The effect of cereal Β-glucan on body weight and adiposity: A review of efficacy and mechanism of action.

The current review examines the totality of the evidence to determine if there exists a relationship between ß-glucan and body weight and adiposity and whether such a relationship is a consistent, causal and plausible one. Observational studies suggest an association between oat (i.e., ß-glucan) intake and reduced body weight, waist circumference and adiposity. High and moderate quality randomized controlled trials that were specifically designed to evaluate the efficacy of ß-glucan on anthropometric outcomes were given the highest weight. Several of these studies indicated a causal relationship between ß-glucan consumption and reduction in body weight, BMI, and at least one measure of body fat within diets that were not calorie-restricted. A review of additional animal and human evidence suggests multiple plausible mechanisms by which ß-glucan may impact satiety perception, gastric emptying, gut hormones, gut microbiota and short chain fatty acids in the complex interplay of appetite and energy regulation.Supplemental data for this article is available online at http://dx.doi.org/10.1080/10408398.2021.1994523.

The effect of extracted and isolated fibers on appetite and energy intake: A comprehensive review of human intervention studies.

In light of the increasing prevalence of obesity and cardiometabolic diseases, the underconsumption of fiber is concerning due to its various associated health benefits such as weight management. Adding extracted or isolated dietary fibers into various consumer products is a practical strategy for addressing the fiber gap. This comprehensive review identified evidence on the efficacy of different types of extracted and isolated fibers in reducing appetite and energy intake. Published reports of randomized controlled trials assessing appetite or energy intake in healthy adults were systematically searched, and those investigating extracted and isolated fibers following acute or chronic intake were selected. A total of 136 studies, consisting of 107 acute studies and 29 chronic studies, were included in the review. Overall, most fiber types did not show significant effects on appetite ratings and energy intakes. Acute intakes of two viscous fibers, alginate or guar gum, as well as oat fiber, were observed to most frequently result in reductions in appetite ratings. Additionally, chronic, but not acute, intakes of resistant maltodextrin/dextrin were also beneficial for appetite ratings. Viscous fibers were more likely to improve appetite ratings compared to non-viscous fibers, and fermentability did not appear to affect appetite ratings. Unfortunately, the current evidence base is highly varied due to the many differences in methodology and limited research on many of the fibers. While the possible benefits of extracted and isolated fibers on appetite sensations, food intake, and ultimately body weight regulation should not be completely dismissed, our review highlights the complexity of this research area and the gaps that need to be addressed to improve the robustness of the evidence.

Role of probiotics/synbiotic supplementation in glycemic control: A critical umbrella review of meta-analyses of randomized controlled trials.

The evidence regarding the beneficial effects of probiotics/synbiotic supplementation have been revealed by several meta-analyses, however some of these studies have fielded inconsistent results and a conclusion has yet to be reached. Therefore, the aim of present umbrella meta-analyses was to assess relevant evidence and elucidate the efficacy of probiotics/synbiotic supplementation in glycemic control. A comprehensive search in four databases (Cochrane library, PubMed, Web of science and Scopus) was performed to collect relevant studies up to August 2022, the pooled effects were measured with the use of random/fix-effect model depends on the heterogeneity. A total of 47 eligible meta-analyses involving 47,720 participants were identified to evaluate the pooled effects. The overall results showed that probiotics/synbiotic supplementation delivered significant decreases in fast plasma glucose (ES = -0.408, 95% CI: -0.518, -0.298; P < 0.001; I2 = 82.996, P < 0.001), fast plasma insulin (ES = -1.165, 95% CI: -1.454, -0.876; P < 0.001; I2 = 89.629, P < 0.001), homeostasis model assessment of insulin resistance (ES = -0.539, 95% CI: -0.624, -0.454; P < 0.001; I2 = 56.716, P < 0.001), and glycosylated hemoglobin (ES = -0.186, 95% CI: -0.270, -0.102; P < 0.001; I2 = 59.647, P = 0.001). Subgroup analysis showed that patients with impaired glucose homeostasis might benefit the most from probiotics/synbiotic supplementation. In conclusion, current umbrella meta-analysis strongly supporting the beneficial health effects of probiotics/synbiotic supplementation in glycemic control.

