Researchers Differ Over Long-Range Effects of Sweetener

NutraSweet--the trade name for aspartame, an artificial sweetener packaged under the name Equal--has recently been approved for use in six additional categories including frozen desserts, flavored milk beverages, fruit wine beverages and yogurt products, joining the 1,200 products already using aspartame.

Despite widespread use of aspartame, controversy over its safety has left a murky residue that may take time to settle, if at all.

“Aspartame took 17 years to petition successfully (for home use) to the Food and Drug Administration, and it is one of the most thoroughly tested food substances on the market, with more than 100 tests done to assure its safety,” said Janet Klich, media representative for NutraSweet Center in Illinois. “We’ve even gotten a clean bill of health after we subjected anecdotal criticisms to scientific scrutiny.”

Aspartame, the methyl ester of the amino acids phenylalanine and aspartic acid, is about 180 times sweeter than sugar. Because only a small amount of aspartame is required to provide the sweet taste of sugar, it has been used to successfully mimic the taste of sugar in numerous products while substantially lowering the caloric content of these products.

However, some of the major safety concerns voiced about aspartame in the past are still stirring. These concerns center on several health risks, primarily the inability of certain adults and children with phenylketonuria (PKU) to metabolize phenylalanine correctly, thus causing a brain dysfunction resulting in epileptic seizures and risks of retardation to offspring.

The potential for the phenylalanine component in NutraSweet to affect brain function has, according to the NutraSweet Co., been “thoroughly examined by medical and regulatory authorities in the United States and Europe.”

But Dr. Richard Wurtman, mood and behavior specialist at the Massachusetts Institute of Technology, questions the FDA’s wisdom in approving the sweetener in the preface to the recently published “Dietary Phenylalanine and Brain Function,” edited by Wurtman and Eva Ritter-Walker (Birkhauser). In it he describes that sweetener as one that “beside being neurotoxic in high concentrations, can, in concentrations much lower than those associated with clinical PKU, affect production of neurotransmitters and thereby modify any of the numerous brain functions that depend on these compounds.”

In the same publication, which contains manuscripts and papers presented at a conference on dietary phenylalanine and brain function in Washington in May, 1987, Louis Elsas of Atlanta’s Emory University reported on aspartame-controlled studies on human volunteers showing changes in brain wave function. The scientific findings reported in the book include further evidence of epileptic seizures and brain damage in rats, human metabolic and electrophysiological changes as well as other studies showing no evidence of damage following ingestion of aspartame and phenylalanine.

In a letter to the editors of the New England Journal of Medicine (Volume 318, No. 19, 1988), Elsas called for a “more unbiased peer review of clinical research protocols, claiming that the NutraSweet Co., which supported this experimental design (showing that aspartame was safe), may have had an interest in protocols that would find that their product had no untoward effects.”

According to Klich, there is a blood-to-brain selective barrier for substances entering the brain. “The likelihood of phenylalanine levels rising is not likely and has not been seen in studies,” she said.

William M. Pardridge MD, of the UCLA School of Medicine, described in a letter to the editor of the Journal of American Medical Assn. (Nov. 21, 1986) how easy it is for children in particular to consume dangerous amounts of aspartame. Because of their lower body weight, children consuming adult-size quantities of the sweetener achieve far higher blood concentrations. In fact, as few as five servings of products containing NutraSweet can impair brain function in a 50-pound child, according to Pardridge.

Pardridge holds to the theory to this day. “That’s still my theoretical argument based on basic research on animals,” he said.

The Centers for Disease Control evaluated consumer reports on various symptoms, including seizures, and concluded that NutraSweet “was unlikely to act as a trigger for seizure activity,” but they could not rule out the possibility of a relationship.

The FDA relied on CDC reports and said that they interviewed hundreds of individuals with PKU reactions before approving use of aspartame for general consumption. According to Gordon Scott, media spokesperson for the FDA in Los Angeles, persons with PKU (a disease diagonsed in infancy) “must markedly reduce consumption of protein foods containing phyenalaline.” For this reason products containing asparatame must by law be labeled with the warning, “Phenylketonurics: Contains Phenylaline.”

The Epilepsy Institute recently investigated the allegation that NutraSweet was associated with seizures and found aspartame to be safe for people with epilepsy.

Other criticism centers on possible effects of methanol when used with aspartame. The methanol resulting from the hydrolysis of aspartame is oxidized to formaldehyde by alcohol dehydrogenase. According to Joe Stroop, director of media relations at NutraSweet Co. in Deerfield, Ill., critics of aspartame expressed concern that the bond that holds two amino acids together is not a heat-stable bond and would break down in high storage temperatures (as in soft drinks) into individual amino acids and methanol, which, say the critics, cause blindness in toxic amounts.

