Effects of dietary protein deficiency on mineral metabolism and bone mineral density

Abstract:  Effects of dietary protein deficiency on mineral metabolism and bone mineral density. Orwoll E, Ware M, Stribrska L, Bikle D, Sanchez T, Andon M, Li H. Portland Veterans Administration Medical Center, OR 97207. 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. PMID: 1636610 [PubMed - indexed for MEDLINE]