There has been considerable debate over the benefits of strontium for treating osteoporosis. Prior research indicates strontium ranelate both increases bone mineral density and reduces fractures of the spine (but not the hip) by up to 40%. Although the benefits of strontium look promising, it has been difficult to determine how much of strontium’s effect on bone density is from a real increase in bone mass and how much of it is simply artifact. The strontium atom is almost twice as heavy as calcium (38 vs 20 on the atomic chart) and when strontium enters bone tissue it creates more impedance to x-rays. On subsequent bone density (DXA) examinations, this creates the illusion of a higher than actual improvement in bone density.
In a recently accepted article for publication in the Journal of Bone and Mineral Research,
Chavassieux et al. compared the effects of strontium ranelate and alendronate (a bisphosphonate) on bone. Strontium is often considered to have both an antiresorptive effect by reducing osteoclast cell activity plus an anabolic effect by stimulating osteoblasts to form bone. Alendronate, on the other hand, is only antiresorptive in its therapeutic effect.
The study included 387 postmenopausal women with osteoporosis. Bone biopsies (transiliac) were performed at baseline and then again after 6 or 12 months to determine the effects of these two medications. The results indicated that although bone formation remained higher and there was overall less of a decrease in bone remodeling with strontium compared with alendronate, the strontium did not show significant anabolic (bone building) action.
Chavassieux, P., et al. 2013. Bone histomorphometry of transiliac paired bone biopsies after 6 or 12 months of treatment with oral strontium ranelate in 387 osteoporotic women. Randomized comparison to alendronate. Journal of Bone and Mineral Research doi: 10.1002/jbmr.2074.