Aspartame, deja vu.

Brain cancer rates jumped at about the time bottlers started adding the artificial sweetener aspartame (NutraSweet, Equal) to soft drinks, says a new study by John Olney of Washington University Medical School in St. Louis.

But the "jump" may be just a blip in a steady, 20-year climb in brain cancer. What's more, Olney claims that there was a sudden jump in cancer rates within months, or at most a year or two, after aspartame became widely available, while carcinogens ordinarily take a decade or more to cause cancer.

Twenty years ago, aspartame appeared to cause brain cancer in a rat study. But in the early 1980s, the Food and Drug Administration overruled its own expert advisory committee and approved aspartame for soft drinks and other foods. The National Cancer Institute is now studying whether people who have brain cancer were more likely to consume aspartame, use cellular phones, or do other things that might have raised their risk. What should you do until the study is done?

"While evidence of a slight increased risk of cancer is small, our advice is to consume little or no aspartame," says CSPI executive director Michael Jacobson.

"Aspartame's manufacturer, Monsanto, should sponsor independent, high-quality animal studies to determine whether or not it is safe."