Genetic Variation and Nutrient Metabolism

One of the continuing challenges of nutrition research is dealing with the variability in response to nutrients and other bioactive substances that are consumed. Response can be any phenotype such as blood levels of a nutrient, biomarker or disease. There is growing interest among researchers and health -care practitioners in utilizing genomic information to predict and manage the large interindividual differences in response to nutrient intakes. Recent advances in human genomics have uncovered extensive variations in genes affecting nutrient metabolism, but their full impact on nutrient requirements remains to be elucidated. Developments in high -throughput technologies have enabled cost -effective and rapid detection of genetic variants, which facilitates their incorporation into clinical and observational studies of nutrition. Differences in the rates of absorption, distribution, uptake, utilization, biotransformation, and excretion ultimately impact the concentration of a nutrient at a target site of interest. Variations in genes that code for target proteins such as receptors, enzymes, transporters or ion channels can also impact the response to a nutrient. Nutrigenomics describes the use of high-throughput "omics" technologies to study how nutrients interact with the genome at all levels of regulation, and nutrigenetics is sometimes used specifically to refer to the effect of genetic variations on nutrient response. The purpose of this chapter is to provide an overview of the current state of knowledge of the role of human genetic variation in nutrient metabolism, and to present some notable examples that illustrate particular developments in the field. Incorporating markers of genetic variation into studies of nutrition and health aims to benefit those seeking personalized dietary advice, and should also improve public health recommendations by providing sound scientific evidence linking diet and health.