https://www.weizmann.ac.il/immunology/elinav/sites/immunology.elinav/files/personalized_nutrition_by_prediction_of_glycemic_responses_0.pdf

Personalized Nutrition by Prediction of Glycemic Responses

Recent studies have suggested that the intestinal microbiome plays an important role in modulating risk of several chronic diseases, including inflammatory bowel disease, obesity, type 2 diabetes, cardiovascular disease, and cancer. At the same time, it is now understood that diet plays a significant role in shaping the microbiome, with experiments showing that dietary alterations can induce large, temporary microbial shifts within 24 h. Given this association, there may be significant therapeutic utility in altering microbial composition through diet. This review systematically evaluates current data regarding the effects of several common dietary components on intestinal microbiota. We show that consumption of particular types of food produces predictable shifts in existing host bacterial genera. Furthermore, the identity of these bacteria affects host immune and metabolic parameters, with broad implications for human health. Familiarity with these associations will be of tremendous use to the practitioner as well as the patient.

/pdf/influence-of-diet-on-the-gut-microbiome-and-implications-for-4i0trq9u9q.pdf

Influence of diet on the gut microbiome and implications for human health.

The interplay between the commensal microbiota and the mammalian immune system development and function includes multifold interactions in homeostasis and disease. The microbiome plays critical roles in the training and development of major components of the host’s innate and adaptive immune system, while the immune system orchestrates the maintenance of key features of host-microbe symbiosis. In a genetically susceptible host, imbalances in microbiota-immunity interactions under defined environmental contexts are believed to contribute to the pathogenesis of a multitude of immune-mediated disorders. Here, we review features of microbiome-immunity crosstalk and their roles in health and disease, while providing examples of molecular mechanisms orchestrating these interactions in the intestine and extra-intestinal organs. We highlight aspects of the current knowledge, challenges and limitations in achieving causal understanding of host immune-microbiome interactions, as well as their impact on immune-mediated diseases, and discuss how these insights may translate towards future development of microbiome-targeted therapeutic interventions.

/pdf/interaction-between-microbiota-and-immunity-in-health-and-2f4xu1il6h.pdf

Interaction between microbiota and immunity in health and disease

The gastrointestinal microbiota has an important role in human health, and there is increasing interest in utilizing dietary approaches to modulate the composition and metabolic function of the mic...

https://www.tandfonline.com/doi/pdf/10.1080/19490976.2017.1290756

Dietary fiber and prebiotics and the gastrointestinal microbiota.

Since the renaissance of microbiome research in the past decade, much insight has accumulated in comprehending forces shaping the architecture and functionality of resident microorganisms in the human gut. Of the multiple host-endogenous and host-exogenous factors involved, diet emerges as a pivotal determinant of gut microbiota community structure and function. By introducing dietary signals into the nexus between the host and its microbiota, nutrition sustains homeostasis or contributes to disease susceptibility. Herein, we summarize major concepts related to the effect of dietary constituents on the gut microbiota, highlighting chief principles in the diet-microbiota crosstalk. We then discuss the health benefits and detrimental consequences that the interactions between dietary and microbial factors elicit in the host. Finally, we present the promises and challenges that arise when seeking to incorporate microbiome data in dietary planning and portray the anticipated revolution that the field of nutrition is facing upon adopting these novel concepts.

You are what you eat: diet, health and the gut microbiota.

The involvement of the gut microbiota in metabolic disorders, and the ability of whole grains to affect both host metabolism and gut microbial ecology, suggest that some benefits of whole grains are mediated through their effects on the gut microbiome. Nutritional studies that assess the effect of whole grains on both the gut microbiome and human physiology are needed. We conducted a randomized cross-over trial with four-week treatments in which 28 healthy humans consumed a daily dose of 60 g of whole-grain barley (WGB), brown rice (BR), or an equal mixture of the two (BR+WGB), and characterized their impact on fecal microbial ecology and blood markers of inflammation, glucose and lipid metabolism. All treatments increased microbial diversity, the Firmicutes/Bacteroidetes ratio, and the abundance of the genus Blautia in fecal samples. The inclusion of WGB enriched the genera Roseburia, Bifidobacterium and Dialister, and the species Eubacterium rectale, Roseburia faecis and Roseburia intestinalis. Whole grains, and especially the BR+WGB treatment, reduced plasma interleukin-6 (IL-6) and peak postprandial glucose. Shifts in the abundance of Eubacterium rectale were associated with changes in the glucose and insulin postprandial response. Interestingly, subjects with greater improvements in IL-6 levels harbored significantly higher proportions of Dialister and lower abundance of Coriobacteriaceae. In conclusion, this study revealed that a short-term intake of whole grains induced compositional alterations of the gut microbiota that coincided with improvements in host physiological measures related to metabolic dysfunctions in humans.

/pdf/gut-microbiome-composition-is-linked-to-whole-grain-induced-1zab45zkwe.pdf

Gut microbiome composition is linked to whole grain-induced immunological improvements

This study sought to assess criterion validity of the Actical monitor step-count function in children via ankle and waist placement, compared with observed video recordings. Children attending a summer program (12 boys, 7 girls, mean age = 9.6yrs, range 7–11yrs) wore two synchronized Acticals, attached at the ankle (AA) and waist (AW). Children performed treadmill walking at varying speeds, and two research assistants counted steps using observed video recordings (OVR). Results showed high correlations for AW-OVR (r = .927, p 11.2, p < .001). AW provided better step estimates than AA for step rates above 130 steps per minute. In contrast, AA was superior to AW for slow walking, and measured more steps during the (nontreadmill) program time. Overall, the Actical monitor showed good evidence of validity as a measure of steps in children for population-based studies.

/pdf/validity-of-the-actical-accelerometer-step-count-function-in-1qpb1fd3b6.pdf

Validity of the Actical accelerometer step-count function in children.

Validity of the Actical accelerometer step count function in children

The glycemic index (GI) is used to rank foods based on postprandial blood glucose response. GI test requires that 50 g of available carbohydrate be used. Available carbohydrate is often calculated as total carbohydrate minus dietary fiber; yet, AOAC fiber methods do not always include resistant starch (RS). The objective of this study was to examine GI response and fermentation properties of crystalline short-chain α-glucan (CSCA), which has high RS content, but no total dietary fiber (TDF) content as measured by AOAC method 991.43. Using the standard GI method, 10 adults were fed 50 g of waxy maize starch and CSCA, consumed alone and in mixed formulation. Breath hydrogen was also determined over 6 h. Fifty grams of CSCA was not entirely available in vivo, and breath hydrogen testing indicated that CSCA was as likely to ferment. Products high in RS, but with no TDF, would yield reduced GI values, and this calls for the need of a method to define available carbohydrate.

Casey Weber

Papers

Gut microbiome composition is linked to whole grain-induced immunological improvements

Validity of the Actical accelerometer step-count function in children.

Validity of the Actical accelerometer step count function in children

Glycemic Response and Fermentation of Crystalline Short Linear α-Glucans from Debranched Waxy Maize Starch.