Why Food Tastes Bad to Chemo Recipients

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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

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, 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 Cerrato, both of

Blacksburg, Va., will work on this project.

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