Too little salt makes for a bland meal. But too much is
offensively briny. Now, scientists have discovered why too much
tastes bad. The work is in journal Nature. [Yuki Oka et al.,
High salt recruits aversive taste pathways] As the previous
podcast noted, the cells that process taste send a unique signal
to the brain for each kind of flavor. The signals for sweet and
umami make animals crave more, while sour and bitter are often
rejected. But saltiness is appealing in low doses and aversive
at high levels. The researchers found out why: too much salt
activates the cells that sense sourness and bitterness, sending
unpleasant signals to the brain and transforming a tasty bite
into a turn-off. The study used mice unable to taste sourness,
bitterness, or both. Animals that could still sense one of the
flavors rejected overly salty water. But mice unable to taste
sour and bitter were happy to lick up liquid that was far too
briny for normal animals. With salt being a variable flavor, our
bodies can better keep its