A carrot genetically modified to contain more calcium could help prevent bone deterioration caused by osteoporosis, using a method that could be applied to other fruits and vegetables, scientists say.

The calcium-fortified carrots contain double the calcium of ordinary carrots, according to a study by Texas A&M University released today by the Proceedings of the National Academy of Sciences. Extra calcium through genetic tweaking could also "improve plant productivity and extend product shelf life," researchers said.

"When applied to a wide variety of fruits and vegetables, this strategy could lead to more calcium consumption in the diet," researchers said. "In the U.S., dietary calcium intake has decreased, such that 90 percent of adolescent girls and 50 percent of adolescent boys consume less than the optimal amount of calcium."

In the U.S., more than 8 million women and 2 million men have osteoporosis, a bone-thinning disorder that increases the risk of fractures. Scientists blame the disease on inadequate calcium intake that could be improved with fortified food. Still, opponents of genetically modified food argue the health effects and risk to the ecosystem are unknown.

By eating 100 grams of the modified carrots — which contain about 60 milligrams of calcium — women absorbed 45.9 percent more calcium, and men took in 38.7 percent more than by eating the same amount of regular carrots, containing 30 milligrams of calcium, scientists found.

Still, the body absorbed a smaller percentage of the additional calcium by eating fortified carrots, the study found. People absorb about 52 percent of the calcium in normal carrots, but only 42 percent in the altered version, Jay Morris, one of the lead researchers and study co-author, said in an e-mail response to questions.

"Forty-two percent of 60 milligrams is much greater than 52 percent of 30 milligrams," said Morris, who researches children's nutrition at the university's Baylor College of Medicine in Houston.

For the study, scientists fed modified and normal carrots to 30 healthy adults aged between 21 and 30 years and measured absorption.

"A fraction of the modified carrot calcium is not absorbed," said Kendal Hirschi, study co-author and a lead researcher said in an e-mail response to questions. "However, the vast quantity of the modified carrots' increased calcium is absorbed, meaning more calcium even if the fraction of the total absorbed is slightly lower."