In an evolving health landscape, emerging research continues to highlight concerns that could impact everyday wellbeing. Here’s the key update you should know about:
A new mouse study suggests that sweeteners consumed by parents may reshape gut bacteria, microbial metabolites, and metabolic signals in offspring, with sucralose leaving the strongest multigenerational imprint.
Study: Artificial and natural non-nutritive sweeteners drive divergent gut and genetic responses across generations. Image Credit: Andrii Zastrozhnov / Shutterstock
In a recent study published in the journal Frontiers in Nutrition, researchers showed that non-nutritive sweeteners (NNS) elicit divergent genetic and gut responses across generations.
High-sugar diets promote adiposity, hyperinsulinemia, and impaired glucose tolerance, and are associated with a higher risk of noncommunicable diseases in children and adults. NNS, such as aspartame, saccharin, acesulfame K, stevia, sucralose, and cyclamate, are widely used as non-calorific sugar substitutes. NNS consumption has substantially increased across all age groups, including women of childbearing age.
According to a survey in the United States (US), more than 140 million adults used NNS in 2020. Furthermore, a recent World Health Organization (WHO) guideline suggests that long-term NNS use may be associated with adverse effects, such as a higher risk of cardiovascular disease and diabetes. Despite the pervasive NNS usage by women of childbearing age, the impact of parental intake of NNS on offspring is understudied.
Parental NNS Mouse Study Design
In the present study, researchers evaluated how parental intake of stevia or sucralose influences fecal microbiota (FM) and short-chain fatty acid (SCFA) production, hepatic and intestinal gene expression, and whether any changes are transmitted to the offspring. First, four-week-old male and female mice (parental, or F0, generation) were randomized to receive water (control) or water supplemented with stevia or sucralose for 16 weeks.
Mice from the same group were crossed at week 6. Four weeks after lactation, the first (F1) generation was weaned and followed until 20 weeks of age. Unrelated F1 mice from the same group were crossed to produce the second (F2) generation. F1 and F2 animals received only standard chow and pure water, without direct NNS exposure. Changes in food and water intake and body weight were monitored every week.
At week 20, mice from all generations were euthanized, and hepatic and ileal tissues were harvested. Before euthanasia, an oral glucose tolerance test (OGTT) was performed. Further, fecal samples were obtained before euthanasia from each generation and group. FM composition was assessed using 16S ribosomal ribonucleic acid (rRNA) gene sequencing. SCFAs were quantified using gas chromatography.
Total ribonucleic acid (RNA) was extracted from intestinal and hepatic tissues to quantify the expression of genes involved in inflammation (tumor necrosis factor [Tnf] and toll-like receptor 4 [Tlr4]), gut barrier function (tight junction protein 1 [Tjp1]), and metabolism (sterol-regulatory element-binding protein 1 [Srebp1]). The Kruskal-Wallis test and the post hoc Dunn test were used to compare inter-generational and inter-group differences.
Stevia and Sucralose Glycemic Findings
The OGTT test showed no differences in glucose levels between the control and sucralose groups in F0 mice. Nevertheless, males in the stevia group showed lower glucose levels at 120 minutes than those in the sucralose and control groups. Male F1 mice in the sucralose group had lower glucose levels than those in the stevia and control groups, although glycemic changes were overall modest and selective. F2 females in the stevia group had higher fasting glycemia.
In contrast, F2 males in the sucralose group had lower glycemia than the stevia group and higher fasting glucose than controls. There were no inter-generational changes in glycemia for the control group. NNS intake did not affect intestinal Tjp1 expression in F0 animals and the offspring. In contrast, sucralose was associated with elevated Tnf and Tlr4 expression in the intestine and reduced hepatic Srebp1 expression in F0 mice relative to controls.
![Experimental design for intergenerational exposure to sucralose and stevia. At 4 weeks of age, non-consanguineous, primiparous female and male C57BL/6J mice [parental (F0) generation] were randomly distributed into three groups to receive water alone (control) or water supplemented with sucralose (0.1 mg/ml) or stevia (0.1 mg/ml) for 16 weeks. To assess the intergenerational effect of non-nutritive sweeteners (NNSs), F0 mice belonging to the same treatment group were mated at 10 weeks of age. After 4 weeks of lactation, the F1 offspring were weaned and followed until 20 weeks of age. F1 and F2 generations did not receive direct NNS exposure. All mice were maintained under identical housing and husbandry conditions, including the same animal room, cage type and bedding, chow batch, water source and bottle cleaning protocol, and standardized cage cleaning schedule.](https://www.news-medical.net/images/news/ImageForNews_835077_17761227849093569.jpg)
Experimental design for intergenerational exposure to sucralose and stevia. At 4 weeks of age, non-consanguineous, primiparous female and male C57BL/6J mice [parental (F0) generation] were randomly distributed into three groups to receive water alone (control) or water supplemented with sucralose (0.1 mg/ml) or stevia (0.1 mg/ml) for 16 weeks. To assess the intergenerational effect of non-nutritive sweeteners (NNSs), F0 mice belonging to the same treatment group were mated at 10 weeks of age. After 4 weeks of lactation, the F1 offspring were weaned and followed until 20 weeks of age. F1 and F2 generations did not receive direct NNS exposure. All mice were maintained under identical housing and husbandry conditions, including the same animal room, cage type and bedding, chow batch, water source and bottle cleaning protocol, and standardized cage cleaning schedule.
Gut Microbiota and SCFA Changes Across Generations
In F1 animals, intestinal Tnf and Tlr4 were overexpressed in NNS groups relative to controls, and these changes were normalized in F2 mice. In F0 animals, alpha diversity did not differ between groups, but the Shannon index was higher in the stevia group than in the sucralose and control groups. Beta diversity exhibited significant differences across groups.
In F1 mice, the sucralose group had more observed species than controls; the Shannon index was higher in NNS groups than in controls, and the beta diversity differed across groups. In F2 animals, the sucralose group had more observed species and a higher Shannon index than the stevia and control groups; the beta-diversity differences persisted in this generation. The control group showed no inter-generational differences in alpha or beta diversity.
Further, NNS intake induced substantial changes in the FM composition in F0 and F1 animals, especially in the sucralose group. Moreover, the NNS-related changes in the FM composition were transmitted to the F1 generation but were partially restored in the F2 generation. In the F0 generation, NNS groups showed lower fecal valerate and acetate levels than controls, with no differences in butyrate and propionate levels or in SCFA proportions.
In the F0 generation, total SCFA levels were lower in NNS groups than in controls. In F1 animals, acetate, butyrate, valerate, and propionate levels were significantly reduced in the sucralose group. In F2 mice, the sucralose group had lower propionate and acetate levels, and the stevia group had lower valerate, butyrate, acetate, and propionate levels than controls. Total SCFA levels were lower in NNS groups.
Transgenerational Health Implications of NNS Exposure
Together, parental NNS intake induced inter-generational changes in gut microbiota composition, microbial metabolite production, host glycemic responses, and hepatic and intestinal gene expression in the offspring. These findings challenge the assumption that NNS are metabolically inert and highlight their potential to impact offspring health. Overall, sucralose showed the stronger and more persistent transgenerational signal, whereas stevia-related effects were more prominent in F1, and several changes were attenuated by F2. Further research is needed to delineate the underlying mechanisms and relevance to human health.
