Dietary Oligosaccharides Attenuate Stress-Induced Disruptions in Immune Reactivity and Microbial B-Vitamin Metabolism.

Background: Exposure to stressful stimuli dysregulates inflammatory processes and alters the gut microbiota. Prebiotics, including long-chain fermentable fibers and milk oligosaccharides, have the potential to limit inflammation through modulation of the gut microbiota. To determine whether prebiotics attenuate stress-induced inflammation and microbiota perturbations, mice were fed either a control diet or a diet supplemented with galactooligosaccharides, polydextrose and sialyllactose (GOS+PDX+SL) or sialyllactose (SL) for 2 weeks prior to and during a 6-day exposure to a social disruption stressor. Spleens were collected for immunoreactivity assays. Colon contents were examined for stressor- and diet- induced changes in the gut microbiome and metabolome through 16S rRNA gene sequencing, shotgun metagenomic sequencing and UPLC-MS/MS. Results: Stress increased circulating IL-6 and enhanced splenocyte immunoreactivity to an ex vivo LPS challenge. Diets containing GOS+PDX+SL or SL alone attenuated these responses. Stress exposure resulted in large changes to the gut metabolome, including robust shifts in amino acids, peptides, nucleotides/nucleosides, tryptophan metabolites, and B vitamins. Multiple B vitamins were inversely associated with IL-6 and were augmented in mice fed either GOS+PDX+SL or SL diets. Stressed mice exhibited distinct microbial communities with lower abundances of Lactobacillus spp. and higher abundances of Bacteroides spp. Diet supplementation with GOS+PDX+SL, but not SL alone, orthogonally altered the microbiome and enhanced the growth of Bifidobacterium spp. Metagenome-assembled genomes (MAGs) from mice fed the GOS+PDX+SL diet unveiled genes in a Bifidobacterium MAG for de novo B vitamin synthesis. B vitamers directly attenuated the stressor-induced exacerbation of cytokine production in LPS-stimulated splenocytes. Conclusions: Overall, these data indicate that colonic metabolites, including B vitamins, are responsive to psychosocial stress. Dietary prebiotics reestablish colonic B vitamins and limit stress-induced inflammation.

Oral administration of palatinose vs sucrose improves hyperglycemia in normal C57BL/6J mice.

Palatinose is a sucrose analog with a slower digestion rate than that of sucrose. For this reason, palatinose shows better effects on hepatic lipogenesis and cholesterol homeostasis compared with sucrose. We hypothesized that supplementation with palatinose instead of sucrose improves postprandial hyperglycemia and hyperinsulinemia in mice. Herein, we compared the digestion rates in vitro and observed physiological changes in vivo between sucrose- and palatinose-containing diets given to mice. Palatinose was hydrolyzed only by enzymes of the small intestine and was digested more slowly compared with sucrose in vitro. In mice, a diet containing palatinose resulted in significantly lower body weight gain and food efficiency rate values than those given a diet with sucrose. In this study, changes in serum biochemistry; hepatic fatty acid synthesis; cholesterol homeostasis; glucogenic, proinflammatory cytokines; and oxidative stress-related genes and proteins in the palatinose- and sucrose-fed mice were measured. Compared with the mice fed the sucrose diet, the palatinose diet resulted in lower serum glucose, insulin, and total cholesterol levels, as well as lower expression of several lipogenesis-related genes and proteins. Histological analysis of hepatic cells of palatinose-fed mice showed normal morphology. In conclusion, palatinose intake results in lower hepatic lipogenesis and better cholesterol homeostasis than the effects from sucrose.

The Effects of Carbohydrates, in Isolation and Combined with Caffeine, on Cognitive Performance and Mood-Current Evidence and Future Directions.

This review examines the effects of carbohydrates, delivered individually and in combination with caffeine, on a range of cognitive domains and subjective mood. There is evidence for beneficial effects of glucose at a dose of 25 g on episodic memory, but exploration of dose effects has not been systematic and the effects on other cognitive domains is not known. Factors contributing to the differential sensitivity to glucose facilitation include age, task difficulty/demand, task domain, and glucoregulatory control. There is modest evidence to suggest modulating glycemic response may impact cognitive function. The evidence presented in this review identifies dose ranges of glucose and caffeine which improve cognition, but fails to find convincing consistent synergistic effects of combining caffeine and glucose. Whilst combining glucose and caffeine has been shown to facilitate cognitive performance and mood compared to placebo or glucose alone, the relative contribution of caffeine and glucose to the observed effects is difficult to ascertain, due to the paucity of studies that have appropriately compared the effects of these ingredients combined and in isolation. This review identifies a number of methodological challenges which need to be considered in the design of future hypothesis driven research in this area.

Optimizing the management of hypoglycaemia in individuals with type 2 diabetes: A randomized crossover comparison of a weight-based protocol compared with two fixed-dose glucose regimens.

AIMS: To determine whether an individualized body weight-based glucose treatment in adults with type 2 diabetes (T2DM) is more likely to resolve hypoglycaemia with a single treatment without excessive rebound hyperglycaemia compared to fixed doses of 12 or 30 g of glucose. METHODS: Adults with T2DM were enrolled in a cross-over study. Each episode of hypoglycaemia (capillary glucose <4.0 mmol/L) was randomly assigned to 1 of 3 treatment protocols: 0.3 g glucose/kg body-weight or a fixed dose of either 12 or 30 g glucose, independent of weight. All participants received each treatment in random order for up to 15 hypoglycaemic episodes. Glucose was re-tested 10 minutes after treatment, with a repeat dose if still <4 mmol/L. RESULTS: Mean (SD) age of the 30 participants was 68 (8.1) years, mean weight was 91.5 (16.8) kg and mean HbA1c was 58.7 (9.2) mmol/mol. Among a total of 244 episodes of hypoglycaemia, 10 participants had 15 treatment episodes and 18 participants had fewer than 10 treatment episodes. The odds ratio, adjusted for multiple comparisons, for resolution of hypoglycaemia at 10 minutes, comparing weight-based treatment and 12 g treatment was 3.2 (95% CI, 1.1-9.0), P = .009, comparing 30 g treatment and 12 g treatment was 8.9 (95% CI, 2.2-36.6), P < .001, and comparing weight-based treatment and 30 g treatment was 0.36 (95% CI, 0.08-1.67) P = .10. CONCLUSION: In T2DM, both a weight-based 0.3 g/kg treatment and a fixed 30 g glucose treatment result in higher blood glucose than a 12 g treatment, along with increased probability of resolution of hypoglycaemia after 10 minutes. Both treatments result in an excess of mild rebound hyperglycaemia (>8 mmol/L) at 30 minutes.