Oats and CVD risk markers: a systematic literature review

The effects of cereal β-glucans on cardiovascular risk factors and the role of the gut microbiome

The human gut microbiome has emerged as a key influencer of human health and disease, particularly through interactions with dietary fiber. However, national dietary guidelines worldwide are only beginning to capitalize on the potential of microbiome research, which has established the vital role of host-microbe interactions in mediating the physiological effects of diet on overall health and disease. β-glucans have been demonstrated to modulate the composition of the gut microbiota, leading to improved outcomes in cardiovascular disease (CVD). Raised serum cholesterol and blood pressure are important modifiable risk factors in the development of CVD and emerging evidence highlights the role of the gut microbiota in ameliorating such biomarkers and clinical characteristics of the disease. The proposed mechanism of action of β-glucans on the pathophysiological mechanisms of disease have yet to be elucidated. Validating gaps in the literature may substantiate β-glucans as a potential novel dietary therapy against modifiable risk factors for CVD and would further support the public health significance of including a habitual fiber-rich diet.

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.

Perspectives in the Application of High, Medium, and Low Molecular Weight Oat β-d-Glucans in Dietary Nutrition and Food Technology-A Short Overview

For centuries human civilization has cultivated oats, and now they are consumed in various forms of food, from instant breakfasts to beverages. They are a nutrient-rich food containing linear mixed-linkage (1 → 3) (1 → 4)-β-d-glucans, which are relatively well soluble in water and responsible for various biological effects: the regulation of the blood cholesterol level, as well as being anti-inflammatory, prebiotic, antioxidant, and tumor-preventing. Numerous studies, especially in the last two decades, highlight the differences in the biological properties of the oat β-d-glucan fractions of low, medium, and high molecular weight. These fractions differ in their features due to variations in bioavailability related to the rheological properties of these polysaccharides, and their association with food matrices, purity, and mode of preparation or modification. There is strong evidence that, under different conditions, the molecular weight may determine the potency of oat-extracted β-d-glucans. In this review, we intend to give a concise overview of the properties and studies of the biological activities of oat β-d-glucan preparations depending on their molecular weight and how they represent a prospective ingredient of functional food with the potential to prevent or modulate various pathological conditions.

Distribution of Micronutrients in Arborg Oat (Avena sativa L.) Using Synchrotron X-ray Fluorescence Imaging

It is important to know the mineral distribution in cereal grains for nutritional improvement or genetic biofortification. Distributions and intensities of micro-elements (Mn, Fe, Cu, and Zn) and macro-elements (P, S, K and Ca) in Arborg oat were investigated using synchrotron-based on X-ray fluorescence imaging (XFI). Arborg oat provided by the Crop Development Center (CDC, Aaron Beattie) of the University of Saskatchewan for 2D X-ray fluorescence scans were measured at the BioXAS-Imaging beamline at the Canadian Light Source. The results show that the Ca and Mn were mainly localized in the aleurone layer and scutellum. P, K, Fe, Cu, and Zn were mainly accumulated in the aleurone layer and embryo. Particularly the intensities of P, K, Cu, and Zn in the scutellum were higher compared to other areas. S was also distributed in each tissue and its abundance in the sub-aleurone was the highest. In addition, the intensities of S and Cu were highest in the nucellar projection of the crease region. All these elements were also found in the pericarp but they were at lower levels than other tissues. Overall, the details of these experimental results can provide important information for micronutrient biofortification and processing strategies on oat through elemental mapping in Arborg oat.

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.

Bacterially Converted Oat Active Ingredients Enhances Antioxidative and Anti-UVB Photoaging Activities

Oat (Avena sativa L.) is one of the most widely consumed cereal grains worldwide and is considered as an important cereal crop with high nutritional value and potential health benefits. With different bacterial strains, fermented oat extracts were examined for the antioxidant and antiaging effects on the skin after optimization of extraction conditions. Fermented oats contained high avenanthramides, and its function was investigated on matrix metalloproteinase-1 and collagen expression with human dermal fibroblast cells. After fractionation, butanol layers showed the highest avenanthramides contents. Therefore, the microbial fermentation of oats enhances the quality and content of functional ingredients of oats, which provide natural dietary supplements, antioxidants, and antiaging agents.

