Diet, nutrition and cancer

(Part VIII)

Nutrient-gene interaction

Good nutrition is vital to good health, optimal growth and development, and prevention of diseases. Through untold millennia, people have come to appreciate the food-health connection and different civilizations have incorporated this concept into their approach to healing. With the advent of nutritional sciences, we now understand that nutrients and other food substances obtained when eating a wide variety of foods promote health, maintain metabolic homeostasis, and fulfill our energy requirements.

After World War II, various governments began to establish dietary guidelines for their populations to address the state of nutrient deficiencies and to conquer deficiency-related diseases public health policy recommendations. The current US dietary guidelines are population-and evidence-based advice on diet. However, humans differ in many ways in their response to diet because of inter-individual variations in genetic, epigenetic, and metabolic phenotype status. Therefore, to transform current population-based dietary guidelines into future personalized dietary recommendations, we will need tools and knowledge to investigate the molecular basis of genetic variation. These tools will provide an overview of the metabolic status and biochemical events associated with cellular and biological organ systems as well as nutrient-specific responses, including genotype expression, which determines the metabolic phenotype that leads to the various predispositions to diet-related diseases.

Although genetics is an important component, it accounts for only a portion of this variation. An individual’s overall phenotype, including health status, is achieved and maintained by the sum of metabolic activities functioning under different circumstances within the life cycle and the complex interactions among genotype, metabolic phenotype, diet, life-style and the environment. Metabolic biochemical functions as well as the nutritional and dietary needs of an individual. Therefore, genetic disposition and metabolic needs are important in determining the optimal diet for an individual. In this post-genomic era, high throughput-technologies in genomics, proteonomics and metabolomics can now measure and analyze DNA sequences, RNA transcripts, proteins, and nutrient-metabolic fluxes in a single experiment. The overall integration of information obtained through such high-throughput technologies will lead to individual metabolic genotype and phenotype analysis and can give rise to personalized nutrition and dietary diseases. This manuscript will review the current population-evidenced-based Dietary Guidelines for Americans 2005, the technological advances investigating the metabolic genotype-phenotype continuum, and the relationship and application of nutrigenomic concepts to individual diet and cancer prevention.

(To be continued)