One word on the label, two unrelated ingredients
EU labels call both classes “sweetener”. High-intensity sweeteners like E950 (acesulfame K) and E951 (aspartame) are used in milligrams and pass through. Polyols like E420 (sorbitol) are used in grams, are only partly absorbed, and ferment in the large intestine.
If you have ever read the back of a sugar-free chewing gum, a protein bar and a diet drink, you have read the word “sweetener” three times about three quite different things. The functional class on an EU label describes what an additive does to the taste, not what it does to you — and for sweeteners that gap is unusually wide.
The practical split is dose. A high-intensity sweetener is hundreds of times sweeter than sugar, so a serving contains a few milligrams and there is nothing left to digest. A polyol — a sugar alcohol — is roughly as sweet as sugar or less, so it has to be used in comparable quantity. A single stick of sugar-free gum can carry over a gram of it, and a bag of sugar-free sweets several grams.
That is why one class is essentially invisible to your digestion and the other is the reason “sugar-free” sweets have a reputation. It is also why a scanner that treats “sweetener” as one category cannot tell you the thing you actually want to know.
The high-intensity sweeteners: E950, E951, E954, E955, E960
Acesulfame K, aspartame, saccharin, sucralose and the steviol glycosides. All EFSA-assessed, all used in milligram quantities, all with an Acceptable Daily Intake that ordinary consumption does not approach.
E950 is acesulfame K, roughly 200 times sweeter than sucrose. E951 is aspartame, about the same. E954 is saccharin, E955 sucralose, and E960 the steviol glycosides extracted from stevia leaves. They are frequently blended, because each has a slightly different taste profile and the combination masks the aftertaste any one of them has alone — which is why a diet drink often lists two or three.
EFSA re-evaluated aspartame in 2013 and confirmed an Acceptable Daily Intake of 40 mg per kilogram of body weight per day. For a 70 kg adult that is 2,800 mg, or somewhere around a dozen cans of a typical diet drink every day for life. In 2023 the IARC classified aspartame as “possibly carcinogenic to humans” (Group 2B) while the JECFA review published alongside it left the ADI unchanged — two bodies answering two different questions, hazard and risk, which is a distinction worth holding onto when a headline collapses them.
For almost everyone these additives are a question of preference rather than physiology. There is one genuine exception, and EU law puts it on the pack — see the warnings section below.
The polyols: E420, E421, E953, E965, E966, E967
Sorbitol, mannitol, isomalt, maltitol, lactitol and xylitol. Sugar alcohols, used in gram quantities, incompletely absorbed in the small intestine — and therefore fermented further down.
Polyols are the “P” in FODMAP. They are absorbed slowly and incompletely, so a meaningful fraction reaches the large intestine, where gut bacteria ferment it. The result is gas, distension and an osmotic pull of water into the bowel — bloating and, at higher doses, a laxative effect. This is a normal property of the molecule, not an adverse reaction or an allergy.
For most people that simply means not eating a whole bag of sugar-free sweets. For someone with IBS it is different in degree: the Monash University low-FODMAP work identifies sorbitol and mannitol specifically as polyols that provoke symptoms at doses many people encounter without noticing, and a low-FODMAP diet restricts them deliberately.
Xylitol (E967) carries a separate, unrelated warning that has nothing to do with humans: it is seriously toxic to dogs, and a dropped piece of sugar-free gum is a genuine veterinary emergency. Worth knowing if a sugar-free product lives in a house with a dog.
One more asymmetry worth noticing on a label: polyols contribute calories — typically around 2.4 kcal per gram, against sugar’s 4 — so a “sugar-free” product sweetened with maltitol is not a zero-energy product, and its nutrition table will say so if you look at the carbohydrate line rather than the claim on the front.
The two warnings EU law actually requires
Regulation (EU) No 1169/2011 Annex III mandates exactly two sweetener-related statements, and both tell you something the ingredient list alone does not.
**Above 10% added polyols, a food must state that “excessive consumption may produce laxative effects.”** This is the clearest signal on the pack that you are looking at the gram-quantity class rather than the milligram one. If you see that sentence, the product contains enough polyol to matter.
**A product containing aspartame must state that it “contains a source of phenylalanine.”** This is aimed at people with phenylketonuria (PKU), a rare inherited condition in which phenylalanine cannot be metabolised. It is not a general safety warning, and it is one of the most widely misread sentences on any label.
Neither statement is optional and neither is a marketing choice, which makes both more reliable than any front-of-pack claim. “Sugar-free”, by contrast, is a nutrition claim about sugars — it says nothing at all about which sweetener replaced them.
How Ingredo.app reads sweeteners
The two classes are tagged separately, because they raise different questions for different people. Neither is treated as a generic “additive” penalty.
Polyols — flagged for Low-FODMAP (IBS)
- E420 sorbitol, E421 mannitol, E953 isomalt, E965 maltitol, E966 lactitol, E967 xylitol
- Flagged as a caution, not a block — tolerance is individual and dose-dependent
- Switch on the Low-FODMAP module and these surface on the product page
High-intensity sweeteners — noted, not penalised
- E950, E951, E954, E955, E960 and the rest of the class
- Recorded so you can see them, with no toxicity claim attached
- Aspartame’s phenylalanine statement is a labelling fact we surface, not a warning we invent
Not flagged by
- Any EU Annex II allergen module — no sweetener in either class is a declarable allergen
- Our high-risk additive tier — none of these carries an EU ban or restriction that caps a score
Frequently asked questions
Acesulfame K (acesulfame potassium), a high-intensity sweetener roughly 200 times sweeter than sugar. It is heat-stable, so it appears in baked goods as well as drinks, and it is very often blended with aspartame or sucralose because the combination tastes cleaner than any of them alone. EFSA has assessed it and it carries an Acceptable Daily Intake of 9 mg per kg of body weight.
No, and this is the distinction the label hides. E420 is sorbitol, a polyol used in gram quantities and only partly absorbed, so it ferments in the large intestine and can cause bloating or a laxative effect. E950 is used in milligrams and is not fermented. They share a functional class on the label and share almost nothing else.
Almost certainly the polyol, not the sweetness. A stick of sugar-free gum can contain over a gram of sorbitol, maltitol or xylitol, and several sticks across an afternoon adds up to a dose that ferments. If a pack carries the “excessive consumption may produce laxative effects” line, it contains more than 10% polyols and that is the mechanism.
Not necessarily. “Sugar-free” is a regulated nutrition claim about sugars, and a product can meet it while being sweetened with polyols, which contribute roughly 2.4 kcal per gram. Products sweetened only with high-intensity sweeteners are effectively energy-free from the sweetener itself. The carbohydrate line of the nutrition table tells you which situation you are in.
The regulators and the cancer-hazard classification are answering different questions. In 2023 the IARC placed aspartame in Group 2B, “possibly carcinogenic to humans” — a statement about whether a hazard exists at all. The JECFA risk assessment published at the same time reaffirmed the Acceptable Daily Intake of 40 mg/kg body weight, which ordinary consumption does not approach. The one group for whom aspartame genuinely matters is people with PKU, which is why the phenylalanine statement is mandatory.
No — they are poorly absorbed, which is a different thing. They do not accumulate and are not toxic. For most people the only consequence is digestive, and only at dose. For someone managing IBS on a low-FODMAP diet, they are one of the categories being deliberately limited, which is exactly why Ingredo flags them for that profile rather than for everyone.