Maternal high-fat diet-induced microbiota changes are associated with alterations in embryonic brain metabolites and adolescent behaviour.

The developing central nervous system is highly sensitive to nutrient changes during the perinatal period, emphasising the potential impact of alterations of maternal diet on offspring brain development and behaviour. A growing body of research implicates the gut microbiota in neurodevelopment and behaviour. Maternal overweight and obesity during the perinatal period has been linked to changes in neurodevelopment, plasticity and affective disorders in the offspring, with implications for microbial signals from the maternal gut. Here we investigate the impact of maternal high-fat diet (mHFD)-induced changes in microbial signals on offspring brain development, and neuroimmune signals, and the enduring effects on behaviour into adolescence. We first demonstrate that maternal caecal microbiota composition at term pregnancy (embryonic day 18: E18) differs significantly in response to maternal diet. Moreover, mHFD resulted in the upregulation of microbial genes in the maternal intestinal tissue linked to alterations in quinolinic acid synthesis and elevated kynurenine levels in the maternal plasma, both neuronal plasticity mediators related to glutamate metabolism. Metabolomics of mHFD embryonic brains at E18 also detected molecules linked to glutamate-glutamine cycle, including glutamic acid, glutathione disulphide, and kynurenine. During adolescence, the mHFD offspring exhibited increased locomotor activity and anxiety-like behaviour in a sex-dependent manner, along with upregulation of glutamate-related genes compared to controls. Overall, our results demonstrate that maternal exposure to high-fat diet results in microbiota changes, behavioural imprinting, altered brain metabolism, and glutamate signalling during critical developmental windows during the perinatal period.

Carbohydrates for glycemic control: functional and microbiome aspects.

PURPOSE OF REVIEW: Glycemia goals are used as indicators of control and progression in prediabetes and diabetes. Adopting healthy eating habits is essential. It is worth considering the quality of carbohydrates to help with dietary glycemic control. The present article aims to review recent meta-analyses published in the years 2021-2022 on the effects of dietary fiber and low glycemic index/load (LGI/LGL) foods on glycemic control and how gut microbiome modulation contributes to glycemic control. RECENT FINDINGS: Data involving more than 320 studies were reviewed. The evidence allows us to infer that LGI/LGL foods, including dietary fiber intake, are associated with reduced fasting glycemia and insulinemia, postprandial glycemic response, HOMA-IR, and glycated hemoglobin, which are more evident in soluble dietary fiber. These results can be correlated with changes in the gut microbiome. However, the mechanistic roles of microbes or metabolites implicated in these observations continue to be explored. Some controversial data highlight the need for more homogeneity between studies. SUMMARY: The properties of dietary fiber are reasonably well established for their glycemic homeostasis effects, including the fermentation aspects. Findings of gut microbiome correlations with glucose homeostasis can be incorporated into clinical nutrition practice. Target dietary fiber interventions on microbiome modulation can offer options to improve glucose control and contribute to personalized nutritional practices.