Act II, Scene VII
WHAT DO TEA, beer, pomegranates, Japanese knotweed (yum), Shakespeare, futurists, and death by
E. Coli have in common? Well, I'm delighted you asked. YOU DID ASK, DIDN'T YOU? I'M SURE YOU DID.
Shakespeare, as usual, has observed everything first. In
As You Like It, Jacques the Ever Melancholic starts "The Seven Stages of Man" soliloquy with the grand line, "All the world's a stage," and ends with the depressing bit I quoted at the beginning of this blog post. He's given a depressing character an unusually depressing picture of the life of the elderly. In particular, let's pick out the lines, "sans taste, sans everything."
the bad news
Humans have only five tastes we can sense with our tongues (sweet, sour, salt, bitter, and
umami), but we can smell thousands of distinct odors. Most of what we perceive as taste is really a combination of true tastes and odors. And, wow, we sure have a variety of smells we can detect.
Elise Hancock at Johns Hopkins describes it thus:
Compared with other mammals, how well do people detect smells?
That depends what you mean by "how well." We are low on receptors: Current estimates say that humans have roughly five million olfactory receptor cells, about as many as a mouse. A rat has some 10 million, a rabbit 20 million, and a bloodhound 100 million.
"Across species, there is a relatively good correlation between the number of receptor cells and olfactory acuity," says Reed. "You can hardly find the olfactory bulb in a human brain--it's a pea-sized object. In a mouse, it's a little bigger. It's bean- sized in a rat, about the size of your little finger in a rabbit, and the size of your thumb in a bloodhound."
Oh. So our sense of smell is not very acute.
Not exactly. While we may not have the olfactory range of other creatures, the receptors we do have are as sensitive as those of any animal. Several recent papers indicate that humans are capable, at least in experimental conditions, of smelling a single molecule. If so, in that sense not even a bloodhound could hope to do better.
We can also think, making conscious (and successful) efforts to sort smells out. A trained "nose," a professional in the perfumery business, can name and distinguish some 10,000 odors. Reed says that a master perfumer can sniff a modern scent that has a hundred different odorants in it, go into the lab, and list the ingredients. "In a modest amount of time, he comes back with what to you or me would smell like a perfect imitation of that perfume. It's amazing." Similarly, using smell alone, trained wine tasters can tell you a wine's alcohol content, year of production, grape variety, and even the district in which the grapes were grown.
While a few people do have a dramatically better sense of smell, most of us probably just don't pay attention. "Noses" say that their abilities are a matter of training, in which the important thing is to practice, to make the distinctions conscious, and to attach words to each one. That makes sense, given the acute sense of smell found in the few remaining aboriginal peoples of the world, for whom smell remains a matter of survival.
Okay, so a trained
parfumeur can detect 10,000 different smells. How about the rest of us? We tend not to notice what we're trained to smell, even though we're capable of the same olfactory feats as a trained perfume designer. So far, so good, right?
Wrong.
There are dangers lurking. As our noses and tongues become less sensitive to taste and smell as we age, we are less likely to be able to detect spoiled food or other dangers (such as lurking wildebeests or falling pianos, or the presence
E. Coli, perhaps). At the University of Colorado's School of Medicine, we find that
Professor Diego Restrepo had determined the following:
We found clear changes in olfactory sensory neuron responses to odors for those 60 and up," said Professor Diego Restrepo, Ph.D., director of the Center for NeuroScience at the University of Colorado School of Medicine who led the researchers. "When we presented two different odors to the olfactory sensory neurons of younger people they responded to one or the other. The sensory neurons from the elderly responded to both. This would make it harder for the elderly to differentiate between them."
According to the study published in the latest issue of Neurobiology of Aging, those losing their sense of smell are at a higher risk of malnutrition since taste and smell are closely related, they may also be unable to detect spoiled food, leaking gas or toxic vapors.
Social Issues Research Institute tells us that people's olfactory senses tend to peak at around eight years old, and it's all downhill from there. And in people 65 and older, there's a serious drop-off in acuity in senses like smell and taste (though at all ages, women perform better than men do).
