Onions can spice up your meals - and maybe strengthen your bones, preliminary study findings suggest.

Investigators from the University of Bern in Switzerland found that after eating a small fraction of an ounce of onion with their food, rats became significantly less likely to lose bone.

These findings suggest that adding onion to food may help people fight off the bone-thinning disease Osteoporosis, study author Dr. Rudolf Brenneisen told Reuters Health.

He added that people would need to eat at least 400 grams - or 14 ounces - of onions each day to equal the amount rats ate during the study.

Brenneisen noted that this is not the first study to show that what you add to your food can add to the health of your bones. For instance, he and his colleagues have shown that other vegetables and fruits may also inhibit bone loss in rats.

The researcher added that people using diet to strengthen their bones should make sure to include dairy products, since those foods can also strengthen bones.

To look further into whether onion helps keep bones strong and healthy, Brenneisen and his colleagues fed rats 1 gram of onion, then tested them to see how their bones were faring.

The findings, which appear in the Journal of Agricultural and Food Chemistry, show that after eating onions, the rats underwent significantly less bone resorption, the loss of minerals from the bones that characterizes osteoporosis. “Onion added to the food of rats inhibited significantly bone resorption,” according to Brenneisen.

To investigate what in onions was helping bones, the researchers mixed different components of an onion extract with bone cells.

One onion ingredient -called gamma glutamyl peptide - appeared to be most effective at inhibiting bone resorption, suggesting it is responsible for onion’s bone-boosting effects, the authors note.

SOURCE: Journal of Agricultural and Food Chemistry, May 4, 2005.