A Guide to Osteoporosis Drugs: Strontium

Institute for Better Bone Health’s Guide to Osteoporosis Drugs, part 3: Strontium (Protelos®, Protos® Osseor®)

strontium UPDATE: The Risk Assessment Committee of the European Medicines Agency recommends suspending use of Protelos/Osseor (strontium) for the treatment of osteoporosis, citing  serious heart problems (including heart attacks) along with blood clots or blockages of blood vessels in addition to a number of other risks, such as serious skin reactions, disturbances in consciousness, seizures (fits), liver inflammation and reduced number of blood cells. Strontium is not approved by the FDA for osteoporosis treatment in the U.S. but is still used in some supplements. All persons taking strontium supplements are warned that significant risks have been identified.

The case against strontium as a medical treatment for osteoporosis is strong. However, an unpatentable form of strontium is widely available in supplements that lack oversight and research.  The public is slowly become more aware of the risks of supplementing with strontium for the prevention and management of osteoporosis.

Strontium is a trace element found in seawater and soil. The main dietary source of strontium is seafood. Foods with lesser amounts of strontium include whole milk, wheat bran, meat, poultry, and root vegetables. Strontium is chemically similar to calcium, which is where the confusion begins. Strontium is much heavier than calcium, and actually replaces the natural calcium in bone.  The increased weight makes bone appear denser on x-ray tests that can be misread as increased bone mineral density.  And unlike calcium, which leaves the body, strontium accumulates in the body and bloodstream and remains there long term.

A few European countries and Australia market strontium ranelate (brand name Protelos® or Protos®) as a prescription medication for the treatment and prevention of osteoporosis and related fractures.  Studies using 2 grams of strontium ranelate a day taken orally show improved bone strength and reduced fracture rates in women with osteoporosis, but there are reports of increased risks of blood clots.  Long-term concerns also include mental confusion and memory loss.

Osteoporosis International recently reported the effects of taking strontium for more than 10 years : one in fifty women reported problems with mental function. Strontium also replaces calcium in nerves, which changes fundamental nerve signaling pathways.  The European Medicines Agency (EMA) Committee for Medicinal Products for Human Use (CHMP) recently recommended a restriction in the use of these drugs, following an assessment of data showing an increased risk of serious heart problems.

For these reasons, strontium ranelate is NOT approved by the FDA for use in the United States.  Regardless, supplement makers ignore the FDA’s recommendation and continue to market strontium supplements, as strontium citrate.  But it's not the citrate or the ranelate that replace calcium –  it’s the strontium ions – so this form is not necessarily any safer.

Strontium supplements have not been tested in large scientific studies. Moreover, because the FDA does not regulate supplements to the same degree as prescription drugs it is much more difficult to assure product quality and that ingredients are contained in safe amounts. Routine supplementation with metals including zinc, manganese, copper and strontium is generally agreed as unnecessary, and excessive supplementation may be harmful. Supplementation with strontium should also be questioned until long-term risks and benefits are better understood.

Silical®* supplements do not contain strontium in any form. (Silical® contains 100% food-based vitamins and minerals formulated to complete nutritional needs for bone health).

*Adequate calcium and vitamin D, throughout life, as part of a well-balanced diet, may reduce the risk of osteoporosis.

Continue reading our Guide to Osteoporosis Drugs series.  Part 1 : Bisphosphonates, or Part 2: Hormone Therapy

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