Nutrigenomics applications comprise transcript-, proteome- and metabolome-profiling techniques in which responses to diets or individual ingredients are assessed in biological samples. They may also include the characterization of heterogeneity in relevant genes that affect the biological processes. This review explores various areas of nutrition and food sciences in which transcriptome-, proteome- and metabolome-analyses have been applied in human intervention studies, including nutrigenetics aspects and discusses the advantages and limitations of the methodologies. Despite the power of the profiling techniques to generate huge data sets, a critical assessment of the study outcomes emphasizes the current constraints in data interpretation, including huge knowledge gaps, the need for improved study designs and more comprehensive phenotyping of volunteers before selection for study participation. In this respect, nutrigenomics faces the same problems as all other areas of the life sciences, employing the same tools. However, there is a growing trend toward systemic approaches in which different technologies are combined and applied to the same sample, allowing physiological changes to be assessed more robustly throughout all molecular layers of mRNA, protein and metabolite changes. Nutrigenomics is thereby maturing as a branch of the life sciences and is gaining significant recognition in the scientific community.