This book chapter focuses on nutrigenomics and its impact on human health; the persons involved in nutrigenomics; the limitations of nutrigenomics; and, the technologies involved (nutrigenetics, transcriptomics, metabolomics, and proteomics). The effects of various nutrients (carbohydrates, dietary fat, polyenoic fatty acids, proteins, amino acids, minerals and vitamins) on gene expression are described. The associations between nutrition, genes and diseases; between nutrigenomics and communication; and between nutrigenomics and bioactive nutrients are discussed. Ethical considerations and market implications relating to nutrigenomics are also reviewed.