Two completely different mind circuits assist regulate salt consumption, in response to a examine within the journal Cell. One adjusts salt cravings, the opposite determines whether or not we discover salty meals scrumptious or disgusting.
ARI SHAPIRO, HOST:
Meals and drinks which can be actually salty could be interesting sooner or later and off-putting the subsequent. Now scientists assume they know why. NPR’s Jon Hamilton studies on a examine that discovered two separate mind circuits that affect our style for salt.
JON HAMILTON, BYLINE: Our relationship with salt is sophisticated. Yuki Oka, a scientist at Caltech, says sodas, sports activities drinks and even faucet water all comprise a bit of salt, also called sodium chloride.
YUKI OKA: You take pleasure in low sodium water, however if you happen to think about very excessive focus of sodium like ocean water, you actually hate it.
HAMILTON: Except your physique is admittedly low on salt. That is fairly uncommon in individuals lately. However Oka says experiments with animals present that when salt ranges plummet, the tolerance for salty water goes up.
OKA: In case your physique wants sodium, then animals instantly begin liking ocean water.
HAMILTON: They crave sodium, they usually can tolerate it in excessive concentrations they’d usually keep away from. Oka needed to understand how this technique works within the mind, so he and a staff of scientists studied mice. They confirmed that one set of neurons towards the again of the mind regulates the longing for salt.
OKA: Should you stimulate these neurons, then animals run to sodium supply after which begin consuming.
HAMILTON: One other group of neurons towards the entrance of the mind usually units an higher restrict on salt tolerance, however when salt ranges get low sufficient, Oka says, these neurons get switched off.
OKA: Which means that the sodium craving and the sodium tolerance are managed by utterly various kinds of neurons.
HAMILTON: The discovering, which seems within the journal Cell, is a part of a rising area of examine known as interoception. It offers with inner sensations like starvation and ache. Stephen Liberles, a cell biologist at Harvard Medical Faculty, says scientists already know quite a bit about how the mind offers with sensory info coming from the eyes, ears, nostril and pores and skin.
STEPHEN LIBERLES: The mind additionally receives tons of sensory info from the physique, from the center, the lungs, the abdomen, the gut, and the way these work has remained extra mysterious.
HAMILTON: The brand new examine means that mind cells concerned in salt tolerance are managed by hormone-like substances known as prostaglandins. These substances, which flow into within the bloodstream, are finest identified for his or her position in inflicting irritation, fever and ache. Liberles says it now seems that prostaglandins additionally play a task in salt tolerance.
LIBERLES: So the query is, how is identical chemical, the identical prostaglandin molecule re-used throughout organic programs in several contexts?
HAMILTON: Answering that query may make it potential to develop a prostaglandin drug to discourage salt overconsumption. Nirupa Chaudhari of the College of Miami says we are inclined to eat an excessive amount of salt as a result of evolution ready our our bodies for a world through which salt is scarce.
NIRUPA CHAUDHARI: Wars had been fought over salt just some centuries in the past. So we consider sodium chloride – desk salt – as so plentiful in our food plan and in the environment however it wasn’t at all times.
HAMILTON: Chaudhari says an excessive amount of salt can result in hypertension and coronary heart illness.
CHAUDHARI: Salt ingestion is a serious concern. Calorie ingestion is a serious concern. So it turns into actually vital to know how all of those completely different programs work.
HAMILTON: She says understanding how the mind processes saltiness might assist meals firms develop a palatable salt substitute. At the very least one earlier effort failed badly.
CHAUDHARI: It tasted actually foul, so individuals did not need to use it.
HAMILTON: Chaudhari says discovering a greater choice might require extra analysis on not solely how the mind displays salt consumption however the way it interacts with our style buds. Jon Hamilton, NPR Information.
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