YPSILANTI – It’s a key element in ever-present food items such as potato chips, bacon, shrimp, pizza and soup. It is also one of the oldest known preservatives, and in that sense has certainly benefitted humanity.
“Indeed, sodium is essential to life,” says Joseph Breza, an associate professor of Neuroscience at Eastern Michigan University. Because of this, there is an innate drive among humans to consume it.
“In developed countries, the majority of sodium is consumed through processed foods, which are high in sodium content. As a result, humans in industrialized countries consume far more than the recommended amount of sodium, and this is associated with numerous health risks, such as hypertension and stroke.”
With that in mind, Breza and other EMU researchers have sought to identify how the nervous system responds to salt and drives behavior, acknowledging that salt is a fundamental component of our diet, but that the receptor cell associated with sodium detection remains unidentified.
“By identifying how the nervous system responds to salt and drives behavior, we have essentially identified an important biological target,” he says.
“The ultimate goal would be to enhance the way that the brain processes salt taste without added sodium. The ability to do that would reduce the amount of sodium in foods and save the billions of dollars in salt-related health consequences that result from ingesting too much sodium.”
Mice with an appetite for salt
Breza and colleague Thomas Mast, an associate professor of Neurobiology at Eastern, and a team of undergraduate and graduate students used a genetic technique to modify Type I glial like taste bud cells in mice so that the taste cells responded to light.
In these genetically modified mice, light stimulation of the tongue preferentially activated sodium-sensitive taste neurons. The genetically modified mice voraciously drank illuminated water when they were in a sodium-depleted state.
“Collectively, these data shed light on the role of Type I taste cells and the sensation of sodium taste,” Breza said.
The research was sponsored by the National Institute on Deafness and Other Communication Diseases of the National Institutes of Health, with a grant of nearly $430,000. The findings will be published in JNeurosci, the Journal of Neuroscience, the top publication in the field.
Seeking a flavor experience
Breza and Mast received their doctorates in neuroscience from Florida State University, a program known for its expertise in chemosensory systems.
Breza, who has been at EMU six years, is coordinator of the Experimental Master’s Program in Psychology at Eastern. Mast has been at EMU for seven years and is the premed and neuroscience advisor.
Both Breza and Mast are founding members of the undergraduate Neuroscience Program and have published several articles together on the neural mechanisms of taste sensation. A major driver for them is to understand the neural mechanisms of taste and smell, as nutrient intake is intimately related to human health and disease.
“The modern human diet is laden with salt, and we have developed an appetite for it,” Breza says. “Sodium increases the palatability of foods and food is certainly an important aspect of our lives.
“We derive a certain amount of pleasure associated with food, and we are willing to pay good money to go to a restaurant (certainly in pre-COVID days) and have a flavor experience. Restaurant cuisine is often high in sodium, as it brings out the flavors of other foods. It’s why we go there – for the flavor experience.
“It would certainly benefit human health if we could reduce sodium content without reducing food palatability – but we still have much to uncover before we can achieve that goal.”
About Eastern Michigan University
Founded in 1849, Eastern is the second oldest public university in Michigan. It currently serves nearly 18,000 students pursuing undergraduate, graduate, specialist, doctoral and certificate degrees in the arts, sciences and professions. In all, more than 300 majors, minors and concentrations are delivered through the University's Colleges of Arts and Sciences; Business; Education; Engineering and Technology; Health and Human Services; and, its graduate school. EMU is regularly recognized by national publications for its excellence, diversity, and commitment to applied education. For more information about Eastern Michigan University, visit the University's website.