What Is E951?
E951 is the E-number for aspartame, an artificial sweetener approximately 200 times sweeter than sugar. It's used in diet sodas, sugar-free chewing gum, low-calorie desserts, and many "diet" or "light" products.
Aspartame was discovered in 1965 and approved for use in the UK and US in the 1980s. It's made from two amino acids (aspartic acid and phenylalanine) plus a small amount of methanol.
⚠️ Safety Verdict: Use Caution
Aspartame is approved by UK, EU, and US regulators, but remains controversial. Recent research (2023) led the WHO to classify it as "possibly carcinogenic" at high intakes. Individual sensitivity varies widely.
Common Uses of E951 (Aspartame)
You'll find aspartame in many "diet" and "sugar-free" products:
- Diet drinks: Diet Coke, Coke Zero, Pepsi Max, sugar-free squash
- Chewing gum: Most sugar-free gums contain aspartame
- Low-calorie desserts: Sugar-free jelly, ice cream, yoghurt
- Protein products: Some protein bars and shakes
- Table-top sweeteners: Canderel, NutraSweet brands
- Sugar-free sweets: Mints, lozenges, hard candies
Is Aspartame Safe?
Aspartame is one of the most studied food additives with over 200 scientific studies. However, it remains contentious.
Regulatory Approval
Aspartame is approved by:
- European Food Safety Authority (EFSA) — Approved with ADI of 40mg/kg body weight
- US FDA — Approved with ADI of 50mg/kg body weight
- UK Food Standards Agency — Considers it safe at current use levels
2023 WHO Classification Update
In July 2023, the World Health Organization (WHO) classified aspartame as "possibly carcinogenic to humans" (Group 2B). This is the same classification as aloe vera extract and working night shifts.
What this means: There's limited evidence suggesting a possible link to cancer at very high intakes (more than 9-14 cans of diet soda per day). The evidence isn't strong enough for a definitive warning, but enough to warrant caution.
Who Should Avoid Aspartame?
⚠️ People with PKU (Phenylketonuria)
MUST AVOID aspartame completely. PKU is a rare genetic disorder where the body cannot break down phenylalanine (one of aspartame's components). Products with aspartame must carry a warning: "Contains a source of phenylalanine."
Reported Side Effects
Some people report symptoms after consuming aspartame, though scientific studies show mixed results:
- Headaches and migraines: Most commonly reported (studies are inconclusive)
- Dizziness: Some people report feeling lightheaded
- Mood changes: Anxiety, irritability, depression (limited evidence)
- Digestive issues: Bloating, stomach discomfort
- Sleep disturbances: Difficulty falling asleep
If you notice consistent reactions after consuming aspartame-containing products, consider eliminating it for 2-4 weeks to see if symptoms improve.
Cancer Risk: What Does the Science Say?
The cancer question is highly debated:
- Animal studies: Some rodent studies in the 2000s suggested increased cancer risk at extremely high doses
- Human studies: Large population studies show mixed results — some found slight associations, many found none
- WHO 2023 classification: "Possibly carcinogenic" based on limited evidence, mostly at very high intakes
- ADI (Acceptable Daily Intake): Regulators maintain that up to 40-50mg/kg body weight per day is safe (a 70kg person can have 2,800-3,500mg, or about 10-14 cans of diet soda)
💡 Key Takeaway
Occasional consumption (1-2 diet drinks per day) is considered safe by regulators. Heavy daily consumption (5+ diet sodas) may carry unknown long-term risks. If you're concerned, consider natural sweeteners like stevia (E960) as an alternative.
How Much Aspartame Is In Common Products?
Typical aspartame content:
- 330ml can of Diet Coke: ~180mg aspartame
- Stick of sugar-free gum: ~5-10mg aspartame
- Sachet of Canderel: ~18mg aspartame
- Sugar-free jelly pot: ~30-50mg aspartame
For a 70kg adult, the ADI is 2,800mg per day — equivalent to 15-16 cans of Diet Coke. Most people consume far less than this.
How to Avoid E951 (Aspartame)
If you want to limit or avoid aspartame:
- Read ingredient labels: Look for "E951", "aspartame", "NutraSweet", or "Canderel"
- Check for PKU warning: If a label says "Contains a source of phenylalanine", it has aspartame
- Choose alternative sweeteners: Stevia (E960), sucralose (E955), or natural sugar in moderation
- Avoid "diet" and "sugar-free" products: Most contain aspartame or similar artificial sweeteners
- Use a food scanner: Apps like NutraSafe instantly identify aspartame in packaged foods
Alternatives to Aspartame
If you're looking for sweetener alternatives:
- Stevia (E960): Natural plant-based sweetener, generally well-tolerated
- Sucralose (E955): Artificial but considered safer, no PKU concerns
- Erythritol: Sugar alcohol, minimal calories, doesn't spike blood sugar
- Monk fruit: Natural sweetener, no known side effects
- Natural sugar: In moderation, regular sugar may be preferable for some people
The Bottom Line on Aspartame
Aspartame is approved as safe by major regulators, but carries more controversy than most additives. The 2023 WHO classification as "possibly carcinogenic" at high intakes adds caution, though the risk appears low at typical consumption levels.
Occasional use (1-2 diet drinks per day) is unlikely to cause harm for most people. Heavy daily use (5+ servings) may carry unknown risks. People with PKU must avoid it entirely.
If you experience headaches, mood changes, or other symptoms after consuming aspartame, consider switching to stevia or other alternatives.
Check Foods for E951 Instantly
Wondering if a product contains aspartame? Use NutraSafe's free barcode scanner to check any UK food instantly. The app identifies all E-numbers, including E951, and explains potential health concerns.