Calcium-fortified vegetables?

Consumers wishing to fortify their diets with calcium might one day find a whole new crop of allies -- in the produce aisle.

In earlier studies, scientists working with Dr. Kendal Hirschi, a plant physiologist at the USDA/ARS Children's Nutrition Research Center at Baylor College of Medicine, discovered that turning "on" the production of a protein called CAX1 in the cells of a tiny weed known as Arabidopsis thaliana increased the calcium content of the plant's leaf and root cells by 30 to 100 percent. Now, they have identified a tiny slice of nine amino acids that gives the protein its calcium-boosting prowess, and successfully transferred the slice to similar proteins, called transporters.

The researchers believe that these findings are an important step toward the development of vegetable varieties that are "naturally fortified" with calcium.

"We knew we had found the key slice of CAX1 because removing it rendered the protein non-functional, while inserting it into another transporter that "looked like" CAX1 turned that protein into one that also functioned like CAX1," said Hirschi, also an assistant professor of pediatrics at Baylor.

CAX1 is known as a calcium transporter because it pulls calcium out of cellular fluids and stashes it in cell storage structures called vacuoles. Hirschi's team hopes to use CAX1 and other calcium transporters to move more calcium into "storage" inside cells, which could set off a physiological chain reaction that might ultimately cause plants to pull more calcium out of the soil and improve their overall calcium content.

"Our success with this tiny weed is encouraging, but the real test will be whether this new knowledge will translate into improving the calcium content of popular foods like potatoes and tomatoes," he said.

If it does, a calcium-rich diet might be an order of fries away.