[Current challenges of nutrition applied research: ¿person or population?]

During the last half of the 20th century, Nutrition has evolved in a quick way based on the knowledge of both basic sciences as Biochemistry and Physiology and applied sciences as Epidemiology and Public Health. In that period the nutritional requirements for different population groups grouped by sex, age and physiological conditions have been established. However, in spite of the enormous knowledge in food and nutritional sciences, malnutrition by nutrient deficiencies (protein-energy undernutrition and micronutrient deficiencies) and by excess of nutrient intake (overweight and obesity) continues being a critical burden and challenge for numerous countries. In September 2015, the General Assembly of the United Nations established the "Sustainable Development Goals" with the aim of "to warrant a healthy life and promote the welfare for all in all ages", and defined a number of targets to reach maternal, infant and childhood nutrition, as well as to prevent non-communicable chronic diseases. Even though there are food intake guidelines and general recommendations for population nutrient intakes, individuals respond differently to lifestyle interventions depending on their genetic variants, which in turn influence the absorption and metabolism of nutrients. Indeed, the response of an individual to food intake and nutrients is the result of the interaction of a number of metabolic, genetic, environmental and social factors. Nutritional genomics is the science trying to facilitate an explanation at molecular levels of how nutrients and other bioactive food components interact with the genes of an individual and their effects on health. The new "omics" science tools (genomics, epigenomics, transcriptomics, proteomics and metabolomics) applied to nutrition is currently allowing the development of nutritional genomics. While "personalized nutrition" refers to the adaptation of the diet to individual needs and preferences, "precision nutrition" predicts whether an individual is responding or not to specific nutrients and food and dietary patterns in such a way they can contribute to the prevention of disease based on the genetic information and phenotype of that particular individual. One of the biggest challenges of nutrition today is to make possible precision nutrition in order to contribute to the improvement of the population and decrease the burden of non-communicable chronic diseases.