Document Detail


Does it make a difference how and when you take your calcium? The acute effects of calcium on calcium and bone metabolism.
MedLine Citation:
PMID:  11522557     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
BACKGROUND: Calcium supplements are widely used to prevent osteoporosis. However, little is known about the metabolic effects of different dosages and of the timing of the dosages. OBJECTIVE: The aim was to study the effects of the timing of the dose (study 1), the effects of the size of the dose (study 2), and the effects of small repetitive doses (study 3) of calcium on calcium and bone metabolism in women. DESIGN: The investigation was conducted in 3 parts, each with 10 participants. In study 1, calcium loads (0 and 25 mg/kg body wt) were taken at 0900 and 2100. In study 2, calcium loads of 0, 250, and 1000 mg were taken at 0900. In study 3, calcium loads of 0 and 200 mg were taken 4 times/d. Markers of calcium and bone metabolism were followed. RESULTS: There was no significant difference in the response of serum parathyroid hormone (PTH) to the calcium load taken at 0900 and that at 2100. There was a significant dose-response effect of the calcium load on serum ionized calcium (P = 0.00005) and serum PTH (P = 0.0003). Small calcium doses (200 mg) taken 4 times/d kept the PTH secretion at a lower level than during the control day (P = 0.016). None of the doses caused significant changes in the markers of bone formation and resorption measured. CONCLUSIONS: The calcium loads had no significant effect on the markers of bone formation and resorption measured, although even small calcium doses decreased serum PTH and increased serum ionized calcium concentrations rapidly. The effect was similar whether calcium was taken in the morning or in the evening.
Authors:
M U Kärkkäinen; C J Lamberg-Allardt; S Ahonen; M Välimäki
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Publication Detail:
Type:  Clinical Trial; Journal Article; Randomized Controlled Trial    
Journal Detail:
Title:  The American journal of clinical nutrition     Volume:  74     ISSN:  0002-9165     ISO Abbreviation:  Am. J. Clin. Nutr.     Publication Date:  2001 Sep 
Date Detail:
Created Date:  2001-08-27     Completed Date:  2001-09-27     Revised Date:  2004-11-17    
Medline Journal Info:
Nlm Unique ID:  0376027     Medline TA:  Am J Clin Nutr     Country:  United States    
Other Details:
Languages:  eng     Pagination:  335-42     Citation Subset:  AIM; IM    
Affiliation:
Calcium Research Unit, the Department of Applied Chemistry and Microbiology, University of Helsinki, and the Helsinki University Central Hospital, Finland.
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MeSH Terms
Descriptor/Qualifier:
Adult
Biological Markers
Bone Resorption / metabolism
Bone and Bones / metabolism*
Calcium / blood,  metabolism*,  pharmacokinetics
Calcium, Dietary / administration & dosage*
Diet Records
Dietary Supplements
Dose-Response Relationship, Drug
Female
Humans
Intestinal Absorption
Osteoporosis / etiology*,  metabolism,  prevention & control
Parathyroid Hormone / blood*
Phosphates / analysis
Time Factors
Chemical
Reg. No./Substance:
0/Biological Markers; 0/Calcium, Dietary; 0/Parathyroid Hormone; 0/Phosphates; 7440-70-2/Calcium

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