Nutrients and other food components influence the function of the body, protect against disease, restore health, and determine people’s response to changes in the environment. Under certain circumstances and in some individuals, diet can be a serious risk factor for a number of diseases. Common dietary chemicals can act on the human genome, either directly or indirectly, to alter gene expression or structure. 

The degree to which diet influences the balance between healthy and disease states may depend on an individual’s genetic makeup. Some diet-regulated genes (and their normal, common variants) are likely to play a role in the onset, incidence, progression, and/or severity of chronic diseases. Dietary intervention based on knowledge of nutritional requirement, nutritional status, and genotype (i.e., “personalised nutrition”) can be used to prevent, mitigate or cure chronic disease.