Bitter taste receptors for saccharin and acesulfame K
What it found
In lab tests, saccharin and acesulfame K switched on two human bitter taste receptors, hTAS2R43 and hTAS2R44.
In people, tasting one of these sweeteners dulled the bitterness of the other, suggesting they share the same receptors.
What they found
Studies in people
Shared receptors in people
In eight people, tasting saccharin first made acesulfame K and aristolochic acid taste much less bitter. Tasting acesulfame K first did the same to saccharin and aristolochic acid. This points to common receptors for these substances.
Bitter intensity over time
The bitterness of saccharin and acesulfame K faded to less than 10% and 7% of the starting intensity within 105 and 90 seconds, respectively. Aristolochic acid bitterness dropped to about 15% within 90 seconds.
Animal and lab studies
Receptor activation in cells
Saccharin and acesulfame K activated hTAS2R43 and hTAS2R44 in lab tests. Saccharin worked on both receptors, while acesulfame K worked strongly on hTAS2R44 and only weakly on hTAS2R43.
Sweet receptor not involved
The sweet taste blocker lactisole stopped saccharin from activating the sweet receptor hTAS1R2-hTAS1R3, but did not stop it from activating hTAS2R43 or hTAS2R44. This suggests the two bitter receptors are not part of the sweet taste of these sweeteners.
Receptors in tongue tissue
Both receptor mRNAs were found in a small number of cells in human circumvallate taste buds. This supports their role as bitter taste receptors on the tongue.
What the authors conclude
“Thus, hTAS2R43 and hTAS2R44 function as cognate bitter taste receptors and do not contribute to the sweet taste of saccharin and acesulfame K.”
Also in their conclusions
- They conclude that hTAS2R43 and hTAS2R44 function as bitter taste receptors for saccharin and acesulfame K and do not contribute to their sweet taste.
- They suggest that the bitter taste of other artificial sweeteners is likely caused by activation of other TAS2R bitter taste receptors.
- They state that the identification of these receptors is an important step toward understanding the biological function of the TAS2R gene family.
How it was done
Saccharin and acesulfame K have a bitter aftertaste that limits their use, and the mechanism behind it was unknown. The authors wanted to find the receptors responsible.
They tested saccharin and acesulfame K on human embryonic kidney cells engineered to carry 25 different human bitter taste receptors. They also had eight people rate the bitterness of saccharin, acesulfame K, aristolochic acid and salicin solutions, and measured how one taste affected the next.
What it can’t tell you
- The lab tests used engineered cells, so they cannot show exactly how the receptors behave in the human mouth.
- The study in people was small, with eight participants, and looked only at how bitterness changed over seconds, not at any long-term health effects.
- The authors note they may have missed other bitter receptors that did not work in their cell system.
Who paid
- Authors work at
- German Institute of Human Nutrition Potsdam-Rehbruecke, Germany
The paper
- Title
- Bitter taste receptors for saccharin and acesulfame K
- Type
- Study
- Evidence
- Studies in people · animals · lab
- Summarised from
- Full text
- Cite
- Kuhn C, Bufe B, Winnig M, et al (2004). Bitter taste receptors for saccharin and acesulfame K. The Journal of neuroscience. doi:10.1523/JNEUROSCI.1225-04.2004Free full textPubMed 15537898DOI
Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error