The Super Tasters
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Tepper, who grew up in Boston and studied biology at Northeastern University, was a member of the first nutrition school class at Tufts. Looking back, she is glad that she and her classmates were required to study not only basic nutritional biochemistry, but also the impact of nutrition on people, including those in the developing world. "You really understood the interdisciplinary nature of nutrition, and I find that is a bit lacking in some programs," she said.
After graduating with her Ph.D. in 1986, she completed a postdoctoral fellowship at the Philadelphia-based Monell Chemical Senses Center, a research institute focused on taste and smell research. Her interest in sensory evaluation was born. When a position came up at Rutgers for a sensory scientist in 1989, she took it.
As director of Rutgers' Sensory Evaluation Laboratory, Tepper often collaborates with food companies. "When I work with industry, usually there is something applied in it that they are interested in and something basic research-oriented that I'm interested in. It's really a marriage of the two." She has worked with the Linguagen Corp., a biotechnology company that received a patent for the first molecular compound that blocks bitter tastes in foods and drugs. In her lab—which has a kitchen and 11 tasting booths equipped with computers where test participants record their reactions to foods—she tested the bitter blocker in combination with black coffee, dark chocolate, white grapefruit juice and tonic water. The blocker helped blunt the bitterness of the coffee, but nothing else.
Diets for diabetics
Other tests are purely for scientific elucidation. Tepper has been interested in diabetes research since her graduate school days. One of her first studies was to confirm the long-held medical belief that people with type 2 diabetes have an increased desire for sweets.
More recently, she has been focusing on women with gestational diabetes. Her studies so far have found that pregnant women with diabetic symptoms tend to like sweetened drinks, such as strawberry milk, and report that they consume more sweet foods in their diet. Tepper is interested in how pregnant women's increased desire for sweet foods may influence their dietary compliance. Women who are diagnosed with gestational diabetes usually receive the same dietary recommendations as those given for type 2 diabetics, but they do not always follow those recommendations. In the long run, she hopes this research will help focus nutritional recommendations for women with gestational diabetes and for diabetics in general.
Most of Tepper's students go on to work in the food industry. "A lot of our students have backgrounds in biology or microbiology or chemistry, and often they are students who like science, but they can't see the application. They come into food science, and they see chemical and biological principles being illustrated in something they know very well, which is food, and all of the sudden the spark happens, and they get very excited about it."
Of the 22 full-time faculty who work in the food science department at Rutgers, just two have backgrounds in nutrition. Most food scientists are concerned with the chemical and biological aspects of foods rather than the organisms that eat them. They leave that to the nutritionists.
Partnering nutrition and science
Tepper says her nutrition education gives her a special vantage point, one that convinces her there should be more collaboration between nutrition and food science departments. "I think they should be closer," she said. "If you have someone who understands the basic biology of a fat cell, and then you have a food scientist who understands the physical and biological dimensions of putting fat into a food product, I see a lot of strength there."
Tepper and other PROP researchers are looking at several ways that this one genetic proclivity may affect public health. At least one study has found that heavy smokers are significantly more likely to be non-tasters than tasters, who appear more sensitive to the irritation of smoke and the bitterness of nicotine. Similarly, tasters perceive more bitterness and irritation from ethyl alcohol, and research has found that tasters consume fewer alcoholic beverages per year than non-tasters. Tepper stresses that more work needs to be done in both areas, and that if there is a PROP connection, it would only be a risk factor, not a genetic mandate.
"My view is this is just another indicator as to whether a person is going to find alcohol acceptable or not," she said. "But to conclude that this determines whether it makes them an alcoholic or not is kind of far-fetched."
In the future, Tepper believes PROP research will be especially useful in the fight against obesity. Although there have been hundreds of studies looking at PROP status over the decades, only recently has it been recognized for its potential influences on eating behavior and body weight.
To epidemiologists who study obesity, PROP status may be the new kid on the block. But Tepper thinks it will win them over. "We have identified a lot of obesity genes, but many of those genes are involved in very rare forms of human obesity," Tepper said. "Whereas here's a phenotype that's really easy to measure, that seems to be related to body weight."
She is already collaborating with one scientist who is studying a genetically isolated population in a village in southern Italy, which, because the villagers have similar genetic backgrounds and diets, should provide a clearer understanding of PROP status' relationship to diet and disease outcomes.
Profile written by Julie Flaherty, Editor, Tufts Nutrition.
Homepage photo by Vito Aluia. Tepper photos by Thomas E. Franklin.
This story originally appeared in the Winter 2006 issue of Tufts Nutrition. It ran online on January 22, 2007.