An Oat ß-Glucan Beverage Reduces LDL Cholesterol and Cardiovascular Disease Risk in Men and Women with Borderline High Cholesterol: A Double-Blind, Randomized, Controlled Clinical Trial.

BACKGROUND: High-molecular-weight (MW) oat ß-glucan (OBG), consumed at 3-4 g/d, in solid foods reduces LDL cholesterol by a median of ∼6.5%. OBJECTIVES: We evaluated the effect of a beverage providing 3 g/d high-MW OBG on reduction of LDL cholesterol (primary endpoint) when compared with placebo. METHODS: We performed a parallel-design, randomized clinical trial at a contract research organization; participants, caregivers, and outcome assessors were blinded to treatment allocation. Participants with LDL cholesterol between 3.0 and 5.0 mmol/L, inclusive [n = 538 screened, n = 260 ineligible, n = 23 lost, n = 48 withdrawn (product safety); n = 207 randomly assigned, n = 7 dropped out, n = 9 withdrawn (protocol violation); n = 191 analyzed; n = 72 (37.7%) male, mean ± SD age: 43.3 ± 14.3 y, BMI: 29.7 ± 5.2 kg/m2], were randomly assigned to consume, 3 times daily for 4 wk, 1 g OBG (n = 104, n = 96 analyzed) or rice powder (Control, n = 103, n = 95 analyzed) mixed into 250 mL water. Treatment effects were assessed as change from baseline and differences analyzed using a 2-sided t test via ANOVA with baseline characteristics as covariates. RESULTS: After 4 wk, change from baseline least-squares-mean LDL cholesterol on OBG (-0.195 mmol/L) was less than on Control (0.012 mmol/L) by mean: 0.207 mmol/L (95% CI: 0.318, 0.096 mmol/L; P = 0.0003); the following secondary endpoints were also reduced as follows: total cholesterol (TC) (0.226 mmol/L; 95% CI: 0.361, 0.091 mmol/L; P = 0.001), TC:HDL cholesterol ratio (0.147; 95% CI: 0.284, 0.010; P = 0.036), non-HDL cholesterol (0.194 mmol/L; 95% CI: 0.314, 0.073 mmol/L; P = 0.002), and Framingham cardiovascular disease (CVD) risk (0.474; 95% CI: 0.900, 0.049, P = 0.029). Changes in HDL cholesterol, triglycerides, glucose, and insulin did not differ between treatment groups (P > 0.05). Lipid treatment effects were not significantly modified by age, sex, BMI, or hypertension treatment. There were no major adverse events, but both treatments transiently increased gastrointestinal symptoms. CONCLUSIONS: Consuming a beverage containing 1 g high-MW OBG 3 times daily for 4 wk significantly reduced LDL cholesterol by ∼6% and CVD risk by ∼8% in healthy adults with LDL cholesterol between 3 and 5 mmol/L.This trial was registered at clinicaltrials.gov as NCT03911427.

A Systematic Review and Meta-Analysis of Randomized Controlled Trials on the Effects of Oats and Oat Processing on Postprandial Blood Glucose and Insulin Responses.

BACKGROUND: Oats are a whole grain cereal with potentially favorable effects on the postprandial glycemic response; however, the effects of oat processing on these glycemic benefits are not well understood. OBJECTIVES: The study objective was to determine the effects of differently processed oats on the postprandial blood glucose and insulin responses relative to refined grains. METHODS: Eleven electronic databases were systematically searched to identify studies published up to and including May 2019. Randomized controlled trials comparing the postprandial blood glucose and insulin responses to oats compared with any refined grain were included, so long as the available carbohydrate content of the test meals was similar. Pooled effect sizes were computed using the difference in incremental area under the curves for blood glucose and insulin following the consumption of oats compared with the refined grain control. RESULTS: Ten publications were included, with intact oat kernels studied in 3 comparisons, thick oat flakes (>0.6 mm) in 7 comparisons, and thin/quick/instant oat flakes (≤0.6 mm) in 6 comparisons. Compared with the consumption of the refined grain control, the consumption of intact oat kernels was associated with significant reductions in postprandial blood glucose (-45.5 mmol x min/L; 95% CI: -80.1, -10.9 mmol x min/L; P = 0.010) and insulin (-4.5 nmol x min/L; 95% CI: -7.1, -1.8 nmol x min/L; P = 0.001) responses; the consumption of thick oat flakes was associated with significant reductions in postprandial blood glucose (-30.6 mmol x min/L; 95% CI: -40.4, -20.9 mmol x min/L; P < 0.001) and insulin (-3.9 nmol x min/L; 95% CI: -5.3, -2.5 nmol x min/L; P < 0.001) responses; but, the consumption of thin/quick/instant oat flakes was not associated with any effects on the postprandial blood glucose and insulin responses. CONCLUSIONS: A disruption in the structural integrity of the oat kernel is likely associated with a loss in the glycemic benefits of oats.

