The vital role taste plays as the body's gatekeeper has been highlighted in a new study from the Monell Center.
It has shown that strong bitter taste can cause people to both report the sensation of nausea and display a pattern of stomach activity characteristic of actual nausea.
"Nausea is a huge negative modulator of quality of life for many people, including pregnant women, patients undergoing chemotherapy, and virtually all types of GI patients," said senior author Paul A.S. Breslin, a sensory scientist at Monell.
"Our findings may help clinicians ease suffering in these patients by advising them to avoid strongly bitter foods," added Breslin.
The findings demonstrate that our bodies anticipate the consequences of food we eat. It was already known that the taste of nutrients such as sugars and fats causes the body to release hormones in preparation for digestion and metabolism. The current study reveals that the body also responds to the taste of possible toxins.
Bitter taste is thought to have evolved to signal the potential presence of toxins, which are abundantly present in plants.
Breslin believes that strong bitter taste causes the bad feeling of nausea "to punish us so that we won't eat that toxin again."
Thus nausea serves to distinguish the everyday bitterness of foods like coffee, chocolate, and beer from the very strong bitterness of potentially poisonous substances.
"This is a wonderful example of what is called 'the wisdom of the body,'" said Breslin.
"The findings show that taste detects toxins before they enter our bodies. Further, their ingestion is punished by the feeling of nausea and our gastric function is disturbed to minimize their entry into our blood," added Breslin.
The study has been published in Current Biology.