Combined molecular spectroscopic techniques (SR-FTIR, XRF, ATR-FTIR) to study physiochemical and nutrient profiles of Avena sativa grain and nutrition and structure interactive association properties

Synchrotron radiation based on Fourier transform infrared radiation (SR-FTIR), X-ray fluorescence (XRF) and attenuated total reflection based on Fourier transform infrared radiation (ATR-FTIR) spectroscopy are both fast determining and minimal sample preparing techniques. They are capable of detecting the internal molecular structures. However, these techniques are still not well understood by nutrition researchers for the analysis of feed. The purpose of this review is to introduce advanced SR-FTIR, XRF, and ATR-FTIR molecular techniques, use these techniques to study chemical and nutrient profiles of Avena sativa grain, and lastly to study the nutrition and structure interactive association properties. The review mainly focuses on the following aspects: 1) the background information of Avena sativa grain; its history, chemical composition, nutrient profile, inherent structure, and production; 2) molecular spectroscopic techniques; principles and spectral analysis methodology of SR-FTIR, XRF and ATR-FTIR; 3) the application of SR-FTIR, XRF, and ATR-FTIR as a novel approach. This review provides an insight on how molecular spectroscopic techniques could be used for the study of nutrition and structure interactive association properties.

In vitro digestion of eight types of wholegrains and their dietary recommendations for different populations

Wholegrains have been promoted for human consumption due to their various health benefits. However, different wholegrains vary in nutritional composition and their beneficial impact on health. In this study, we compared the in vitro starch and protein digestibility, as well as dietary fiber content of eight different wholegrains including barley, buckwheat, coix seed, foxtail millet, oat, proso millet, quinoa, and sorghum and their porridges. We found that boiling improved starch digestibility of all grains, and protein digestibility except proso millet and sorghum. Porridges made from oats, quinoa, or buckwheat are considered healthier than others due to their lower glycemic index and glycemic load, higher digestible protein content and amino acid bioaccessibility, and higher dietary fiber content (>12%). This study could provide a comprehensive nutritional composition and digestibility of the eight types of wholegrains and their porridges. Dietary recommendations were also given for different populations based on factor analysis.

Evaluation of novel nutraceuticals based on the combination of oat beta-glucans and a green coffee phenolic extract to combat obesity and its comorbidities. A randomized, dose-response, parallel trial

Obesity and its associated comorbidities are a major public health concern worldwide. Reduced energy intake and increased physical activity interventions have limited success in the long term. Nutraceuticals might be an alternative means to help lose weight and reduce obesity-associated cardiometabolic risk factors without changes in the habitual diet. The objective of the present study was to comparatively evaluate the efficiency of nutraceuticals based on the combination of a decaffeinated green coffee bean extract (GCBE) and two types of oat beta-glucans (BG) with different physiochemical properties on obesity related biomarkers in overweight/obese subjects. A randomized, dose-response, parallel, blind study was carried out in four groups of subjects (n = 15 each) who consumed for 6 weeks, twice a day, a nutraceutical containing 3 g d^-1 or 5 g d^-1 doses of 35% or 70% BG and a fixed amount of GCBE providing 600 mg d^-1 of phenols. 35% BG showed a 10 and 100 times higher molecular weight and viscosity, respectively, compared to 70% BG. Food intake, anthropometry and different cardiometabolic markers were assessed at the beginning and end of the intervention. According to the general model of variance with repeated measure analysis, the intervention caused positive changes in the levels of total cholesterol, LDL cholesterol, VLDL cholesterol, triglycerides, alanine aminotransferase, aspartate aminotransferase, haemoglobin A1c, insulin, systolic blood pressure (SBP), total body fat percentage (TBF%), visceral fat percentage, and waist and hip circumferences without differences among the treatments, except for SBP and TBF%. Looking into the rates of change [(end value - beginning value)/beginning value] of these parameters, 5 g - 70% BG was the treatment that lowered TBF% the most. In conclusion, 5 g - 70% BG may be more effective in helping to lose weight and additionally, it produced the least bloating according to participants' subjective perception.

The Genetic Architecture of Milling Quality in Spring Oat Lines of the Collaborative Oat Research Enterprise

Most oat grains destined for human consumption must possess the ability to pass through an industrial de-hulling process with minimal breakage and waste. Uniform grain size and a high groat to hull ratio are desirable traits related to milling performance. The purpose of this study was to characterize the genetic architecture of traits related to milling quality by identifying quantitative trait loci (QTL) contributing to variation among a diverse collection of elite and foundational spring oat lines important to North American oat breeding programs. A total of 501 lines from the Collaborative Oat Research Enterprise (CORE) panel were evaluated for genome-wide association with 6 key milling traits. Traits were evaluated in 13 location years. Associations for 36,315 markers were evaluated for trait means across and within location years, as well as trait variance across location years, which was used to assess trait stability. Fifty-seven QTL influencing one or more of the milling quality related traits were identified, with fourteen QTL mapped influencing mean and variance across location years. The most prominent QTL was Qkernel.CORE.4D on chromosome 4D at approximately 212 cM, which influenced the mean levels of all traits. QTL were identified that influenced trait variance but not mean, trait mean only and both.

