From time to time, “horror stories” about the dangers of sugar substitutes, or, as they are called scientifically, low-calorie sweeteners, surface on the Internet. At first, people were afraid of carcinogenicity, but they moved away from this topic in the absence of any evidence. Then they turned to intimidation with insulin resistance and a negative effect on the gut microbiome. So are there any artificial sweeteners’ side effects?
The most interesting thing is that neither authoritative scientists nor organizations carrying out control over food safety (their opinion is just the opposite), but those who are interested in attracting attention to themselves – the media and bloggers, are frightening commoners.
General Info About Side Effects of Artificial Sweeteners
Ignorant citizens take it for the truth and spread it further. And science, as usual, has its own position based on the assessment of all types of evidence in the aggregate, both confirming and not confirming this or that hypothesis. We will voice it below.
And immediately an example of what consensus exists on this topic at the present time.
A recent in-depth review of research with the self-explanatory title “Evaluation of in vivo data on low-calorie sweeteners and gut microbiota”  highlights the following highlights:
- Many dietary factors influence the composition of the human gut microbiota.
- The impact on the microbiota is complicated by uncontrolled background nutrition (that is, the effects of sweeteners are studied – without monitoring diet, which can significantly affect changes in the microbiome).
- Exposure to sweeteners in animal studies generally exceeded intakes; therefore, the relevance of this data to humans is limited.
- Current research shows no evidence of an adverse effect of sweeteners on the gut microbiota.
“Several rodent studies using saccharin have reported changes in the gut microbiome, but mostly at high doses that have nothing to do with human consumption. This and other studies suggesting the effects of low-calorie sweeteners on gut microbiota have shown no evidence of actual adverse effects on human health. Taken together, these data provide clear evidence that dietary changes not associated with low-calorie sweeteners are likely to be the main determinants of changes in the size and type of gut microbiota, confirming a view supported by all major international food safety and health regulatory bodies.”
Low-calorie sweeteners (acesulfame potassium, aspartame, saccharin, sucralose, and steviol glycosides) are safe at the currently approved levels.
Effects of Sucralose and Aspartame on Gut Microbiota
And here is the most recent publication, which was published just the other day, “The Effects of Non-Nutritive Artificial Sweeteners, Aspartame and Sucralose, on the Gut Microbiome in Healthy Adults: Secondary Outcomes of a Randomized Double-Blinded Crossover Clinical Trial.”  It is a randomized controlled human trial to determine the effect of sucralose consumption and aspartame on gut microbiota using realistic doses of low-calorie sweeteners, rather than in rodents that are literally poisoned with megadoses.
The study’s findings led to very definite conclusions: “These data suggest that daily re-consumption of pure aspartame or sucralose at doses reflecting typical high intakes has minimal effect on gut microbiota composition or short-chain fatty acid production.“
It should be clarified here that short-chain fatty acids are synthesized by the intestinal microbiota by fermentation of raw materials that enter the large intestine – dietary fiber or resistant starch. These fatty acids have a very beneficial effect on the body, which accounts for most of the benefits of dietary fiber in the human diet. Therefore, the scientists also studied the side effects of artificial sweeteners on the production of fatty acids, whether they would lead to a decrease in this production.
Consuming High Doses of Sucralose Is Safe
Another relatively recent interesting study “Short-term impact of sucralose consumption on the metabolic response and gut microbiome of healthy adults.”  It is noteworthy that it repeated the 2014 experiment “Artificial sweeteners induce glucose intolerance by altering the gut microbiota” , which was most often used, and may still be used as a horror story.
Moreover, horror stories about all artificial sweeteners’ side effects, although only saccharin was studied. Despite the low quality (a small sample – 7 people, the absence of a control group, the absence of an average indicator for the entire study group, despite the fact that 4 people had deterioration, and 3 improved, lack of control over background nutrition) and harsh criticism from the scientific world, they spread through the media and blogs as the ultimate truth. The new study did not just repeat it, but with the elimination of these shortcomings, maintaining the duration of the experiment and replacing the currently little-used saccharin with the much more common sucralose.
The authors conducted a randomized, double-blind study involving 34 subjects, divided into two equal groups, one of whom consumed sucralose capsules (780 mg/day for 7 days), and the control group received a placebo. The conclusion contradicted the findings of an earlier study: “Thus, consuming high doses of sucralose for 7 days does not alter glycemic control, insulin resistance, or gut microbiome in healthy individuals.”
The Safety of Sweeteners Is Scientifically Proven
An earlier critical review of all existing studies on the safety of sucralose, “Critical review of the current literature on the safety of sucralose” , already reported no cause for concern:
“The recent safety studies of sucralose on the carcinogenic potential and effects of sucralose on the intestinal microflora are reviewed. Following the discovery of sweet taste receptors in the gut and studies examining the activation of these receptors by sucralose, numerous human clinical studies have emerged evaluating the effect of sucralose on overall glycemic control. Estimated daily consumption of sucralose in various subpopulations, including recent studies in children with special dietary needs, consistently shows that consumption of sucralose by all members of the population remains well below the acceptable daily intake. Taken together, a critical review of an extensive research database indicates that sucralose is safe for its intended use as a non-nutritive alternative to sugar.”
This material does not encourage the use of sweeteners in your diet. For most people, regular sugar and sweetening are great for flavoring food. But if a person, for one reason or another, decides to replace sugar with non-nutritive sweeteners, they have the right to receive comprehensive information about their safety.
Sources About Side Effects of Artificial Sweeteners
- Assessing the in vivo data on low/no-calorie sweeteners and the gut microbiota. Food and Chemical Toxicology. Alexandra R.LobachaIan R.Rowlandb. Volume 124, February 2019, Pages 385-399
- The Effects of Non-Nutritive Artificial Sweeteners, Aspartame and Sucralose, on the Gut Microbiome in Healthy Adults: Secondary Outcomes of a Randomized Double-Blinded Crossover Clinical Trial Samar Y. Ahmad, James Friel, Dylan Mackay. Nutrients 2020, 12(11), 3408;
- Short-term impact of sucralose consumption on the metabolic response and gut microbiome of healthy adults Pamela Thomson et al. Br J Nutr. 2019.
- Artificial sweeteners induce glucose intolerance by altering the gut microbiota Jotham Suez, Tal Korem, Eran Elinav. Nature volume 514, pages181–186(2014)
- Critical review of the current literature on the safety of sucralose. Bernadene A Magnuson et al. Food Chem Toxicol. 2017 Aug.
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