London: People who find some vegetables like sprouts and broccoli unbearably bitter are better at fighting off bugs due to chemicals in their nose, researchers say.
Experiments found that such people have more receptors that pick up the flavour of these foods and also work as an early warning system about bacterial invaders.
The researchers found that hating sprouts could actually mean you get ill less often and said that a third of people have a ``supertaster`` gene that makes sprouts taste bitter - but mean they can fight infection.
They were traditionally thought to be located only on the tongue but are now known to be in the linings of the nasal and sinus cavities as well.
These receptors are also involved in activating the body``s natural defence against common infections.
However, almost a third of the population do not have the specific version of the bitter taste receptor gene called TAS2R38 that activates an immune response.
"If you are a supertaster, it is going to be very rare you are going to get sinusitis," the Daily Mail quoted Dr Noam Cohen from the University of Pennsylvania in the United States as saying.
However, he added that this bitter-tasting ability does not protect against all infections.
For the study, the researchers grew cells in lab dishes, forming structures that resembled the multilayered lining of the nose and sinus, to test out how bitter receptors affect the initial stages of the infection process.
Chemicals produced by common bacteria called Pseudomonas aeruginosa activated the TAS2R38 bitter receptor, and caused the hair-like cilia that line the sinuses to start sweeping away microbial intruders.
The activation also resulted in the release into the sinuses of nitric oxide which kills bacteria.
The researchers looked at just one of 25 bitter receptors and it remains to be seen if the others affect the immune system.
The study also suggests that supertasters may have a higher risk of chronic sinusitis, and that non-tasters have more upper respiratory infections.
Upon testing nasal tissue samples from patients who had undergone surgery related to sinus problems, the researchers found none of the eleven supertasters had Pseudomonas bacteria in their tissues, whereas seven out of twenty non-tasters had infections.
"Certain people have strong innate defences against these bacteria, which is based on their ability to detect bitterness," New Scientist quoted Cohen as saying.
"Others who don’t really ``taste`` these bitter compounds have a weakened defence,” he added.
The study has been published in the Journal of Clinical Investigation.