Virtual food components: functional food effects expressed as food components

Background: The ability to communicate food benefits is essential for the successful development of functional foods and their role in improving public health. However, the functional efficacy of foods often cannot be represented by food composition. The concept of virtual food components (VFCs)-food data that express health-related effects, properties or functions of foods in the format of food components-is therefore proposed. Objective: To develop protocols for designing VFC data sets that communicate functional efficacies of foods to end users, in order to facilitate evidence-based food choice, and allow data management systems to provide a more complete description of nutritional effects of foods than has been possible with values for actual food components alone. Method: A framework within which to develop VFCs was constructed, linking food choice to health end points. It involves scientific validation, generation of relative indices, their translation into a meaningful language based on equivalents to known and understood reference foods, followed by data consolidation and ecological validation. Criteria used to evaluate VFCs were importance, independence, validity, accuracy, robustness, sensitivity, linearity/additivity, relevance, comprehensiveness, acquirability, completeness, meaningfulness, acceptability and safety. The developmental framework and evaluative criteria were applied to glycaemic glucose equivalents (GGE), a VFC representing postprandial glycaemia, and to wheat bran equivalents for faecal bulk (WBE(fb)), a VFC representing faecal bulking efficacy. Results: VFCs were used to identify foods according to health-related effects that cannot be accurately predicted from food composition data, and were used in a nutrition management system to concurrently show nutrient intake and physiological effects in the same units. The proposed evaluative criteria identified points requiring further research, and showed that lack of integrity-tested VFC data is an immediate challenge. Conclusion: VFCs are a means of communicating relative functional efficacy of foods as a continuous variable, and provide end users with a more accurate and complete view of the health effects of foods than can be provided by health claims or food composition data alone.