Sweeteners: Are They Safe? Aspartame, Sucralose, Stevia and Erythritol with Their Daily Limits

First, the concept that makes sense of everything: the acceptable daily intake (ADI) is the amount that can be consumed every day over a lifetime without appreciable risk. It is calculated from the dose with no effects in studies, usually divided by 100 as a safety margin. Exceeding it on one day is not dangerous; what matters is that habitual intake stays below it. In its latest re-evaluations, EFSA found that this was the case for aspartame, sucralose and saccharin; for erythritol, however, its estimates (which EFSA itself considers overestimates) exceeded it in high consumers.

Each sweetener, its ADI and what it equals for 70 kg

How to read it: to reach the ADI of any of them you would need dozens of packets a day or, in the case of aspartame, more than 9-14 cans daily (the WHO assumes 200-300 mg per can). Erythritol is different: it is consumed in grams, not milligrams, and its limit (35 g for 70 kg) was set because of the laxative effect; EFSA warned that people who consume a lot of it could exceed it and notice digestive discomfort. To find out what a product contains, look for the E number in the ingredient list: you can learn how in the guide to reading nutrition labels.

Aspartame and cancer: what IARC's “2B” means

In July 2023 two assessments were published at the same time. IARC, which classifies hazards (whether something could cause cancer under some circumstance, without looking at the dose), placed aspartame in group 2B, “possibly carcinogenic”, based on limited evidence in humans for one type of liver cancer (hepatocellular carcinoma), limited evidence in animals and limited mechanistic evidence. JECFA, which assesses risk (how much you would need to consume), concluded that the data did not justify changing the ADI of 40 mg per kilo a day that it set in 1981. The two conclusions do not contradict each other: the 2B says the question deserves more study, and the ADI says that at habitual intake the risk is not a concern. EFSA had already set the same ADI in its 2013 re-evaluation, and it makes clear that it does not apply to people with phenylketonuria, who must avoid phenylalanine.

Sweeteners and weight: the WHO guideline and its nuance

In May 2023 the WHO recommended not using non-sugar sweeteners (aspartame, acesulfame K, saccharin, sucralose, stevia and others) to control body weight or to reduce the risk of chronic diseases. Its review found no long-term benefit on body fat, and in observational studies long-term use was associated with more type 2 diabetes, cardiovascular disease and mortality. But the WHO itself calls it a conditional recommendation, because those associations may be due to the baseline characteristics of the people who use them: it is common to start consuming them when overweight or metabolic risk is already present. The guideline does not apply to people who already have diabetes, to polyols such as erythritol, or to toothpaste or medicines. Trials tell another part of the story: Rogers (2016) found that replacing sugar with sweeteners was associated with 1.35 kg less body weight in trials lasting 4 weeks to 40 months (in a paper with food-industry co-authors), and Toews (2019), in a review following Cochrane methods, found only small benefits with low or very low certainty evidence, and no effect in people actively trying to lose weight.

• If you swap a 330 ml can of regular cola (about 33 g of sugar and 140 kcal, according to USDA) for its sugar-free version, you remove those calories that day: the immediate effect is real.
• What has not been shown is that consuming sweeteners, by itself, makes you lose fat in the long term.
• To cut sugar, the WHO suggests other routes: fruit, with its naturally occurring sugar, or unsweetened foods and drinks.

Erythritol: what the 2023 study says and what it does not

Witkowski's study (Nature Medicine, 2023) had three parts. First, in 1,157 people undergoing cardiac evaluation, several polyols in the blood, especially erythritol, were associated with more heart attacks, strokes or deaths over 3 years; the finding was then confirmed in 2,149 patients from the United States and 833 from Europe, with a 1.8- and 2.2-fold higher risk in the quarter with the most erythritol compared with the quarter with the least. Second, in the laboratory and in animals, erythritol at concentrations like those observed increased platelet reactivity and clot formation. Third, 8 healthy volunteers drank 30 g of erythritol and their blood level rose more than a thousand-fold and stayed high for more than 2 days. The limits matter: it is an association study, in patients who already had cardiovascular risk, with a single fasting measurement, and the body also produces erythritol, so the blood level does not reflect only what is eaten. It does not show that erythritol causes heart attacks, but it justifies studying its long-term safety, as its authors call for.

In short: authorised sweeteners have reviewed limits and normal intake stays far below them; aspartame's 2B classification is about hazard, not risk at usual doses; the WHO does not recommend them for weight loss, with nuances; and erythritol has a signal that needs to be followed up. Lean on Renzy to gradually reduce the total sweetness in your diet.