Do non-nutritive sweeteners harm the gut microbiome?

April 18, 2023

In a recent review published in the journal nutrients, Italian researchers discussed findings from various preclinical and clinical studies evaluating the effects of nonnutritive sweeteners such as aspartame, saccharin, sucralose and acesulfame-K on the gut microbiota.

review: Effect of non-nutritive sweeteners on gut microbiotaImage credit: cruspan / Shutterstock

Background

The bacteria that make up the human gut microbiome include over 50 phyla and 1,500 species, with 99% of the bacterial population composed of 30-40 species. Gut microbiota vary among individuals and are influenced by a variety of factors, including age, genetics, antibiotics, and diet. A healthy balance of beneficial bacteria in the gut is known as eubiosis, while an imbalance that results in the growth of pathogenic bacteria is known as dysbiosis. The ratio (F/B ratio) is important in maintaining intestinal homeostasis, and gut microbiota abnormalities are associated with a variety of diseases affecting different organ systems.

In recent years, there has been an increase in the consumption of non-nutritive sweeteners, which are sweeter than sucrose and significantly lower in calories. Nonnutritive sweeteners approved for consumption vary from country to country based on testing for potential carcinogenic effects and other health issues. may be associated with cardiovascular disease, glucose intolerance, obesity, insulin resistance, and inflammation, and the gut microbiota may serve as a potential mediator.

Given the widespread use of non-nutritive sweeteners due to their low calorie content and the pivotal role of the gut microbiota in human health, the potential determinants of non-nutritive sweeteners on the gut microbiota It is essential to understand the impact of

Main findings

This review evaluated the evidence from studies examining the effects of four nonnutritive sweeteners on the gut microbiota: aspartame, saccharin, sucralose and acesulfame-K. Aspartame is a dipeptide methyl ester containing L-phenylalanine and L-aspartic acid (two amino acids commonly found in vegetables, fruits, dairy, and nuts). Saccharin is a water-soluble organic acid and acesulfame-K is a hydrophilic derivative of organic acids. Sucralose is a disaccharide containing 4-chloro-4-deoxygalactose and 1,6-dichloro-1,6-dideoxyfructose and is not readily metabolized by humans.

Six preclinical studies, including two in rat models and four in humans, examined the effects of aspartame consumption on the gut microbiota. In a study on a rat model, aspartame consumption reduced caloric intake and weight gain when combined with a high-fat diet, but decreased insulin-stimulated disposal of glucose, increased fasting glucose levels, and reduced F/ An increase in B was reported. ratio.

In humans, studies examining individuals who consumed aspartame or acesulfame-K found that between individuals who consumed either or both of the two non-nutritive sweeteners and those who did not consume any non-nutritive sweeteners. It was reported that there was no difference in overall bacterial counts. The gut microbiota diversity he decreased from 24 phyla to 7 phyla.

One study in humans reported that aspartame consumption caused no changes in the gut microbiome or short-chain fatty acids, whereas another randomized controlled trial found that consumption of aspartame and other nonnutritive sweeteners caused changes in the gut. It has been reported that the composition and function of the endogenous microbiota changed significantly.

A study on a mouse model investigating the effects of acesulfame-K yielded contrasting results. Some studies reported no significant changes in the composition of the fecal microbiome, while others showed increases and decreases in the F/B ratio, gut damage, and gut microbiota. increase. The effects of sucralose on the gut microbiota have been examined in a variety of mouse models and human studies, resulting in significant changes in the human and mouse gut microbiota. For mouse changes, Ruminococcus, Clostrididae, Ackermanthiaproteobacteria, Escherichia coliFirmicutes, and F/B ratios, and increased hepatic proinflammatory markers, cholic acid, and cholesterol.

Similarly, studies examining the effects of saccharin consumption on the gut microbiota in mice have reported decreased glucose tolerance and increased hepatic pro-inflammatory markers. However, few studies on the effects of saccharin intake in dogs, piglets, and humans have reported significant effects or changes.

Conclusion

Overall, the review indicated conflicting findings from studies examining the effects of nonnutritive sweeteners on the gut microbiome in humans and animal models. reported gut microbiota associated with low sweetener intake, but other clinical trials reported no significant changes in the gut or fecal microbiomes of humans or animals. , there is no scientific consensus on biomarkers or outcomes that can determine the impact of low-nutrition sweetener consumption on the gut microbiota.