Researchers have recently discovered taste receptors in an unlikely location: deep in our bronchial tubes, in the smooth muscle that controls air flow into the lungs. There are no other types of functional taste receptors in the lungs, just bitter detectors. After this discovery, the obvious question was, “What the hell are taste receptors doing in the lungs?” And the obvious (but wrong) answer was that since a bitter taste is often an indicator of the presence of a toxin, that those bitter receptors in the lungs must trigger a “batten down the hatches” sort of response.
The bitter-taste receptors were discovered by accident, when researchers at the University of Maryland School of Medicine were studying the lung-muscle receptors that regulate airway contraction and relaxation; these are the same muscles that contract or tighten when an asthma sufferer is having an asthma attack. After the taste-receptors were discovered lurking in the lungs, the researchers exposed bitter-tasting compounds to human and mouse airways, to individual bronchial smooth muscle cells, and to asthmatic mice.
Professor Stephen Liggett, pulmonologist and the study’s senior author said: “I initially thought the bitter-taste receptors in the lungs would prompt a ‘fight or flight’ response to a noxious inhalant, causing chest tightness and coughing so you would leave the toxic environment, but that’s not what we found.” The research team tested a few standard bitter substances such as quinine and chloroquinine, and according to Dr. Liggett, “It turns out that the bitter compounds worked the opposite way from what we thought. They all opened the airway more profoundly than any known drug that we have for treatment of asthma or chronic obstructive pulmonary disease (COPD).”
The researchers found that administering bitter substance in an aerosolized form relaxed the airways of asthmatic mice, while eating bitter foods or compounds did nothing to relax mouse airways.
Previous research has shown that some molecules produced by bacteria trigger bitter receptors. Now researchers speculate that relaxed airways may prevent lung infections from festering: “When you get a lot of gunk in there it leads to a closed airway. That would have been fatal in the days before antibiotics,” said professor Liggett.
My immediate reaction upon reading this was: “Boy, isn’t it amazing the way that our untested assumptions about biological systems almost always turn out to be wrong?” And, “Wow! We know that asthma attacks are frequently triggered by stress. Is it possible that breathing bitter aromatics might be able to give a ‘relax and calm down’ signal to our brains as well as to our bronchial tubes?”
I talked to my friend Traci about this, and she mentioned that she gets really giddy and euphoric when she processes horseradish every autumn. And I have noticed that when I ingest extremely hot Chinese mustard, it not only clears out my entire head and sinuses with a sudden WHOOSH! it also makes me a bit silly.
Several years ago we Sandbecks were in Bayfield, Wisconsin, during apple picking time, cruising the backroads for wildling apple trees. These roadside trees are the offspring of very good orchard trees, so many of these feral apples are quite delicious. We cruised from tree to tree tasting, and when we found a variety we liked, we picked until we filled up a grocery bag or box or two, then we moved along. So we were happily crunching our way from tree to tree, when Addie and I stumbled upon a truly extraordinary little apple, certainly the most memorable apple variety I have ever tasted. This apple was so extremely nasty tasting, so bitter and cardboardy, that I immediately burst into hysterical laughter, and informed Addie that she had to taste it. She did, and we both laughed until we cried. We picked a couple more, and carried our precious cargo out to the road, where Walt was talking to a man who had driven up in a pickup truck. We insisted that Walt try the apple too. The taste was lingering, and so was the euphoria. It was the best and the worst apple I’ve ever eaten. After talking to Traci about the benefits of bitter, I’m beginning to think that we made a huge mistake when we neglected to cut a few twigs of scion wood off the mother tree. We actually had the Apple of Happiness within our grasp, and we tossed it aside! Who knew?
So now I am looking for a few good women and men who are willing to try a little experiment: If you are prone to low moods, or are susceptible to Seasonal Affective Disorder (S.A.D.), would you be willing to start your day off by taking a very large whiff of horseradish, hot mustard, or some other bitter aromatic vapor of your choice? And then record the effects? And then, later in the day, if you are feeling a little low, do it again? And then report back by leaving a comment on this post.
Disclaimer: Sniffing horseradish should not be used as a substitute for professional mental health services or for prescription medication. If you are feeling very low or suicidal, please, please, please seek professional help!