Bitter News for Tender Tongues
DENVER--Good taste is always good. But supertaste is another story. According to new research, men with an especially keen sense of taste are at heightened risk for obesity, cancer, and other serious health problems. The findings, reported here on 14 February at the annual meeting of the American Association for the Advancement of Science, which publishes ScienceNOW, are the first to indicate that individual variations in taste perception can affect diet enough to compromise health.
Researchers have long observed a wide variation in how intensely people experience bitterness and other tastes, and in people's sensitivity to the feel of fat in foods. About 25% of the population consists of "supertasters" who are three times more sensitive to bitterness and other taste sensations as people with the least taste sensitivity, known as nontasters. Most people fall in between the two extremes. These differences in taste sensitivity stem from genetic differences in the number of structures on the tongue called fungiform papillae that contain taste buds and are surrounded by pain- and touch-sensitive fibers. Supertasters boast about 10 times as many fungiform papillae as nontasters. Although researchers believe sensitivity to bitter tastes may have evolved to protect against bitter poisons, some have wondered whether supertasters' aversion to bitter--but healthful--compounds in many vegetables might predispose them to cancer and other illness.
In a study of about 200 men, Yale University psychophysicist Linda Bartoshuk and colleague Marc Basson, a gastroenterologist at Wayne State University in Detroit, found that among those age 65 and older, greater sensitivity to bitterness was associated with more colorectal polyps, precursors to colon cancer. Men with polyps also ate fewer vegetables and were more overweight--both risk factors for colon cancer--than men without polyps. In another study of almost 4000 participants, Bartoshuk and colleagues found that men--especially supertasters--with a history of ear infections were more overweight than men without such a history. Repeated infections can damage a nerve that normally keeps taste and fat sensation in check; the damage leads to greater ability to detect fat. Although the data are preliminary, Bartoshuk's group speculates that this greater sensitivity to fat may lead supertaster men, already predisposed to like fat, to eat even more of it.
The new results provide "fascinating evidence that people really are living in different taste worlds," comments Cynthia Beall, an anthropologist who studies at Case Western Reserve University in Cleveland.