Whole- and Refined-Grain Consumption and Longitudinal Changes in Cardiometabolic Risk Factors in the Framingham Offspring Cohort

BACKGROUND

Greater whole grain (WG) consumption is associated with reduced risk of cardiovascular disease (CVD); however, few prospective studies have examined WG or refined grain (RG) intake and intermediate cardiometabolic risk factors.

OBJECTIVES

We examined the longitudinal association between WG and RG intake on changes in waist circumference (WC); fasting HDL cholesterol, triglyceride, and glucose concentrations; and blood pressure.

METHODS

Subjects were participants in the Framingham Offspring cohort study [n = 3121; mean ± SD baseline age: 54.9 ± 0.2 y; BMI (kg/m2) 27.2 ± 0.1]. FFQ, health, and lifestyle data were collected approximately every 4 y over a median 18-y follow-up. Repeated measure mixed models were used to estimate adjusted mean changes per 4-y interval in risk factors across increasing categories of WG or RG intake.

RESULTS

Greater WG intake was associated with smaller increases in WC (1.4 ± 0.2 compared with 3.0 ± 0.1 cm in the highest compared with the lowest category, respectively; P-trend < 0.001), fasting glucose concentration (0.7 ± 0.4 compared with 2.6 ± 0.2 mg/dL; P-trend < 0.001), and systolic blood pressure (SBP; 0.2 ± 0.5 compared with 1.4 ± 0.3 mm Hg; P-trend < 0.001) per 4-y interval. When stratified by sex, a stronger association with WC was observed among females than males. Higher intake of WG was associated with greater increases in HDL cholesterol and declines in triglyceride concentrations; however, these differences did not remain significant after adjustment for change in WC. Conversely, greater RG intake was associated with greater increases in WC (2.7 ± 0.2 compared with 1.8 ± 0.1 cm, P-trend < 0.001) and less decline in triglyceride concentration (-0.3 ± 1.3 compared with -7.0 ± 0.7 mg/dL, P-trend < 0.001).

CONCLUSIONS

Among middle- to older-age adults, replacing RG with WG may be an effective dietary modification to attenuate abdominal adiposity, dyslipidemia, and hyperglycemia over time, thereby reducing the risk of cardiometabolic diseases.

Incorporation of oat flour into wheat flour noodle and evaluation of its physical, chemical and sensory attributes

Abstract Noodles are popular food and fortified noodles with vital nutrients may build a healthy food habit among people. Oat is a cereal with high nutritional value. Therefore, the current research was undertaken to increase the nutrient content of noodles using oat flour and to evaluate the effects of oat flour on the physicochemical properties and sensory attributes of the noodles. The noodles were prepared following five different formulations (oats: wheat flour in the ratio of 0:100, 20:80, 25:75, 30:70 and 35:65). Other ingredients like table salt, carboxymethyl cellulose (CMC), corn starch, and water were equal in each formulation. To evaluate the best formulation, proximate analysis, functional characteristics and sensory assay were conducted on samples. The formulation having 70% of wheat flour and 30% of oat flour showed the best performance in proximate analysis and sensory evaluation. This formulation of noodles has 13.03% of protein, 1.51% of fat, 1.46% of total ash, 0.76% of fibre, 73.87% of carbohydrate, 361.19 kcal of energy and also a good amount of important minerals. The formulation regarding wheat flour 70% and oat flour 30% may be suggested to the large population who are habituated to consume noodles regularly as the main diet.

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.

Whole grain and cereal fibre intake in the Australian Health Survey: associations to CVD risk factors

OBJECTIVE

To explore associations of whole grain and cereal fibre intake to CVD risk factors in Australian adults.

DESIGN

Cross-sectional analysis. Intakes of whole grain and cereal fibre were examined in association to BMI, waist circumference (WC), blood pressure (BP), serum lipid concentrations, C-reactive protein, systolic BP, fasting glucose and HbA1c.

SETTING

Australian Health Survey 2011-2013.

PARTICIPANTS

A population-representative sample of 7665 participants over 18 years old.

RESULTS

Highest whole grain consumers (T3) had lower BMI (T0 26·8 kg/m2, T3 26·0 kg/m2, P < 0·0001) and WC (T0 92·2 cm, T3 90·0 cm, P = 0·0005) compared with non-consumers (T0), although only WC remained significant after adjusting for dietary and lifestyle factors, including cereal fibre intake (P = 0·03). Whole grain intake was marginally inversely associated with fasting glucose (P = 0·048) and HbA1c (P = 0·03) after adjusting for dietary and lifestyle factors, including cereal fibre intake. Cereal fibre intake was inversely associated with BMI (P < 0·0001) and WC (P < 0·0008) and tended to be inversely associated with total cholesterol, LDL-cholesterol and apo-B concentrations, although associations were attenuated after further adjusting for BMI and lipid-lowering medication use.

