Measuring calcium absorption and utilization in humans.
OBJECTIVE
Calcium metabolism is comprised primarily of absorption, urinary excretion, endogenous secretion and bone turnover. This review evaluates recent findings relating to the role of genetic and environmental factors, especially diet, on perturbing parameters of calcium metabolism. Calcium dynamics are studied with the use of isotopic tracers. We also cover state-of-the-art methods for stable calcium isotope ratio analysis and offer insights on experimental design.


RESULTS
Some progress has been made identifying genetic and hormonal regulators of calcium absorption. Much progress has been made in understanding the role of diet on influencing calcium retention, especially with regard to dietary protein and salt. Long-held views on dietary factors thought to contribute to bone loss through urinary calcium loss have been shown to have no impact on net calcium retention because of compensatory changes in other aspects of calcium metabolism.


CONCLUSIONS
Much more work needs to be done on understanding genetic regulators of calcium metabolism. Despite recent advances in our knowledge of dietary influences on calcium metabolism, more studies are needed on the role of environmental factors, especially physical activity.
Weaver
Connie M
CM
Department of Foods and Nutrition, Purdue University, West Lafayette, Indiana 47907-2059, USA. weavercm@purdue.edu
Rothwell
Arlene P
AP
Wood
Karl V
KV
D001128:Argon; D001842:Bone and Bones / Q000378:metabolism*; D002127:Calcium Isotopes; D002136:Calcium, Dietary / Q000008:administration & dosage / Q000493:pharmacokinetics* / Q000652:urine; D004032:Diet; D015444:Exercise / Q000502:physiology*; D006801:Humans; D007408:Intestinal Absorption; D013058:Mass Spectrometry / Q000379:methods; D009753:Nutritive Value
D002127:Calcium Isotopes; D002136:Calcium, Dietary; D001128:Argon