Book excerpt: The Committee on Examination of the Evolving Science for Dietary Supplements of the Institute of Medicine's Food and Nutrition Board was directed to review, retrospectively, selected case studies of diet and health relationships that were relevant to dietary supplements and identified as important in the National Research Council report, Diet and Health: Implications for Chronic Disease Risk (D&H) (NRC, 1989). It was then to determine the extent to which subsequent scientific evidence from the peerreviewed literature used in published reports from the Dietary Reference Intakes (DRI) series (IOM, 1997, 1998, 2000a, 2001) either agreed with the preliminary evidence used to support the relationship identified originally in the 1989 review or significantly modified the original hypotheses and preliminary conclusions. The committee's analysis was to include characteristics of research with apparent high probability of predicting future confirmation by new science in support of a diet and health relationship. It also was to consider characteristics of information useful to consumers that would allow them to make scientifically informed judgments about the role that a specific food component or nutrient plays in health.