Is it safe to consume artificial sweeteners? The safety of saccharin–a calorie-fee substance with 300 times the sweetening power of sugar–has been in question since shortly after its discovery, in the late nineteenth century.
Harvey Washington Wiley, the chief of the Bureau of Chemistry in the Department of Agriculture from 1883 to 1912, asked in 1908 for a ban on the use of saccharin in foods under the authority of the Pure Food and Drugs Act of 1906. President Theodore Roosevelt, who used saccharin in a futile attempt to diminish his girth, objected, and the ban was set aside. In 1912 the government decided that saccharin could be used in products for healthy people.
Despite the government’s restriction, Monsanto Chemical Works, of St. Louis, then the country’s largest producer of saccharin, continued to make and sell the artificial sweetener for general use. The government brought charges against the company in 1916, but the case was struck from the docket in 1925, because it had become clear that no jury in St. Louis would convict Monsanto of wrongdoing.
In 1958 the Food and Drug Administration included saccharin on its famous GRAS (“generally recognized as safe”) list. Through the years saccharin was never absent from the shelves.
The first convincing evidence that saccharin poses a risk to health came in the 1970s, when studies undertaken here and in Canada showed that rats that had ingested a large quantity of the artificial sweetener developed bladder cancer at a higher than normal rate. In 1977, as a result of this finding, the FDA announced its intention to ban saccharin under the Delaney clause of the Food, Drug, and Cosmetics Act, which prohibits the sale of any food additive shown to cause cancer in test animals or human beings.
The public outcry against this decision was loud. Consumers had had to give up cyclamates, an alternative to saccharin, in 1970, when the FDA had banned the substance as a possible carcinogen. They were horrified at the prospect of having no low-calorie artificial sweetener whatsoever.
Congress quickly responded to the protest by declaring a moratorium on the ban and requiring only that saccharin and foods containing it carry warning labels. It has renewed the moratorium every two years since.
Saccharin’s rival for the market in artificial sweeteners is aspartame, the product known as Equal in its tabletop form and as NutraSweet when used by food manufacturers to sweeten processed foods and beverages. Made by the pharmaceutical manufacturer G. D. Searle & Co., aspartame has enjoyed overwhelming consumer acceptance since its approval by the Food and Drug Administration.
Aspartame contains as many calories by weight as sugar but is 180 times sweeter. Although Searle’s contention that aspartame tastes “nearly identical” to sugar is not universally accepted, the product does lack the metallic aftertaste of saccharin, and therefore many consumers prefer it. Already aspartame is being used to sweeten more than seventy products, including cereal, desserts, drink mixes, and chewing gum, many of which are clearly aimed at children.
Aspartame is composed of aspartic acid and phenylalanine, amino acids that occur naturally in many foods–in large amounts in meat, milk, and eggs. Although Searle has made much of the fact that the components of aspartame are found in protein, the claim is somewhat misleading. Although the aspartic acid and phenylalanine in aspartame have natural analogues, aspartame itself is far from a natural construct. Ordinarily, aspartic acid and phenylalanine combine with as many as eighteen other amino acids to form proteins. Because aspartame consists of only aspartic acid and phenylalanine, it delivers these amino acids in a much more concentrated form than a person would normally consume.
About one out of every sixty people carries a gene that makes phenylalanine somewhat difficult to metabolize. People with two such genes have a disease called phenylketonuria, or PKU, a rare disorder that can very quickly result in retardation if the victim consumes more than carefully controlled amounts of phenylalanine. People with PKU must avoid natural sources of protein. Aspartame is also off-limits to this group, and the labels of products that contain it are required by law to bear warnings.
Searle says in its promotional literature that “the entire family can enjoy products made with NutraSweet,” although it does caution parents of children with PKU or with one PKU gene to “consult their physicians or dieticians” before using the sweetener. Searle does not mention that screening for a single PKU gene is not at all routine or that very few of the country’s four million PKU carriers have been identified as such.
Seymour Kaufman, a biochemist at the National Institute of Mental Health, fears that pregnant PKU carries could endanger their unborn children by consuming aspartame. “There’s a bad misconception that aspartame is the same thing as protein,” he says. “The trouble is that the taking of aspartame is not at all to be equated with the eating of protein.
Phenylketonuria is believed to be the result of an imbalance of amino acids, and this can be mimicked when we take aspartame. It cannot be mimicked by eating meat.”
According to Neil Holtzman, the chairman of the Committee on Genetics of the American Academy of Pediatrics, fetuses and children under the age of six would be especially vulnerable to these effects, because their brains are still forming. In 1980, when the FDA established a board of inquiry to judge the safety of aspartame, Searle estimated that the average consumer would ingest no more than ten milligrams a day per kilogram of body weight. But in hearings on the artificial sweetener held by Congress, an attorney for the FDA said that consumption is hovering at around 30 milligrams per kilogram on average and that the FDA considers safe.
“The fact that television commercials encourage people to eat aspartame straight really drops the bottom out of the issue,” Holtzman says.
The national Centers for Disease Control reviewed more than 500 reports of such symptoms as headache, dizziness, and mood changes out of roughly 600 that had been filed by people who associated these symptoms with their consumption of aspartame. The centers concluded that a systematic clinical study of these people would be necessary to determine whether or not their complaints could be linked directly to aspartame. According to James Greene, a spokesman for the FDA, such a study is under way at Duke University, with funding from Searle.