SEATTLE—”Super-tasters—people with a genetically inherited sensitivity to bitter tastes—may avoid cancer preventive compounds found in bitter and tart vegetables and fruit,” according to a study at the University of Michigan.

“Super-tasters are highly sensitive to bitter taste and tend to reject bitter tasting foods. Many antioxidant flavonoids that are so important for cancer prevention are either bitter or occur in bitter tasting vegetables and fruit,” said Adam Drewnowski, director of the Human Nutrition Program at the U-M School of Public Health.

Drewnowski presented the findings from his study Sunday Science. Researchers are currently trying to identify which chromosome carries the genetic taste marker and the marker’s location on the chromosome. About 25 percent of the 400 women in the U-M study fell into the “super-taster” category, another 25 percent were “non- tasters” with a “taste blindness” to bitter flavors, and the rest were regular tasters.

Drewnowski has conducted taste sensitivity studies in the laboratory to determine the potential impact of taste acuity on dietary choices and food selection. “In our tests, we found that women who rejected the bitter taste of a laboratory compound called PROP (6-n-propylthiouracil) had different taste preference profiles and disliked more sharp and bitter foods than did non- tasters,” Drewnowski said. “Sensitivity to PROP appears to influence dietary choices, and may limit exposure to dietary substances already known to alter cancer risk.”

For instance, the PROP super-tasters disliked naringin, an antioxidant flavonoid that is the principal bitter ingredient in grapefruit juice. “Like other flavonoids, naringin helps inhibit cancer-causing compounds in the body, and has potential chemotherapeutic value,” Drewnowski explained.

In general, women who are sensitive to bitter tastes may limit their consumption of sharp and bitter foods containing diverse flavonoids and isothiocyantes (antioxidants found in cruciferous vegetables) thought to be effective in cancer prevention. These foods may include bitter cruciferous vegetables, such as broccoli and Brussels sprouts; citrus fruits such as grapefruit; and a variety of bitter berries and roots.

“People who are tasters or super-tasters should be aware that some of their eating habits are not the result of a simple dislike but are genetically determined. They also should be aware that they may be disguising or moderating bitter tastes by covering vegetables with extra butter, cream, or a cheese sauce, thereby introducing more fat into their diets,” Drewnowski added.

“If they are conscious of their genetic status and its impact on their food choices, they can make healthier decisions about their diet,” he explained. “Health care professionals also should be aware that genetically inherited sensitivity to bitter foods may be an obstacle to cancer prevention programs and be prepared to guide patients in their diets.”

Drewnowski added that “we need to study further the impact of genetic taste markers on dietary choices to determine if a healthy diet might lower disease risk.”

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