Molecular weight of barley β-glucan does not influence satiety or energy intake in healthy male subjects

Dietary Supplements Containing Oat Beta-Glucan and/or Green Coffee (Poly)phenols Showed Limited Effect in Modulating Cardiometabolic Risk Biomarkers in Overweight/Obese Patients without a Lifestyle Intervention

Obesity has reached pandemic proportions and has become a major health concern worldwide. Therefore, it is necessary to find new strategies against this condition and its associated comorbidities. Green coffee polyphenols (GCP) and oat beta-glucans (BGs) have proven their hypolipidaemic and hypoglycaemic effects. This study aimed to examine the effects of the long-term consumption of supplements containing GCP, BG or the novel GCP/BG combination on lipid and glucose metabolism biomarkers in overweight/obese subjects who maintained their dietary habits and physical activity, hence addressing the difficulty that this population faces in adapting to lifestyle changes. A randomised, crossover, blind trial was carried out in 29 volunteers who consumed either GCP (300 mg), BG (2.5 g) or GCP/BG (300 mg + 2.5 g) twice a day for 8 weeks. Blood samples were collected, and blood pressure and body composition were measured at the beginning and end of each intervention. Total cholesterol, triglycerides, high-density lipoprotein (HDL-C), low-density lipoprotein (LDL-C), very low-density lipoprotein (VLDL-C) cholesterol, glycated haemoglobin, fasting glucose, insulin, aspartate transaminase, alanine transaminase and different hormones and adipokines were analysed. Only VLDL-C (p = 0.01) and diastolic blood pressure (p = 0.027) decreased after the intervention, especially with the BG supplement. There were no other significant changes in the analysed biomarkers. In conclusion, the regular intake of GCP, BG and GCP/BG without lifestyle changes is not an efficient strategy to improve lipid and glucose homeostasis in overweight/obese subjects.

Effects of whole-grain barley and oat β-glucans on postprandial glycemia and appetite: a randomized controlled crossover trial

This study aimed to determine the postprandial effects of barley bread (BB) and oat bread (OB), grain sources of β-glucans, on glycaemia and appetite by comparison with white bread (WB) and whole-wheat bread (WWB). This randomized controlled crossover trial included 20 healthy individuals (10 males and 10 females) who consumed WB, WWB, BB, and OB with a standard breakfast followed by an ad libitum lunch. Postprandial glucose and appetite responses were quantified as the incremental area under the curve (iAUC). Although the iAUC for glycaemic response was lower by 23.7%, 29.9%, and 27.9% after the consumption of BB, OB, and WWB compared with WB (p = 0.023), no differences were observed between BB, OB, and WWB (p > 0.05). BB had a lower iAUC for appetite sensation by 21.5%, 23.9%, and 55.7% compared with WB, WWB, and OB (p = 0.005). OB had no effect on appetite and was also less palatable than BB. Subsequent food intakes were similar after the consumption of all test breads (p > 0.05). The encouragement of healthier bread formulations that can beneficially modulate postprandial glycemia and appetite may contribute to the promotion of public health. This trial was registered at ClinicalTrials.gov as NCT04749498.

Systematic assessment of oat β-glucan catabolism during in vitro digestion and fermentation

β-Glucan as a component of grain cell walls is consumed daily. However, little is known about whether β-glucan is influenced by the gastrointestinal environment. In this study, we aim to investigate the integrated metabolic process of cereal β-glucan. In vitro simulated digestion and fermentation combined with microbiome and metabolome analysis were used to profile the metabolism of β-glucan. Intriguingly, we found that β-glucan was not hydrolyzed by digestive enzymes but partially degraded by gastric acid environment during in vitro digestion. Moreover, β-glucan was utilized by gut microbiota to produce acetate, propionate and butyrate, concurrently, the relative abundance of Lactobacillus significantly increased and Escherichia-Shigella significantly decreased. The correlation analysis between metabolomics datasets and microorganisms revealed that β-glucan catabolism was also accompanied by amino acid catabolism and linoleic acid biosynthesis. Our study offered a forceful basis for the further exploration of the role of β-glucan and gut microbiota in host health.

Reformulation of Pastry Products to Improve Effects on Health

Obesity is increasing at an alarming rate and has been described as a global pandemic. This increase has several explanations, including an increase in caloric intake, low levels of physical activity and the nutritional composition of our diets. In addition to public health policies based on healthy dietary patterns and recommendations based on the Mediterranean and other healthy diets, food reformulation, especially of commonly consumed processed foods, such as bakery products and pastries, is needed in the fight against obesity. Among nutritional reformulation strategies, reductions in caloric density, salt, added sugar, saturated and trans-fats are important in order to reduce the associated risk of developing chronic diseases, including cardiovascular diseases, diabetes and cancer.

