Artificial Sweeteners: Harmful or Helpful — What the Research Says

The sweetener debate is structured so that almost any headline is either an overstatement or an understatement. On one side, regulators have confirmed safety within acceptable intakes for decades. On the other, the WHO advised in 2023 against using them for weight control, and prominent papers on erythritol and aspartame have made news. Here is what has actually been shown, and what has been extrapolated.

Who's who#

Sweetener	Sweetness vs sugar	ADI, mg/kg/day	Notes
Aspartame (E951)	200×	40 (EFSA/JECFA)	Breaks down when heated; contraindicated in phenylketonuria
Sucralose (E955)	600×	15	Heat-stable, works in baking
Steviol glycosides (E960)	200–300×	4 (as steviol)	Plant-derived, distinctive aftertaste
Acesulfame K (E950)	200×	9	Common in blends, boosts other sweeteners
Saccharin (E954)	300–400×	5	The oldest; metallic note
Erythritol (E968)	0.7×	not specified	Sugar alcohol, barely absorbed, up to 90 % excreted in urine
Xylitol (E967)	1×	not specified	Laxative effect above 30–50 g; lethal to dogs

To grasp the scale of the ADI: a 70 kg adult would need to drink roughly 9–14 cans of diet soda every day, for a lifetime, to reach the aspartame limit. Approved intakes are set with a 100-fold safety margin below the level at which no effects were seen in studies.

What the WHO actually said#

The 2023 recommendation reads: non-sugar sweeteners are not recommended as a means of achieving weight control or reducing the risk of non-communicable diseases. Three qualifications usually get lost in the headlines:

1. The recommendation is flagged as conditional — the weakest tier in the GRADE system, meaning the right choice may differ between individuals.
2. The certainty of evidence was rated low, because most of the data is observational and highly vulnerable to reverse causation: people with excess weight switch to diet drinks, not the other way around.
3. It does not apply to people with diabetes, and it is not a safety verdict — safety falls to EFSA and JECFA.

Aspartame and group 2B#

The IARC classification is routinely misread. It answers the question "how convincing is the evidence that this substance can cause cancer", not "how large is the risk at normal intake". Group 2B, where aspartame landed, also contains aloe vera, Asian-style pickled vegetables and ginkgo extract. Group 1 ("carcinogenic to humans") contains smoking, alcohol and processed meat — yet the risk from a cigarette and from a sausage differ enormously.

Alongside the IARC decision, JECFA reaffirmed the existing acceptable intake of 40 mg/kg. Formally that means: the hazard evidence is weak, and at real consumption levels no risk has been established.

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Erythritol: what we know#

The 2023 Nature Medicine paper found that high plasma erythritol was associated with increased three-year risk of heart attack and stroke, and in the laboratory arm with enhanced platelet aggregation. That is worth attention — with one caveat: erythritol is produced endogenously from glucose via the pentose phosphate pathway, and levels rise with metabolic dysfunction. So high erythritol may be a marker of cardiometabolic risk rather than its cause.

The practical position today: panic is premature, but treating erythritol as unambiguously inert is also unwarranted. Separately, remember its laxative effect — above 30–50 g in one sitting many people get bloating and diarrhoea, because sugar alcohols draw water into the gut.

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When sweeteners make sense#

Situation	Guidance
Moving off 1–2 litres of sugary soda a day	The swap is justified as an intermediate step
Type 1 and type 2 diabetes	Helpful for glycaemic control; the WHO recommendation excludes them
Dental health	A clear benefit; xylitol even suppresses cariogenic bacteria
Weight loss as the only goal	Don't expect the swap alone to do it — the overall deficit does
Children	Prioritise water and unsweetened drinks over diet versions
Pregnancy	Approved sweeteners within the ADI are acceptable; aspartame is contraindicated in phenylketonuria

Читайте также: Calorie Deficit Explained: How to Calculate It and Stick to It

What to do in practice#

1. Lower overall sweetness, not just its source. Taste receptors adapt within weeks, and fruit starts tasting sweet again.
2. Deal with sugary drinks first — they deliver calories without satiety. Swapping to a diet version beats nothing, but water and tea beat both.
3. Don't stack sweeteners unnecessarily: blends often combine acesulfame K and sucralose, and sugar alcohols add gut trouble.
4. Read the label on protein bars and "healthy" desserts — 20–40 g of sugar alcohols per pack is common, enough to upset the gut.
5. Judge the whole product, not one ingredient: a stevia-sweetened biscuit is still an ultra-processed food.

Читайте также: How to Read Food Labels: What the Numbers Really Mean

The bottom line#

Approved sweeteners are safe within acceptable intakes that ordinary consumption never comes close to. The aspartame and erythritol headlines rest on real papers, but those papers describe weak evidence and unproven causation, not established harm. The 2023 WHO guideline is not a safety verdict — it says don't count on sweeteners as a weight-loss tool. The sensible strategy: remove sugary drinks, dial down overall sweetness, and treat sweeteners as a temporary bridge rather than a permanent fixture of the diet.