Calcium supplements: citrate better than carbonate?

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Rheumawire

June 8, 2004 Zosia Chustecka

Calcium supplements: citrate better than carbonate?

Farmington, CT - A study comparing 2 commercially available calcium

supplements used for osteoporosis found that the effects of calcium

citrate on bone markers of resorption were greater than those seen with

calcium carbonate, suggesting that it may have a greater effect on

preventing bone loss. The study is reported in Osteoporosis

International [1].

The study involved 40 postmenopausal women with a bone-mineral density

(BMD) T score at the spine or hip of -1 to -3.5, indicating osteopenia

or osteoporosis. In an open-label design, the women took 1000 mg/day of

calcium citrate (Citracal® 250+Vitamin D, Mission Pharmacal), 2 tablets

at breakfast and 2 at supper for 12 weeks, followed by a 2-week washout

with no supplements, and then took 1000 mg/day calcium carbonate (OsCal®

250+D, GlaxoKline) on the same schedule. All the women also took a

daily multivitamin to raise the intake of vitamin D to approximately 900

IU/day.

After 12 weeks, the researchers found a significant decline in all 4

biochemical markers of bone resorption (urine N- and C-telopeptide

cross-links of collagen, free deoxypyridinoline cross-links, and serum

N-telopeptide cross-links of collagen) with the citrate formulation but

not with the carbonate formulation (p<0.05 for between-treatment period

differences). Both formulations had similar effects on all the other

biochemical measures (including urinary calcium excretion and

parathyroid hormone), with the exception of vitamin-D levels, which were

higher in the carbonate group. " This exception may be explained by

higher compliance with calcium carbonate and higher dietary vitamin-D

intake during the carbonate-treatment period, " the researchers explain.

" The results with biochemical markers suggest that calcium citrate

produced a greater inhibition of bone resorption than calcium

carbonate, " the researchers comment. They add that further comparative

studies are needed, particularly to assess antifracture efficacy.

Previous studies have shown decreased fracture rates with both calcium

citrate malate and calcium carbonate, with an overall decrease in

fracture rate of approximately 22%. However, the only study to date to

have looked at different calcium preparations found better BMD

preservation with calcium citrate malate than calcium carbonate,

especially at the lumbar spine [2], they point out.

Sources

Kenny AM, Prestwood KM, Biskup B, et al. Comparison of

the effects of calcium loading with calcium citrate or calcium carbonate

on bone turnover in postmenopausal women. Osteoporos Int 2004 Apr;

15(4):290-4.

Dawson- B, Dallal GE, Krall EA, et al. A

controlled trial of the effect of calcium supplementation on bone

density in postmenopausal women. N Engl J Med 1990 Sep 27;

323(13):878-83.

I'll tell you where to go!

Mayo Clinic in Rochester

http://www.mayoclinic.org/rochester

s Hopkins Medicine

http://www.hopkinsmedicine.org