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Mystery of the nose

Created date

December 21st, 2009

An accident led to the discovery of aromatherapy at the beginning of the 20th century, and the investigation of its medicinal benefits continues to stir up questions today. ... 1910, French chemist Ren -Maurice Gattefoss doused his hand in lavender oil after burning himself in a laboratory explosion. To his amazement, not even a scar remained. Thus began his research, which led him to coin the term aromatherapy and write the first of many books on the subject, published in 1937. Yet, while the chemist and ancients before him may have believed wholeheartedly in the power of essential oils (fragrant essences found in plants), just as many present-day doctors and researchers aren t convinced. We all respond to scents that s why we like nice soaps, bubble baths, and scented candles. But as far as any physical effects, I m not sure there s any good scientific evidence, says Susan Reeder, M.D., medical director at Henry Ford Village in Dearborn, Mich. I don t usually recommend it as treatment.

Shifting theories

Originally, we began with this idea that there was a lock and key model for smell, says Alan Hirsch, M.D., who founded the Smell & Taste Treatment and Research Institute in Chicago, Ill. One odor has one effect: lavender increases alpha waves in the back of the head, producing a calm state; jasmine increases beta waves in the front of the head, associated with an alert state. Over time, we developed a different theory: if you like a smell and it makes you happy, you induce a baseline [normal/healthy] state. The latest hypothesis is that essential oils effect is based on environment. Traditionally, lavender makes you more relaxed; jasmine makes you more alert. Those have been pretty well established, explains Hirsch. But if you take somebody and put them in a situation where they have to be very alert, lavender will make them more alert, as will jasmine. Alternatively, if you put the person in an environment where they are about to fall asleep, both jasmine and lavender will help them fall asleep. What this suggests is that odor makes you more susceptible to the demands of the external environment. In which case, our whole way of thinking about odors may be totally wrong.

Smell and emotion

What makes objective research on the effects of essential oils, in part, so challenging is that smell is tied to emotion. The olfactory lobe [where smell is processed] is part of the limbic system, or emotional brain. You ll smell something and immediately decide, I like it or I don t like it. Then you figure out what it is a rose or a lilac. That is totally different from the other sensory spheres. For instance, when you see a picture of a tree or horse, first you identify it; then you decide whether you like it or not, says Hirsch. Given its connection with the emotional brain where memories are stored it s not surprising that smell is the quickest way to conjure a memory. But what if the memory is a bad one, perhaps of something you would rather not recall? With recurrent exposure to a smell, you can break the connection between a smell and memory, says Hirsch. For example, your grandma smelled like lavender. Every time you smell lavender, you think of your grandma. Much less odor-associated memory occurs with things like peppermint because you re exposed to it over and over again, through things like toothpaste and gum. So by recurrent exposure to the scent in situations unrelated to the original pairing, you can lose this connection.

Loss of smell

While you might want to forget a memory, you don t want to lose smell; decreased ability to smell can cause problems with nutrition and safety. People with less acute smelling abilities tend to over-season their food. That s because about 90% of what we call taste is really smell that comes in through the mouth to the throat to the top of the nose, says Hirsch. To compensate, people may add excessive amounts of salt to their food, which can result in health problems like hypertension. Another common pattern is avoidance of leafy green vegetables, which without their sweet smell just taste bitter. Danger also is often overlooked because of a diminished sense of smell, like gas leaks and spoiled food. Half of people over 65 and three-quarters of those over 80 have lost their sense of smell. The change may be the result of a loss of nerve endings in the nose, which occurs naturally with age. An easy way to test your sense of smell is to take a bite of chocolate and vanilla ice creams and see if you can tell the difference in flavor.

Sniff therapy

What happens if you discover your sense of smell is diminished? Is it over for your nose? No, says Hirsch. We can do this sort of sniff therapy where we get patients who have lost their sense of smell to sniff their favorite odor several times a day for a few months. And oftentimes, the smell will come back for that odor. This is unlike all the other sensory spheres. People who are color-blind can go through their whole life looking at red and green and never be able to see the difference. But with people who are odor-blind [can t smell something at all], that s not true. With practice, you begin to develop the smell.