Nutrigenomics in the whole-genome scanning era: Crohn's disease as example.

Nutrigenomics has the potential to tailor diets to optimize health, based on knowledge of key genetic polymorphisms. Identification of candidate genes is often based on a priori knowledge of disease processes. However, genome-wide association methods are not only validating previously identified genes and polymorphisms, but also revealing new gene-disease associations not anticipated from prior knowledge. In Crohn's disease (CD), such studies not only confirm the importance of caspase-activated recruitment domain 15 and major histocompatibility complex II molecules, but also reveal strong associations with the proinflammatory cytokine interleukin-23 receptor and autophagy-related 16-like gene. Genes identified to date in CD can be linked into two interrelated pathways: receptor-mediated cytokine induction or autophagocytosis. New genomic technologies need to be matched with innovative methodologies to characterize the likely impact of foods and to take the field to another dimension of value for human diet development and optimized health.