A Matter of Taste (and Smell): Latest Research in Chemoreception

Do chemical cues actually regulate social behavior? How does our brain distinguish between different tastes? Why do men and women experience the sense of smell differently? Can the obesity epidemic be blamed on our love of the taste of fat?

A special new online meeting supplement to the Annals of the New York Academy of Sciences, “Chemoreception Scientists Gather under the Florida Sun: The 31st Annual Association for Chemoreception Sciences Meeting” explores these and other provocative questions.

This report summarizes key research presented at the 31st Annual Association for Chemoreception Sciences (AChemS), in Sarasota, Fla. April 22–26. Authored by AChemS President Donald A. Wilson of New York University, and colleagues, the report highlights both basic and applied research in the chemical senses, emphasizing “central and peripheral processing of gustatory, olfactory, pheromonal, and common chemical stimuli, such as irritants.” It focused on the “growing importance of understanding chemical senses in the identification, treatment, or prevention of health-related issues, such as obesity and Alzheimer’s disease.”

The section on “Gender and Chemosensation,” for example, describes progress in understanding gender differences in the sense of smell. “Molecular and neural mechanisms that underlie most sensory processing are thought to be equivalent between males and females,” the report says. “An exception lies in the sensory response to chemical cues that regulate innate social behavior.”

Other research on genes and behavior in rodents and humans provides intriguing support for the idea that fat, “specifically free fatty acid, can activate the gustatory system.” This is consistent with the conclusion that along with the tastes of sweet, sour, salty, bitter and umami (detection of the carboxylate anion of glutamic acid), there might be a “taste of fat.” Such work challenges “the longstanding notion that pure fat was tasteless and that its only salient cue was its texture.”

The section “Primary Taste and Olfactory Processing Networks” describes recent data indicating that early taste and olfactory regions are influenced by, and might themselves directly influence, top-down processes. In other words, brain processes, such as expecting something will taste a certain way, can “markedly affect subjects’ perceptual judgments” of food, the authors note.

The report accompanies a July Annals volume of the proceedings at the “International Symposium on Olfaction and Taste”, held in San Francisco in July 2008. The volume offers an up-to-date review of research in the areas of taste, smell, and trigeminal chemoreception.