UK researchers tested choline-stabilized orthosilicic acid, marketed under the BioSil brand by US company Jarrow Formulas.
The body can only absorb silicon in the form of orthosilicic acid,a dissolved form of the mineral that consists of a single molecule or monomer and produced in small amounts in the stomach from dietary silicon.
BioSil is therefore marketed as a more bioavailable form of the mineral than other dietary sources.
For the new study, Professor T.D. Spector from St Thomas Hospital in London investigated the effect of a low dose of the supplement on markers of bone turnover and bone mineral density (BMD) in 114 women with osteopenia or osteoporosis over 12 months.
Divided into four groups, all of the women received 1000 mg of calcium and 800 IU of vitamin D3 each day. Three of the groups also took supplements of either 3, 6 or 12 mg of BioSil.
The study, presented at the American Society for Bone and Mineral Research (ASBMR) conference in Nashville, Tennessee last weekend, found the supplement added to the benefits of the calcium and vitamin D supplementation.
The researchers reported improvements to several markers of bone formation, especially procollagen type I N-terminal propeptide (PINP).
There were significant improvements after 12 months in those people taking 6 and 12 mg of the supplement, said the researchers.
Although spinal BMD did not change significantly, subgroup analysis (81 women) showed that volunteers taking 6 mg of silicon per day, and whose femur T score was less than -1 at the start of the study, showed significant femoral neck BMD improvements.
These results seem to confirm the results of previously conducted studies on chickens and ovariectomized rats where ch-OSA also significantly increased the BMD of the femur (long bone) at the hip, but not the spine.
The researchers concluded: "This study suggests that combined therapy of ch-OSA plus Ca/Vit D3 is a safe, well tolerated treatment that has a potentially beneficial effect on bone turnover, especially bone collagen, and possibly femoral BMD, compared to Ca/Vit D3 alone."
Previously presented research suggests that ch-OSA helps build and maintain bone by regulating bone mineralization, helping to trigger the deposition of calcium and phosphate, reducing the number of osteoclasts (bone destroying cells) and increasing the number of osteoblasts (bone building cells).
A recent epidemiological study indicates that higher dietary silicon intake is associated with greater BMD in both men and pre-menopausal women.