No Flavor? It's Scents-less

You know how foods taste strange, or indeed, rather flavor-less when you have a head cold? Well, some people are born with a permanent genetic impairment that prevents their nose from ever picking up scents, volatile cues that are critical to experiencing a food's full flavor. Over the past year, Washington, D.C., physician Robert I. Henkin, began homing in on what underlies the problem for most afflicted individuals. Two days ago, the genial neurologist reported his findings--and a partial cure--at the Experimental Biology '07 meeting, in Washington, D.C.

For most of his patients, their scentsless existence traces to a lack of growth factors in nasal mucus. These proteins are needed to support the health of sensory cells in tissue lining the inside of the nose. In their absence, those sensory cells can become impaired or disappear, he noted.

Afflicted individuals can sense that there are odors around, and their general intensity, but can't distinguish between them, Henkin explains. Their taste buds work fine, so they can detect salt, sweet, bitter, and sour. But they'd never discern the difference between a strawberry flavor and straight sugar, because the primary berry essence is a scent.

Once he realized what was missing in the mucus, Henkin's team at the Taste and Smell Clinic began treating people with drugs--generally phosphodiesterase inhibitors--that help the body make adequate amounts of the missing proteins. Months may go by before nasal secretions become anywhere near replete enough to rescue scent-sensing cells. Once they do, his patients suddenly find themselves bathed in a complex world of strange, wondrous, and often enticing odors.

At the meeting, Henkin reported data from the first 25 patients treated. Even with long-term drug therapy, their mucus growth-factor concentrations never reached normal levels, he told me, "but they get close to it." More to the point, these people get to lead richer, safer lives. Indeed, he notes, some patients had become sickened in the past by not detecting the smell of spoiled foods.

After our talk, I tried to imagine a world devoid of the smells of coffee, chocolate, newly mown grass, or a freshly bathed infant. Who would willingly give that up?

Which explains why Henkin's patients tend to stick with their drug therapy, despite the side effects it can bring, such as increased anxiety or a racing heart rate.

Oh, he did mention one additional therapeutic drawback: weight gain. It seems that once his patients wake up the world of smells, the flavors of their foods can seduce them into downing larger portions.