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 subjects and the applicability of their results to the elderly population on a mixed vegetable:animal diet remains unclear.


OBJECTIVE
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.
Moriguti
J C
JC
Division of General Internal and Geriatric Medicine, Department of Internal Medicine, School of Medicine of Ribeirão Preto, São Paulo University, Ribeirão Preto, SP Brazil.
Ferriolli
E
E
Marchini
J S
JS
D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001205:Ascorbic Acid / Q000097:blood; D015992:Body Mass Index; D002118:Calcium / Q000652:urine*; D002136:Calcium, Dietary / Q000008:administration & dosage; D003401:Creatine / Q000187:drug effects / Q000652:urine; D004044:Dietary Proteins / Q000008:administration & dosage*; D005492:Folic Acid / Q000097:blood; D006801:Humans; D008297:Male; D016226:Phosphorus, Dietary / Q000008:administration & dosage; D012885:Skinfold Thickness; D014801:Vitamin A / Q000097:blood; D019207:beta Carotene / Q000097:blood
D002136:Calcium, Dietary; D004044:Dietary Proteins; D016226:Phosphorus, Dietary; D019207:beta Carotene; D014801:Vitamin A; D005492:Folic Acid; D003401:Creatine; D001205:Ascorbic Acid; D002118:Calcium