Blacksburg, Va. –– 据一项医学研究表明，目前接受特定药物治疗和化疗的大约二百万位癌症患者认为食物和饮料有一种难闻的金属味道。大体上，有超过40% 的住院病人遭受着味觉、嗅觉功能障碍所引起的营养不良。
Virginia Tech的城市与环境工程学（CEE）教授Andrea Dietrich说：“很遗憾，影响患者营养水平和生活质量的这些问题没有引起重视，而且肿瘤学家主要研究的对象并非是此类问题。”
Dietrich认为所谓的金属味道是由两部分产生的——舌头上金属离子的味道，嘴里由金属催化气味产生的重-鼻效果。Dietrich 说：“我正试图更好的了解金属感，它的预防作用，和在人类健康方面的应用。”
和一个维吉尼亚的成员技术-守夜森林大学学校， Dietrich接受了来自公共卫生和水研究学会（IPWR）的200000 美元赠款，用于调查水中有难闻味道的问题。她同两位大学同事一起工作，她们分别是食品科学技术教授Susan E. Duncan，生物医药学和病理系助理教授YongWoo Lee（a member of the Virginia Tech-Wake Forest University School of Biomedical Engineering and Sciences）。跨学科的研究队伍结合了精通食物氧化和去味、水化学，细胞生物学和人类知觉的人才。
Dietrich是此次调查研究项目的负责人，是在水质、治疗及味道和气味评估方面的专家。事实上，饮用水中有33种已识别的味道被the American Water Works Association and Research Foundation（AwwaRF）承认。 他们按照从“ 泥煤似的” 到“粉碎了草的”、“湿纸的”、“塑料的”描述进行排列。
前些年，AwwaRF赞助Dietrich在美国各地对职员和经理，就如何通过感官分析发现水质变化，进行了培训。她也是用于对未经处理的水进行每日监控的三个测试气味方法的开发者之一。
如今，她希望能与像她一样的医学人员一起合作，去对照感觉阈值、被推荐的营养标准及水中对健康有害的铜铁含量水平与健康相关问题（比如，接受化疗的患者持续出现口中金属味道）的关系。
她们希望能找出，当饮用含有金属离子（尤其是铁和铜）的水时，口中有金属味道的原因。她们的研究也将会评估抗氧化剂的使用价值，这些抗氧化剂可用来避免口中产生金属味道。Dietrich 说：“如果我们能发现产生金属味道的原因，那么就能应用相应的预防方法。”
总之，饮用水的金属物质实际上是人类饮食中微量元素的重要来源。 事实上，铁和铜普遍存在于饮用水中，他们又是微量元素的重要来源。但其含量是有阈值的。如果一次摄取的铁和铜的浓度超过每升3毫克，就“可能造成反胃、呕吐、腹泻、肾和肝脏损害，”Dietrich 解释说。
以后将会在志愿者身上作一些试验来观察挥发性化合物在嘴中的反应。因为唾液中包含蛋白质和酶类，这些物质可能有增强金属味道的作用。Dietrich补充道，她们将会采用体外试验的方法，以便在不危害人体的情况下进行较高浓度的实验。
味道和气味的感知过程非常复杂, 和营养需求类似，这一过程随着年龄、性别、种族、健康状态、原先曾有过的经验等而改变。
Pinar Omur-Ozbek和Jose Cerrato是两位从Blacksburg, Va.毕业，已获得CEE学位的学生。他们均将参与此研究项目的工作。
说明：IPWR 是一个非营利、独立的科学教育组织。它旨在为了提高人们健康水平，而支持关于饮用水质量的研究和教育。Brita 产品公司对IPWR的支持，就是为了提高人们对水与健康关系的理解。
Researchers examine why food tastes bad to chemotherapy recipients
Blacksburg, Va. –– About two million cancer patients currently receiving certain drug therapies and chemotherapy find foods and beverages to have a foul metallic flavor, according to a medical study. In general, more than 40 percent of hospitalized patients suffer from malnutrition due to taste and smell dysfunction.
"Unfortunately, these problems that impact nutrition and quality of life are underestimated and understudied by oncologists," said Andrea Dietrich, Virginia Tech professor of civil and environmental engineering (CEE).
Dietrich believes there are two components to the metallic flavor –– the taste of metal ions on the tongue and the production of metal-catalyzed odors in the mouth that create a retro-nasal effect. "I am attempting to gain a better understanding of the metallic sensation, its prevention, and application to human health," Dietrich said.
Along with two of her university colleagues, Susan E. Duncan, professor of food science and technology, and YongWoo Lee, an assistant professor in the biomedical sciences and pathology department and a member of the Virginia Tech-Wake Forest University School of Biomedical Engineering and Sciences, Dietrich is the recipient of a $200,000 grant from the Institute of Public Health and Water Research (IPWR) to examine the problems of foul flavored water. The interdisciplinary investigative team combines proficiency in food oxidation and off-flavors, water chemistry, cell biology, and human perception.
Dietrich, the principal investigator on the project, is an expert on water quality and treatment, as well as its taste and odor assessment. In fact there are some 33 identified flavors of drinking water acknowledged by the American Water Works Association and Research Foundation (AwwaRF). They range in description from "wet paper" to "crushed grass" to "peaty" to "plastic."
Several years ago, AwwaRF sponsored Dietrich to travel around the U.S. to educate utility staff and managers on how to use sensory analysis to detect changes in water quality. She is also a co-developer of three odor-testing methods for the daily monitoring of raw and untreated water.
Now she is hoping to work with medical personnel as she, Duncan, and Lee compare the sensory thresholds, recommended nutritional levels, and adverse health effect levels of iron and copper in water, and their relationship to health-based problems such as persistent metallic tastes of patients receiving chemotherapy.
They hope to identify the cause of the metallic flavor in the mouth when drinking water contains metal ions, specifically iron and copper. Their research will also evaluate the use of antioxidants to prevent the metallic flavor production. "If we can discover the cause of the production of metallic flavor, then preventive methods can be taken accordingly," Dietrich said.
In correct amounts, metals in drinking water are actually important sources of micronutrients in the human diet. In fact, iron and copper are commonly found in drinking water, and they can be an important source of these mircronutrients. However, there are thresholds. If ingested at higher concentrations, greater than three milligrams per liter, iron and copper "may cause nausea, vomiting, diarrhea, kidney and liver damage," Dietrich explained.
Some tests will be done with human volunteers to determine reactions of volatile compounds in the mouth. Since saliva contains proteins and enzymes, it may have some effect in enhancing the metallic flavor. They will also use in-vitro experiments in order to conduct experiments at higher concentrations without endangering anyone, Dietrich added.
Perception of taste and odor is very complex, and like nutritional needs, varies depending on age, gender, race, health status, prior exposure and experience.
Two graduate CEE students, Pinar Omur-Ozbek and Jose Cerrato, both of Blacksburg, Va., will work on this project.
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IPWR is a non-profit, independent science and education organization that promotes research and education on the value of drinking quality water for the improvement of health. The Brita Products Company supports IPWR for the purposes of advancing the understanding of the relationship between water and health.
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