8. The Food Exposome

Estimating the food exposome, that is, the totality of dietary exposures, represents a substantial challenge because of the wide nature of foods consumed and the variability of the amount and frequency of intake according to food preference, season, and other individual characteristics. Classical approaches to estimating dietary intake have used dietary assessment instruments such as questionnaires and food composition tables. However, these are subject to a number of biases and errors, including misreporting and recall bias. The use of dietary biomarkers provides a more objective approach to assess exposures to dietary compounds and their food sources. Approximately 150 dietary biomarkers have been measured so far in cohort or biomonitoring studies and many new candidate biomarkers are now regularly proposed following the rapid development of mass spectrometry techniques and metabolomics. Several 100 food-derived compounds can be simultaneously measured as part of the human exposome in very small human biospecimens collected in large populations. These approaches and their implementation in dietary-wide association studies are reviewed. This could significantly advance nutritional epidemiology and its utility in linking dietary exposures with disease outcomes.