.

Technical Abstract: Currently there is no consensus on the impact of dietary protein on calcium and bone metabolism. This study was conducted to examine the effect of increasing protein intake, from meat sources, on urine calcium excretion and to compare circulating levels of IGF-1 and biochemical markers of bone turnover in healthy older men and women who consumed either the high or the low protein food supplements for 9 weeks. Thirty-two subjects with usual protein intakes < 0.85 g/kg/d were randomly assigned to high (0.75 g/kg) or iso-caloric low (0.04 g/kg) protein supplement groups. Selected biochemical measurements were made at baseline and on days 35, and either 49 or 63. Changes in urine calcium excretion in the 2 groups didn't differ significantly over the course of the study. The high protein group had significantly higher levels of serum IGF-1 (P= 0.008) and lower levels of urinary N-telopeptide (P= 0.038) over the period of day 35 to day 49 or 63. We conclude that increasing protein intake from 0.78 to 1.55 g/kg/d with meat supplements did not alter urine calcium excretion but it was associated with higher circulating levels of IGF-1, a bone growth factor, and lowered levels of urinary N-telopeptide, a marker of bone resorption. Thus meat supplements may have a favorable impact on the skeleton in healthy older men and women.