Short-term high dietary calcium intake during bedrest has no effect on markers of bone turnover in healthy men
| Autor: | Petra Frings-Meuthen, Martina Heer, Natalie Baecker, Scott M. Smith |
|---|---|
| Rok vydání: | 2009 |
| Předmět: |
Adult
Male medicine.medical_specialty Endocrinology Diabetes and Metabolism Osteoporosis chemistry.chemical_element Parathyroid hormone Calcium bone Bone resorption Bone and Bones Collagen Type I Bone remodeling Blood serum bone loss N-terminal telopeptide Internal medicine medicine Humans Nutrition and Dietetics Cross-Over Studies business.industry medicine.disease Alkaline Phosphatase Urinary calcium Peptide Fragments Calcium Dietary nutrition immobilisation Endocrinology chemistry Parathyroid Hormone Bone Remodeling business Peptides Bed Rest Procollagen |
| Zdroj: | Nutrition (Burbank, Los Angeles County, Calif.). 26(5) |
| ISSN: | 1873-1244 |
| Popis: | Objective Immobilization and space flight are causes of disuse osteoporosis. Increasing calcium intake may counteract this disuse-induced bone loss. Methods We conducted two bedrest experiments (crossover design: bedrest versus ambulatory control) in a metabolic ward, studying the effect of 1000 mg/d of calcium intake (study A, length of intervention 14 d) compared with that of a high calcium intake of 2000 mg/d (study B, 6 d) on markers of bone turnover. Both studies were randomized, controlled studies with the subjects staying under well-controlled environmental conditions (study A, 9 male subjects, age 23.6 ± 3.0 y; study B, 8 male subjects, age 25.5 ± 2.9 y). Blood was drawn to analyze serum calcium, parathyroid hormone, procollagen type I C-terminal propeptide, and bone alkaline phosphatase. Urine (24-h) was collected for analysis of calcium, C-terminal telopeptide of collagen type I, and N-terminal telopeptide of collagen type I. Results In both studies, serum calcium levels remained unchanged. Procollagen type I C-terminal propeptide was lower (P = 0.03) in the bedrest phase than in the ambulatory phase in study A and tended to be lower (P = 0.08) in bedrest in study B, whereas bone alkaline phosphatase was not affected in either study. Urinary calcium excretion was greater during bedrest than during the ambulatory phase (study A, P = 0.005; study B, P = 0.002). C-terminal telopeptide of collagen type I excretion was also greater during bedrest in both studies (study A, P Conclusion Doubling calcium intake to 2000 mg/d does not prevent increased bone resorption induced by bedrest. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect