Urinary calcium loss in elderly men on a vegetable : animal (1 : 1) high-protein diet

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 subjec ts and the applicability of their results to the elderly population on a mi xed vegetable:animal diet remains unclear, Objectives: To study whether a m ixed vegetable:animal high-protein intake increases urinary calcium loss in elderly volunteers, as has been shown for younger subjects on a purified h igh-protein intake. Methods: Eight male volunteers, with ages ranging from 66 to 88 years, recruited from the University Hospital Geriatric Medicine O utpatients Clinic, were studied. 24-hour urinary calcium, phosphorus, and c reatinine were measured during a period of usual protein intake (approximat ely 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 u rinary 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 ph osphorus and creatinine levels also remained stable throughout the entire s tudy. Conclusions: This study has not detected any increased calcium urinar y excretion in male elderly volunteers submitted to the mixed vegetable:ani mal 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 m en.