Aspartame tTOo

Feeling forgetful? You might not be having a "senior moment" after all, especially if you're a fan of diet cola.

New research suggests that people who consume a lot of the artificial sweetener aspartame -- commonly known by its brand name, NutraSweet -- are more likely to suspect they have memory problems.

But representatives of NutraSweet's maker maintain there's no evidence that the sweetener does anything to affect memory.

Because aspartame long has been blamed for memory problems, researchers at Texas Christian University decided to take another look at the sweetener and its effects on people, says Timothy Barth, a psychology professor and director of the university's neuroscience department. Previous studies, he says, had not proven a link.

"There's been this void, this big divide between what the people have said they're experiencing and what the laboratory studies have been able to show," Barth says.

The idea was to determine if aspartame users were likely to complain about memory problems or if previous reports just came from a so-called "noisy minority," he says.

Researchers questioned 90 male and female students, from age 18 to the early 30s. "You wouldn't think there would be any serious memory problems within these people," Barth says. "They're all here, getting through their courses reasonably well, at least most of them are."

Some participants were heavy users of aspartame products, such as diet colas or the sugar substitute Equal. All participants were given standard memory tests.

Responses on the questionnaires indicated that the students who used the most aspartame were the most likely to think they had problems with what's known as episodic memory.

That's the ability to remember having accomplished a task earlier, Barth says. "You might be reading an article in a newspaper and realize you already read it," he explains. "It could be that you're ready to give your child medicine, and you think you did it about 30 minutes ago."

But several things could explain why the aspartame-using students reported memory problems, he says.

"The fact that they think they have a memory problem doesn't mean they do have a memory problem," he emphasized.

n perhaps because they're more likely to be dieters trying to lose weight and more likely to criticize themselves, he says.

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"It may be that people who decide to consume aspartame are of a certain personality type," he adds. "The next series of studies will try to give tests of self-esteem and mood."

Also, he cautions that it's difficult to measure episodic memory using tests, adding that more research will need to be done in that area. Results of the latest study were presented to the Society of Neuroscience earlier this month in New Orleans.

Dr. Harriett H. Butchko, NutraSweet's vice president of medical and scientific affairs, downplayed the significance of Barth's findings, saying other, more sophisticated research has yielded different results.

"The results of [other] studies clearly demonstrated that aspartame, even in amounts well above those typically consumed from products, has no effect on memory," Butchko says.

Aspartame is digested into its three components _ the amino acids aspartic acid and phenylalanine, and methanol -- but the body gets these components in much higher quantities from ordinary foods, she says.

According to the NutraSweet company, aspartame is manufactured mainly from amino acids, which make up protein. While it has about the same caloric makeup as sugar, it is much sweeter, meaning that much less is required to sweeten a food or drink.

Paul Spiers, a neuropsychologist at the Massachusetts Institute of Technology, has studied aspartame and found no link to memory loss. One of his studies was funded by the parent company of NutraSweet, but Spiers denies any conflict of interest.

"I know from our own research that students drink aspartame when they're under stress," Spiers says. "They often drink Diet Coke for the caffeine, but don't want to gain weight. They're writing papers, and if you're writing three papers that you haven't done all semester, it's hard to keep track of what you're doing and what you're writing."

The Texas Christian University study, Spiers says, simply was not fine-tuned enough to detect whether aspartame caused the memory problems cited by students.

Regardless of whether the findings have been accepted by others, TCU students who participated in the research seem to have reached a consensus on its use in their own lives.

Diet soft drinks seem to have vanished from Barth's lab. Students simply stopped drinking them during the study, he says.

Short-term use of aspartame may be OK, he says, but studies have not investigated exposure over many years. "There is a potential [for harm] there," Barth says. "If you don't have to take that chance, why take it?"