Association of whole-grain and dietary fiber intake with cardiometabolic risk in children and adolescents.

BACKGROUND: Diet is known to affect many risk factors of cardiovascular disease (CVD), a leading cause of mortality and morbidity. AIM: The objective of this study was to explore the potential association between whole grain and dietary fiber with CVD risk factors, including metabolic syndrome (MetS) in children and adolescents using National Health and Nutrition Examination Survey (NHANES) 2003-2014. METHODS: Two days of 24-hour recall data from 16,507 children and adolescents age 2-18 years were used to estimate dietary intakes. Continuous MetS scores (cMetS) were computed by aggregating age/sex regressed z-scores of waist circumference, mean arterial blood pressure, high-density lipoprotein-cholesterol, triglycerides, and glucose. Regression analyses were used to assess association of fiber and whole grain intake with cardiometabolic markers including MetS after adjusting for demographic factors. RESULTS: Increasing tertiles of fiber intake were significantly associated with 3% lowered risk MetS in adolescents age 13-18 years. Additionally, increasing intake tertiles of fiber were associated with reduced risk elevated cholesterol (5-11% reduction), elevated diastolic blood pressure (10-23% reduction) in adolescents age 13-18 years, and risk of obesity (3-5% reduction) in children and adolescent age 2-18 years. Increasing tertiles of whole grain intake were only associated with reduced risk of elevated triglycerides (52% risk reduction) in adolescents age 13-18 years. CONCLUSION: The results suggest that intake of dietary fiber was inversely associated with several markers of cardiovascular disease risk including MetS.

Impact of oat processing on glycaemic and insulinaemic responses in healthy humans: a randomised clinical trial.

Oats can be processed in a variety of ways ranging from minimally processed such as steel-cut oats (SCO), to mildly processed such as large-flake oats (old fashioned oats, OFO), moderately processed such as instant oats (IO) or highly processed in ready-to-eat oat cereals such as Honey Nut Cheerios (HNC). Although processing is believed to increase glycaemic and insulinaemic responses, the effect of oat processing in these respects is unclear. Thus, we compared the glycaemic and insulinaemic responses elicited by 628 kJ portions of SCO, OFO, IO and HNC and a portion of Cream of Rice cereal (CR) containing the same amount of available-carbohydrate (23 g) as the oatmeals. Healthy males (n 18) and females (n 12) completed this randomised, cross-over trial. Blood was taken fasting and at intervals for 3 h following test-meal consumption. Glucose and insulin peak-rises and incremental AUC (iAUC) were subjected to repeated-measures ANOVA using Tukey's test (two-sided P<0·05) to compare individual means. Glucose peak-rise (primary endpoint, mean (sem) mmol/l) after OFO, 2·19 (sem 0·11), was significantly less than after CR, 2·61 (sem 0·13); and glucose peak-rise after SCO, 1·93 (sem 0·13), was significantly less than after CR, HNC, 2·49 (sem 0·13) and IO 2·47 (sem 0·13). Glucose iAUC was significantly lower after SCO than CR and HNC. Insulin peak rise was similar among the test meals, but insulin iAUC was significantly less after SCO than IO. Thus, the results show that oat processing affects glycaemic and insulinaemic responses with lower responses associated with less processing.

Effect of Two Oat-based Cereals on Subjective Ratings of Appetite.

