Artificial sweeteners

Artificial sweeteners are widely use by the food industry in the production of countless foods and beverages with a low calorie content. “Sugar free” desserts/candies/gums/juices, “diet” sodas, “light” foods and drinks… Any product with one of these tags in its name indicates the use of an artificial sweetener in place of sugar.

What are artificial sweeteners?

MedlinePlus defines artificial sweeteners as “substances that are used in place of sweeteners with sugar (sucrose) or sugar alcohols. They may also be called sugar substitutes, non-nutritive sweeteners (NNS), and noncaloric sweeteners.”

Some of the most common artificial sweeteners are aspartame, sucralose, saccharin and acesulfame K, but the list of chemical substances that meet the definition can be completed with:

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  • xylitol
  • sorbitol
  • Erythritol
  • Mannitol
  • Neotame
  • isomalt
  • maltitol
  • polydextrose
  • glycerine
  • Polyglucitol
  • lactitol
  • glycerol

Some of these sweeteners have a low-calorie content and some are calorie-free.

Do artificial sweeteners have any impact on the gut microbiome?

Current research on the effect that artificial sweeteners intake has on human health is limited and controversial. Different studies with different outcomes mean that there is no clear evidence about the impact of these substances and the mechanisms of their possible effects.

Saying that evidence of artificial sweeteners affecting our health is lacking does not mean we do not need to be cautious (as with every man made chemical for which a harmless effect has not been well proved).

Artificial sweeteners were once thought to be “metabolically inactive” or “inert”, meaning that they passed through the gut without being metabolised or having metabolic effects on our bodies. They just provided a sweet taste without the calories sugars carry with them. Thus, they were the perfect healthy substitutes to include in your diet if you were concerned about weight gain or trying to lose excess weight. Now, though, many scientific papers agree that they are more “active” than it was believed and there is a need for more research on the matter.

Some studies have found a link between artificial sweeteners intake and weight gain, metabolic syndrome and type 2 diabetes. Other studies imply that there may be an association between these chemicals and gut symptoms, alterations in motility or increased gastric acid secretion. But these associations are still unclear and some other published papers have not found any effect.

What seems to be clear from the research done until now is that consumption of artificial sweeteners change the balance and diversity of the gut microbiota. The main issues with this research, however, is that is has mostly been done in animals and that the specific ways in which they may affect the microbiome are unknown.

For instance, one known study found that artificial sweeteners alter the gut microbiota and that this change results in glucose intolerance, both in mice and humans. In humans, though, the glucose intolerance effect was only true for susceptible individuals and this susceptibility was dependent on previous microbial composition. Another limitation is that it only assessed three common sweeteners: sucralose, aspartame and saccharin.

Therefore, future research will need to consider the effects of artificial sweeteners individually, especially in the human gut microbiota, and the way in which they exert their effect.