"Bitter" Taste Sense Contributes to Immune Defense

As children, we all learned about the 4 different taste qualities the human tongue can appreciate: salty, sugar, bitter, and sour. Savory or umami was added in 1985. "Calcium" has been proposed in 2008 as well as more recently, "fatty" taste.

However, we are slowly learning that "taste" is much more complex than simply the ability to perceive the taste qualities associated with food.

That tongue map we all memorized in elementary school? It's a lie... Read more here.

But even cooler... the "bitter" taste may actually help fight infections!

University of Pennsylvania researchers have discovered that the bitter taste receptor T2R38 also participates in upper airway immune defense.

They demonstrated that the T2R38 receptor was expressed in the upper respiratory tract lining and could be activated by molecules (acyl-homoserine lactone) secreted by Pseudomonas aeruginosa and other gram-negative bacteria (staph and strep are gram-positive bacteria). When the receptor is activated, it stimulates muco-ciliary clearance and initiates direct cellular antibacterial effects.

Furthermore, small mutations in the T2R38 gene had a direct influence on the frequency of bacterial sinus infections.

These findings may explain WHY some patients are more prone to getting infections versus another patient... It's because of their bitter taste receptor!

Reference:
T2R38 taste receptor polymorphisms underlie susceptibility to upper respiratory infection. J Clin Invest. doi:10.1172/JCI64240.