WASHINGTON -- Despite The NutraSweet Co.'s insistence that scores of company studies have proved the sweetener is harmless, here's a sampling of the concerns from a hard core of scientific critics:
-Dr. Reuben Matalon of the University of Illinois has reported that heavy consumption of NutraSweet's main component -- the amino acid phenylalanine -- may cause neurological problems such as loss of memory and concentration. Matalon and Dr. Louis Elsas of Emory University say they fear aspartame consumption by some pregnant women can cause irreversible brain damage in fetuses. They worry most about women among an estimated 4 million to 20 million Americans who are carriers of the genetic disease phenylketonuria -- characterized by the liver's inability to process phenylalanine. While there are an estimated 20,000 to 30,000 PKU victims nationwide who are warned not to take NutraSweet, carriers - or heterozygotes -- do not have the disease and generally are unaware of their sensitivity, they said. The company has said that the Food and Drug Administration concluded 'NutraSweet did not present any additional health risk to pregnant women.'
-Dr. Paul Spiers, a clinical neuropsychologist at Boston's Beth Israel Hospital, found in a recent pilot study that, after consuming NutraSweet, some subjects with no previous problems failed to show the usual improvement in performance on cognitive tests. He plans further research.
-In St. Louis, Washington University allergist Dr. Anthony Kulczycki found that two women given NutraSweet capsules and a placebo suffered allergic reactions to NutraSweet. The women had reported hives and other skin reactions after using the sweetener.
-Dr. Donald Johns, a neurology resident at Massachusetts General Hospital, reported last year that a 'double-blind' study of a woman suffering migraine headaches showed her problems were aggravated by consumption of NutraSweet. NutraSweet, known generically as aspartame, consists of phenylalanine and another amino acid, aspartic acid, linked to a small quantity of methyl alcohol. Scientific critics seem to worry most about phenylalanine.
-Dr. Richard Wurtman, a Massachusetts Institute of Technology neuroscientist, says heavy NutraSweet consumption may so flood the bloodstream with phenylalanine that other essential amino acids are blocked from reaching the brain, causing chemical changes that can affect behavior and lower the threshhold at which many people suffer epileptic seizures. Wurtman and Dr. Donald Schomer of Harvard University are testing seizure victims who used NutraSweet, particularly some whose bodies may have trouble processing phenylalanine. The NutraSweet Co. concedes aspartame raises brain phenylalanine levels, but says no harm results and that consuming the amino acids in NutraSweet 'is just like eating other foods containing the same protein components.'
-A Wurtman protege, Dr. Timothy Maher of Massachusetts General Hospital, supported his mentor by reporting that mice given a seizure-inducing drug and NutraSweet suffered more seizures than those receiving the drug alone. Dr. Henry Haigler, a scientist in a NutraSweet Co. sister firm, said his similar study showed 'no effect on seizure threshholds.'
-Dr. William Pardridge of the UCLA Medical School, who also has done phenylalanine research, said he most fears the sweetener's effect on children, who he says are more likely to approach the FDA's acceptable daily intake level of 50 milligrams per kilogram of body weight. 'If you're a child, seven to 12 years of age, the chances are good you'll have five servings per day' -- close to the acceptable level, he said.
-Dr. Woodrow Monte, an Arizona State University food scientist, and Dr. Morgan Raiford, an ophthalmology professor at Emory, worry that a NutraSweet breakdown product, methyl alcohol, could produce severe eye damage. Last year, Raiford examined more than a half dozen persons who said they suffered eye problems after consuming NutraSweet heavily. He said he diagnosed some cases of optic nerve damage and suspects NutraSweet's methyl alcohol is the culprit. The company denies any connection between NutraSweet and eye problems.
-Dr. Sidney Wolfe, executive director of the Washington-based Health Research Group, said, 'The thing that's really worrisome is that it clearly affects brain metabolism in animals, and anyone who disputes that is irresponsible.'
-Dr. John Olney of Washington University expresses fears about brain tumors -- a problem he and other scientists say would not show up in humans for 20 years and would be difficult to trace to NutraSweet. Olney said Searle rat studies have shown conflicting brain tumor data. As early as 1971, Olney reported that aspartic acid in aspartame killed cells in the brain's hypothalamus region, which regulates glandular and hormonal functions.
