Abstract
Vitamin D functions in many body systems, but perhaps the best attested of the nutrient's actions-and certainly the one first associated with human disease-is its role in transferring calcium (and phosphorus) from ingested food into the body fluids. In this capacity, vitamin D functions as a part of a control system that operates to maintain constancy of the calcium ion concentrations in the extracellular fluid against the demands of obligatory excretory losses and skeletal mineralization. In both transfers, vitamin D works in concert with parathyroid hormone. Quantitative analysis of the inputs and drains of the calcium economy reveals that, at contemporary calcium intakes, D-mediated absorptive enhancement only partially mitigates the impact of low calcium intake or large calcium losses. While 1,25(OH)2D is clearly the most potent form of the vitamin, 25(OH) D exerts significant vitamin-D-like activity in its own right at physiological serum levels. Optimal vitamin D status is operationally defined as a level of D intake (or production) high enough to ensure that the D-mediated transfers are not limited by D availability. However, at intakes closer to those prevailing during hominid evolution, minor shifts in vitamin D mediated absorption are fully adequate to compensate for stresses on the calcium economy.
| Original language | English |
|---|---|
| Title of host publication | Vitamin D |
| Publisher | Elsevier Inc. |
| Pages | 607-624 |
| Number of pages | 18 |
| ISBN (Print) | 9780123819789 |
| DOIs | |
| State | Published - 2011 |
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All Science Journal Classification (ASJC) codes
- Dentistry(all)
- Medicine(all)
Cite this
Vitamin D : Role in the calcium and phosphorus economies. / Heaney, Robert P.
Vitamin D. Elsevier Inc., 2011. p. 607-624.Research output: Chapter in Book/Report/Conference proceeding › Chapter
}
TY - CHAP
T1 - Vitamin D
T2 - Role in the calcium and phosphorus economies
AU - Heaney, Robert P.
PY - 2011
Y1 - 2011
N2 - Vitamin D functions in many body systems, but perhaps the best attested of the nutrient's actions-and certainly the one first associated with human disease-is its role in transferring calcium (and phosphorus) from ingested food into the body fluids. In this capacity, vitamin D functions as a part of a control system that operates to maintain constancy of the calcium ion concentrations in the extracellular fluid against the demands of obligatory excretory losses and skeletal mineralization. In both transfers, vitamin D works in concert with parathyroid hormone. Quantitative analysis of the inputs and drains of the calcium economy reveals that, at contemporary calcium intakes, D-mediated absorptive enhancement only partially mitigates the impact of low calcium intake or large calcium losses. While 1,25(OH)2D is clearly the most potent form of the vitamin, 25(OH) D exerts significant vitamin-D-like activity in its own right at physiological serum levels. Optimal vitamin D status is operationally defined as a level of D intake (or production) high enough to ensure that the D-mediated transfers are not limited by D availability. However, at intakes closer to those prevailing during hominid evolution, minor shifts in vitamin D mediated absorption are fully adequate to compensate for stresses on the calcium economy.
AB - Vitamin D functions in many body systems, but perhaps the best attested of the nutrient's actions-and certainly the one first associated with human disease-is its role in transferring calcium (and phosphorus) from ingested food into the body fluids. In this capacity, vitamin D functions as a part of a control system that operates to maintain constancy of the calcium ion concentrations in the extracellular fluid against the demands of obligatory excretory losses and skeletal mineralization. In both transfers, vitamin D works in concert with parathyroid hormone. Quantitative analysis of the inputs and drains of the calcium economy reveals that, at contemporary calcium intakes, D-mediated absorptive enhancement only partially mitigates the impact of low calcium intake or large calcium losses. While 1,25(OH)2D is clearly the most potent form of the vitamin, 25(OH) D exerts significant vitamin-D-like activity in its own right at physiological serum levels. Optimal vitamin D status is operationally defined as a level of D intake (or production) high enough to ensure that the D-mediated transfers are not limited by D availability. However, at intakes closer to those prevailing during hominid evolution, minor shifts in vitamin D mediated absorption are fully adequate to compensate for stresses on the calcium economy.
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U2 - 10.1016/B978-0-12-381978-9.10034-4
DO - 10.1016/B978-0-12-381978-9.10034-4
M3 - Chapter
SN - 9780123819789
SP - 607
EP - 624
BT - Vitamin D
PB - Elsevier Inc.
ER -