The Olfactory Factor

By Sarah Mahoney

Certain odors have a profound effect on memory, mood, energy, libido--even overall health. Here's what the latest research found and how to use it to your advantage

The smell of baby powder. Or pool chlorine, freshly grated nutmeg, an ocean breeze. We all have a cache of fragrant memories stored in our brains, and just a whiff of a special scent can evoke a happy, magical moment.

As it turns out, the influence of smells, especially ones we link to specific times and events, is more significant than previously thought. Neuroscientists are learning that the human sense of smell, while pitiful compared with that of the average hamster, a German shepherd, or our cave-dwelling ancestors, is a powerful asset--10,000 times more precise than our sense of taste, and capable of recognizing thousands of aromas. Originally designed to alert us to such dangers as smoke, poison, and a lurking predator, odor now serves a thoroughly modern utility: New research shows it can lower our stress levels, improve mental and physical performance, ease pain, end insomnia, and even help us lose weight.

The process is complex. We have several hundred types of smell receptors, and millions of these cells line our nasal passages. Once a cell detects a scent, it shoots the information to the olfactory bulb--a pea-size cluster of neurons in the brain. The signals are sorted and then relayed to the limbic system. This primitive part of the brain governs many memories and emotions; some of our most basic behaviors--feeding, fighting, or fleeing, for example; as well as sexual arousal, pleasure, and maybe even addiction. Because of their close proximity, the neurological controls for these behaviors often become entangled. That's why, for instance, during the early stages of attraction, dinner is often a prelude to sex.

Recently, researchers discovered how a particular fragrance can change your mood. In a brand-new study from Ohio State University, they exposed subjects to two fragrances--lavender, which is known to have a calming effect, and lemon, which many studies have shown to be invigorating. Subjects were then told to sniff these before and after a mildly stressful event (in this case, after putting a foot in freezing water).

In tests that followed, the scientists uncovered "robust evidence that lemon oil reliably enhances positive mood." In fact, blood levels of an energizing hormone, nor epinephrine, spiked and stayed high for the subjects who smelled the lemony scent, while the lavender sniffers got no boost.

But research shows that fragrance has benefits well beyond a simple mood lift. Special aromas can also help you:

Lose weight

In a new study, 1,436 overweight people lost an average of 30.5 pounds over 6 months, just by sprinkling intensely scented crystals on their food (the researchers used flavors such as taco, pizza, and Parmesan cheese). "We're not sure of the precise mechanism," says Alan Hirsch, MD, founder of the Smell & Taste Treatment and Research Foundation in Chicago, which conducted the study. "But clearly, satiating your odor and taste receptors can play a key role in weight loss."

Try this: Hirsch says you can achieve "smell satiety" simply by making an effort to savor every bite before you put it in your mouth.