New York, NY (February 13, 2013) For consumers of the typical Western dietladen with levels of salt detrimental to long-term healthit may be hard to believe that there is such a thing as an innate aversion to very high concentrations of salt.
But Charles Zuker, PhD, and colleagues at Columbia University Medical Center have discovered how the tongue detects high concentrations of salt (think seawater levels, not potato chips), the first step in a salt-avoiding behavior common to most mammals.
The findings could serve as a springboard for the development of taste modulators to help control the appetite for a high-salt diet and reduce the ill effects of too much sodium. The findings were published today online in Nature.
The sensation of saltiness is unique among the five basic tastes. Whereas mammals are always attracted to the tastes of sweet and umami, and repelled by sour and bitter, their behavioral response to salt dramatically changes with concentration.
"Salt taste in mammals can trigger two opposing behaviors," said Dr. Charles Zuker, professor in the Departments of Biochemistry & Molecular Biophysics and of Neuroscience at Columbia University College of Physicians & Surgeons. "Mammals are attracted to low concentrations of salt; they will choose a salty solution over a salt-free one. But they will reject highly concentrated salt solutions, even when salt-deprived."
Over the past 15 years, the receptors and other cells on the tongue responsible for detecting sweet, sour, bitter, and umami tastesas well as low concentrations of salthave been uncovered largely through the efforts of Dr. Zuker and his collaborator Nicholas Ryba from the National Institute of Dental and Craniofacial Research.
"But we didn't understand what was behind the aversion to high concentrations of salt," said Yuki Oka, a postdoctoral fellow in Dr. Zuker's laboratory and the lead author of the study.
|Contact: Karin Eskenazi|
Columbia University Medical Center