But if vegetables and fruits could be bred to contain more calcium, then a diet that includes a variety of these produce might come closer to providing necessary calcium, Morris said.
"Increased fruits and vegetables (in the diet) are better for a myriad of reasons," he said.
The finding will be reported in the Proceedings of the National Academy of Sciences online edition Jan. 14. Funding for this research came from the National Institutes of Health, the Vegetable and Fruit Improvement Center at Texas A&M University and the USDA/ARS Children's Nutrition Research Center at Baylor College of Medicine.