The effects of beta-glucan rich oat bread on serum nitric oxide and vascular endothelial function in patients with hypercholesterolemia

The nutritional contribution and relationship with health of bread consumption: a narrative review

Bread consumption dates back thousands of years, being one of the oldest and most widespread staple food worldwide. While bread is often associated with taste, pleasure, and tradition, its perception as a vehicle of nutrition and health remains complex. Today, there is no scientific consensus on whether bread consumption is beneficial or deleterious to human health. The objective of this review is therefore to present and discuss epidemiological and clinical evidence on the nutritional contribution of bread and its relationship with health. We also present different aspects of bread such as flour type and inclusions that may modulate this relationship. Studies included in this review investigate bread as part of a dietary pattern as well as the effect of bread alone on overweight, cardiometabolic health, and digestive health. Bread is an integral part of diets around the world, with a significant contribution to key nutrients. Although evidence on the impact of bread consumption on health is still lacking and depends on the overall diet, whole grain breads have shown consistent beneficial effects on human health. Substitution modeling studies and well-designed clinical trials are warranted to fill the research gaps and understand the role of bread consumption in health and disease.

An encompassing review of meta-analyses and systematic reviews of the effect of oats on all-cause mortality, cardiovascular risk, diabetes risk, body weight/adiposity and gut health

The ability of oats to reduce blood cholesterol is well established but there is increasing evidence that its health benefits extend well beyond that. The purpose of this review was to critically evaluate the state of the science of oats in relation to all-cause mortality, cardiovascular and diabetes risk and the effects of oats on blood lipids, blood glucose, blood pressure, weight management and gut health from meta-analyses and systematic reviews. Limited epidemiological data indicated a possible beneficial effect of oats on all-cause mortality and incident diabetes when high versus low oat consumers were compared, but its effect on cardiovascular events was not adequately discerned. Observational data also showed an inverse association between oat intake and blood cholesterol, blood pressure, body weight and obesity variables in different populations. Randomized controlled oat intervention studies demonstrated a significant reduction in postprandial blood glucose in both diabetic and non-diabetic subjects, fasting blood glucose in diabetic subjects, blood pressure in prehypertensive individuals, and body weight and adiposity in overweight individuals. Increased fecal bulk was observed but clinical data for a potential gut barrier effect is lacking. The mechanism of action of each health effect was reviewed. While beta-glucan viscosity was once considered the only mode of action, it is evident that the fermentation products of beta-glucan and the associated gut microbial changes, as well as other components in oats (i.e., avenanthramides etc.) also play an important role.

The Effect of Dietary Oat Consumption and Its Constituents on Fat Storage and Obesity

This review is to summarize and analyze the currently available knowledge concerning the action of oat (Avena sativa L.) consumption on obesity, as well as possible constituents and extra- and intracellular mediators responsible for its anti-obesity effect. The oat constituents could reduce fat storage via several mediatory mechanisms - brain centers regulating appetite, gastrointestinal functions, gut bacteria, fat synthesis and metabolism and maybe via changes in oxidative processes, steroid hormones receptors and adipose tissue vascularization. Several oat constituents (starch, fiber and beta-glucan) could have anti-obesity properties, whilst one oat constituent (starch or fiber) could affect fat storage via several mechanisms of action.

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 β-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 β-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.

Effect of oat supplementation interventions on cardiovascular disease risk markers: a systematic review and meta-analysis of randomized controlled trials

PURPOSE

Oat supplementation interventions (OSIs) may have a beneficial effect on cardiovascular disease (CVD) risk. However, dietary background can modulate such effect. This systematic review assesses the effects of OSIs on CVD risk markers among adults, accounting for different dietary backgrounds or control arms.

METHODS

We included randomized clinical trials (RCTs) that assessed the effect of oat, oat beta-glucan-rich extracts or avenanthramides on CVD risk markers.

RESULTS

Seventy-four RCTs, including 4937 predominantly hypercholesterolemic, obese subjects, with mild metabolic disturbances, were included in the systematic review. Of these, 59 RCTs contributed to the meta-analyses. Subjects receiving an OSI, compared to control arms without oats, had improved levels of total cholesterol (TC) [weighted mean difference and (95% CI) - 0.42 mmol/L, (- 0.61; - 0.22)], LDL cholesterol [- 0.29 mmol/L, (- 0.37; - 0.20)], glucose [- 0.25 nmol/L, (- 0.36; - 0.14)], body mass index [- 0.13 kg/m2, (- 0.26; - 0.01)], weight [- 0.94 kg, (- 1.84: - 0.05)], and waist circumference [- 1.06 cm, (- 1.85; - 0.27)]. RCTs on inflammation and/or oxidative stress markers were scarce and with inconsistent findings. RCTs comparing an OSI to heterogeneous interventions (e.g., wheat, eggs, rice, etc.), showed lowered levels of glycated haemoglobin, diastolic blood pressure, HDL cholesterol and apolipoprotein B. The majority of included RCTs (81.1%) had some concerns for risk of bias.

