To taste or not to taste

How individuals experience taste varies greatly, which explains why some people like broccoli and others flee at its very mention. An industrial chemist named Arthur Fox documented one basis for taste preference in 1931 while working with a compound called phenylthiocarbamide (PTC) for the DuPont Co. After the chemical was released accidentally into the air one day, a colleague remarked how bitter it tasted. Fox had noticed nothing.

Investigating further, the two scientists concluded that people fell into one of two groups: tasters and nontasters of PTC. Fox reported the findings later the same year in Science News. “The geneticists jumped right in,” says Linda Bartoshuk, Ph.D., “and by the next year, two family studies had been done dividing the world between tasters and nontasters. The research showed that the nontasters had two recessive genes.”

Bartoshuk began exploring the subtleties of taste in the 1970s as a Yale faculty member and investigator at the John B. Pierce Laboratory. She took Fox’s notion one step further, coining the term “supertaster” after identifying a third group of subjects whose taste buds were so numerous and so densely packed that foods such as grapefruit, coffee and dark green vegetables were overwhelmingly bitter. According to Bartoshuk, who uses a compound known as PROP (a thyroid medication) in her studies, the world falls into three groups: 25 percent nontasters, 50 percent medium tasters and 25 percent supertasters.

What’s the significance of her results? “The taste world you live in affects your food preferences,” she says. “The foods you choose to eat are associated with risk factors, and there are consequences to eating a high-sweet, high-salt, low-fiber diet. Being a supertaster also predisposes you to oral pain, another area we’re investigating.” Bartoshuk and her colleagues developed a taffy containing capsaicin, the substance that gives jalapeño peppers their fire, and proved it effective in relieving oral pain in cancer patients.

Long-standing research by taste scientists has established links between taste and sexual maturation (girls who are tasters mature six months earlier, on average, while boys are delayed six months), depression (tasters are more prone) and alcoholism (nontasters are more at risk). But those studies predate the discovery of the supertaster. “There’s work to be redone,” says Bartoshuk, “and there are many other avenues still not explored.” A colleague is working out the molecular biology of PROP sensitivity, a step forward that may lead to new pain therapies and a better understanding of taste disorders, diet and nutrition.