Web-enabled and improved software tools and data are needed to measure nutrient intakes and physical activity for personalized health research

Single-Subject Studies in Translational Nutrition Research

There is a great deal of interest in personalized, individualized, or precision interventions for disease and health-risk mitigation. This is as true of nutrition-based intervention and prevention strategies as it is for pharmacotherapies and pharmaceutical-oriented prevention strategies. Essentially, technological breakthroughs have enabled researchers to probe an individual's unique genetic, biochemical, physiological, behavioral, and exposure profile, allowing them to identify very specific and often nuanced factors that an individual might possess, which may make it more or less likely that he or she responds favorably to a particular intervention (e.g., nutrient supplementation) or disease prevention strategy (e.g., specific diet). However, as compelling and intuitive as personalized nutrition might be in the current era in which data-intensive biomedical characterization of individuals is possible, appropriately and objectively vetting personalized nutrition strategies is not trivial and requires novel study designs and data analytical methods. These designs and methods must consider a very integrated use of the multiple contemporary biomedical assays and technologies that motivate them, which adds to their complexity. Single-subject or N-of-1 trials can be used to assess the utility of personalized interventions and, in addition, can be crafted in such a way as to accommodate the necessarily integrated use of many emerging biomedical technologies and assays. In this review, we consider the motivation, design, and implementation of N-of-1 trials in translational nutrition research that are meant to assess the utility of personalized nutritional strategies. We provide a number of example studies, discuss appropriate analytical methods given the complex data they generate and require, and consider how such studies could leverage integration of various biomarker assays and clinical end points. Importantly, we also consider the development of strategies and algorithms for matching nutritional needs to individual biomedical profiles and the issues surrounding them. Finally, we discuss the limitations of personalized nutrition studies, possible extensions of N-of-1 nutritional intervention studies, and areas of future research.

AVALIAÇÃO DA ATIVIDADE FÍSICA DE ESCOLARES COM UM QUESTIONÁRIO VIA INTERNET

RESUMO Introdução: A atividade física é um comportamento que se estabelece na infância, tende a se manter na vida adulta e influencia a regulação do balanço energético, do peso e da adiposidade corporal, prevenindo a obesidade. Por isso, criar e validar métodos de avaliação e monitoramento da atividade física de crianças e adolescentes no nível populacional é necessário para formular políticas públicas. Objetivo: Avaliar validade e reprodutibilidade de comportamentos sedentários e atividades físicas autorrelatadas no questionário Consumo Alimentar e Atividade Física de Escolares (Web-CAAFE), um instrumento computacional baseado na internet. Métodos: Escolares do 2º ao 5º ano (n = 390) foram observados durante o horário do recreio e preencheram o questionário no dia seguinte. Uma subamostra (n = 94) preencheu o Web-CAAFE duas vezes com três horas de intervalo. O custo energético, como equivalentes metabólicos (MET), foi calculado para cada atividade física e somado ao nível do indivíduo. O MET individual de atividades físicas e o total de comportamentos sedentários autorrelatados foram os principais desfechos analisados separadamente, utilizando regressão de Poisson e regressão de Poisson hierárquica (aluno no primeiro nível e a repetição dos métodos no segundo nível). Os resultados foram apresentados como razões de incidências (RI). Os resíduos foram analisados graficamente por sexo e idade. Resultados: O Web-CAAFE superestimou o total de comportamentos sedentários (RI = 2,90, IC 95%: 2,05-4,10), principalmente entre as garotas mais jovens (7-10 anos), enquanto as mais velhas (11-15 anos) tenderam à subestimação. A superestimação nos MET de atividades físicas foi menor e não estatisticamente significante. Não houve diferença estatisticamente significante no total de comportamentos sedentários ou MET de atividades físicas entre o primeiro e o segundo autorrelato. Conclusão: O Web-CAAFE mostrou boa confiabilidade e maior precisão quando aplicado à avaliação de MET de atividades físicas dos estudantes mais velhos.

The genomics of micronutrient requirements

Healthy nutrition is accepted as a cornerstone of public health strategies for reducing the risk of noncommunicable conditions such as obesity, cardiovascular disease, and related morbidities. However, many research studies continue to focus on single or at most a few factors that may elicit a metabolic effect. These reductionist approaches resulted in: (1) exaggerated claims for nutrition as a cure or prevention of disease; (2) the wide use of empirically based dietary regimens, as if one fits all; and (3) frequent disappointment of consumers, patients, and healthcare providers about the real impact nutrition can make on medicine and health. Multiple factors including environment, host and microbiome genetics, social context, the chemical form of the nutrient, its (bio)availability, and chemical and metabolic interactions among nutrients all interact to result in nutrient requirement and in health outcomes. Advances in laboratory methodologies, especially in analytical and separation techniques, are making the chemical dissection of foods and their availability in physiological tissues possible in an unprecedented manner. These omics technologies have opened opportunities for extending knowledge of micronutrients and of their metabolic and endocrine roles. While these technologies are crucial, more holistic approaches to the analysis of physiology and environment, novel experimental designs, and more sophisticated computational methods are needed to advance our understanding of how nutrition influences health of individuals.