CONCLUSION

Dietary OSIs resulted in lowered levels of blood lipids and improvements in anthropometric parameters among participants with predominantly mild metabolic disturbances, regardless of dietary background or control. Further high-quality trials are warranted to establish the role of OSIs on blood pressure, glucose homeostasis and inflammation markers.

Oat Intake and Risk of Type 2 Diabetes, Cardiovascular Disease and All-Cause Mortality: A Systematic Review and Meta-Analysis

Cardiovascular disease (CVD) and type 2 diabetes (T2D) remain the top disease and mortality burdens worldwide. Oats have been shown to benefit cardiovascular health and improve insulin resistance. However, the evidence linking oat consumption with CVD, T2D and all-cause mortality remains inconclusive. We conducted a comprehensive systematic review and meta-analysis of prospective cohort studies to evaluate the associations between oat consumption and risks of T2D, CVD and all-cause mortality in the general population. Five electronic databases were searched until September, 2020. Study specific relative risks (RR) were meta-analyzed using random effect models. Of 4686 relevant references, we included 9 articles, based on 8 unique studies and 471,157 participants. Comparing oat consumers versus non-consumers, RRs were 0.86 (95% CI 0.72–1.03) for T2D incidence and 0.73 (95% CI 0.5–1.07) for combined CVD incidence. Comparing participants with highest versus lowest oat intake, RRs were 0.78 (95% CI 0.74–0.82) for T2D incidence, 0.81 (95% CI 0.61–1.08) for CHD incidence and 0.79 (95% CI 0.59–1.07) for stroke. For all-cause mortality one study based on three cohorts found RR for men and women were 0.76 (95% CI 0.69–0.85) and 0.78 (95% CI 0.70–0.87), respectively. Most studies (n = 6) were of fair to good quality. This meta-analysis suggests that consumption of oat could reduce the risk for T2D and all-cause mortality, while no significant association was found for CVD. Future studies should address a lack of standardized methods in assessing overall oat intake and type of oat products, and investigate a dose-dependent response of oat products on cardiometabolic outcomes in order to introduce oat as preventive and treatment options for the public.

Lipid-lowering nutraceuticals update on scientific evidence

: Cardiovascular diseases (CVDs) are the main cause of mortality worldwide. Risk factors of CVD can be classified into modifiable (smoking, hypertension, diabetes, hypercholesterolemia) through lifestyle changes or taking drug therapy and not modifiable (age, ethnicity, sex and family history). Elevated total cholesterol (TC) and low-density lipoprotein-cholesterol (LDL-C) levels have a lead role in the development of coronary heart disease (CHD), while high levels of high-density lipoprotein-cholesterol (HDL-C) seem to have a protective role.The current treatment for dyslipidemia consists of lifestyle modification or drug therapy even if not pharmacological treatment should be always considered in addition to lipid-lowering medications.The use of lipid-lowering nutraceuticals alone or in association with drug therapy may be considered when the atherogenic cholesterol goal was not achieved.These substances can be classified according to their mechanisms of action into natural inhibitors of intestinal cholesterol absorption, inhibitors of hepatic cholesterol synthesis and enhancers of the excretion of LDL-C. Nevertheless, many of them are characterized by mixed or unclear mechanisms of action.The use of these nutraceuticals is suggested in individuals with borderline lipid profile levels or with drug intolerance, but cannot replace standard lipid-lowering treatment in patients at high, or very high CVD risk.Nutraceuticals can also have vascular effects, including improvement in endothelial dysfunction and arterial stiffness, as well as antioxidative properties. Moreover, epidemiological and clinical studies reported that in patients intolerant of statins, many nutraceuticals with demonstrated hypolipidemic effect are well tolerated.

