Calcium requirements in the U.S. are determined by the Food and Nutrition Board (FNB), National Academy of Sciences of the National Research Council. These recommendations are published on a periodic basis and the last RDAs were published in 2004. You can read about calcium requirements in the U.S. online or purchase the Dietary Reference Intakes for Calcium, Phosphorus, Magnesium, Vitamin D, and Fluoride
The best method to assess bone calcium is DEXA (dual energy x-ray absorptiometry). I would recommend you contact the US National Osteoporosis Foundation for coordination with your organization needs.
The U.S. also gathers information about food intake by its citizens which would include an assessment of calcium intake. The results of these nutritional surveys are available online or CD-ROM for the National Health and Nutrition Examination Survey (NHANES latest is 2009 -2010), the Continuing Survey of Food Intakes by Individuals (CSFII 1994 to 1998) and the Diet and Health Knowledge Survey (DHKS from 1994 -1996).< /div>
