Biomarkers are the backbones of our daily medical decision making. They indicate the malfunction of organ systems and efficacy of therapeutic interventions. However, only in a few areas related to human nutrition and metabolism, biomarkers play important roles to predict health and functional outcome, and are routinely used in clinical practice. Parameters indicating the lipid status/metabolism which predict long-term cardiovascular risk and efficacy of targeted interventions have been included in routine patient management for a longtime. Biomarkers of lipid status have also shown the limitations of our present nutritional intervention strategies. Iron deficiency and overload can be precisely diagnosed and managed by biomarkers, and it has recently been shown that the best ‘biomarker’ to guide treatment may be the physiological ‘determinant’of iron utilization (hepcidin). Interestingly, out of the ‘big four’ global nutritional deficiencies (vitamin A, zinc, iodine, and iron) which are associated with significant morbidity and mortality in humans, three still cannot be precisely diagnosed by employing (biochemical) biomarkers. Therefore, intervention strategies are mostly still targeted at population level and biomarkers play a limited role in research and decision making. Satisfactory pediatric nutritional biomarkers of outcome must be predictive of later functional health and ideally remain stable over the period from infancy to childhood and adult life. Current traditional biomarkers such as anthropometry and blood pressure are indices that best fulfill those criteria. They are important to monitor long-term health of children who were born with low birth weight in terms of malnutrition or obesity. Our epigenome and metabolome can be influenced by dietary, lifestyle, and environmental factors, which contribute to the heterogeneity observed in humans. Therefore, the risk factors determined for populations cannot be applied to the individual, one has Foreword XI to accept ‘individual variability’. New biomarkers which indicate the individual risk or benefit must not neglect the complexity of foods, lifestyle, and metabolic processes that contribute to health or disease and are significant challenges for personalizing dietary advice for healthy or diseased individuals. The 84th Nestlé Nutrition Institute (NNI) Workshop focused on values and limitations of traditional nutritional biomarkers and opportunities of new biomarkers. NNI would like to thank the three Chairmen, Prof. Emmanuel E.Baetge (Switzerland), Prof. Anil Dhawan (UK), and Prof. Andrew Prentice,(UK) for their challenging and interesting program together and all speakers for their significant contributions. We would also thank the Nestlé Health Science Institute and the Nestlé Research Centre for cooperation and support.