Enabling nutrient security and sustainability through systems research

Human and companion animal health depends upon nutritional quality of foods. Seed varieties, seasonal and local growing conditions, transportation, food processing, and storage, and local food customs can influence the nutrient content of food. A new and intensive area of investigation is emerging that recognizes many factors in these agri-food systems that influence the maintenance of nutrient quality which is fundamental to ensure nutrient security for world populations. Modeling how these systems function requires data from different sectors including agricultural, environmental, social, and economic, but also must incorporate basic nutrition and other biomedical sciences. Improving the agri-food system through advances in pre- and post-harvest processing methods, biofortification, or fortifying processed foods will aid in targeting nutrition for populations and individuals. The challenge to maintain and improve nutrient quality is magnified by the need to produce food locally and globally in a sustainable and consumer-acceptable manner for current and future populations. An unmet requirement for assessing how to improve nutrient quality, however, is the basic knowledge of how to define health. That is, health cannot be maintained or improved by altering nutrient quality without an adequate definition of what health means for individuals and populations. Defining and measuring health therefore becomes a critical objective for basic nutritional and other biomedical sciences.

Translational genomics

The term "Translational Genomics" reflects both title and mission of this new journal. "Translational" has traditionally been understood as "applied research" or "development", different from or even opposed to "basic research". Recent scientific and societal developments have triggered a re-assessment of the connotation that "translational" and "basic" are either/or activities: translational research nowadays aims at feeding the best science into applications and solutions for human society. We therefore argue here basic science to be challenged and leveraged for its relevance to human health and societal benefits. This more recent approach and attitude are catalyzed by four trends or developments: evidence-based solutions; large-scale, high dimensional data; consumer/patient empowerment; and systems-level understanding.

Nutritional phenotype databases and integrated nutrition: from molecules to populations

In recent years, there has been a great expansion in the nature of new technologies for the study of all biologic subjects at the molecular and genomic level and these have been applied to the field of human nutrition. The latter has traditionally relied on a mix of epidemiologic studies to generate hypotheses, dietary intervention studies to test these hypotheses, and a variety of experimental approaches to understand the underlying explanatory mechanisms. Both the novel and traditional approaches have begun to carve out separate identities vís-a-vís their own journals, their own international societies, and their own national and international symposia. The present review draws on the advent of large national nutritional phenotype databases and related technological developments to argue the case that there needs to be far more integration of molecular and public health nutrition. This is required to address new joint approaches to such areas as the measurement of food intake, biomarker discovery, and the genetic determinants of nutrient-sensitive genotypes and other areas such as personalized nutrition and the use of new technologies with mass application, such as in dried blood spots to replace venipuncture or portable electronic devices to monitor food intake and phenotype. Future development requires the full integration of these 2 disciplines, which will provide a challenge to both funding agencies and to university training of nutritionists.

Consensus statement understanding health and malnutrition through a systems approach: the ENOUGH program for early life

Nutrition research, like most biomedical disciplines, adopted and often uses experimental approaches based on Beadle and Tatum's one gene-one polypeptide hypothesis, thereby reducing biological processes to single reactions or pathways. Systems thinking is needed to understand the complexity of health and disease processes requiring measurements of physiological processes, as well as environmental and social factors, which may alter the expression of genetic information. Analysis of physiological processes with omics technologies to assess systems' responses has only become available over the past decade and remains costly. Studies of environmental and social conditions known to alter health are often not connected to biomedical research. While these facts are widely accepted, developing and conducting comprehensive research programs for health are often beyond financial and human resources of single research groups. We propose a new research program on essential nutrients for optimal underpinning of growth and health (ENOUGH) that will use systems approaches with more comprehensive measurements and biostatistical analysis of the many biological and environmental factors that influence undernutrition. Creating a knowledge base for nutrition and health is a necessary first step toward developing solutions targeted to different populations in diverse social and physical environments for the two billion undernourished people in developed and developing economies.

Mass spectrometry-based metabolomics for the discovery of biomarkers of fruit and vegetable intake: citrus fruit as a case study

Elucidation of the relationships between genotype, diet, and health requires accurate dietary assessment. In intervention and epidemiological studies, dietary assessment usually relies on questionnaires, which are susceptible to recall bias. An alternative approach is to quantify biomarkers of intake in biofluids, but few such markers have been validated so far. Here we describe the use of metabolomics for the discovery of nutritional biomarkers, using citrus fruits as a case study. Three study designs were compared. Urinary metabolomes were profiled for volunteers that had (a) consumed an acute dose of orange or grapefruit juice, (b) consumed orange juice regularly for one month, and (c) reported high or low consumption of citrus products for a large cohort study. Some signals were found to reflect citrus consumption in all three studies. Proline betaine and flavanone glucuronides were identified as known biomarkers, but various other biomarkers were revealed. Further, many signals that increased after citrus intake in the acute study were not sensitive enough to discriminate high and low citrus consumers in the cohort study. We propose that urine profiling of cohort subjects stratified by consumption is an effective strategy for discovery of sensitive biomarkers of consumption for a wide range of foods.

