Sweeteners, metabolism, gut hormones and gut bacteria
What it found
In people, animals and lab tests, sweeteners gave mixed results for weight, blood sugar, insulin and gut bacteria.
The authors say the evidence is still too scarce to draw firm conclusions.
What they found
Studies in people
Xylitol and erythritol in people
In a randomised, placebo-controlled, crossover trial in lean and obese volunteers, a single dose of xylitol or erythritol did not significantly change circulating glucose and insulin levels. It did stimulate the gut hormones CCK and GLP-1 and slowed gastric emptying.
Sucralose with carbohydrates
In healthy people, sucralose alone did not affect glycemic control or insulin sensitivity. When taken together with carbohydrates, it rapidly impaired glucose metabolism and the brain response to sweet taste, with a more pronounced effect in adolescents.
Animal and lab studies
Aspartame and cancer in rats
A long-term rat study found more lymphomas, leukemias, carcinomas of the renal pelvis and ureter, and schwannomas in rodents treated with aspartame until natural death. These results were confirmed even at doses of 20 mg/kg body weight, lower than the recommended maximum daily intake in Europe and the United States.
Studies in people and animals
Polyols and blood sugar
Polyols do not affect glucose homeostasis. They have been suggested as sugar substitutes that may help insulin resistance and glucose control in people with type 2 diabetes or metabolic syndrome, but strong long-term evidence is still scarce and inconclusive.
Saccharin and gut bacteria
Saccharin-fed mice developed glucose intolerance through changes to their gut bacteria, and germ-free mice given fecal transplants from these animals also developed glucose intolerance. Similar findings were reproduced in healthy people consuming saccharin for 1 week.
Sweeteners and gut bacteria
Most sweeteners affect gut bacterial composition and may cause dysbiosis. Polyols seem to have a good profile: they are non-cariogenic, do not negatively affect gut bacteria and have a very low energy value.
Sweeteners and weight
Studies in rodents and people have linked low-calorie sweetener consumption with weight gain and diabetes, while other studies linked it with lower BMI and weight loss, and others found no link to metabolic parameters.
Sweeteners in pregnancy
Sweeteners cross the placenta and are found in maternal milk. Animal studies suggest prenatal exposure may affect offspring gut bacteria and fat cell development, but data from animal studies were not confirmed in humans, and current evidence does not suggest adverse effects in pregnancy.
What the authors conclude
“Nonetheless, at present there is still scarce evidence to establish conclusively whether the consumption of different types of sweeteners (e.g., low-calorie sweeteners vs. non-calorie sweeteners) can result in significant beneficial or detrimental effects on energy balance, appetite, body weight, and/or cardiometabolic risk factors in healthy subjects and patients with metabolic diseases (particularly obesity and type 2 diabetes).”
Also in their conclusions
- They say there is still scarce evidence to establish conclusively whether different types of sweeteners have significant beneficial or detrimental effects on energy balance, appetite, body weight or cardiometabolic risk factors in healthy people and patients with metabolic diseases.
- They call for future prospective studies on the short- and long-term safety and efficacy of different sweeteners in various clinical settings and age groups.
- They advise that sweeteners be consumed in moderate amounts, adhering to the acceptable daily intake standards set by regulatory agencies.
How it was done
Sugar intake has risen and has been linked to obesity, type 2 diabetes and heart disease. Sweeteners may help cut calories, but studies on their safety and usefulness over the short and long term are scarce and give conflicting results.
The authors pulled together and described the existing research on low-calorie sweeteners (polyols) and non-calorie sweeteners. They looked at studies in people, animals and cells covering metabolism, the brain, gut hormones and gut bacteria.
What it can’t tell you
- Many of the findings come from animals or cells, so they cannot show what happens in people.
- The studies in people used different designs, doses and lengths of time, so the results cannot be combined into one clear answer.
- The long-term effects of sweeteners on weight, blood sugar and gut bacteria in people are still not known.
Who paid
- Authors work at
- Laboratory of Cardiovascular Endocrinology, Italy; Sapienza University of Rome, Italy; University of Rome Tor Vergata, Italy
The paper
- Title
- Neuroendocrine and Metabolic Effects of Low-Calorie and Non-Calorie Sweeteners
- Type
- ReviewThe authors read earlier studies and describe what they found. It isn’t a new study.
- Evidence
- Studies in people · animals · lab
- Summarised from
- Full text
- Licence
- CC BY. Words in quotation marks are the authors’; the rest is our summary.
- Cite
- Moriconi E, Feraco A, Marzolla V, et al (2020). Neuroendocrine and Metabolic Effects of Low-Calorie and Non-Calorie Sweeteners. Frontiers in endocrinology. doi:10.3389/fendo.2020.00444Free full textPubMed 32765425DOI
Summary written 30 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error