There's good news and bad news about Americans' intake of calcium says a new study in the April issue of the Journal of the American College of Nutrition.
The good news is, that after years of decline in calcium consumption, the drop has not only leveled off, calcium intake is actually going up in some groups.
The bad news is that teenage girls and young women, especially African Americans, are not getting enough calcium at the time in their lives when calcium is most critical to building bone density.
"The start of adolescence to about age 30 is the most important time to get enough calcium," says the study's lead author, Richard Forshee, of the University of Maryland's Center for Food, Nutrition and Agriculture Policy (CFNAP). "It's that small window of time when they build the bone density that can help prevent osteoporosis in later years."
"These results tell us that we should look at what calcium fortification and supplements can do to increase calcium intake during this critical time," says Maureen Storey, a study co-author and director of CFNAP.
The study examined changes in calcium intake and its association with milk and other beverage consumption over a 10-year period. Other studies have suggested a connection between soda consumption and reduced intake of some nutrients, including calcium.
Using data from 24-hour dietary recalls taken between 1994 and 2002 in the Continuing Survey of Food Intake by Individuals and the National Health and Nutrition Examination Survey, the researchers analyzed data on calcium intake for different age-gender categories.
They found that while non-diet soft drink consumption increased, calcium intake was either unaffected or increased for some groups. Milk consumption declined in some groups, but stayed the same or increased in others. The study's key findings include:
Calcium intake increased for most age-gender categories, including adolescent females. Despite the increase, calcium intake is well below the recommended levels for adolescent and young adult women. The Adequate Intake for calcium is 1,300 milligrams per day for 9-18-year-old females, but the study found the group's average consumption was only 814 milligrams per day. The problem is especially serious among African-American females.
Average regular carbonated soft drink (RCSD) consumption increased in most age-gender categories, with the highest consumption being in the 20-39-year-old category.
Soft drink consumption was not associated with lower calcium intake, except for a small association among females 40-59 years old. Fluid milk was the only variable that had a strong association with calcium intake.
Average milk consumption decreased in the 6-11-year-old age category, but was unchanged or higher in the other age-gender categories. Many categories that showed increased average RCSD consumption had no change in average milk consumption.
Females 40-59 years, the only category to have a significant increase in average milk consumption, also had a significant increase in average RCSD consumption.
"Consumption of low-fat milk and dairy products should continue to be encouraged," says Forshee. "And it is time to seriously consider carefully targeted calcium fortification programs and calcium supplementation to help adolescent and young females meet their recommended calcium intake levels."