Calcium and Vitamin D: Is Supplementation an Efficient Countermeasure to Bone Loss in Immobilization?
- Paper number
IAC-06-A1.2.03
- Author
Dr. Natalie Baecker, German Aerospace Center (DLR), Germany
- Coauthor
Mrs. Andrea Boese, German Aerospace Center (DLR), Germany
- Coauthor
Mrs. Petra Frings, German Aerospace Center (DLR), Germany
- Coauthor
Dr. Martina Heer, German Aerospace Center (DLR), Germany
- Year
2006
- Abstract
Reduction of mechanical stress on bone inhibits osteoblast-mediated bone formation and increases osteoclast-mediated bone resorption, and leads to what has been called disuse osteoporosis. Prolonged therapeutic bed rest, immobilization and space flight are common causes of disuse osteoporosis. During spaceflight dietary calcium intake of astronauts is very moderate when they eat ad libitum. In contrast to postmenopausal osteoporosis – where bone loss is mainly due to estrogen deficiency – immobilization in space flight or during bed rest causes bone density reduction by decoupling of bone formation and resorption processes. A huge amount of data exists supporting the use of calcium in combination with vitamin D in the prevention and treatment of osteoporosis in postmenopausal women and during growth. Although sufficient calcium and vitamin D intake is mandatory to prevent bone loss because of respective malnutrition it is questionable if increasing calcium intake above recommended intake levels is a solution for immobilized people. Results from bed rest experiments and data from space missions, where the astronauts’ calcium intake was at a high level, indicate that even high calcium intake does not counteract disuse induced bone loss. In contrast to the apparently positive effect of a high calcium intake and vitamin D supplementation in postmenopausal women and in adolescence, high calcium intake alone may neither be applicable to humans in microgravity nor to immobilized people as it does not efficiently counteract disuse-induced bone loss.
- Abstract document
- Manuscript document
IAC-06-A1.2.03.pdf (🔒 authorized access only).
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