Many people think that smells even have the power to shape health. They light vanilla candles, burn jasmine incense and pour lavender into their baths in search of relaxation, stress reduction and protection against illness.
Of all the scents used in aromatherapy, lavender holds a prestigious place. It's been around for ages, and it's still extremely popular. Whether you're browsing online or shopping at a health food store, you'll have no trouble finding more lavender than your nose could ever stand.
You can buy large lavender aromatherapy candles for about $40. A small half-ounce vial of essential oil to dab on your skin or pour into your bath will cost about $10. For $20, QVC will sell you a lavender-scented aromatherapy shawl to wear after a shower. Other options include lavender-infused lotions as well as pillows and toy bunnies stuffed with the dried flowers.
The claims: Lavender is often promoted as a remedy for stressful, hectic lives. Two fairly typical examples: Lavender Fanatic, a website selling a wide variety of lavender products, claims that the scent creates "instant calm and relaxation." The same site also says that aromatherapy can treat anxiety, depression, insomnia and headaches. Another site, Essentials-of-Aromatherapy, claims that lavender and other aromatherapy scents can stimulate the immune system, energize the body and ease inflammation. Potential customers are assured that "aromatherapy is a great, natural complement or alternative to other health treatment options such as certain prescribed medications."
The bottom line: Charles Wysocki, a researcher with the Monell Chemical Senses Center in Philadelphia and an expert in the science of smells, has one positive thing to say about aromatherapy: "The marketers do a fantastic job."
Unfortunately, he says, most of their claims don't hold up.
Though some scents -- including lavender -- may be pleasantly satisfying or even emotionally evocative, Wysocki says scent alone isn't likely to significantly improve a person's health. People who enjoy the scent of lavender may want the scent to permeate every corner of their lives. They just shouldn't expect any benefits beyond olfactory satisfaction. "There's a lot of misinformation about what odor is capable of doing. Smells don't have a magic ability to alter mood or physiology," he says.
Certainly, a fragrant bath or massage with essential oils can feel great, he adds. But it's the hot water or the masseur's fingertips -- not the odors -- that do the real work.
The few scientific studies on aromatherapy have had mixed results. A small Japanese study published in 2007 found that the scent of lavender and rosemary lowered stress hormones in saliva.
But a 2006 study conducted at an Illinois hospital found that lavender didn't reduce anxiety of patients preparing for a colonoscopy.
Lavender certainly didn't shine in a study to be published next month in the journal Psychoneuroendocrinology. Fifty-six healthy people volunteered to wear cotton balls under their noses for several hours on three different occasions. The cotton was soaked in lavender, lemon or distilled water, and volunteers had a chance to breathe in each scent.
In a questionnaire administered immediately afterward, subjects reported slightly better moods, on average, after smelling lemon. But lavender had no effect on their state of mind. In addition, blood tests showed that neither lemon nor lavender aromas stimulated the immune system (as measured by activity of the blood's T cells) or reduced levels of stress hormones. The scents didn't affect blood pressure or heart rate either.
Anecdotally, most subjects said they preferred the smell of lemon, says Janice Kiecolt-Glaser, a professor of psychiatry and lead author of the study. "People had less pleasant associations with lavender," she says -- commenting, for example, that it smelled "musty" or of "old people."
Some of the subjects believed in aromatherapy before the study, and the results didn't seem to change their minds, Kiecolt-Glaser says. At least one volunteer claimed that aromatherapy worked no matter what the tests showed.
When it comes to odors, expectations matter, Wysocki says. He once conducted a study showing that people felt ill if told they were smelling an industrial chemical. The identical smell had little effect on people who thought they were sniffing something harmless.
People who have especially high hopes for aromatherapy are the most likely to benefit, he says. For that reason, he says, the most important aromatherapy accessory isn't a spray bottle or a incense holder. "It will work best if it comes with a very effective marketing campaign."
For many people, aromatherapy comes down to one simple fact: They enjoy the fragrance. "I wear perfume because I like the smell," Kiecolt-Glaser says. "People use these products for the same reason."
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