Viscosity generated by oat ß-glucan induces gastrointestinal mechanisms that influence appetite. Two oat-based ready-to-eat cereals (RTEC) with similar amounts of ß-glucan but differing in their protein and sugar content were compared for their effects on appetite. Forty-seven healthy individuals, ≥18 years old, enrolled in a crossover trial consumed RTEC1 or RTEC2 in random order at least a week apart. Breakfasts contained 250kcals cereal and 105kcals fat-free milk. Subjective ratings of appetite were completed at baseline, and at 30, 60, 120, 180 and 240 minutes after consumption of the breakfast meals. Responses were analyzed as area under the curve (AUC) and per time-point. Significance was set at α=0.05. Fullness (p=0.01) and stomach fullness (p=0.02) were greater with RTEC 1 compared to RTEC 2 at 240 minutes. Stomach fullness (p=0.01) was greater at 30 minutes, and desire to eat (p=0.04) was reduced at 120 minutes with RTEC2 compared to RTEC1. There was no difference in the AUC for hunger, fullness, stomach fullness, desire to eat, or prospective intake. Ready-to-eat cereals containing similar amounts of oat ß-glucan differed in the timing of significant differences in fullness or desire to eat, but appetite ratings over a four hour period did not differ.

Instant Oatmeal Increases Satiety and Reduces Energy Intake Compared to a Ready-to-Eat Oat-Based Breakfast Cereal: A Randomized Crossover Trial.

BACKGROUND: Foods that enhance satiety can help consumers to resist environmental cues to eat and help adherence to calorie restriction. The objective of this study was to compare the effect of 2 oat-based breakfast cereals on appetite, satiety, and food intake. METHODS: Forty-eight healthy individuals, 18 years of age or older, were enrolled in a randomized, crossover trial. Subjects consumed isocaloric servings of either oatmeal or an oat-based ready-to-eat breakfast cereal (RTEC) in random order at least a week apart. Visual analogue scales measuring appetite and satiety were completed before breakfast and throughout the morning. Lunch was served 4 hours after breakfast. The physicochemical properties of oat soluble fiber (ß-glucan) were determined. Appetite and satiety responses were analyzed by area under the curve. Food intake and ß-glucan properties were analyzed using t tests. RESULTS: Oatmeal increased fullness (p = 0.001) and reduced hunger (p = 0.005), desire to eat (p = 0.001), and prospective intake (p = 0.006) more than the RTEC. Energy intake at lunch was lower after eating oatmeal compared to the RTEC (p = 0.012). Oatmeal had higher viscosity (p = 0.03), ß-glucan content, molecular weight (p < 0.001), and radius of gyration (p < 0.001) than the RTEC. CONCLUSIONS: Oatmeal suppresses appetite, increases satiety, and reduces energy intake compared to the RTEC. The physicochemical properties of ß-glucan and sufficient hydration of oats are important factors affecting satiety and subsequent energy intake.

Avenanthramide supplementation attenuates eccentric exercise-inflicted blood inflammatory markers in women.

PURPOSE: Rigorous exercise is known to generate reactive oxygen species (ROS) and inflict inflammatory response. The present study investigated whether dietary supplementation of avenanthramides (AVA) in oats would increase antioxidant protection and reduce inflammation in humans after an acute bout of eccentric exercise. METHODS: Young women (age 18-30 years, N = 16) were randomly divided into two groups in a double-blinded fashion, receiving two cookies made of oat flour providing 9.2 mg AVA (AVA) or 0.4 mg AVA (Control, C) each day for 8 weeks. Before and after the dietary regimen each group of subjects ran downhill (DR) on a treadmill at -9% grade for 1 h at a speed to elicit 75% of maximal heart rate. Blood samples were collected at rest, immediately and 24 h post-DR. RESULTS: Before dietary supplementation plasma creatine kinase activity and tumor necrosis factor (TNF)-α concentration were increased immediately after DR (P < 0.05), whereas neutrophil respiratory burst (NRB) was elevated 24 h post-DR (P < 0.05). CK and TNF-α response to DR was abolished during post-supplementation tests in both AVA and C groups, whereas NRB was blunted only in AVA but not in C. Plasma interleukin-6 level and mononuclear cell nuclear factor (NF) κB activity were not affected by DR either before or after dietary supplementation, but were lowered 24 h post-DR in AVA versus C (P < 0.05). Both groups increased plasma total antioxidant activity following 8-week dietary regimen (P < 0.05), whereas only AVA group increased resting plasma glutathione (GSH) concentration (P < 0.05), decreased glutathione disulfide response to DR, and lowered erythrocyte GSH peroxidase activity (P < 0.05). CONCLUSIONS: Our data of pre- and post-supplementation difference reflect an interaction between repeated measure effect of eccentric exercise and AVA in diet. Long-term AVA supplementation can attenuate blood inflammation markers, decrease ROS generation and NFkB activation, and increased antioxidant capacity during an eccentric exercise bout.

