dietary reports from the integrated survey became known as What We Eat in America (WWEIA). For this report data for the 2003 to 2004 and 2005 to 2006 period were used because the data for the 2007 and 2008 period did not become available until after the committee had completed its deliberations. Calcium intake has been estimated since NHANES I. Intakes for vitamin D were first published in 2009 and currently are available for the 2003–2006 survey period. The NHANES is said to “follow the sun” in that the survey is generally conducted in the southern states during the winter months and in the northern states in the summer months.

The NHANES is unique in that it collects and tracks both total intake and health measures in a national sample of Americans, and provides an important aspect of the nation’s health monitoring system. As would be expected, total intake estimates are limited by survey respondents’ abilities to accurately report foods and amounts consumed and by the accuracy, specificity, and timeliness of the food composition databases linked to foods reported in the survey. Respondents are also prone to under-reporting intake (IOM, 2000). Issues related to estimation of usual intake from WWEIA-NHANES have been reviewed by others (Dwyer et al., 2003), including the challenges of updating food composition tables and addressing the under-reporting of intake amounts by participants.

In the case of nutrient intake data for the United States, calcium and vitamin D intake estimates from the WWEIA report series⁴ have formed the basis of an expanded analysis conducted and made available by the National Cancer Institute (NCI) of the National Institutes of Health. The NCI analysis was used in this report, as described below.

The USDA has produced the Vitamin D Addendum to the USDA Food and Nutrient Database for Dietary Studies 3.0,⁵ and in turn WWEIA reported the vitamin D intake from foods as well as calcium intake from foods.⁶ The expanded analysis carried out by NCI has allowed the incorporation of estimates of intake from dietary supplements collected as part of the NHANES but not included in the WWEIA reports, thereby providing an estimate of total calcium and vitamin D intake. Calcium intake data were available for the entire period 2003 to 2006 for the United States. However, although the USDA released vitamin D intake data for the 2003 to 2006