New Delhi, Apr 10 (PTI) Negative effects of artificial sweeteners, such as sucralose and stevia, on the gut microbiome and gene expression may pass on to the next generation, according to a study in mice.
Studies have linked artificial sweeteners with gastrointestinal and neurological issues, including headache, and with metabolic conditions such as cardiovascular risk and diabetes.
"We found it intriguing that despite the growing consumption of these additives, the prevalence of obesity and metabolic disorders such as insulin resistance has not declined," lead author Francisca Concha Celume of the University of Chile said.
"This does not mean that sweeteners are responsible for these trends, but it raises the question of whether they influence metabolism in ways we do not yet fully understand," Concha said.
The study, published in the journal Frontiers in Nutrition, divided 47 male and female mice into three groups, each of which received either plain water or water with a dose of sucralose or stevia, comparable to the amount a human might consume as part of a normal diet.
The groups of mice were then bred for two consecutive generations, both of which received plain water.
Each generation received a test for glucose oral tolerance, which tests insulin resistance -- a warning sign for diabetes. The researchers also took faecal samples to look for changes in the gut microbiome and the concentration of short-chain fatty acids.
The authors wrote, "Sucralose consumption affects glucose tolerance, the expression of liver Srebp1 and intestinal Tnf and Tlr4, faecal microbiota composition and SCFA (short chain fatty acids) concentrations, and these changes are transmitted across generations. The effects of stevia are mainly observed in the F1 (next) generation."
"When we compared generations, these (negative) effects were generally strongest in the first generation and tended to decrease in the second generation. Overall, the effects linked to sucralose were more consistent and persistent across generations," Concha said.
In the first generation, only the male offspring of sucralose-consuming mice showed signs of an impaired glucose tolerance, but by the second generation, an elevated fasting blood sugar was detected in male descendants of sucralose-consuming mice and female descendants of stevia-consuming mice.
Both the groups of mice that consumed sweeteners were found to have more diverse faecal microbiomes but lower levels of short-chain fatty acids, suggesting that the bacteria were producing fewer beneficial metabolites.
Both the succeeding generations also had lower concentrations of short-chain fatty acids.
Sucralose-consuming mice were seen to be more seriously and more persistently affected by changes to the faecal microbiome, with more pathogenic species and fewer beneficial species of bacteria in the faeces.
Sucralose appeared to kick-start the expression of genes linked to inflammation and dampen the expression of those linked to metabolism for two generations after consumption. Stevia also impacts gene expression, but its effects are smaller and are not passed on for more than one generation.
Concha said that the observed changes in glucose tolerance and gene expression could be seen as "early biological signals related to metabolic or inflammatory processes."
For example, the animals did not develop diabetes, but instead showed changes in glucose regulation and expression of genes associated with inflammation and metabolic regulation -- these can increase one's vulnerability to metabolic disturbances under conditions such as a high-fat diet, the author said. PTI KRS
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