Strontium is a bone-seeking mineral incorporated by ionic substitution for calcium onto the crystal surface of bone.4 Researchers have looked at the therapeutic potential of strontium based on in vitro, animal and human studies. After assessing and analyzing the results of several investigations, scientists theorize that strontium may benefit bone health via a two-pronged effect. It appears that strontium interacts with the cells responsible for the normal bone remodeling process. The cells responsible for bone formation are known as osteoblasts, and the cells responsible for bone breakdown, or resorption, are called the osteoclasts. Strontium may stimulate the replication of pre-osteoblasts, leading to an increased proliferation of osteoblasts (cells that build bone). This causes an increased synthesis of bone matrix. In terms of effects on osteoclasts (cells responsible for bone resorption), in vitro work shows that strontium directly inhibits their activity and prevents bone breakdown.5,6 

Animal studies suggest that extremely high dietary intakes of strontium, in the absence of adequate calcium intake, can actually disturb bone mineralization. At such concentration levels strontium replaces calcium ions in bone. The unbalanced incorporation of strontium into bone tissue in the place of calcium may cause a disturbance of the bone lattice, resulting in decreased bone mineral density.³ It is precisely for this reason that calcium intake must be adequate when supplementing with strontium. 

Further studies in animals reveal that strontium given as a part of the normal diet (when calcium intake is adequate) may have profound effects on bone formation and density. Oral administration of strontium doses to rats was shown to enhance the rate of bone formation and trabecular bone density.³ 

In a three-year, randomized, double-blind, placebo controlled study using 680 milligrams of strontium daily, women suffering from osteoporosis experienced a 41 percent reduction in risk of a vertebral fracture, compared with placebo. And, overall vertebrae density in the strontium group increased by 11.4 percent but there was a 1.3 percent decrease in the placebo group.

In a second study, 353 women who had suffered at least one vertebral fracture due to osteoporosis took varying levels of a prescription medication for of strontium referred to as strontium ranelate or a placebo. The women who took 680 milligrams of strontium daily had an increase in lumbar bone mineral density of approximately 3 percent per year, significantly greater than placebo. By the second year of the study, there was a significant decrease in additional fractures in the strontium group as compared with the placebo group.

In 1985, Dr. Stanley C. Skoryna of McGill University in Montreal conducted a small-scale study that pointed to a potential role for strontium in the treatment of humans.3a Three men and three women with osteoporosis were each given 600 to 700 mg/day of strontium in the form of strontium carbonate. Bone biopsies were taken in each patient at the iliac crest (hip bone), before and after six months of treatment with strontium. Biopsy samples showed a 172 percent increase in the rate of bone formation after strontium therapy, with no change in bone resorption. The patients receiving strontium remarked that the pains in their bones had diminished and their ability to move around had improved. 

A much larger trial by another research team included 1,649 osteoporotic postmenopausal women. These subjects received 2 gm/day of strontium ranelate (providing 680 mg strontium) or placebo for three years.5a Calcium and vitamin D supplements were also given to both groups before and during the study. In addition to suffering fewer fractures, patients in the strontium group noted a risk reduction of 49 percent in the first year of treatment and 41 percent during the three-year study period. Patients in the strontium group increased lumbar bone mineral density by an average of 14.4 percent and femoral neck BMD an average of 8.3 percent. The authors concluded that “treatment of postmenopausal osteoporosis with strontium ranelate leads to early and sustained reductions in the risk of vertebral fractures.” 

A. BEUTTENMULLER, and R. DZIAK, SDM College of Dental Sciences, Buffalo, NY, USA

Recent research has shown that stable strontium as well as some strontium salts increase bone metabolism in osteoblasts obtained from rodent calvaria cultures and that this element, particularly in the form of strontium ranelate, may be useful in the treatment of osteoporosis and other diseases of bone remodeling. Objectives: To assess the effects of strontium citrate, a product commonly available as a nutritional supplement, on the proliferation and differentiation of osteoblastic cells obtained from human alveolar bone. Methods: Primary osteoblasts, obtained with patients' consent from human alveolar bone residues at the time of third molar extractions and explanted in culture, were seeded at a concentration of 105 cells/ml in 24 well polystyrene plates in BGJb media containing 10% FCS. After the cells reached a semiconfluent stage, strontium citrate (bibasic anhydrous, pure grade from Jost Chemical) at various concentrations (0.05-1.0 mM) was added. The experiments performed included a MTT test which assesses viability/proliferation with a measure of mitochondrial activity and a biochemical assay for alkaline phosphate activity, an early maker of osteoblastic cell differentiation. Measurements were performed at 24, 48, and 72hrs. Results: The data were analyzed using ANOVA. The MTT test showed the cells to be responsive to strontium citrate with significant increases (p<0.05) in cellular activity/proliferation at 24 and 48 hrs. Alkaline phosphatase activity was significantly enhanced (p<0.05) at 48 and 72 hrs with strontium citrate concentrations in the test range. Conclusion: The data support the hypothesis that strontium citrate increases the proliferative/alkaline phosphatase activity of human osteoblastic cells from alveolar bone. The results validate previous research that has been done with other forms of strontium in clinical studies and rodent calvarial cells and indicates that strontium citrate could be a promising agent in treating oral as well as systemic bone disorders. Resource

Supplementing with strontium is an effective means for supporting bone health and optimal bone density. When taken orally as recommended, strontium is well-tolerated and very safe.