2003 W. O. Atwater Memorial Lecture: Defining Nutrient Requirements from a Perspective of Bone-Related Nutrients

The U.S. Department of Agriculture, Agricultural Research Service has a valued tradition of sponsoring an annual lecture in honor of W. O. Atwater. I will always treasure the wonderful experience of sharing my thoughts on nutrient requirements and the lively reception that followed with so many supportive colleagues, students and friends at the annual meeting of the American Society for Nutritional Sciences at Experimental Biology. Atwater studied food composition, nutrient availability from the diet, nutrient intake of American families and nutrient requirements. It is not surprising then that related topics are often the focus of Atwater lectures. Elsie Widdowson claimed in her Atwater lecture that “Atwater contributed more to our knowledge about the energy value of human foods than anyone who has ever lived, either before or since his time” (1). The most recently published Atwater lecture by Vernon Young advanced Atwater’s legacy by reflecting on the role that the sequencing of the human genome would have on determining human nutrient requirements (2). My participation on the Dietary Reference Intake (DRI) Panel for calcium and bone-related nutrients (3) acquainted me with the process of weighing the science to set nutrient requirements and Upper Levels (UL). The tremendous amount of information that had accumulated on calcium requirements was gathered in an NIH Consensus Conference on Defining Optimal Calcium Intakes (4), which became one of the motivating factors for embarking on the new iteration of nutrient requirements, the DRI, which were released in 1997 for calcium, vitamin D, phosphorus, magnesium and fluoride. The Atwater Lecture gave me the opportunity to tell the story of my own research contributions to the increased body of literature available for establishing calcium requirements in adolescents and screening most of the calcium sources in the human diet for bioavailability with my long time co-investigators, Robert Heaney, Munro Peacock, George McCabe, Meryl Wastney and my capable research group. The volume of science generated on vitamin D since 1997 is calling into question both the Adequate Intakes (AI) and UL our panel set for vitamin D. The Atwater Lecture was a chance to review the science, discuss the remaining gaps, and speculate that this nutrient will be a driving force for the next iteration of setting nutrient requirements. Finally, the Atwater Lecture was an opportunity to express the importance of considering the interaction of nutrients on defining nutrient requirements. The interdependency of calcium and vitamin D requirements provides a classic example.