Systematic review of the effect of processing of whole-grain oat cereals on glycaemic response.

Whole-grain oats have been identified as a type of food that blunts blood glucose increase after a meal. However, processing of oats changes the physical characteristics of the grain, which may influence human glycaemic response. Therefore, the effect of different processes on acute postprandial glycaemic response, quantified using glycaemic index (GI) measurements, was investigated in a systematic review. A review of the literature identified twenty publications containing fifty-six individual tests. An additional seventeen unpublished tests were found in an online database. Of the seventy-two measurements included in the review, two were for steel-cut oats, eleven for large-flake oats, seven for quick-cooking (small flake) oats, nine for instant oatmeal and twenty-eight for muesli or granola. One granola measurement was identified as an outlier and was removed from the statistical analysis. In all, fifteen clinical tests were reported for rolled oat porridge that did not specify the type of oats used, and thus the effect of processing could not be assessed. Steel-cut oats (GI=55 (se 2·5)), large-flake oats (GI=53 (se 2·0)) and muesli and granola (GI=56 (se 1·7)) elicited low to medium glycaemic response. Quick-cooking oats and instant oatmeal produced significantly higher glycaemic response (GI=71 (se 2·7) and 75 (se 2·8), respectively) than did muesli and granola or large-flake oatmeal porridge. The analysis establishes that differences in processing protocols and cooking practices modify the glycaemic response to foods made with whole-grain oats. Smaller particle size and increased starch gelatinisation appear to increase the glycaemic response.

Avenanthramide supplementation attenuates exercise-induced inflammation in postmenopausal women.

During aging, chronic systemic inflammation increases in prevalence and antioxidant balance shifts in favor of oxidant generation. Avenanthramide (AVA) is a group of oat phenolics that have shown anti-inflammatory and antioxidant capability. The present study investigated whether dietary supplementation of avenanthramides (AVA) in oats would increase antioxidant protection and reduce inflammation after a bout of downhill walking (DW) in postmenopausal women. Women at age of 50-80 years (N = 16) were randomly divided into two groups in a double-blinded fashion, receiving two cookies made of oat flour providing 9.2 mg AVA or 0.4 mg AVA (control, C) each day for 8 weeks. Before and after the dietary regimen, each group of subjects walked downhill on a treadmill (-9% grade) for 4 bouts of 15 minutes at a speed of 4.0 km/h with 5 minutes rest between sessions. Blood samples were collected at rest, 24 h post-DW, and 48 h post-DW pre- and post-supplementation. Both DW sessions increased plasma creatine kinase activity (P < 0.05). Before supplementation, in vitro neutrophil respiratory burst (NRB) activity was increased at 24 h post-DW (P < 0.05) and C-reactive protein (CRP) was increased 48 h post-DW (P < 0.05). AVA supplementation decreased DW-induced NRB at 24 h (P < 0.05) and CRP level 48 h (P < 0.05). Plasma interleukin (IL)-1ß concentration and mononuclear cell nuclear factor (NF) κB binding were suppressed at rest and during post-DW period in AVA but not C group (P < 0.05). Plasma total antioxidant capacity (P < 0.05) and erythrocyte superoxide dismutase activity were increased in AVA vs. C (P < 0.05), whereas glutathione redox status was elevated 48 h post-DW but not affected by AVA. Thus, chronic AVA supplementation decreased systemic and DW-induced inflammation and increased blood-borne antioxidant defense in postmenopausal women.

The role of meal viscosity and oat ß-glucan characteristics in human appetite control: a randomized crossover trial.