“The criticism is not valid because no one could ingest enough aspartame to cause harm. Based on body weight, the average person consumes about 50 milligrams per kilogram of body weight per day. Put in useable terms, a person weighing 132 pounds would have to consume 86 packages of Equal to approach overdose,” Stroop said.

“You would have to drink 700 cans of diet soft drink with NutraSweet at one time to get an overdose,” Stroop said. A can of aspartame-sweetened soda contains about the same amount of methanol as a banana and less than many fruit juices. “In fact,” Stroop said, “there is six times more methanol in a can of tomato juice than in a soft drink.”

Aspartic acid, one of the two amino acids in aspartame, was feared to induce fetal damage in human offspring. Laboratory tests on pregnant animals concluded that intake levels at least three times the 99th percentile of the projected daily intake of aspartame showed no evidence to suggest a risk to the fetus from the aspartic acid, methanol or phenylalanine.

What is the consumer to think?

The FDA, the conscience and big brother of the consumer, has given the green light to consumers as well as to manufacturers seeking sweet alternatives to sugar.

Dietetic Assn. Concern

Adding a wary voice to the question of aspartame is the American Dietetic Assn., which expressed concern about the long-term use of aspartame. “Even though studies support its safety, we still do not know what the long-term effect will be,” said Rita Storey, media representative for the American Dietetic Assn., a nonprofit organization of registered dietitians.

Another concern, according to Storey, is that foods to which NutraSweet has been added do not generally carry other nutrients. “These foods tend to be devoid of other nutrients. The consumer selects them because they are low in calories, therefore diluting their overall nutrient intake. What I see happening, especially among families and mothers of teen-age children, is that they are allowing their children to choose these kinds of foods in lieu of more nutritious fruit, vegetables and whole-grain products. The danger, therefore, is that these young people are setting themselves up for marginal nutrition,” Storey said. “We are concerned that young people are moving toward these highly processed and highly advertised foods and substituting them over the more nutritious foods that should make up the bulk of the young and adult diet, yet rarely get the attention of the consumer because they are not advertised.”

Storey advises consumers to read labels and be aware of the frequency of use of these non-nutritive products, particularly if children are consuming them. Childrens’ lower body mass and higher need for nutrients could spell nutritional danger in the long haul, according to Storey. Moderation, she thinks, is the key.

If you do use the artificial sweetener, you will find that NutraSweet is available only under the brand name Equal for consumer use. The contents--most of it made up of bulking agents--include (in order of highest amount present) dextrose, NutraSweet, silicon dioxide, cellulose (fillers) and calcium phosphate.

A granular package of Equal yields four calories and less than one gram carbohydrates. The sweetening equivalent of Equal is two teaspoons sugar. In other words, six packages of Equal are equivalent to cup sugar and 24 packages are equivalent to one cup sugar.

NutraSweet’s success is based mainly on taste. “The taste is much like sugar, with none of the metallic aftertaste associated with other sweeteners,” Klich said.

An advantage of using NutraSweet in beverages or cooked foods requiring sweetening is the calorie savings, the company points out. “Using NutraSweet results in a saving of 67 calories per serving over the same recipe for cranberry relish made with sugar,” Stroop explained.

NutraSweet can also be used by diabetics and persons on low-sodium or carbohydrate-restricted diets. One can use NutraSweet like sugar to sweeten hot and cold beverages, cereals and fruit. NutraSweet can be used in many recipes calling for sugar, but cannot replace sugar in baked goods because it does not provide the bulk and structure of sugar. In addition, prolonged exposure to oven or range heat will result in loss of sweetness. Food manufacturers are presently in search of a bulking agent to use in conjunction with NutraSweet to formulate products such as cake mixes, according to Klich.

However, NutraSweet can be added to heated recipes after cooking.

For instance, NutraSweet can be added to puddings or custards made on top of the stove by being stirred into the mixture after cooking is completed. It can be used to sweeten no-bake graham cracker crusts and sweeten fillings for prebaked pie shells. It can be sprinkled over muffins, breads and baked fruits after these are removed from the oven.

For a quart of ice coffee or tea, six packages of the NutraSweet product--equivalent to cup sugar--can be used.

Questions about Aspartame can be directed to a NutraSweet-sponsored hot line, (800) 321-7254, which operates between 9 a.m. and 3 p.m., Central Standard Time. Operators will answer questions on the use of aspartame and its composition and will supply articles and recipe booklets.

The booklet contains tables of equivalents, recipe ingredient alternatives and other tips. There are recipes for appetizers, salads, entrees and desserts.

Here are some of the recipes that use Equal in cooked foods.