Amino acid supplementation alters bone metabolism during simulated weightlessness
| Autor: | Douglas Paddon-Jones, Janis E. Davis-Street, Scott M. Smith, Sara R. Zwart, Robert R. Wolfe, Arny A. Ferrando |
|---|---|
| Rok vydání: | 2005 |
| Předmět: |
Adult
Male Deoxypyridinoline medicine.medical_specialty Physiology medicine.medical_treatment Bed rest Bone resorption Collagen Type I Bone remodeling chemistry.chemical_compound Calcification Physiologic N-terminal telopeptide Physiology (medical) Internal medicine medicine Humans Hypercalciuria Amino Acids Bone Resorption Weightlessness Simulation Calcium metabolism medicine.disease Alkaline Phosphatase Urinary calcium Endocrinology chemistry Dietary Supplements Calcium Amino Acids Essential Collagen Peptides |
| Zdroj: | Journal of applied physiology (Bethesda, Md. : 1985). 99(1) |
| ISSN: | 8750-7587 |
| Popis: | High-protein and acidogenic diets induce hypercalciuria. Foods or supplements with excess sulfur-containing amino acids increase endogenous sulfuric acid production and therefore have the potential to increase calcium excretion and alter bone metabolism. In this study, effects of an amino acid/carbohydrate supplement on bone resorption were examined during bed rest. Thirteen subjects were divided at random into two groups: a control group (Con, n = 6) and an amino acid-supplemented group (AA, n = 7) who consumed an extra 49.5 g essential amino acids and 90 g carbohydrate per day for 28 days. Urine was collected for n-telopeptide (NTX), deoxypyridinoline (DPD), calcium, and pH determinations. Bone mineral content was determined and potential renal acid load was calculated. Bone-specific alkaline phosphatase was measured in serum samples collected on day 1 (immediately before bed rest) and on day 28. Potential renal acid load was higher in the AA group than in the Con group during bed rest ( P < 0.05). For all subjects, during bed rest urinary NTX and DPD concentrations were greater than pre-bed rest levels ( P < 0.05). Urinary NTX and DPD tended to be higher in the AA group ( P = 0.073 and P = 0.056, respectively). During bed rest, urinary calcium was greater than baseline levels ( P < 0.05) in the AA group but not the Con group. Total bone mineral content was lower after bed rest than before bed rest in the AA group but not the Con group ( P < 0.05). During bed rest, urinary pH decreased ( P < 0.05), and it was lower in the AA group than the Con group. These data suggest that bone resorption increased, without changes in bone formation, in the AA group. |
| Databáze: | OpenAIRE |
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