BACKGROUND: Foods that enhance satiety can help consumers to resist environmental cues to eat, and improve the nutritional quality of their diets. Viscosity generated by oat ß-glucan, influences gastrointestinal mechanisms that mediate satiety. Differences in the source, processing treatments, and interactions with other constituents in the food matrix affect the amount, solubility, molecular weight, and structure of the ß-glucan in products, which in turn influences the viscosity. This study examined the effect of two types of oatmeal and an oat-based ready-to-eat breakfast cereal (RTEC) on appetite, and assessed differences in meal viscosity and ß-glucan characteristics among the cereals. METHODS: Forty-eight individuals were enrolled in a randomized crossover trial. Subjects consumed isocaloric breakfast meals containing instant oatmeal (IO), old-fashioned oatmeal (SO) or RTEC in random order at least a week apart. Each breakfast meal contained 218 kcal (150 kcal cereal, and 68 kcal milk) Visual analogue scales measuring appetite were completed before breakfast, and over four hours, following the meal. Starch digestion kinetics, meal viscosities, and ß-glucan characteristics for each meal were determined. Appetite responses were analyzed by area under the curve. Mixed models were used to analyze response changes over time. RESULTS: IO increased fullness (p = 0.04), suppressed desire to eat (p = 0.01) and reduced prospective intake (p < 0.01) more than the RTEC over four hours, and consistently at the 60 minute time-point. SO reduced prospective intake (p = 0.04) more than the RTEC. Hunger scores were not significantly different except that IO reduced hunger more than the RTEC at the 60 minute time-point. IO and SO had higher ß-glucan content, molecular weight, gastric viscosity, and larger hydration spheres than the RTEC, and IO had greater viscosity after oral and initial gastric digestion (initial viscosity) than the RTEC. CONCLUSION: IO and SO improved appetite control over four hours compared to RTEC. Initial viscosity of oatmeal may be especially important for reducing appetite.

Acute effect of oatmeal on subjective measures of appetite and satiety compared to a ready-to-eat breakfast cereal: a randomized crossover trial.

OBJECTIVE: The physicochemical properties of soluble oat fiber (ß-glucan) affect viscosity-dependent mechanisms that influence satiety. The objective of this study was to compare the satiety impact of oatmeal with the most widely sold ready-to-eat breakfast cereal (RTEC) when either was consumed as a breakfast meal. METHODS: Forty-eight healthy individuals ≥18 years of age were enrolled in a randomized crossover trial. Following an overnight fast, subjects consumed either oatmeal or RTEC in random order at least a week apart. The breakfasts were isocaloric and contained 363 kcal (250 kcal cereal, 113 kcal milk). Visual analogue scales measuring appetite and satiety were completed before breakfast and throughout the morning. The content and physicochemical properties of oat ß-glucan were determined. Appetite and satiety responses were analyzed by area under the curve (AUC). Physicochemical properties were analyzed using t tests. RESULTS: Oatmeal, higher in fiber and protein but lower in sugar than the RTEC, resulted in greater increase in fullness (AUC: p = 0.005 [120 minute: p = 0.0408, 180 minute: p = 0.0061, 240 minute: p = 0.0102]) and greater reduction in hunger (AUC: p = 0.0009 [120 minute: p = 0.0197, 180 minute: p = 0.0003, 240 minute: p = 0.0036]), desire to eat (AUC: p = 0.0002 [120 minute: p = 0.0168, 180 minute: p < 0.0001, 240 minute: p = 0.0022]), and prospective intake (AUC: p = 0.0012 [120 minute: p = 0.0058, 180 minute: p = 0.006, 240 minute: p = 0.0047]) compared to the RTEC. Oatmeal had higher ß-glucan content, higher molecular weight (p < 0.0001), higher viscosity (p = 0.025), and larger hydration spheres (p = 0.0012) than the RTEC. CONCLUSION: Oatmeal improves appetite control and increases satiety. The effects may be attributed to the viscosity and hydration properties of its ß-glucan content.

Narrative Review on the Effects of Oat and Sprouted Oat Components on Blood Pressure.