[Effectiveness of hydroxycinamates and beta-glucans as dietary tools against obesity and its associated dysfunctions, and their application as nutraceuticals]

Introduction

Over the last few years the prevalence of overweight and obesity has increased, affecting in certain parts of the world more than half of the adult population. Obesity has been related to disorders such as type-2 diabetes, non-alcoholic fatty liver disease, and cardiovascular diseases, among others, which has made of obesity the second cause of preventable death, only behind smoking. Bearing this in mind, it is necessary to find new strategies to overcome overweight/obesity and its associated pathologies. In this context, nutraceuticals and dietary supplements have become interesting tools thanks to their composition, rich in bioactive compounds beneficial to health. Among bioactive compounds, this study will focus on β-glucans, a type of soluble dietary fiber, and hydroxycinnamic acids, a group of phenols. Both types of compounds show complex and multifactorial effects, acting as hypolipemic, hypoglycemic, antioxidant, prebiotic and satiating agents. They act by modulating different metabolic pathways, affecting the absorption and metabolism of lipids and carbohydrates, reducing oxidative damage, promoting the proliferation of beneficial bacterial species, and reducing dietary intake. It may be concluded that both beta-glucans and hydroxycinnamates have potential as a nutritional tool for the management of obesity and its associated metabolic dysfunctions.

Effect of viscous fiber supplementation on obesity indicators in individuals consuming calorie-restricted diets: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Dietary fiber has played a consistent role in weight management, with efficacy potentially attributed to increased viscous fiber consumption.

PURPOSE

To summarize the effects of viscous fiber on body weight and other anthropometric parameters, along with a calorie-deficient diet, through a systematic review and meta-analysis.

METHODS

MEDLINE, EMBASE, and the Cochrane library were searched through July 24, 2019 for randomized controlled trials that assessed the effect of viscous fiber supplementation as part of a restricted calorie diet for ≥ 4 weeks relative to comparator diets. Data were pooled using the generic inverse-variance method with random-effects models and expressed as mean differences with 95% confidence intervals. Inter-study heterogeneity was assessed using Cochran's Q and quantified with I². The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach was used to evaluate the overall certainty of evidence.

RESULTS

Findings from 15 studies (n = 1347) showed viscous fiber supplementation significantly decreased body weight (- 0.81 kg [- 1.20, - 0.41]; p < 0.0001), BMI (- 0.25 kg/m² [- 0.46, - 0.05]; p = 0.01), and body fat (- 1.39% [- 2.61, - 0.17]; p = 0.03), compared to control. No effect on waist circumference was found. The certainty of evidence was graded as "moderate" for body weight, BMI, and body fat based on downgrades for imprecision. Waist circumference was graded "low" for downgrades of inconsistency and imprecision.

CONCLUSION

Viscous fiber within a calorie-restricted diet significantly improved body weight and other markers of adiposity in overweight adults and those with additional risk factors for cardiovascular disease. This trial is registered at www.clinicaltrials.gov as NCT03257449.

REGISTRATION

ClinicalTrials.gov identifier: NCT03257449.

Agaricus bisporus-derived β-glucan prevents obesity through PPAR γ downregulation and autophagy induction in zebrafish fed by chicken egg yolk

β-(1,4)-d-Glucan with (1,2) and (1,6)-linked branches (short for β-glucan), extracted from Agaricus bisporus (Lange) Sing, had significant anti-obesity and lowering-fat effect. FITC-β-glucan was absorbed by adipocytes of zebrafish larvae when stained by Nile Red. β-Glucan decreased the adiposity mass, reduced the expression of ppar g, mtp, L-fabp, ifabp in ISH, which was coincident as the results of RT-PCT. β-Glucan lowered the level of C/EBP α, c SREBP1, LXR α, PPAR γ by WB analysis, which were accompanied by an increase level in LC3 II/LC3 I and a decline level in p62 in dose-dependent manner. This study explored the effect and mechanisms of Agaricus bisporus derived-β-glucan to regulate lipid metabolism and prevent lipid deposits, and provided the experimental data for its use in diet food and food addictive.

Cholesterol-Lowering Nutraceuticals Affecting Vascular Function and Cardiovascular Disease Risk

PURPOSE OF REVIEW

The aim of this review is to provide an update on the effects of the dietary supplementation with cholesterol-lowering nutraceuticals and nutraceutical combinations affecting vascular function and CV risk in clinical interventional studies.

RECENT FINDINGS

Current evidence supports the mild-to-moderate cholesterol-lowering efficacy of red yeast rice, berberine, plant sterols, fibers, and some nutraceutical combinations whereas data on the individual cholesterol-lowering action of other nutraceuticals are either less striking or even inconclusive. There is also promising evidence on the vascular protective effects of some of the aforementioned nutraceuticals. However, except for red yeast rice, clinical interventional studies have not investigated their impact on CV outcomes. Evidence of both cholesterol-lowering and vascular protection is a prerogative of few single nutraceuticals and nutraceutical combinations, which may support their clinical use; however, caution on their uncontrolled adoption is necessary as they are freely available on the market and, therefore, subject to potential misuse.