The future direction of personalised nutrition: my diet, my phenotype, my genes

Although personalised nutrition is frequently considered in the context of diet-gene interactions, increasingly, personalised nutrition is seen to exist at three levels. The first is personalised dietary advice using Internet-delivered services, which ultimately will become automated and which will also draw on mobile phone technology. The second level of personalised dietary advice will include phenotypic information on anthropometry, physical activity, clinical parameters and biochemical markers of nutritional status. It remains possible that in addition to personalised dietary advice based on phenotypic data, advice at that group or metabotype level may be offered where metabotypes are defined by a common metabolic profile. The third level of personalised nutrition will involve the use of genomic data. While the genomic aspect of personalised nutrition is often considered as its main driver, there are significant challenges to translation of data on SNP and diet into personalised advice. The majority of the published data on SNP and diet emanate from observational studies and as such do not offer any cause-effect associations. To achieve this, purpose-designed dietary intervention studies will be needed with subjects recruited according to their genotype. Extensive research indicates that consumers would welcome personalised dietary advice including dietary advice based on their genotype. Unlike personalised medicine where genotype data are linked to the risk of developing a disease, in personalised nutrition the genetic data relate to the optimal diet for a given genotype to reduce disease risk factors and thus there are few ethical and legal issues in personalised nutrition.

The evolution of nutrition research

"The doctor of the future will no longer treat the human frame with drugs, but will rather cure and prevent disease with nutrition". Thomas Edison's contemplation may come to fruition if the nutritional revolution continues in its current course. Two realizations have propelled the world into a new age of personalized nutrition: (i) food can provide benefits beyond its intrinsic nutrient content, and (ii) we are not all created equal in our ability to realize to these benefits. Nutrigenomics is concerned with delineating genomic propensities to respond to various nutritional stimuli and the resulting impact on individual health. This review will examine the current technologies utilized by nutrigeneticists, the available literature regarding nutrient-gene interactions, and the translation of this new awareness into public health.

Assessment of research models for testing gene-environment interactions

Throughout the last century, possible effects of exposure to toxicants, nutrients or drugs were examined primarily by studies of groups or populations. Individual variation in responses was acknowledged but could not be analyzed due to lack of information or tools to analyze individual genetic make-ups and lifestyle factors such as diet and activity. The Human Genome, Haplotype Map, 1000Genomes, and Human Variome Projects are identifying and cataloging the variation found within humans. Advances in DNA sequencing technologies will soon permit the characterization of individual genomes in clinical and basic research studies, thus allowing associations to be made between an individual genotype and the response to a particular exposure. Such knowledge and tools have generated a significant challenge for scientists: to design and conduct research studies that account for individual genetic variation. However, before these studies are done in humans, they will be performed in various in vivo and in vitro models. The advantages and disadvantages of some of the model test systems that are being used or developed in relation to individual genetic make-up and responses to xenobiotics are discussed.

Virtual reality technologies for research and education in obesity and diabetes: research needs and opportunities

The rising rates, high prevalence, and adverse consequences of obesity and diabetes call for new approaches to the complex behaviors needed to prevent and manage these conditions. Virtual reality (VR) technologies, which provide controllable, multisensory, interactive three-dimensional (3D) stimulus environments, are a potentially valuable means of engaging patients in interventions that foster more healthful eating and physical activity patterns. Furthermore, the capacity of VR technologies to motivate, record, and measure human performance represents a novel and useful modality for conducting research. This article summarizes background information and discussions for a joint July 2010 National Institutes of Health - Department of Defense workshop entitled Virtual Reality Technologies for Research and Education in Obesity and Diabetes. The workshop explored the research potential of VR technologies as tools for behavioral and neuroscience studies in diabetes and obesity, and the practical potential of VR in fostering more effective utilization of diabetes- and obesity-related nutrition and lifestyle information. Virtual reality technologies were considered especially relevant for fostering desirable health-related behaviors through motivational reinforcement, personalized teaching approaches, and social networking. Virtual reality might also be a means of extending the availability and capacity of health care providers. Progress in the field will be enhanced by further developing available platforms and taking advantage of VR's capabilities as a research tool for well-designed hypothesis-testing behavioral science. Multidisciplinary collaborations are needed between the technology industry and academia, and among researchers in biomedical, behavioral, pedagogical, and computer science disciplines. Research priorities and funding opportunities for use of VR to improve prevention and management of obesity and diabetes can be found at agency websites (National Institutes of Health: http://grants.nih.gov/grants/guide/index.html; Department of Defense: www.tatrc.org).