Hypertension (HTN) is a major risk factor for cardiovascular disease (CVD) and cognitive decline. Elevations in blood pressure (BP) leading to HTN can be found in young adults with increased prevalence as people age. Oats are known to decrease CVD risk via an established effect of ß-glucan on the attenuation of blood cholesterol. Many past studies on CVD and oats have also reported a decrease in BP; however, a thorough assessment of oats and BP has not been conducted. Moreover, oats deliver several beneficial dietary components with putative beneficial effects on BP or endothelial function, such as ß-glucan, γ-amino butyric acid (GABA), and phytochemicals such as avenanthramides. We conducted a comprehensive search for systematic reviews, meta-analyses, and clinical intervention studies on oats and BP and identified 18 randomized controlled trials (RCTs) and three meta-analyses that supported the role of oats in decreasing BP. Emerging data also suggest oat consumption may reduce the use of anti-hypertensive medications. The majority of these studies utilized whole oats or oat bran, which include a vast array of oat bioactives. Therefore, we also extensively reviewed the literature on these bioactives and their putative effect on BP-relevant mechanisms. The data suggest several oat components, such as GABA, as well as the delivery of high-quality plant protein and fermentable prebiotic fiber, may contribute to the anti-HTN effect of oats. In particular, GABA is enhanced in oat sprouts, which suggests this food may be particularly beneficial for healthy BP management.

Decreasing the RAG:SAG ratio of granola cereal predictably reduces postprandial glucose and insulin responses: a report of four randomised trials in healthy adults.

Dietary starch contains rapidly (RAG) and slowly available glucose (SAG). To establish the relationships between the RAG:SAG ratio and postprandial glucose, insulin and hunger, we measured postprandial responses elicited by test meals varying in the RAG:SAG ratio in n 160 healthy adults, each of whom participated in one of four randomised cross-over studies (n 40 each): a pilot trial comparing six chews (RAG:SAG ratio 2·4-42·7) and three studies comparing a test granola (TG1-3, RAG:SAG ratio 4·5-5·2) with a control granola (CG1-3, RAG:SAG ratio 54·8-69·3). Within studies, test meals were matched for fat, protein and available carbohydrate. Blood glucose, serum insulin and subjective hunger were measured for 3 h. Data were subjected to repeated-measures analysis of variance (ANOVA). The relationships between the RAG:SAG ratio and postprandial end points were determined by regression analysis. In the pilot trial, 0-2 h glucose incremental areas under the curve (iAUC0-2; primary end point) varied across the six chews (P = 0·014) with each 50 % reduction in the RAG:SAG ratio reducing relative glucose response by 4·0 %. TGs1-3 elicited significantly lower glucose iAUC0-2 than CGs1-3 by 17, 18 and 17 %, respectively (similar to the 15 % reduction predicted by the pilot trial). The combined means ± sem (n 120) for TC and CG were glucose iAUC0-2, 98 ± 4 v. 118 ± 4 mmol × min/l (P < 0·001), and insulin iAUC0-2, 153 ± 9 v. 184 ± 11 nmol × h/l (P < 0·001), respectively. Neither postprandial hunger nor glucose or hunger increments 2 h after eating differed significantly between TG and CG. We concluded that TGs with RAG:SAG ratios <5·5 predictably reduced glycaemic and insulinaemic responses compared with CGs with RAG:SAG ratios >54. However, compared with CG, TG did not reduce postprandial hunger or delay the return of glucose or hunger to baseline.

Oats Lower Age-Related Systemic Chronic Inflammation (iAge) in Adults at Risk for Cardiovascular Disease.

Despite being largely preventable, cardiovascular disease (CVD) is still the leading cause of death globally. Recent studies suggest that the immune system, particularly a form of systemic chronic inflammation (SCI), is involved in the mechanisms leading to CVD; thus, targeting SCI may help prevent or delay the onset of CVD. In a recent placebo-controlled randomized clinical trial, an oat product providing 3 g of ß-Glucan improved cholesterol low-density lipoprotein (LDL) levels and lowered cardiovascular risk in adults with borderline high cholesterol. Here, we conducted a secondary measurement of the serum samples to test whether the oat product has the potential to reduce SCI and improve other clinical outcomes related to healthy aging. We investigated the effects of the oat product on a novel metric for SCI called Inflammatory Age® (iAge®), derived from the Stanford 1000 Immunomes Project. The iAge® predicts multimorbidity, frailty, immune decline, premature cardiovascular aging, and all-cause mortality on a personalized level. A beneficial effect of the oat product was observed in subjects with elevated levels of iAge® at baseline (>49.6 iAge® years) as early as two weeks post-treatment. The rice control group did not show any significant change in iAge®. Interestingly, the effects of the oat product on iAge® were largely driven by a decrease in the Eotaxin-1 protein, an aging-related chemokine, independent of a person's gender, body mass index, or chronological age. Thus, we describe a novel anti-SCI role for oats that could have a major impact on functional, preventative, and personalized medicine.

