The importance of the gut-brain axis in maintaining homeostasis has long been appreciated. However, the past 15 yr have seen the emergence of the microbiota (the trillions of microorganisms within ...

The Microbiota-Gut-Brain Axis

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

https://www.focusopvoeding.nl/wp-content/uploads/2015/05/JAMDA-PROT-AGE-paperBauer.pdf

Evidence-Based Recommendations for Optimal Dietary Protein Intake in Older People: A Position Paper From the PROT-AGE Study Group

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

This study assessed the relationships of urinary D-chiro-inositol and myo-inositol excretions to indices of whole-body glucose tolerance and total content and tyrosine phosphorylation of the insulin receptor (activation) in skeletal muscle of older nondiabetic subjects. Fifteen adults (age, 65 +/- 8 years; body mass index, 27.9 +/- 3.3 kg/m(2) [mean +/- SD]) completed duplicate assessments of oral (75-g oral glucose tolerance test [OGTT]) and intravenous (300 mg/kg body weight intravenous glucose tolerance test) glucose tolerance challenges and 24-hour urinary D-chiro-inositol and myo-inositol excretions. Skeletal muscle (vastus lateralis) biopsies were obtained at minute 60 of the OGTTs. Subjects with higher urinary D-chiro-inositol excretion had higher insulin (rho = 0.51, P < or = .05) and C-peptide (rho = 0.56, P < or = .05) area under the curves, and lower insulin sensitivity index (rho = -0.60, P < or = .05) during the intravenous glucose tolerance test. The urinary myo- to D-chiro-inositol ratio was also inversely related to insulin area under the curve (rho = -0.59, P < or = .05). Urinary D-chiro-inositol (rho = -0.60, P < or = .05) and myo-inositol (rho = -0.60, P < or = .05) were inversely related to tyrosine phosphorylation of the insulin receptor (phosphotyrosine 1162/1163), but not total content of the insulin receptor during the OGTT. The apparent relationships were modestly weakened when adjustments were made for sex. These findings support previous research linking higher urinary D-chiro-inositol excretion with a progressive decline in whole-body glucose tolerance. This is the first report to link higher urinary D-chiro-inositol excretion to a blunted activation of skeletal muscle insulin receptor signaling in older nondiabetic subjects.

Relationships between urinary inositol excretions and whole-body glucose tolerance and skeletal muscle insulin receptor phosphorylation.

Aims The goal of this study was to determine insulin sensitivity in a fasted state and during an oral glucose tolerance test (OGTT), in normoglycemic (NGT), lean (L) (n = 35) and, for comparison, overweight/obese (OW/O) (n = 9) college-aged subjects. Materials and Methods Insulin sensitivity for 44 NGT, normotensive subjects, age 18–26 yrs., was determined by homeostasis model assessment (HOMA-IR) and from Matsuda index (ISI Matsuda). Results Subjects were normoglycemic fasted (4.59  +  0.35 mmol/L) and at two hours post OGTT (4.52  +  1.35 mmol/L). Besides anthropometric measures, there were significant differences between OW/O and L for fasting insulin (P  +  0.51, range 0.3–2.7) and an 8-fold range in ISI Matsuda (11.9  +  4.7, range 3.0–24.2). The latter was inversely correlated with systolic blood pressure (r = 0.35, P = 0.04) even though subjects were normotensive. In lean subjects, 2.3% were IR by HOMA-IR  >  2.1, 5.7% by ISI Matsuda   5.9, and 22.9% had > one criteria for metabolic syndrome (MetS); 28.6% had some negative metabolic biomarker. Conclusions Insulin resistance is present in lean, NGT college-age subjects even without MetS criteria and is discernable with an easily applicable OGTT-derived index.

Insulin resistance and metabolic syndrome criteria in lean, normoglycemic college-age subjects

Methods Healthy men and women ages 19-30 who self-reported 150-450 minutes of aerobic exercise per week were recruited at two different laboratories (n= 48; n= 40). All participants were provided with the same three meals and beverages to consume in the 24 hours before each exercise session. Participants consumed one test beverage, while exercising, during each visit including water, a caloric sports beverage and a non-caloric sports beverage at volumes equal to sweat loss during a previous trial. Participants cycled on an ergometer for 60 min at an intensity that elicited a heart rate between 60-65% of heart rate reserve. A sweat collection patch was placed on the lower back and sweat collected at three timepoints including between 10-20 min, 30-40 min, and 50-60 min of exercise. Sweat was frozen on dry ice, stored at -80°C until analysis. Sweat from 21 males (lab 1), 14 females (lab 1), and 13 females (lab 2) was analyzed. Selected samples were matched for age, BMI, and total sweat loss from the previous trial. Sweat was prepared and analyzed using GC/MS and LC/MS/MS. Data analyses were performed usingtwo-way ANOVAs with repeated measures and ANOVA contrasts on natural log-transformed data and a p-value < 0.05 was considered significant. Results Sweat contained 260 compounds including 143 identified metabolites and technical replicates showed 14% median relative standard deviation. Identified compounds included amino acids, peptides, nucleotides, carbohydrates, xenobiotics, and cellular protectants.Previously identified compounds present in sweat included betaine, lactate, pyruvate, urea, caffeine,several amino acids, and others. Extended periods of exercise resulted in a 2-fold decrease in several metabolites associated with energy metabolism, such as lactate and pyruvate. Exercise reduced glucose levels ~30% at 40 and 60 minutes (p<0.05) in subjects drinking water while no significant decrease in glucose was observed when subjects drank the full calorie sports drink. Prolonged exercise caused a significant decrease (≥ 30%) of several amino acids reflecting the importance of acid-base balance and ammonia detoxification in muscle during exercise. A principal component analysis showed sweat composition from females was similar between the two sites. Prolonged exercise elicited a decrease in the sweat concentration of many metabolites at the end of exercise compared to sweat collected between 10-20min.

/pdf/global-untargeted-metabolic-profiling-of-human-sweat-from-1lakldzvvw.pdf

Mark D. Haub

Papers

Relationships between urinary inositol excretions and whole-body glucose tolerance and skeletal muscle insulin receptor phosphorylation.

Insulin resistance and metabolic syndrome criteria in lean, normoglycemic college-age subjects

Global untargeted metabolic profiling of human sweat from exercising men and women

Sorghum-based dietary intervention enriches Faecalibacterium prausnitzii in fecal samples of overweight individuals

Whey, Casein, and Soy Proteins