Earlier this month, the Deutsche Apotheker Zeitung (DAZ) reported that frequent intake of zero-calorie or non-nutritive sweeteners (NNS) may affect the gut flora (i.e. the bacteria populating your gut), and hence our microbiome. Since a healthy and, as regards bacterial diversity, well-balanced microbiome strengthens our immune system and prevents disease, among others, any change to the microbiome as a result of frequent sweetener consumption may, just as the excessive intake of sugar, cause or worsen metabolic, cardiovascular, or skin diseases.
Several years ago, an Israeli study had already demonstrated that compared to a control group, administration of NNS resulted in excessively high blood glucose levels. This appeared to be most prominent in participants who consumed saccharin and sucralose. The impaired glycaemic response was also evident in the microbiome, as stool samples showed (for the study, please see https://www.cell.com/cell/fulltext/S0092-8674(22)00919-9).
A more recent study conducted in Cambridge found that in addition to saccharin and sucralose, aspartame may also negatively affect the gut flora. According to reports, “even a physiological concentration of only 100 micrograms may change the gut flora and make infections more likely” (NDR). Among others, bacteria become more able to form a biofilm which protects harmful bacteria (pathogens) both from their natural enemies (healthy bacteria) and also from antibiotics (https://www.mdpi.com/1422-0067/22/10/5228).
More detailed studies will be necessary to determine precisely which other impacts on physical health may result from excessive sweetener consumption. However, we can already state with considerable certainty that “zero-calorie sugar substitutes do not simply pass through our bodies without influencing them”, as the article in the DAZ said. As usual, it will be a question of the dose – with sugar just as with sugar substitutes. An unbalanced diet and the excessive consumption of specific additives will always have an impact on the gut flora, and hence upset the human natural microbiome. By the same token, a healthy bacterial diversity is vital for a healthy body.