E951: Aspartame

What is E951 (Aspartame)?

Aspartame (E951) is a low-calorie, high-intensity artificial sweetener discovered in 1965. It is approximately 200 times sweeter than sucrose (table sugar), allowing very small quantities to be used to sweeten foods and beverages. Chemically, it is a methyl ester of the dipeptide of two natural amino acids: aspartic acid and phenylalanine.

Source and Production

Aspartame is produced synthetically:

1. Raw Materials: The amino acids L-aspartic acid and L-phenylalanine are the primary starting materials. These are typically produced through bacterial fermentation.
2. Chemical Synthesis: The amino acids are chemically linked together, and the phenylalanine component is esterified with methanol.
3. Purification: The resulting aspartame is purified through crystallization and washing.
4. Formulation: The final product is a white, odorless powder.

Common Uses in Food

Aspartame is used extensively in low-calorie, "diet," or "sugar-free" products:

• Diet Soft Drinks: One of its most common applications.
• Tabletop Sweeteners: Sold under brand names like Equal, NutraSweet, and Canderel.
• Chewing Gum: Sugar-free varieties.
• Yogurts and Dairy Desserts: Low-calorie or sugar-free versions.
• Breakfast Cereals: Reduced sugar varieties.
• Powdered Drink Mixes: Sugar-free options.
• Confectionery: Sugar-free candies and mints.
• Pharmaceuticals: Used to sweeten some liquid medications and chewable tablets.

Note: Aspartame is not heat-stable and loses its sweetness when heated, making it unsuitable for most baked goods.

Health and Safety

Safety Concerns and Controversy

Aspartame is one of the most thoroughly studied food additives, yet it remains highly controversial:

• Phenylketonuria (PKU): Aspartame breaks down into phenylalanine. Individuals with the rare genetic disorder PKU cannot metabolize phenylalanine, and must strictly avoid aspartame. Products containing aspartame must carry a warning label for people with PKU.
• Potential Carcinogenicity: In July 2023, the International Agency for Research on Cancer (IARC) classified aspartame as "possibly carcinogenic to humans" (Group 2B), based on limited evidence for cancer (specifically hepatocellular carcinoma, a type of liver cancer) in humans. However, the Joint FAO/WHO Expert Committee on Food Additives (JECFA), which assesses risk, concluded there was insufficient reason to change the established Acceptable Daily Intake (ADI).
• Neurological Effects: Anecdotal reports and some studies have suggested links to headaches, dizziness, mood changes, and even seizures, but large-scale reviews by regulatory agencies have generally not substantiated these claims for the general population.
• Metabolism Products: Aspartame breaks down in the body into aspartic acid, phenylalanine, and methanol. While methanol can be toxic in large amounts, the quantity produced from typical aspartame consumption is considered safe by regulators, often less than amounts found naturally in fruit juices.
• Gut Microbiome: Emerging research suggests potential impacts of artificial sweeteners, including aspartame, on the gut microbiome.
• Metabolic Effects: Some studies question whether non-nutritive sweeteners might paradoxically affect glucose metabolism or appetite regulation, although evidence is inconclusive.

Regulatory Status

Despite ongoing debate and the IARC classification, major regulatory bodies worldwide continue to deem aspartame safe within established limits:

• European Union: Permitted as E951. EFSA re-evaluated aspartame in 2013 and confirmed its safety, maintaining the ADI of 40 mg/kg body weight/day.
• United States: Approved by the FDA. The ADI set by the FDA is 50 mg/kg body weight/day.
• JECFA: Reaffirmed the ADI of 0-40 mg/kg body weight/day in 2023, despite the IARC classification.
• Global Acceptance: Approved in over 90 countries.

Regulatory agencies emphasize that typical consumption levels are well below the ADI for most people.

Identification on Labels

Aspartame may be listed as:

• E951
• Aspartame
• APM
• NutraSweet, Equal, Canderel (brand names, may appear alongside the chemical name)
• Often accompanied by the warning: "Phenylketonurics: Contains Phenylalanine."

It can also be included under the term "artificial sweetener" or "non-nutritive sweetener."

Alternatives to Aspartame

Consumers seeking alternatives have several options:

• Other Artificial Sweeteners: Sucralose (E955), Acesulfame K (E950), Saccharin (E954) - note that these also have their own controversies.
• Natural Low-Calorie Sweeteners: Stevia (E960), Monk Fruit (Luo Han Guo).
• Sugar Alcohols: Erythritol (E968), Xylitol (E967) - can cause digestive issues in some people.
• Natural Sugars: Sucrose, honey, maple syrup - contain calories.
• Unsweetened Products: Choosing water or naturally unsweetened beverages and foods.

Conclusion

E951 (Aspartame) remains a widely used artificial sweetener approved by major health bodies globally, despite ongoing public concern and a recent classification as "possibly carcinogenic" by IARC. Its moderate toxicity rating (2/5) reflects the discrepancy between regulatory approval within ADI limits and the persistent scientific debate and consumer anxiety.

The breakdown product phenylalanine poses a definite risk to individuals with PKU. For the general population, regulatory agencies maintain that consumption within the ADI is safe. However, the IARC classification, even if based on limited evidence, fuels the controversy and encourages consumers seeking to minimize potential risks to consider alternatives.

Choosing whether to consume aspartame involves weighing the benefits of reduced sugar intake against the unresolved questions about its long-term health effects.