Urinary Calcium Loss in Elderly Menon a Vegetable:Animal (1:1)High-Protein Diet

Abstract

Background: A high purified protein intake has been shown to induce urinary calcium loss. However, these findings could not be reproduced with a high-protein meat diet. Also, most studies have been carried out in young subjects and the applicability of their results to the elderly population on a mixed vegetable:animal diet remains unclear. Objectives: To study whether a mixed vegetable:animal high-protein intake increases urinary calcium loss in elderly volunteers, as has been shown for younger subjects on a purified high-protein intake. Methods: Eight male volunteers, with ages ranging from 66 to 88 years, recruited from the University Hospital Geriatric Medicine Outpatients Clinic, were studied. 24-hour urinary calcium, phosphorus, and creatinine were measured during a period of usual protein intake (approximately 0.6 g/kg/day) and during 7 days of vegetable:animal (1:1) high-protein intake (2 g/kg/day). Calcium and phosphorus intake were adjusted to be kept constant (1 g/day of each) during the whole study. Results: Mean calcium urinary levels did not change significantly during the study (1.89 and 1.83 mmol/24 h during the usual and high-protein diet, respectively). Urinary phosphorus and creatinine levels also remained stable throughout the entire study. Conclusions: This study has not detected any increased calcium urinary excretion in male elderly volunteers submitted to the mixed vegetable:animal high-protein diet. Therefore, it does not support the suggestion that a high-protein intake is a risk factor for urinary calcium loss in elderly men.

The Effects of Resistance Training and Protein Supplementation on Bone Turnover in Young Adult Women.

“…It is possible that the phosphorus content of the supplement and the subjects' habitual diet attenuated the hypothesized effects, as phosphorus has known hypocalciuric effects [68,70]. A few studies have demonstrated blunted calciuric effects when using meat with a substantial phosphorus content, rather than purified isolates, as the source of supplemental protein [71,72]. The present study used a commercially-available form of purified whey protein, but the supplement did contain a noteworthy amount of phosphorus.…”

Effects of resistance training and protein supplementation on bone turnover in young adult women

“…It is possible that the phosphorus content of the supplement and the subjects' habitual diet attenuated the hypothesized effects, as phosphorus has known hypo calciuric effects [68,70]. A few studies have demonstrated blunted calciuric effects when using meat with a substantial phosphorus content, rather than purified isolates, as the source of supplemental protein [71,72]. The present study used a commercially-available form of purified whey protein, but the supplement did contain a noteworthy amount of phosphorus.…”