![]() |
|
|
Department of Nutritional Sciences, University of Wisconsin, Madison, WI 53706
A human metabolic study was conducted to observe the effect of level of protein intake on urinary calcium, calcium absorption and calcium balance in older adults and to further study the mechanisms of protein-induced hypercalciuria. An increase in protein intake from about 47 to 112 g while maintaining calcium, magnesium and phosphorus intakes constant caused an increase in urinary calcium and a decrease in calcium retention. Glomerular filtration rate was increased and fractional renal tubular reabsorption was decreased by the increase in protein intake; total renal acid, ammonium and sulfate excretions more than doubled, whereas urinary sodium decreased by 38%. The changes in urinary calcium were positively correlated with the increase in total renal acid and sulfate excretion as well as with the decrease in fractional renal tubular reabsorption of calcium. Thus, the data indicate that protein-induced hypercalciuria is due to an increase in glomerular filtration rate and a decrease in fractional renal tubular reabsorption of calcium, the latter of which may be caused by the increased acid load on the renal tubular cells.
KEY WORDS: protein-induced hypercalciuria total renal acid urinary sodium urinary sulfate kidney function
1 Supported in part by the College of Agricultural and Life Sciences, University of Wisconsin, Madison: and by Grant AM19290 from the National Institutes of Health, Bethesda, MD.
2 Part of the information reported in this paper was presented at April 1978 FASEB meeting. Fed. Proc. 37, 892, 1978.
Manuscript received 25 June 1979.
This article has been cited by other articles:
![]() |
T. R Fenton, M. Eliasziw, A. W Lyon, S. C Tough, and D. A Hanley Meta-analysis of the quantity of calcium excretion associated with the net acid excretion of the modern diet under the acid-ash diet hypothesis Am. J. Clinical Nutrition, October 1, 2008; 88(4): 1159 - 1166. [Abstract] [Full Text] [PDF] |
||||
![]() |
K. Rafferty and R. P. Heaney Nutrient Effects on the Calcium Economy: Emphasizing the Potassium Controversy J. Nutr., January 1, 2008; 138(1): 166S - 171S. [Abstract] [Full Text] [PDF] |
||||
![]() |
C. S Johnston, S. L Tjonn, P. D Swan, A. White, H. Hutchins, and B. Sears Ketogenic low-carbohydrate diets have no metabolic advantage over nonketogenic low-carbohydrate diets Am. J. Clinical Nutrition, May 1, 2006; 83(5): 1055 - 1061. [Abstract] [Full Text] [PDF] |
||||
![]() |
P. B Rapuri, J C. Gallagher, and V. Haynatzka Protein intake: effects on bone mineral density and the rate of bone loss in elderly women Am. J. Clinical Nutrition, June 1, 2003; 77(6): 1517 - 1525. [Abstract] [Full Text] [PDF] |
||||