In a telephone interview, Dr. Robert P. Heaney, professor of medicine at Creighton University in Omaha, Neb., said calcium consumption has been dropping throughout most of the past century, because of the substitution of carbonated beverages for dairy products and the decrease in food intake from less strenuous lifestyles. Calcium can be obtained from a variety of sources, including supplements, dairy products, certain fruits and vegetables, and grain products. But 75 percent of the calcium in the American diet comes from dairy foods, which are more calcium-dense. Heaney said dairy products are the best way to get calcium. In addition to being calcium-dense, dairy products also contain a lot of other nutrients, such as vitamins A, D and B12, protein, riboflavin, magnesium and phosphorus.
Vitamin D helps the body absorb calcium.
Some food sources that have calcium also contain substances that bind with the mineral so the calcium isn't fully absorbed by the body. The calcium consumption problem begins in childhood, Carlson said. The use of soft drinks and fruit drinks have increased at the expense of milk. During the teen years, milk intake has dropped to the point where nine out of 10 girls and seven out of 10 boys aren't getting the amounts they need. Teenagers drink twice as much soda as milk, with boys drinking an average of 28 ounces of soda a day, Carlson said.