Gut microbial taxa elevated by dietary sugar disrupt memory function

Abstract

Emerging evidence highlights a critical relationship between gut microbiota and neurocognitive development. Excessive consumption of sugar and other unhealthy dietary factors during early life developmental periods yields changes in the gut microbiome as well as neurocognitive impairments. However, it is unclear whether these two outcomes are functionally connected. Here we explore whether excessive early life consumption of added sugars negatively impacts memory function via the gut microbiome. Rats were given free access to a sugar-sweetened beverage (SSB) during the adolescent stage of development. Memory function and anxiety-like behavior were assessed during adulthood and gut bacterial and brain transcriptome analyses were conducted. Taxa-specific microbial enrichment experiments examined the functional relationship between sugar-induced microbiome changes and neurocognitive and brain transcriptome outcomes. Chronic early life sugar consumption impaired adult hippocampal-dependent memory function without affecting body weight or anxiety-like behavior. Adolescent SSB consumption during adolescence also altered the gut microbiome, including elevated abundance of two species in the genus Parabacteroides (P. distasonis and P. johnsonii) that were negatively correlated with hippocampal function. Transferred enrichment of these specific bacterial taxa in adolescent rats impaired hippocampal-dependent memory during adulthood. Hippocampus transcriptome analyses revealed that early life sugar consumption altered gene expression in intracellular kinase and synaptic neurotransmitter signaling pathways, whereas Parabacteroides microbial enrichment altered gene expression in pathways associated with metabolic function, neurodegenerative disease, and dopaminergic signaling. Collectively these results identify a role for microbiota “dysbiosis” in mediating the detrimental effects of early life unhealthy dietary factors on hippocampal-dependent memory function.

Age-Related Cognitive Decline May Be Moderated by Frequency of Specific Food Products Consumption

“…Eating more white meat and fish was related to better memory in the older group and, conversely, consuming more red meat and animal fat was accompanied by lower scores on the memory task. Those findings are especially interesting in light of the recently published paper by Noble et al (2021) on the impact of an unhealthy diet on rat memory performance and the hippocampus [ 65 ]. The results in our research support the idea that diet may be a protective (or worsening) factor in age-related cognitive decline.…”

Effect of High-Fat Diet on the Intestinal Flora in Letrozole-Induced Polycystic Ovary Syndrome Rats

“…Patients with type 2 diabetes and glucose intolerance had greater numbers of Blautia [ 58 ]. Blautia was also positively correlated with indicators of bodyweight (including waistline and body mass index) and serum lipids (including LDL-C, TC, and TG) [ 59 ]. Parabacteroides enrichment may alter gene expression in pathways associated with metabolic function, neurodegenerative disease, and dopaminergic signaling [ 60 ].…”

Crème de la Créature: Dietary Influences on Behavior in Animal Models

“…In addition to inflammation, hallmarks of insulin resistance—such as higher expression of the insulin receptor and lower levels of glucose transporters—were also measured in the hippocampus, as well as a reduction in synaptic scaffolding proteins and in the levels and phosphorylation of activity-regulated genes such as the Activity-regulated cytoskeleton-associated protein 1, c-Fos and Extracellular-signal Regulated Kinase (ERK; Ha and Redmond, 2008 ; Posey et al, 2009 ; Arnold et al, 2014 ; Kothari et al, 2017 ); this interplay between metabolic changes, memory, and disease has been recently reviewed in Garcia-Serrano and Duarte ( 2020 ). Early life exposure to sugar and memory alterations have also been linked to microbiome changes (Noble et al, 2021 ).…”