Strontium, a naturally occurring element, shares chemical similarities with calcium, a fundamental component of healthy bones. While this resemblance allows strontium to be absorbed and integrated into the skeletal system, its presence can sometimes be detrimental. Understanding how strontium interacts with bone tissue reveals why it is often problematic.
How Strontium Mimics Calcium in Bones
Strontium and calcium share comparable chemical properties, allowing the body to mistake strontium for calcium. This leads to its absorption from the diet and incorporation into bone tissue, where approximately 99% of absorbed strontium concentrates. Strontium integrates into the bone’s mineral matrix, primarily into hydroxyapatite crystals. This incorporation can interfere with the normal calcium-phosphate arrangement, impacting the bone’s structural integrity and remodeling.
The Dangers of Radioactive Strontium
Radioactive strontium, particularly Sr-90, poses significant health risks due to its ability to mimic calcium. A byproduct of nuclear fission, Sr-90 is generated during nuclear weapons tests and reactor accidents. Once ingested, often through contaminated food or water, Sr-90 is readily absorbed and deposited in bones and bone marrow. As a “bone seeker” with a long half-life of approximately 29 years, it continuously emits beta radiation. This localized radiation damages bone cells and bone marrow, increasing the risk of bone cancer and leukemia.
Harmful Effects of High Stable Strontium Levels
Even high levels of stable strontium can negatively affect bone health. When present in excessive amounts, it can disrupt normal bone mineralization by replacing calcium in the bone’s mineral structure. This leads to the formation of softer, weaker bone crystals. Conditions like “strontium rickets” or osteomalacia can develop, where bone tissue fails to mineralize properly, resulting in less dense and more deformable bones. This outcome stems from a chemical disruption of bone formation, differing from radioactive damage.
Therapeutic Strontium: Understanding Its Risks
Strontium ranelate, a compound containing stable strontium, was historically used as a therapeutic agent for osteoporosis. Its use became highly restricted due to significant safety concerns. Strontium ranelate was associated with serious side effects, including an increased risk of cardiovascular events like heart attacks and strokes, and blood clots. Severe skin reactions were also reported. These risks led to its withdrawal or highly restricted use in many countries.