Effects of dietary protein deficiency on mineral metabolism and bone mineral density.
The effects of dietary protein restriction on mineral and bone metabolism are uncharacterized. We studied growing rats fed a diet low in protein (5%) for 4, 6, and 8 wks (n = 10 animals/group) and compared them with animals pair-fed with a protein-replete (18%) diet. The low-protein diet rapidly induced a profound hypocalciuria that persisted for greater than or equal to 8 wk. Serum calcium and phosphorus concentrations were not affected but serum total and free 25-dihydroxyvitamin D concentrations as well as gastrointestinal calcium absorption were lower in the low-protein animals. Skeletal dimensions were reduced in the protein-deprived rats but there were no significant differences in bone mineral content between control and low-protein animals at 4, 6, and 8 wks. Hence, dietary protein deprivation resulted in slower growth but bone mineral density was maintained when there was a marked reduction in urinary calcium excretion.
Orwoll
E
E
Portland Veterans Administration Medical Center, OR 97207.
Ware
M
M
Stribrska
L
L
Bikle
D
D
Sanchez
T
T
Andon
M
M
Li
H
H
D000818:Animals; D015519:Bone Density; D002117:Calcitriol / Q000097:blood; D002118:Calcium / Q000378:metabolism* / Q000652:urine; D002136:Calcium, Dietary / Q000008:administration & dosage / Q000493:pharmacokinetics; D003404:Creatinine / Q000097:blood / Q000652:urine; D004044:Dietary Proteins / Q000008:administration & dosage; D007408:Intestinal Absorption; D008297:Male; D010758:Phosphorus / Q000378:metabolism* / Q000652:urine; D011488:Protein Deficiency / Q000378:metabolism* / Q000503:physiopathology; D051381:Rats; D011916:Rats, Inbred F344
D002136:Calcium, Dietary; D004044:Dietary Proteins; D010758:Phosphorus; D003404:Creatinine; D002117:Calcitriol; D002118:Calcium