The Dangers of Aspartame
The Artificial Sweetener Aspartame: Safe or Not?

The Dangers of Aspartame
The Artificial Sweetener Aspartame: Safe or Not?

Aspartame (or APM) is an artificial, non-saccharide sweetener used as a sugar substitute in some foods and beverages. The most notable name brand of aspartame is Nutra-sweet.

In the European Union, it is codified as E951. Aspartame is a methyl ester of the aspartic acid/phenylalanine dipeptide.

It was first synthesized in 1965. The safety of aspartame has been the subject of several political and medical controversies, Congressional hearings and internet hoaxes since its initial approval for use in food products by the U.S. Food and Drug Administration (FDA) in 1974.

A 2007 medical review on the subject concluded that "the weight of existing scientific evidence indicates that aspartame is safe at current levels of consumption as a non-nutritive sweetener".

However, because its breakdown products include phenylalanine, aspartame must be avoided by people with the genetic condition phenylketonuria (PKU).

Aspartame is a methyl ester of the dipeptide of the natural amino acids L-aspartic acid and L-phenylalanine. Under strongly acidic or alkaline conditions, aspartame may generate methanol by hydrolysis. Under more severe conditions, the peptide bonds are also hydrolyzed, resulting in the free amino acids.

There are two approaches to synthesis which are used commercially. In the chemical synthesis, the two carboxyl groups of aspartic acid are joined into an anhydride and the amino group is protected by a compound that will prevent further reactions of that group.

Phenylalanine is methylated and combined with the N-protected aspartic anhydride, then the blocking group is removed from aspartic acid by acid hydrolysis. 

Aspartame (E951) is an artificial sweetener, used in over 6000 products. The food industry claims that aspartame helps in losing weight, but why is obesity then becoming such an ever increasing problem?

The drawback of this technique is that a byproduct, the bitter tasting β-form, is produced when the wrong carboxyl group from aspartic acid links to phenylalanine. A process using an enzyme from Bacillus thermoproteolyticus to catalyze the condensation of the chemically altered amino acids will produce high yields without the β-form byproduct.

A variant of this method, which has not been used commercially, uses unmodified aspartic acid, but produces low yields. Methods for directly producing aspartyl-phenylalanine by enzymatic means, followed by chemical methylation, have also been tried but not scaled for industrial production.

Aspartame, Brain Cancer & the FDA Approval Process

The approval of the artificial sweetener aspartame (E951) was the most contested in FDA history. The approval was not based on any scientific grounds but was granted due to political and financial pressure.

Aspartame was first 'discovered' in 1965 by Searle, a drug company based in Chicago. The FDA finally approved aspartame in 1981, even though scientific research had clearly shown that aspartame caused brain cancer in lab animals.

The tests that Searle used to determine the so-called safety of aspartame were severely flawed. Searle used unscientific lab practices, falsified data and withheld crucial information during the FDA approval process.

Because aspartame caused brain tumors in laboratory animals, it poses a real cancer risk to humans as well. Cancer is increasing in western countries and will soon be the leading cause of death.

Aspartame (E951) is now being used in over 6000 products and millions of people worldwide use the sweetener on a daily basis. In addition to causing cancer, aspartame also causes many other health problems including epilepsy, migraines, diabetes, obesity, brain disorders, ADHD, ADD, MS, etc.

The US Department of Health has recorded 92 symptoms following complaints about aspartame. In fact, over 80% of all complaints filed with FDA are aspartame related.

Aspartame is an artificial sweetener and is approximately 200 times sweeter than sucrose, or table sugar.

Due to this property, though aspartame upon metabolism produces 4 kilocalories of energy per gram, the quantity of aspartame needed to produce a sweet taste is so small that its caloric contribution is negligible.

The taste of aspartame and other artificial sweeteners differ from that of table sugar in the times of onset and how long the sweetness lasts, though aspartame comes closest amongst artificial sweeteners to sugar's taste profile.

The sweetness of aspartame lasts longer than sucrose, so it is often blended with other artificial sweeteners like acesulfame potassium to produce an overall taste more like sugar.

Aspartame can be synthesized from its constituent amino acids, L-phenylalanine and L-aspartate.Like many other peptides, aspartame may hydrolyze (break down) into its constituent amino acids under conditions of elevated temperature or high pH.

This makes aspartame undesirable as a baking sweetener, and prone to degradation in products hosting a high-pH, as required for a long shelf life.

The stability of aspartame under heating can be improved to some extent by encasing it in fats or in maltodextrin. The stability when dissolved in water depends markedly on pH. At room temperature, it is most stable at pH 4.3, where its half-life is nearly 300 days. At pH 7, however, its half-life is only a few days.

