Genetics and nutrition

Abstract

The understanding of the role of nutrients on DNA stability, repair and on the different gene expression processes recently became more prominent in nutritional science. Nutrients and the genomics interact at two levels. Nutrients can induce gene expression thereby altering individual phenotype. Conversely single nucleotide polymorphisms, in a range of genes important in inflammation and lipid metabolism, alter the bioactivity of important metabolic pathways and mediators and influence the ability of nutrients to interact with them.

The study on single effects of nutrients on the individual's phenotype as well as the serial analyses of gene expression patterns in response to specific nutrients will help us to understand how metabolic homeostasis is maintained. Considering that there is wide variation in the ability of nutritional factors to modulate the expression of detrimental or protective proteins at an individual level, the concept of diet-medication could be developed in the light of a better understanding of nutrient–gene interactions. In this way, ‘good responders’ and ‘poor responders’ to diet therapy can be identified. Furthermore, as several vitamins participate in DNA protection and genomic stabilisation, diet-linked therapies could become part of cancer prevention and other treatments with relevant consequences for human health.

Introduction

The unravelling of the secrets of the human genome has provided new opportunities for understanding how mankind responds to the environment in health and disease.

The functioning of living organisms depends on the environmental availability of nutrients. One of the adaptation pathways is the nutrient-dependent regulation of the genome machinery. Although the nutrients can, in this way, influence the development of a particular phenotype, the opposite mechanism has also to be considered, i.e. the response to a specific nutrient as determined by the individual's genotype. The nutrient–gene interaction is therefore complex and bi-directional.

It is well known that not all individuals respond to nutrient therapy in the same way and with the same intensity. For any nutrient used in dietary therapy individuals, may be ‘good’, ‘poor’ or ‘non-responders’. In the past, this phenomenon has created problems in understanding the responses to nutrients and foods used in population-based intervention studies. The great variability in the responses of subjects in nutritional intervention studies has necessitated the recruitment of large numbers of individuals in order to obtain sufficient power to understand what effect, if any, a nutrient may be having. A closer understanding of how genotype influences the response to nutrients may permit efficacy of nutrients to be measured with greater precision than is presently the case.

This review gives an overview of the role of genetics in nutritional science. The bi-directional interactions between nutrients and the genome, referred to above, are discussed.

It also focuses on the nutrient-specific regulation of gene expression. A few representative examples of effects or regulations have been selected rather than an exhaustive list. The nutrient–gene interactions, the nutrient-specific regulation of gene expression and the related technological approaches are overviewed (Fig. 1).