Effects of calcium supplementation on lipids, blood pressure, and body composition in healthy older men: a randomized controlled trial.
BACKGROUND
Calcium supplementation has been suggested to have beneficial effects on serum lipids, blood pressure, and body weight, but these possibilities have not been rigorously assessed in men.


OBJECTIVE
This study evaluated the effect of calcium supplementation on the change in the ratio of HDL to LDL cholesterol (primary endpoint) and on changes in cholesterol fractions, triglycerides, blood pressure, and body composition (secondary endpoints).


METHODS
We carried out a randomized controlled trial of calcium supplementation in 323 generally healthy men over a period of 2 y. Subjects were randomly assigned to take placebo, 600 mg Ca/d, or 1200 mg Ca/d.


RESULTS
There was no significant treatment effect on the ratio of HDL to LDL cholesterol (P = 0.47) nor on weight, fat mass, lean mass, triglycerides, or total, LDL, or HDL cholesterol (P > 0.28 for all). There were downward trends in systolic and diastolic blood pressures within the calcium-supplemented groups, but there were no significant treatment effects over the whole trial period (P > 0.60). In a post hoc analysis of those with baseline calcium intakes below the median value (785 mg/d), blood pressures showed borderline treatment effects (P = 0.05-0.06 for changes at 2 y in those who received 1200 mg Ca/d compared with placebo: systolic, -4.2 mm Hg; diastolic, -3.3 mm Hg). Low magnesium intake showed a similar interaction. No treatment effects on weight or body composition were found.


CONCLUSIONS
These data do not show significant effects of calcium supplementation on serum lipids or body composition. Calcium supplementation in those with low dietary intakes may benefit blood pressure control. This trial was registered with the Australian Clinical Trials Registry as ACTRN 012605000274673.
Reid
Ian R
IR
Department of Medicine, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand. i.reid@auckland.ac.nz
Ames
Ruth
R
Mason
Barbara
B
Bolland
Mark J
MJ
Bacon
Catherine J
CJ
Reid
Helen E
HE
Kyle
Campbell
C
Gamble
Gregory D
GD
Grey
Andrew
A
Horne
Anne
A
D000273:Adipose Tissue / Q000033:anatomy & histology / Q000187:drug effects; D000368:Aged; D001794:Blood Pressure / Q000187:drug effects*; D001823:Body Composition / Q000187:drug effects*; D001835:Body Weight / Q000187:drug effects; D002118:Calcium / Q000494:pharmacology*; D008076:Cholesterol, HDL / Q000097:blood / Q000187:drug effects; D008078:Cholesterol, LDL / Q000097:blood / Q000187:drug effects; D015331:Cohort Studies; D003971:Diastole / Q000187:drug effects; D019587:Dietary Supplements; D006801:Humans; D008055:Lipids / Q000097:blood*; D008274:Magnesium / Q000097:blood; D008297:Male; D008875:Middle Aged; D018579:Patient Selection; D010919:Placebos; D013599:Systole / Q000187:drug effects; D014280:Triglycerides / Q000097:blood
D008076:Cholesterol, HDL; D008078:Cholesterol, LDL; D008055:Lipids; D010919:Placebos; D014280:Triglycerides; D008274:Magnesium; D002118:Calcium