Increasing oat β-glucan viscosity in a breakfast meal slows gastric emptying and reduces glycemic and insulinemic responses but has no effect on appetite, food intake, or plasma ghrelin and PYY responses in healthy humans: a randomized, placebo-controlled, crossover trial

BACKGROUND

The viscosity of oat β-glucan (OBG) determines its effect on serum cholesterol and glycemic responses, but whether OBG viscosity affects gastric emptying, appetite, and ad libitum food intake is unknown.

OBJECTIVES

We aimed to determine the effect of altering the amount or molecular weight (MW) and, hence, viscosity of OBG in a breakfast meal on the primary endpoint of food intake at a subsequent meal.

METHODS

Overnight-fasted males (n = 16) and nonpregnant females (n = 12) without diabetes, aged 18-60 y, with BMI 20.0-30.0 kg/m² who were unrestrained eaters participated in a double-blind, randomized, crossover study at a contract research organization. Participants consumed, in random order, breakfast meals equivalent in weight, energy, and macronutrients consisting of white-bread, butter, jam, and 2% milk plus hot cereal [Cream of Rice (CR), or instant-oatmeal plus either 3 g oat-bran (2gOBG), 10 g oat-bran (4gOBG), or 10 g oat-bran plus β-glucanase (4gloMW) to reduce OBG MW and viscosity compared with 4gOBG]. Gastric emptying, subjective appetite, and glucose, insulin, ghrelin, and peptide tyrosine tyrosine (PYY) responses were assessed for 3 h and then subjects were offered an ad libitum lunch (water and pizza).

RESULTS

Pizza intakes (n = 28) after CR, 2gOBG, 4gOBG, and 4gloMW (mean ± SEM: 887 ± 64, 831 ± 61, 834 ± 78, and 847 ± 68 kcal, respectively) were similar (nonsignificant). Compared with CR, 4gOBG significantly reduced glucose (78 ± 10 compared with 135 ± 15 mmol × min/L) and insulin (14.0 ± 1.6 compared with 26.8 ± 3.5 nmol × min/L) incremental area-under-the-curve and delayed gastric-emptying half-time (geometric mean: 285; 95% CI: 184, 442, compared with geometric mean: 105; 95% CI: 95, 117 min), effects not seen after 4gloMW. Subjective appetite, PYY, and ghrelin responses after 2gOBG, 4gOBG, and 4gloMW were similar to those after CR.

CONCLUSIONS

The results demonstrate that OBG viscosity determines its effect on postprandial glucose, insulin, and gastric emptying. However, we were unable to demonstrate a significant effect of OBG on appetite or food intake, regardless of its viscosity.This trial was registered at clinicaltrials.gov as NCT03490851.

Cereal B-Glucans: The Impact of Processing and How It Affects Physiological Responses

Cereal β-glucans are dietary fibres primarily found in oats and barley, and have several positive effects on health, including lowering the postprandial glucose response and the improvement of blood cholesterol levels. Cereal β-glucans have a specific combination of β-(1→4) and β-(1→3) linkages into linear long-chain polysaccharides of high molecular weight. Due to their particular structure, cereal β-glucans generate viscosity within the intestinal tract, which is thought to be the main mechanism of action responsible for their positive health effects. However, cereal grains are rarely consumed raw; at least one cooking step is generally required before they can be safely eaten. Cooking and processing methods more generally will modify the physicochemical characteristics of β-glucans, such as molecular weight, extractability and the resulting viscosity. Therefore, the health impact of β-glucans will depend not only on the dose administered, but also on the ways they are processed or converted into food products. This review aims at summarizing the different parameters that can affect β-glucans efficacy to improve glucose and lipid metabolism in humans.

Coconut oil has less satiating properties than medium chain triglyceride oil

It is well established that the consumption of medium-chain triglycerides (MCT) can increase satiety and reduce food intake. Many media articles promote the use of coconut oil for weight loss advocating similar health benefits to that of MCT. The aim of this study was to examine the effect of MCT oil compared to coconut oil and control oil on food intake and satiety. Following an overnight fast, participants consumed a test breakfast smoothie containing 205kcal of either (i) MCT oil (ii) coconut oil or (iii) vegetable oil (control) on three separate test days. Participants recorded appetite ratings on visual analogue scales and were presented with an ad libitum lunch meal of preselected sandwiches 180min after consumption of the breakfast. The results showed a significant difference in energy and macronutrient intakes at the ad libitum meal between the three oils with the MCT oil reducing food intake compared to the coconut and control oil. Differences in food intake throughout the day were found for energy and fat, with the control having increased food intake compared to the MCT and coconut. The MCT also increased fullness over the three hours after breakfast compared to the control and coconut oils. The coconut oil was also reported as being less palatable than the MCT oil. The results of this study confirm the differences that exist between MCT and coconut oil such that coconut oil cannot be promoted as having similar effects to MCT oil on food intake and satiety.