Most soft-drinks have a pH between 3 and 5, where aspartame is reasonably stable. In products that may require a longer shelf life, such as syrups for fountain beverages, aspartame is sometimes blended with a more stable sweetener, such as saccharin.

Aspartame's major decomposition products are its:
  • cyclic dipeptide (diketopiperazine form),
  • the de-esterified dipeptide (aspartyl-phenylalanine),
and its constituent components:
  • phenylalanine,
  • aspartic acid,
  • and methanol.
At 180° C, aspartame undergoes decomposition to form a diketopiperazine (DKP) derivative.

In products such as powdered beverages, the amine in aspartame can undergo a Maillard reaction with the aldehyde groups present in certain aroma compounds.

The ensuing loss of both flavor and sweetness can be prevented by protecting the aldehyde as an acetal. Descriptive analyses of solutions containing aspartame report a sweet aftertaste as well as bitter and off-flavour aftertastes.

Aspartame was discovered in 1965 by James M. Schlatter, a chemist working for G.D. Searle & Company. Schlatter had synthesized aspartame in the course of producing an antiulcer drug candidate. He accidentally discovered its sweet taste when he licked his finger, which had become contaminated with aspartame, to lift up a piece of paper.

In 1975, prompted by issues regarding Flagyl and Aldactone, a U.S. FDA task force team reviewed 25 studies submitted by the manufacturer, including 11 on aspartame. The team reported “serious deficiencies in Searle’s operations and practices".

The FDA sought to authenticate 15 of the submitted studies against the supporting data, in 1979 the Center for Food Safety and Applied Nutrition (CFSAN) concluded that, as any problems with the aspartame studies were minor and did not affect the conclusions, the studies could be used to assess aspartame's safety.

In 1980, the FDA convened a Public Board of Inquiry (PBOI) consisting of independent advisors charged with examining the purported relationship between aspartame and brain cancer. The PBOI concluded that aspartame does not cause brain damage, but it recommended against approving aspartame at that time, citing unanswered questions about cancer in laboratory rats.

Citing data from a Japanese study that had not been available to the members of the PBOI, and after seeking advice from an expert panel that found fault with statistical analyses underlying the PBOI's hesitation, yet argued against approval, FDA commissioner Hayes approved aspartame for use in dry goods.

In 1983, the FDA further approved aspartame for use in carbonated beverages, and for use in other beverages, baked goods, and confections in 1993.

In 1996, the FDA removed all restrictions from aspartame, allowing it to be used in all foods. Several European Union countries approved aspartame in the 1980s, with EU-wide approval in 1994. The European Commission Scientific Committee on Food reviewed subsequent safety studies and reaffirmed the approval in 2002.

The European Food Safety Authority reported in 2006 that the previously established Acceptable Daily Intake was appropriate, after reviewing yet another set of studies.

Upon ingestion, aspartame breaks down into natural residual components, including aspartic acid, phenylalanine, methanol, and further breakdown products including formaldehyde and formic acid, accumulation of the latter being suspected as the major cause of injury in methanol poisoning. Human studies show that formic acid is excreted faster than it is formed after ingestion of aspartate.

In some fruit juices, higher concentrations of methanol can be found than the amount produced from aspartame in beverages. High levels of the naturally-occurring essential amino acid phenylalanine are a health hazard to those born with phenylketonuria (PKU), a rare inherited disease that prevents phenylalanine from being properly metabolized.

Since individuals with PKU must consider aspartame as an additional source of phenylalanine, foods containing aspartame sold in the United States must state "Phenylketonurics: Contains Phenylalanine" on their product labels.

In the UK, foods that contain aspartame are legally required by the country's Food Standards Agency to list the chemical among the product's ingredients and carry the warning "Contains a source of phenylalanine" – this is usually at the foot of the list of ingredients.

Manufacturers are also required to print '"with sweetener(s)" on the label close to the main product name' on foods that contain "sweeteners such as aspartame" or "with sugar and sweetener(s)" on "foods that contain both sugar and sweetener".

Aspartame has been the subject of several controversies and hoaxes since its initial approval by the U.S. Food and Drug Administration (FDA) in 1974. Critics allege that conflicts of interest marred the FDA's approval of aspartame, question the quality of the initial research supporting its safety, and postulate that numerous health risks may be associated with aspartame.

The validity of these claims has been examined and dismissed. In 1987, the U.S. Government Accountability Office concluded that the food additive approval process had been followed properly for aspartame.

Aspartame has been found to be safe for human consumption by more than ninety countries worldwide, with FDA officials describing aspartame as "one of the most thoroughly tested and studied food additives the agency has ever approved" and its safety as "clear cut".

The weight of existing scientific evidence indicates that aspartame is safe at current levels of consumption as a non-nutritive sweetener.