Here's a phenomenon Judy Ashby observes when she runs her Alzheimer's Association booth at health fairs around Utah: Middle-aged women tend to keep their distance and middle-aged men will make a nervous joke. "I was going to ask you a question," they'll say to Ashby, sidling up to her booth, "but now I can't remember what it is."

Baby boomers — whose senior members suddenly find themselves on the cusp of old age — are uneasy about the prospect of losing their memories, says Ashby. Meanwhile, the dietary supplement industry has jumped in to provide shelves full of antidotes with names like "Brain and Memory Tonic," and publishers have found a lucrative market with can-do books like "Total Memory Workout."

"They come in here and think they have memory loss," says Salt Lake City physician Fred Gottlieb about his patients in their 40s and 50s. "They'll forget where they put their car keys and think they have dementia." (Of course baby boomers tend to be neurotic anyway, adds Gottlieb, a boomer himself. "They take every ache and pain and every minor failing as a sign of degenerative disease or death.") The first time a boomer forgets his best friend's name, Gottlieb adds, doesn't mean it's time for a brain scan.

Doctors and researchers point out that forgetting where you've put your glasses is not a sign of dementia, but that "if you don't remember you wear glasses, that's when you have problems," as University of Utah professor Raymond Kesner says. Kesner studies the neurobiology of learning and memory.

People typically become more forgetful as they age, perhaps because of cell loss in regions like the parietal cortex, the area that helps you remember the word "cortex" instead of having your mind go blank. Free radical damage may cause some of that cell loss, says Kesner. The rest of the loss might just be chalked up to the passage of time — but that doesn't mean a person can't keep the loss at bay.

The national Alzheimer's Association has started a campaign (at www.alz.org) called "Maintain Your Brain," aimed at the very boomers who are worried (and who, coincidentally, might donate money). The association notes that the disease may be genetic and eventually inevitable for many people (currently, 50 percent of people who reach age 85 have diagnosed Alzheimer's, according to the association) but that certain life choices can delay its appearance.

Eating fruits and vegetables high in antioxidants seems to help, as does engaging in mind-stimulating activities like word puzzles or learning a new language. There is evidence, says Kesner, that brain stimulation helps the brain grow more synapses and dendrites, the information-receiving parts of neurons. Physical activity also helps to keep blood flow to the brain and to keep weight down. High weight is associated with Alzheimer's and other dementias caused by conditions such as ministrokes.