Choosing a diet soda to replace sugar seems a healthy reflex to protect your figure and your heart. Behind these products hide
artificial sweeteners or “non-nutritive”, used to provide sweet taste without calories. However, a Chilean team has shown, in mice, that these additives can leave traces well beyond the generation that consumes them.
In this study published in the journal Frontiers in Nutritionresearchers were interested in
sucralose and to the
steviatwo sweeteners widely used in sodas, desserts and dairy products. “We found it intriguing that despite the increasing consumption of these additives, the prevalence of obesity and metabolic disorders such as insulin resistance has not decreased“, declared Dr. Francisca Concha Celume of the Universidad de Chile, quoted by Frontiers. For her, these products could influence metabolism in a way that is still poorly understood.
Effects of artificial sweeteners on mouse offspring
The scientists divided 47 mice into three groups: plain water, water with sucralose or water with stevia, at a dose close to what a human would consume in a usual diet. The parent animals received these drinks for 16 weeks, then had two generations of young. The descendants only drank water, which made it possible to monitor transmitted effects without direct exposure.
“Animal models allow us to very precisely control environmental conditions and isolate the effect of a specific factor, such as a dietary compound, while following multiple generations in a relatively short period of time“, explained Dr. Francisca Concha Celume.
Each generation took a glucose tolerance test, which assesses how well the body handles sugar, and provided stool samples to analyze the
intestinal microbiota. The parents did not develop any marked intolerance. In contrast, their sons from the sucralose group showed a slightly disrupted glucose response, and the second generation showed higher fasting blood sugar levels in males from the sucralose group and females from the stevia group.
Sucralose, stevia and intestinal microbiota: two very different profiles
On a microbial level, both sweeteners modified the composition of intestinal bacteria. The exposed mice displayed a more diverse microbiota, but with fewer species considered beneficial and more potentially pathogenic bacteria, especially with sucralose. These changes, as well as a drop in short chain fatty acids produced by the bacteria, persisted in the following two generations, a sign of a lasting effect on the intestinal ecosystem. Short-chain fatty acids are essential for intestinal well-being because they nourish the cells forming the lining of the colon, called colonocytes. They can help alleviate a variety of intestinal problems, ranging from minor disorders to chronic illnesses and even cancer.
The researchers also studied key genes in inflammation, intestinal barrier function, and hepatic and intestinal metabolism. Scientists found that sweeteners produced different effects, which changed over time:
- In the first generation, only male offspring of mice that ingested sucralose showed signs of glucose intolerance. However, from the second generation, fasting hyperglycemia was observed in the male descendants of mice that consumed sucralose, as well as in the female descendants of mice that consumed stevia.
- Both groups of mice that ingested sweeteners had a more diverse gut microbiota, but with reduced levels of short-chain fatty acids, indicating less production of beneficial metabolites by the bacteria. Subsequent generations also showed lower concentrations of these fatty acids. Mice that consumed sucralose were more severely and lastingly affected by changes in the gut microbiota, with a greater presence of pathogenic species and a decrease in beneficial bacterial species in their feces.
- Additionally, sucralose appears to stimulate the expression of genes associated with inflammation and reduce the expression of genes related to metabolism over two generations after its consumption. Stevia also influences gene expression, but its effects are less pronounced and are not passed down beyond one generation.
“When we compared generations, these effects were generally more pronounced in the first generation and tended to diminish in the second.”said Dr. Francisca Concha Celume. “Overall, sucralose-related effects were more consistent and persistent across generations.”.
What do these results mean for future human generations?
According to the expert, the changes observed could be interpreted as early biological signals linked to metabolic or inflammatory processes. More clearly, it is possible that such changes may increase susceptibility to metabolic disorders under certain conditions, such as a high-fat diet.
The experiment remains carried out in mice and does not prove that these phenomena occur in humans, but it suggests a risk of intergenerational effects on future generations linked to microbiota and epigenetics. For the team, the goal is not to panic the public. Dr. Francisca Concha Celume summarizes: “It may be reasonable to consider moderation in the consumption of these additives and to continue to study their long-term biological effects.”.