Metabolomics for monitoring dietary exposure

有强有力的证据表明，饮食选择可以调节患一系列慢性疾病的风险，减少疾病负担的战略强调改变饮食模式的重要性。目前的公共卫生指南有一个共同的主题，即鼓励食用特定的食物类别，例如油性鱼类、全麦食品、水果和蔬菜，同时减少脂肪和含糖食物的摄入。为了最大限度地提高英国（和其他地方）健康饮食干预的有效性，我们需要经过验证的人口筛查方法，用于测量干预之前，期间和之后的食物消耗。传统的饮食调查方法对研究参与者来说是一个相当大的负担，并且容易产生偏差。此外，饮食数据的处理和分析是极其劳动密集型的，其最终结果是，这种饮食调查信息可能难以验证。这些困难限制了解释健康饮食干预结果的能力。最近，基于尿液或血液中代谢物的饮食摄入“生物标志物”的开发取得了重大进展，但目前，化学生物标志物仅可用于相对较少的特定食物和食物成分，而且大多数有效性不确定。阿伯里斯特威斯、纽卡斯尔和帝国理工学院的研究团队主要由英国食品标准局资助，他们利用代谢组学方法开发了一种新的策略，用于发现新的食物摄入生物标志物。“代谢组学”描述了对血液或尿液等生物液体中所有（或许多）代谢物（小分子）的测量。在消化、吸收和代谢之后，食物会在人体内产生数千种不同的代谢物，某些代谢物的外观是特定食物的特征。在我们早期的工作中，我们开发了可能适用于人群研究的尿液取样方法，并探索了使用全面的、非靶向的尿液化学分析（代谢组学技术）来识别饮食生物标志物线索。利用这种方法，我们已经确定了几种具有高度公共卫生意义的食物的潜在生物标志物，包括鲑鱼等油性鱼类、柑橘类水果、覆盆子等其他水果和绿色蔬菜西兰花。因此，我们现在打算测试一个假设，即来自自由生活个体的尿液样本的化学成分将准确反映饮食摄入量。研究方案将有以下主要目标：确定尿液中的化学物质与近期食用被认为对公众健康具有高度重要性的特定食物有关。为了证明每种特定食物的摄入量与尿液样本中每种潜在的化学“生物标志物”之间的定量关系。3. 验证一种简单的尿液取样程序，该程序对参与饮食调查的个人的日常活动干扰最小。4. 评估饮食暴露生物标志物在预测英国习惯性饮食中的表现。研究策略的设计将尽可能与英国饮食习惯的主要调查相结合，这将提供未来的机会，以确定生物标志物技术的采用是否提高了人口水平饮食调查的成本效益和准确性。此外，未来的纵向研究将具有独特的优势，旨在产生疾病风险与个人习惯性接触特定食物之间的明确联系。这项研究的结果将为雕像机构提供数据，以完善向消费者提供的饮食建议，并为食品生产商、制造商和零售商提供进一步的机会，以鼓励提供旨在改善英国人口整体健康的食品。

There is strong evidence that dietary choices modulate risk of developing a range of chronic diseases and strategies for reducing disease burden emphasize the importance of changing dietary patterns. Current public health guidelines have common themes that encourage consumption of specific food groups, for example, oily fish, wholegrain foods, fruits and vegetables whilst reducing intakes of fatty and sugary foods. To maximise the effectiveness healthy eating interventions in the UK (and elsewhere), we need validated population screening methods with which to measure food consumption before, during and after the intervention. Conventional dietary survey methods are a considerable burden for study participants and are subject to bias. In addition, the processing and analysis of dietary data is extremely labour intensive with the net result that such dietary survey information may be difficult to validate. Such difficulties limit the ability to interpret the outcomes of healthy eating interventions. Significant advances have been made recently in developing 'biomarkers' of dietary intake based on metabolites found in urine or blood but, currently, chemical biomarkers are available for only a relatively small number of specific foods and food components and most are of uncertain validity. Funded largely by the UK Food Standards Agency the research teams in Aberystwyth, Newcastle and Imperial College have used metabolomics approaches to develop a novel strategy for discovery of new biomarkers of food intake. "Metabolomics" describes the measure of all (or many) of the metabolites (small molecules) in biological fluids such as blood or urine. Following digestion, absorption and metabolism, foods give rise to thousands of different metabolites in the human body and the appearance of certain metabolites is characteristic of particular foods. In our earlier work, we have developed urine sampling methods potentially suitable for use in population studies and have explored the use of comprehensive, non-targeted chemical analysis of urine (metabolomics technology) to identify dietary biomarker leads. Using this approach, we have identified potential biomarkers for several foods of high public health significance including oily fish such as salmon, citrus fruit, other fruit such as raspberries and the green vegetable broccoli. We thus now intend to test the hypothesis that the chemical composition of urine samples from free-living individuals will accurately reflect dietary intake.The research programme will have the following major aims:1. To identify chemicals in urine associated with recent consumption of specific foods deemed to have high public health importance.2. To demonstrate a quantitative relationship between the amount of each specific food eaten and each potential chemical 'biomarker' in urine samples. 3. To validate a simple urine sampling procedure that is minimally intrusive to the every day activities of individuals participating in dietary surveys. 4. To assess the performance of dietary exposure biomarkers in the prediction of habitual diet in the UK. The research strategy will be designed to integrate where possible with major surveys of UK dietary habits which will offer future opportunity to determine whether the adoption of biomarker technology improves the cost effectiveness and accuracy of population-level dietary surveys. In addition there will be distinctive advantages in future longitudinal studies aiming to generate definite links between disease risk and individual habitual exposure to specific foods. The results of this research will provide data to allow statuary bodies to refine dietary advice provided to consumers as well as offering further opportunity to interact with food producers, manufacturers and retailers to encourage provision of foods targeted to improve the overall health of the UK population.