Strontium Popularity in Europe Spurs Supplement Sales in U.S.
The European success of the prescription-only strontium drug Protelos (strontium ranelate) has stimulated U.S. dietary supplement companies to market over-the-conter strontium dietary supplements for bone health, since Protelos is not approved for use in the U.S. (as of late 2006).Naturally occurring strontium compounds cannot be patented for drug sales, but these compounds can be sold as ingredients in dietary supplements. However, they should not be confused with patented prescription drugs like Protelos.
What is strontium?
Strontium exists naturally as a stable mineral and is present in small amounts in soil, foods, and bones. This stable form of strontium should not be confused with a radioactive form that is produced by nuclear reactors or detonation of nuclear weapons. At high doses, the radioactive form of strontium is a potential carcinogen.Stable strontium from the diet, pharmaceutical preparations, or dietary supplements becomes a minor component of bones that appears to significantly benefit bone mineral density and fracture resistance.
Strontium is the active component of a very popular drug, Protelos (strontium ranelate), which is used in Europe to treat osteoporosis. Currently, strontium is not considered to be a nutrient, but it appears to be beneficial to bone health when consumed in relatively small amounts. With further study, it is conceivable that strontium could be considered to be an essential trace element necessary for optimal bone health.
Are Foods a Good Source of Strontium?
There is limited information about the strontium content of foods. However, a study in Finland estimated that the Finnish diet provides about two milligrams of strontium per day. In comparison, the daily dose used in the strontium ranelate studies provided about 700 mg of strontium.
What Types of Strontium Supplements Are Available?
In the United States, where strontium ranelate is not yet an approved drug, strontium is sold in other forms as dietary supplements. Currently, the most common form is strontium citrate. Similar naturally occurring forms of stable strontium (strontium carbonate, chloride, lactate, and gluconate) were used in animal and human studies on bone health as far back as the early 1950s. As a patentable form of strontium, strontium ranelate has undergone the extensive human research needed for it to be marketed as an approved drug in Europe.Although the common forms of strontium found in supplements have been used in animal and human studies, they have not undergone the rigorous evaluation of a drug like strontium ranelate. The most common supplements available provide 300 to 350 mg of strontium per pill and recommend two pills per day to add up to a strontium dose similar to that used in the strontium ranelate studies.
Do Strontium Supplements Have Side Effects or Contraindications?
In the two large studies conducted on strontium ranelate use by women with osteoporosis, there was no difference in adverse reactions between the placebo groups and the strontium ranelate groups. For most people, strontium appears to be rather safe in the common forms that provide about 700 mg of strontium like the strontium ranelate studies. Individuals with severely impaired kidney function should not take strontium supplements. Currently, strontium ranelate is approved only in Europe for use in postmenopausal women with osteoporosis. The long-term safety of strontium supplementation in other groups of women and in men is currently unknown.
Can Strontium Supplements be Combined with Drug Treatments?
Combining strontium supplementation with drug treatments cannot be recommended. Check with your physician before using strontium supplements, especially if you are taking any drugs. Keep in mind that dietary supplements in the U.S. do not have to adhere to strict quality standards, and so the dosage listed on any supplements may not be accurate.
Are Strontium Dietary Supplements as Effective as Strontium Ranelate?
Currently, no human research has compared strontium supplements to strontium ranelate. The strontium component of strontium ranelate is considered to be the active component of the molecule. Essentially, the ranelate part of the strontium ranelate molecule serves as a carrier of strontium. When strontium ranelate is consumed, it dissolves in the stomach, releasing free strontium and free ranelate. There is little or no evidence nor logical rationale that ranelate contributes to any of the drug’s effectiveness.Theoretically, it is likely that any form of strontium that dissolves (ionizes) in water like strontium ranelate and provides comparable amounts of strontium to the body will provide the same benefits to bone density and bone strength.
The main value of strontium ranelate is that it has undergone substantial clinical testing for safety and effectiveness. Other forms of strontium have not been studied as rigorously. Also, strontium ranelate is prescribed by physicians as a drug, assuring medical supervision of patient use.
Based on the limited early human studies with forms of strontium like strontium citrate, it seems likely that these other forms are as safe as strontium ranelate. However, the best clinical evidence for the safety and effectiveness of strontium currently exists mainly for strontium ranelate.
Sources
Genuis, Stephen J and Gerry K. Schwalfenberg. “Picking a bone with contemporary osteoporosis management: Nutrient strategies to enhance skeletal integrity.” Clinical Nutrition (Epub ahead of print, 2006 October 12).Meunier, Pierre J., et al. “The effects of strontium ranelate on the risk of vertebral fracture in women with postmenopausal osteoporosis.” New England Journal of Medicine 350 (2004):459 - 68.
Reginster, Jean-Yves, et al. “Strontium ranelate reduces the risk of nonvertebral fractures in postmenopausal women with osteoporosis: Treatment of Peripheral Osteoporosis (TROPOS) study.” Journal of Clinical Endocrinology and Metabolism 90 (2005):2816 - 22.
Varo, Pertti, et al. “Strontium in Finnish foods.” International Journal for Vitamin and Nutrition Research 52 (1982): 342 - 50.