Aspartame Is Approved for Use in Carbonated Beverages

Date November 1983

When the US Food and Drug Administration approved the use of aspartyl-phenylalanine-1-methyl ester, known as aspartame, for use as an artificial sweetener in carbonated beverages, the popularity of the sugar substitute outweighed concerns about possible negative health effects.

Locale Washington, DC

Key Figures

• Arthur H. Hayes Jr. (b. 1933–2010), physician and commissioner of the US Food and Drug Administration
• James M. Schlatter , American chemist who accidentally discovered aspartame
• Michael Sveda (1912–99), American chemist and inventor who discovered cyclamates
• Ludwig Frederick Audrieth (1907–67), American chemist and educator who discovered cyclamates
• Ira Remsen (1846–1927), American chemist and educator whose work led to the discovery of saccharin
• Constantin Fahlberg (1850–1910), German chemist who first synthesized saccharin

Summary of Event

People have sweetened food and beverages since before recorded history. The use of honey as a sweetener dates from biblical times; other sweeteners include maple syrup (used by American Indians), cane syrup (used in the South Pacific), and granulated sugar and corn syrup. These ingredients enhanced the taste of many foods and acted as a preservative. The most widely used sweetener is sugar, or sucrose. The only real drawback to the use of sucrose is that it is a nutritive sweetener: In addition to adding a sweet taste, it adds calories. Because sucrose is readily absorbed by the body, an excessive amount can be life-threatening to diabetics. This fact alone would make the development of nonsucrose sweeteners attractive.

By the early 1980s, three common nonsucrose-type sweeteners were in use around the world: saccharin, cyclamates, and aspartame. (Sucralose, known by the trade name Splenda, would be approved for use in the United States in 1998.) Saccharin was the first of this group to be discovered, in 1879. Constantin Fahlberg synthesized saccharin based on the previous experimental work of Ira Remsen using toluene. This product was found to be three hundred to five hundred times as sweet as sugar, although some people could detect a bitter aftertaste. With the help of a relative, Fahlberg founded Fahlberg, List & Company and, in 1886, started the production and distribution of this artificial sweetener.

In 1944, the chemical family of cyclamates was discovered by Ludwig Frederick Audrieth and Michael Sveda. These compounds are only thirty to eighty times as sweet as sugar, and they have no detectable aftertaste. By the mid-1960s, cyclamates had replaced saccharin as the leading nonnutritive sweetener in the United States. Although this compound is still in use throughout the world, in October 1969, the US Food and Drug Administration (FDA) removed it from the list of approved food additives because of tests that indicated possible health hazards.

Aspartame, or aspartyl-phenylalanine-1-methyl ester, was the next artificial sweetener to be derived from natural ingredients in this case, two amino acids, one from milk and one from bananas. Discovered by accident in 1965 by American chemist James M. Schlatter when he licked his fingers during an experiment, aspartame is 180 times as sweet as sugar. In 1974, it was approved for use in dry foods such as gum and cereal and as a sugar replacement. Shortly after its approval for these limited applications, the FDA held public hearings on the safety concerns raised by John W. Olney, a professor of neuropathology at Washington University in St. Louis. There was some indication that aspartame, when combined with the common food additive monosodium glutamate (MSG), could cause brain damage in children. These fears were confirmed, but the risk of brain damage was limited to a small percentage of individuals with a rare genetic disorder. At this point, the public debate took a political turn: Senator William Proxmire charged the commissioner of the FDA, Alexander M. Schmidt, with misfeasance, or public misconduct. This controversy resulted in aspartame’s being withdrawn from the marketplace in 1975.

In 1981, the new FDA commissioner, Arthur H. Hayes Jr., reapproved aspartame for the same applications as a tabletop sweetener, as a cold-cereal additive, in chewing gum, and other miscellaneous uses. In November 1983, aspartame received final approval for use in carbonated beverages, its largest application to date. Later safety studies revealed that children with a rare metabolic disease, phenylketonuria, could not ingest this sweetener without severe health risks because of the presence of phenylalanine in aspartame. This condition occurs in individuals who have only a single copy of the phenylalanine hydroxylase gene instead of two copies. This results in a rapid buildup of phenylalanine in the blood. Laboratories simulated this condition in rats and found that high doses of aspartame inhibited the synthesis of dopamine, a neurotransmitter, which can lead to an increase in the frequency of seizures. There was no direct evidence, however, that aspartame actually caused seizures in these experiments.

Aspartame has a tendency to break down when exposed to heat. Even at room temperature, aspartame will break down; it has a half-life of 262 days. In aqueous solutions, it is most stable in a pH of 4, the acidity of vinegar.

Significance

The business fallout from the approval of a new low-calorie sweetener occurred over a short span of time. In 1981, sales of aspartame by G. D. Searle & Company (the largest supplier of the sweetener to the US market) were $74 million. In 1983, sales rose to $336 million and exceeded half a billion dollars the following year. These figures represent more than 2,500 tons of the product. In 1985, 3,500 tons of aspartame were consumed. Clearly, this product’s introduction was a commercial success for Searle. During the same period, the percentage of reduced-calorie carbonated beverages containing saccharin declined from 100 percent to 20 percent in an industry that had $4 billion in sales. Universally, consumers preferred products containing aspartame; the bitter aftertaste of saccharin was rejected in favor of the new, less powerful sweetener.

The health risks associated with aspartame are not inconsequential. As much as 2 percent of the US population has a genetic defect that hinders the efficient metabolism of phenylalanine, one of the two amino acids that make up aspartame. Phenylketonuria, a disease normally limited to infants, can lead to intellectual disabilities and seizures. The FDA has established 50 milligrams per kilogram of body weight as an “acceptable daily intake” for aspartame; the average 340-gram can of diet soda contains 200 milligrams. With moderate consumption of diet beverages, cereal, chewing gum, and other low-calorie products, it is very possible for individuals to exceed this guideline. At these levels of use, some researchers have found that test subjects, with the genetic defect that reduces the body’s ability to break down phenylalanine, exhibit slower brain wave patterns. It was also found that aspartame will lower blood pressure in laboratory animals. These mixed signals caused ambivalence among regulators.

There is a trade-off in using these products. The FDA found evidence linking both saccharin and cyclamates to an elevated incidence of cancer. Cyclamates were banned in the United States because of those studies, and the FDA tried to ban saccharin for the same reason. Public resistance to this measure caused the FDA to back away from its position. The rationale was that because diabetics and overweight people had higher health risks because of the presence of granulated sugar and corn syrup in carbonated beverages, the slight chance of contracting cancer was a risk many would choose to take.

Both the debate over and research on the possible links between aspartame consumption and cancer in humans continued into the 2020s. The International Agency for Research on Cancer, which exists within the larger World Health Organization, launched a reassessment of the sweetener and announced its findings in 2023. At that point, the agency stressed a need for ongoing research into aspartame while deciding, based on limited evidence available, to designate it as "possibly carcinogenic" to humans. Another international body, the Joint Expert Committee on Food Additives, also announced that its intake recommendation of 40 milligrams per kilogram of body weight would not change.

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