Effect of fiber sources on fatty acids profile, glycemic index, and phenolic compound content of in vitro digested fortified wheat bread

In this study, some dietary fiber (DF) sources were investigated as fortifiers of wheat bread: oat (OB), flax (FB), and apple (AB). Adding oat and flax fibers to bread significantly changed the fatty acid profiles. OB was highest in oleic acid (33.83% of lipids) and linoleic acid (24.31% of lipids). Only in FB, γ-linolenic fatty acid was present in a significant amount-18.32%. The bioaccessibility trails revealed that the DF slow down the intake of saturated fatty acids. PUFA were least bioaccessible from all fatty acids groups in the range of (72% in OB to 87% in FB). The control bread had the greatest value (80.5) and was significantly higher than values for OB, FB, and AB in terms of glycemic index. OB, FB and AB addition led to obtain low glycemic index. AB had a significant highest value of total phenolic (897.2 mg/kg) with the lowest values in FB (541.2 mg/kg). The only significant lowering of caloric values in this study was observed in AB. The study could address the gap in the area of research about taking into consideration glycemic index, fatty acid profile and phenolic content in parallel in terms of DF application in breads.

Beta-Glucans Supplementation Associates with Reduction in P-Cresyl Sulfate Levels and Improved Endothelial Vascular Reactivity in Healthy Individuals

BACKGROUND

Oat and barley beta-glucans are prebiotic fibers known for their cholesterol-lowering activity, but their action on the human gut microbiota metabolism is still under research. Although the induction of short-chain fatty acids (SCFA) following their ingestion has previously been reported, no study has investigated their effects on proteolytic uremic toxins p-cresyl sulfate (pCS) and indoxyl sulfate (IS) levels, while others have failed to demonstrate an effect on the endothelial function measured through flow-mediated dilation (FMD).

OBJECTIVE

The aim of our study was to evaluate whether a nutritional intervention with a functional pasta enriched with beta-glucans could promote a saccharolytic shift on the gut microbial metabolism and improve FMD.

METHODS

We carried out a pilot study on 26 healthy volunteers who underwent a 2-month dietary treatment including a daily administration of Granoro "Cuore Mio" pasta enriched with barley beta-glucans (3g/100g). Blood and urine routine parameters, serum pCS/IS and FMD were evaluated before and after the dietary treatment.

RESULTS

The nutritional treatment significantly reduced LDL and total cholesterol, as expected. Moreover, following beta-glucans supplementation we observed a reduction of serum pCS levels and an increase of FMD, while IS serum levels remained unchanged.

CONCLUSIONS

We demonstrated that a beta-glucans dietary intervention in healthy volunteers correlates with a saccharolytic shift on the gut microbiota metabolism, as suggested by the decrease of pCS and the increase of SCFA, and associates with an improved endothelial reactivity. Our pilot study suggests, in addition to cholesterol, novel pCS-lowering properties of beta-glucans, worthy to be confirmed in large-scale trials and particularly in contexts where the reduction of the microbial-derived uremic toxin pCS is of critical importance, such as in chronic kidney disease.

Mushroom Polysaccharides: Chemistry and Antiobesity, Antidiabetes, Anticancer, and Antibiotic Properties in Cells, Rodents, and Humans

More than 2000 species of edible and/or medicinal mushrooms have been identified to date, many of which are widely consumed, stimulating much research on their health-promoting properties. These properties are associated with bioactive compounds produced by the mushrooms, including polysaccharides. Although β-glucans (homopolysaccharides) are believed to be the major bioactive polysaccharides of mushrooms, other types of mushroom polysaccharides (heteropolysaccharides) also possess biological properties. Here we survey the chemistry of such health-promoting polysaccharides and their reported antiobesity and antidiabetic properties as well as selected anticarcinogenic, antimicrobial, and antiviral effects that demonstrate their multiple health-promoting potential. The associated antioxidative, anti-inflammatory, and immunomodulating activities in fat cells, rodents, and humans are also discussed. The mechanisms of action involve the gut microbiota, meaning the polysaccharides act as prebiotics in the digestive system. Also covered here are the nutritional, functional food, clinical, and epidemiological studies designed to assess the health-promoting properties of polysaccharides, individually and as blended mixtures, against obesity, diabetes, cancer, and infectious diseases, and suggestions for further research. The collated information and suggested research needs might guide further studies needed for a better understanding of the health-promoting properties of mushroom polysaccharides and enhance their use to help prevent and treat human chronic diseases.