Strontium is a trace element widely found in nature. It became famous in the 1960s when a radioactive form of strontium produced by atomic bomb testing, strontium-90, became prevalent in the environment. Nonradioactive strontium has recently undergone study as a treatment for osteoporosis, with some promising results.
Therapeutic Uses
Strontium has fundamental chemical similarities to calcium. When dietary intake of strontium is raised, strontium begins to take the place of calcium in developing bone. This replacement appears to be beneficial (at least with low doses of strontium—see Safety Issues ), leading to an increase in bone formation, a decrease in bone breakdown, and an overall rise in bone density. 1-5
The net result is a reduced incidence of fractures due to osteoporosis, according to two very large studies. 1,6
In addition, highly preliminary evidence hints that strontium might also help prevent cavities by strengthening dental enamel. 7
What is the Scientific Evidence for Strontium?
The major human studies of strontium for osteoporosis involved a special form of the mineral called strontium ranelate.
In a 3-year, double-blind , placebo-controlled study of 5,091 women with osteoporosis, use of strontium at a dose of 2 grams daily significantly improved bone density and reduced incidence of all fractures as compared to placebo. 1 Additionally, in a 3-year, double-blind, placebo-controlled study of 1,649 postmenopausal women with osteoporosis and a history of at least one vertebral fracture, use of strontium ranelate at a dose of 2 grams daily reduced the incidence of new vertebral fractures by 49% in the first year and 41% in the full 3-year period (as compared to placebo). 6 Use of strontium also significantly increased measured bone density. No significant side effects were seen.
Benefits were also seen in an earlier, smaller study. 5
A fourth study tested strontium ranelate for preventing osteoporosis in postmenopausal who have not yet developed it. 4 In this 2-year, double-blind, placebo-controlled study, 160 women received either placebo or strontium ranelate at a dose of 125 mg, 500 mg, or 1 gram daily. The results showed greater gains in bone density the more strontium taken.
While some treatments for osteoporosis act to increase bone formation, and other decrease bone breakdown, some evidence suggests that strontium ranelate has a dual effect, providing both these benefits at once. 14
Other forms of strontium besides strontium ranelate, such as strontium chloride, have shown potential benefits in animal studies, but have not undergone significant testing in people. 3,8-13
Therapeutic Dosages
Based on current evidence strontium ranelate can be taken at a dose of 500 mg to 1 gram daily to prevent osteoporosis and at a higher dose of 2 grams daily to treat existing osteoporosis.
Note: It is not yet clear whether combining strontium with standard treatments for osteoporosis will enhance or diminish the ultimate benefits.
Safety Issues
When taken in recommended doses, strontium supplements appear to be safe and usually free of side effects other than occasional mild gastrointestinal upset, including diarrhea. There is some weak evidence that long term use of strontium ranelate could, rarely, cause memory loss or seizures. 15 Similarly weak evidence hints that strontium could raise risk of blood clots; 15 however, one small study was somewhat reassuring on this score. 16
Excessive intake of strontium can actually weaken bone by replacing too much of the bone’s calcium with strontium. 11
Maximum safe doses of strontium in young children, pregnant or nursing women, or people with severe liver or kidney disease have not been established.
References
1. Reginster JY, Seeman E, DE Vernejoul MC, et al. Strontium ranelate reduces the risk of invertebral fractures in postmenopausal women with osteoporosis: Treatment of Perpheral Osteoporosis (TROPOS) study. J Clin Endocrinol Metab . 2005 Feb 22 [Epub ahead of print].
2. Reginster JY, Meunier PJ. Strontium ranelate phase 2 dose-ranging studies: PREVOS and STRATOS studies. Osteoporos Int . 2003. [Epub ahead of print].
3. Reginster JY, Deroisy R, Jupsin I. Strontium ranelate: a new paradigm in the treatment of osteoporosis. DrugsToday (Barc) . 2003;39:89–101.
4. Reginster JY, Deroisy R, Dougados M, Jupsin I, Colette J, Roux C. Prevention of early postmenopausal bone loss by strontium ranelate: the randomized, two-year, double-masked, dose-ranging, placebo-controlled PREVOS trial. Osteoporos Int . 2002;13:925–31.
5. Meunier PJ, Slosman DO, Delmas PD, et al. Strontium ranelate: dose-dependent effects in established postmenopausal vertebral osteoporosis—a 2-year randomized placebo controlled trial. J Clin Endocrinol Metab . 2002;87:2060–6.
6. Meunier PJ, Roux C, Seeman E, et al. The effects of strontium ranelate on the risk of vertebral fracture in women with postmenopausal osteoporosis. N Engl J Med . 2004;350:459–68.
7. Brandi ML. New treatment strategies: ipriflavone, strontium, vitamin D metabolites and analogs. Am J Med . 1993;95:69S–74S.
8. Matsumoto A. Effect of strontium chloride on bone resorption induced by prostaglandin E2 in cultured bone. ArchToxicol . 1988;62:240–1.
9. Marie PJ, Hott M. Short-term effects of fluoride and strontium on bone formation and resorption in the mouse. Metabolism . 1986;35:547–51.
10. Marie PJ, Garba MT, Hott M, Miravet L. Effect of low doses of stable strontium on bone metabolism in rats. Miner Electrolyte Metab . 1985;11:5–13.
11. Brandi ML. New treatment strategies: ipriflavone, strontium, vitamin D metabolites and analogs. Am J Med . 1993;95:69S–74S
12. Ferraro EF, Carr R, Zimmerman K. A comparison of the effects of strontium chloride and calcium chloride on alveolar bone. Calcif Tissue Int . 1983;35:258–60.
13. Ferraro EF, Glass RT. The effect of strontium chloride upon alveolar bone. J Periodontol . 1980;51:345–7.
14. Marie PJ. Strontium ranelate: a dual mode of action rebalancing bone turnover in favour of bone formation. Curr Opin Rheumatol. 2006;18 Suppl 1:S11-5.
15. O'donnell S, Cranney A, Wells G, et al. Strontium ranelate for preventing and treating postmenopausal osteoporosis. Cochrane Database Syst Rev. 2006;:CD005326.
16. Halil M, Cankurtaran M, Yavuz BB, et al. Short-Term Hemostatic Safety of Strontium Ranelate Treatment in Elderly Women with Osteoporosis. Ann Pharmacother. 2007;41:41-5.
Last reviewed April 2009 by EBSCO CAM Review Board
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