Whole Wheat and Bran Cereal Affects Microbiome Stability

Objectives Health outcomes in previous fiber intervention studies have been variable, potentially due to differences in gut microbiome composition. This study aimed to determine if the effect of fiber intervention on the microbiome differs by initial microbiome or the quantity of fiber provided. Methods This study was designed as a randomized, un-blinded, cross-over trial of fiber cereal dosage. The cross-over design tested the effect of two 2-week long interventions with a High (28g) and Low (14g) level of daily supplemental fiber from whole wheat and bran cereal. Analysis was also completed on the overall study as a single arm, non-randomized, intervention of fiber cereal. The study enrolled 31 healthy adults. The microbiome was assessed at baseline and after intervention for changes in diversity, composition, and stability. Results Across all individuals, fiber intervention increased microbiome alpha-diversity (paired t-test, P = 0.047), but the microbiome was otherwise resistant to the effects of the intervention. Increasing fiber dose (High v. Low) was not associated with consistent changes in beta-diversity (linear mixed models). Approximately 20% of subjects were identified as responders based on beta diversity effect size. At baseline, responders had higher Prevotella copri and lower Bacteroides abundance than non-responders (Wilcoxon rank sum, qval < 0.05). In responders, fiber intake caused increased abundance of Bacteroides and Alistipes and reduced Prevotella (paired Wilcoxon, q < 0.2). In all subjects, fiber intervention decreased microbiome stability (paired Wilcoxon signed rank test, P = 0.006). In responders, there was a significant effect of the fiber level on stability, with higher fiber further lowering stability (linear mixed model, P = 0.05). Conclusions Our data suggest a responder/non-responder microbiome signature for this whole wheat and bran fiber cereal. We find that many effects were not additive by dosage level. Overall, microbiome diversity was increased and stability was decreased during the fiber cereal intervention and in responders this was dose dependent; the clinical implications of the impact of changes in stability remain unknown, and it is possible that the microbiome would stabilize in a longer intervention study. ClinicalTrials.gov identifier: NCT03623308. Funding Sources General Mills, Inc.

Effect of High Fiber Cereal Intake on Satiety and Gastrointestinal Symptoms during Ramadan

(1) Background: Fasting during Ramadan involves large changes in daily eating patterns which strongly impacts the daily biorhythm and challenges the regular function of the digestive tract. The aim of this study was to assess satiety, bowel habits, body composition, blood glycaemia, and blood lipidemia after the consumption of high fiber cereal at dawn (Sohor) during the month of Ramadan; (2) Methods: A two-arm randomized, controlled, single-blinded, parallel-design study was conducted in Ramadan month. Participants were randomized to consume either 90 g of high fiber cereal (11 g fiber/90 g) at Sohor for 20 consecutive days (intervention group, n = 45) or to maintain their habitual diet intake (control group; n = 36); (3) Results: The intervention group reported higher satiety rating scores, improved bowel habits and reduced bloating frequency after the 20-day intervention. Significantly higher intake of carbohydrates and dietary fiber were observed in the intervention group. Total cholesterol and low density lipoprotein (LDL) cholesterol were significantly lower among the intervention group compared to the control group (p-value = 0.043, and p-value = 0.033, respectively) at the end of the intervention. No significant differences in body weight, body fat percentage, waist circumference, body mass index, blood glucose, high density lipoprotein (HDL) cholesterol, and triglycerides were observed between the two groups; (4) Conclusions: Consuming high fiber cereal had a positive effect on health and well-being during the month of Ramadan with better satiety, improved bowel functions, and improved blood lipids.

Effects of Oatmeal and Corn Flakes Cereal Breakfasts on Satiety, Gastric Emptying, Glucose, and Appetite-Related Hormones

Objective: The extent to which different types of breakfasts affect appetite and food intake is unclear. To assess the satiety effects of a high-fiber cereal, we compared oatmeal, isocaloric corn flakes, and water. Subjects/Methods: Thirty-six subjects (18 lean, 18 overweight) were assigned to three conditions in a randomized sequence on different days. Ratings of hunger and fullness were obtained concurrently with blood samples for measuring concentrations of glucose, insulin, glucagon, leptin, and acetaminophen (gastric emptying tracer). Appetite was assessed by calculating the area under the curve (AUC) for fullness and hunger, and by measuring food intake of an ad libitum lunch meal at 180 min. Results: Lunch meal intake was lowest after consuming oatmeal (p < 0.00001), which was lower for overweight subjects than lean subjects (p = 0.007). Fullness AUC was greatest (p = 0.00001), and hunger AUC lowest (p < 0.001) after consuming oatmeal. At 180 min, blood glucose was lowest after the corn flakes (p = 0.0001). Insulin AUC was greater for both cereals than water (p < 0.00001). Leptin AUC and glucagon AUC values did not differ between conditions. Acetaminophen concentrations peaked latest after consuming oatmeal (p = 0.046), reflecting slower gastric emptying. Conclusions: Satiety was greater and ad libitum test meal intake lower after consuming oatmeal than after corn flakes, especially in the overweight subjects.

Application of roasted rice bran in cereal bars

The objective of this study was to evaluate the viability of using microwave-roasted rice bran as an ingredient in high-fiber cereal bars to obtain a product with good acceptability. The influence of the rice flakes, corn flakes, and roasted rice bran levels on the physical and chemical characteristics of the cereal bars was studied. The overall acceptability of three selected formulations was also evaluated. An increase in the roasted rice bran level in the formulation reduced the force of rupture and water activity, resulted in intermediate density, and caused darkening of the bars. The contents of lipid and total dietary fiber were higher in the formulation with the highest rice bran content, which was therefore classified as functional food. The formulation containing 0.34; 0.32; and 0.34 roasted rice bran, rice flakes, and corn flakes, respectively, seemed to be the best outcome. Cereal bars with roasted rice bran levels between 10 and 20% were accepted by consumers.