Besides adding flavor to food, onions also may be good for your bones. Researchers at the University of Bern in Switzerland have identified a compound in the popular vegetable that appears to decrease bone loss in laboratory studies using rat bone cells. Although further studies are needed, the current study suggests that eating onions might help prevent bone loss and osteoporosis, a disease which predominately affects older women. The disease results in an estimated $17 billion in medical costs in the United States.

Their study, scheduled to appear in the May 4 print issue of the American Chemical Society’s Journal of Agricultural and Food Chemistry, was published March 30 on the journal’s Web site.

In the current study, the researchers analyzed the active chemical components of white onions and found that the most likely compound responsible for the decreased bone loss was a peptide called GPCS. The researchers then obtained a group of isolated bone cells from newborn rats and exposed the cells to parathyroid hormone to stimulate bone loss, then exposed some of the treated cells to GPCS. Treatment with GPCS significantly inhibited the loss of bone minerals, including calcium, when compared to cells that were not exposed to GPCS, according to the researchers. Additional studies are needed to determine whether GPCS will have a similar effect in people, how much onion or GPCS is needed for a positive effect on bone health, and to determine the mechanism of action of GPCS on bone cells, the researchers say.