While our sensitivities to aroma and flavor do slowly deteriorate over time,
training, SIRC says, can nullify some of the effects of aging. "In their experiments on blind and sighted people, the top performers on most tests were (sighted) employees of the Philadelphia Water Department who had been trained to serve on the Department’s water quality evaluation panel. The researchers conclude that training is the factor most likely to enhance performance on smell tests. . . . The importance of ‘training’ in the development of smell-sensitivity is confirmed by many other studies. Indeed, this factor can sometimes be a problem for researchers, as subjects in repetitive experiments become increasingly skilled at detecting the odours involved."
the good news
This brings us back to our
parfumeur, who (despite not being eight years old or younger) was capable of distinguishing 10,000 different aromas. Thus, we find, it may be possible to mitigate somewhat Shakespeare's condemnation of the aged to a life
sans taste, sans everything.
In addition to the possibility that humans can train themselves to be able to taste more and more, even though biology suggests they should taste and smell less and less, we have some realistic-sounding studies about the zealously overhyped resveratol. In spite of the near-hysterical claims one sees in conjunction with this stuff found in red wines and other natural substances, there may be some modestly solid science behind the claim that resveratol may slow down the aging process and possibly the loss of acuity in the senses, as well. In
Big Red Diary, a blog about, well, wine and other red things, I found an article entitled,
"Resveratol Again." The writer quotes
Chemistry and Industry Magazine, which I have no access to, but I can give you a taste of it here.
“Resveratol in wine has been hailed as the elixir of youth and cure for many ailments. It occurs in the seeds and skins of grapes and has reputed anti-tumor, antioxidant and antimicrobial action. It has even allowed for a longer life.
Resveratol prolongs the lifespan of flies, mice and yeast, similar to the effects of a starvation diet, and is believed to work by promoting sirtuin, a protein that helps to repair chromosomes. This wonder polyphenol is more prominent in red wines and especially Pinot Noir.
Many effects were reported from lab studies where the chemical was applied in unnaturally high doses, and you would have to consume buckets of red Burgundy to get the same dose. But not to worry, since Sirtis, a company founded by Harvard University scientist David Sinclair, has begun testing mimics of resveratol. One of these mimics is called SRT1720 and was reported last month to protect mice on fatty diets from getting obese and to enhance their endurance on treadmills. It was lauded as the cure for ‚couch potatoes’. But such mimics are potentially suitable as drugs since they activate sirtuin 1 (SIRT1) at lower doses than resveratol.
SRT1720 tricks the body into thinking food is scarce and has to burn fat to survive. Sirtris believes resveratol mimics could potentially treat diseases such as diabetes, inflammation, cancer and heart disease. According to ceo Christoph Wesphal: ‚The body of clinical data supporting the role of SIRT1 activation as a viable mechanism for treating a broad range of diseases of metabolism and aging is growing’. The company has obviously attracted the right attention; Sirtris was acquired by GlaxoSmithKline during the summer.
Blueberries and pomegranates are good natural sources of resveratol, and it is sold in supplements derived from Japanese knotweed, though some doubt whether this source contains much active ingredient. But functional foods and drinks are another possibility. A Texan university plans to genetically modify yeast to produce the wonder compound so that beer drinkers can similarly imbibe this tonic in their favourite tipple”.
Right. So in mice and fleas and whatnot, massive doses of resveratol, or the application of artificial SIRT1720, can treat diseases of metabolism, and aging, and growing. Good news for us. Maybe. As with all these sorts of studies, one never knows whether today's science turns out to be tomorrow's old wives' tales.
and in conclusion
Tea masters don't become sensitized to the nuances of various aromas overnight. Neither do perfume makers nor workers at the Philadelphia Water Department. We can train our noses and tongues, and thus to some degree overcome the natural deterioration of our senses. Not only that, but there are some advances taking place in the world of pharmacology and undoubtedly natural food advocacy, which might turn out to allow us to taste our Darjeelings and our Dan Cong oolongs well into our 120s, without mistaking them for lighter fluid.
My advice: Drink the best stuff you can, while you are still young enough to smell and taste it. Train yourself by giving focused attention-- this is a function of the mind, not merely how many sensory cells you have operating. Pay attention to advances in the science that may help you live longer, and healthier, and keeping your faculties intact until you and this earth do part. You may not end up being a tea master, but that's not the point: You'll live fuller, more abundantly, and longer by engaging your senses and by taking advantage of the opportunities our brilliant scientists are affording us.
http://www.eurekalert.org/pub_releases/2011-11/uocd-rfe111011.php
http://www.sirc.org/publik/smell_human.html
http://www.futurepundit.com/archives/008377.html
http://www.burgundy-report.com/diary/2009/01/resveratol-again/
http://www.jhu.edu/jhumag/996web/smell.html