Effect of processing on oat ß-glucan viscosity, postprandial glycemic response and subjective measures of appetite.

Oat has procured its acclaim as a health promoting food partially due to its positive effect on glucose control. It has been demonstrated that oat ß-glucan can interfere with postprandial glucose response. A large majority of this action is attributed to the increase in viscosity due to the ß-glucan content in oat foods. While it is known that an increase in viscosity due to higher molecular weight of ß-glucan can improve its glycemic effects, it is not known if an increase in viscosity attained by processing variables can further enhance the positive effect of oat on glucose control. In the current study we have examined the effect of kilning, tempering, microwaving, cooking, soaking and flaking on oat ß-glucan viscosity. An acute randomized crossover clinical trial was also conducted to test oatmeal products containing low, medium and high ß-glucan viscosity for their effect on postprandial glycemic response. Results from the processing experiments demonstrate that kilned samples, when tempered to 25% moisture and microwaved for 2 minutes, can produce much higher final viscosity compared to other samples with similar ß-glucan content, molecular weight and solubility. However, results from the clinical trial show that the increase in the viscosity of the oat ß-glucan attained through processing in this study did not have any effect on postprandial glucose control.

Effect of Oat ß-Glucan on Affective and Physical Feeling States in Healthy Adults: Evidence for Reduced Headache, Fatigue, Anxiety and Limb/Joint Pains.

The gastrointestinal (GI) side-effects of dietary fibers are recognized, but less is known about their effects on non-GI symptoms. We assessed non-GI symptoms in a trial of the LDL-cholesterol lowering effect of oat ß-glucan (OBG). Participants (n = 207) with borderline high LDL-cholesterol were randomized to an OBG (1 g OBG, n = 104, n = 96 analyzed) or Control (n = 103, n = 95 analyzed) beverage 3-times daily for 4 weeks. At screening, baseline, 2 weeks and 4 weeks participants rated the severity of 16 non-GI symptoms as none, mild, moderate or severe. The occurrence and severity (more or less severe than pre-treatment) were compared using chi-squared and Fisher's exact test, respectively. During OBG treatment, the occurrence of exhaustion and fatigue decreased versus baseline (p < 0.05). The severity of headache (2 weeks, p = 0.032), anxiety (2 weeks p = 0.059) and feeling cold (4 weeks, p = 0.040) were less on OBG than Control. The severity of fatigue and hot flashes at 4 weeks, limb/joint pain at 2 weeks and difficulty concentrating at both times decreased on OBG versus baseline. High serum c-reactive-protein and changes in c-reactive-protein, oxidized-LDL, and GI-symptom severity were associated with the occurrence and severity of several non-GI symptoms. These data provide preliminary, hypothesis-generating evidence that OBG may reduce several non-GI symptoms in healthy adults.

The Role of Oat Nutrients in the Immune System: A Narrative Review.

Optimal nutrition is the foundation for the development and maintenance of a healthy immune system. An optimal supply of nutrients is required for biosynthesis of immune factors and immune cell proliferation. Nutrient deficiency/inadequacy and hidden hunger, which manifests as depleted nutrients reserves, increase the risk of infectious diseases and aggravate disease severity. Therefore, an adequate and balanced diet containing an abundant diversity of foods, nutrients, and non-nutrient chemicals is paramount for an optimal immune defense against infectious diseases, including cold/flu and non-communicable diseases. Some nutrients and foods play a larger role than others in the support of the immune system. Oats are a nutritious whole grain and contain several immunomodulating nutrients. In this narrative review, we discuss the contribution of oat nutrients, including dietary fiber (ß-glucans), copper, iron, selenium, and zinc, polyphenolics (ferulic acid and avenanthramides), and proteins (glutamine) in optimizing the innate and adaptive immune system's response to infections directly by modulating the innate and adaptive immunity and indirectly by eliciting changes in the gut microbiota and related metabolites.