CONCLUSIONS

The extent to which cereal fibre is responsible for the CVD-protective associations of whole grains may vary depending on the mediators involved. Longer-term intervention studies directly comparing whole grain and non-whole grain diets of similar cereal fibre contents (such as through the use of bran or added-fibre refined grain products) are needed to confirm independent effects.

Special Commentary: Is diet management helpful in familial hypercholesterolemia?

PURPOSE OF REVIEW

Familial hypercholesterolemia is a genetic condition where low-density lipoprotein (LDL) receptor defects cause severe elevations of LDL cholesterol. As significant LDL-lowering effects are needed, medication is considered the cornerstone of therapy, and dietary therapy has received less emphasis. This review will re-visit older studies of diet intervention and new insights from genetic and mechanistic studies to determine the value of diet management for familial hypercholesterolemia patients.

RECENT FINDINGS

Saturated fat reduction improves cardiovascular outcomes, particularly in those with genetic predisposition to risk. Secular trends in saturated fat intake may have improved familial hypercholesterolemia outcomes. Dietary mechanisms of LDL cholesterol-lowering complement pharmacologic approaches.

SUMMARY

Diet treatment adds incremental health benefit to pharmacologic treatment in familial hypercholesterolemia.

Oat bran, but not its isolated bioactive β-glucans or polyphenols, have a bifidogenic effect in an in vitro fermentation model of the gut microbiota

Wholegrain oats are known to modulate the human gut microbiota and have prebiotic properties (increase the growth of some health-promoting bacterial genera within the colon). Research to date mainly attributes these effects to the fibre content; however, oat is also a rich dietary source of polyphenols, which may contribute to the positive modulation of gut microbiota. In vitro anaerobic batch-culture experiments were performed over 24 h to evaluate the impact of two different doses (1 and 3 % (w/v)) of oat bran, matched concentrations of β-glucan extract or polyphenol mix, on the human faecal microbiota composition using 16S RNA gene sequencing and SCFA analysis. Supplementation with oats increased the abundance of Proteobacteria (P &lt;0·01) at 10 h, Bacteroidetes (P &lt;0·05) at 24 h and concentrations of acetic and propionic acid increased at 10 and 24 h compared with the NC. Fermentation of the 1 % (w/v) oat bran resulted in significant increase in SCFA production at 24 h (86 (sd 27) v. 28 (sd 5) mm; P &lt;0·05) and a bifidogenic effect, increasing the relative abundance of Bifidobacterium unassigned at 10 h and Bifidobacterium adolescentis (P &lt;0·05) at 10 and 24 h compared with NC. Considering the β-glucan treatment induced an increase in the phylum Bacteroidetes at 24 h, it explains the Bacteriodetes effects of oats as a food matrix. The polyphenol mix induced an increase in Enterobacteriaceae family at 24 h. In conclusion, in this study, we found that oats increased bifidobacteria, acetic acid and propionic acid, and this is mediated by the synergy of all oat compounds within the complex food matrix, rather than its main bioactive β-glucan or polyphenols. Thus, oats as a whole food led to the greatest impact on the microbiota.

Oat safety for celiac disease patients: theoretical analysis correlates adverse symptoms in clinical studies to contaminated study oats

Inclusion of oats in a gluten-free (GF) diet can provide whole grain nutritional benefits to celiac disease (CD) patients, but there has been debate regarding oat safety for these individuals. This is because of conflicting research findings, with inconsistencies attributed to varying CD subject's sensitivities to "pure" oats. Clinical trials to date have assumed oats provided to subjects to be lightly contaminated, if at all. This assumption is challenged here since oat's propensity to be "kernel" contaminated with gluten sources like wheat and barley has recently been shown to significantly complicate confirmation of a GF state. We therefore hypothesize that clinical studies may have inadvertently provided pill-like gluten kernels intermittently to study subjects, leading to adverse outcomes that could potentially explain inconsistencies between study conclusions. To test this theory, potential gluten contamination of oats used in a cross-section of 12 important oat feeding studies has been estimated, done according to descriptions of oats used, published contamination rates for various oat types, and study oat dosages. Expected gluten exposures were found to be at levels to elicit clinical effects in a large portion of CD patients, correlating with observed clinical reaction rates in those studies (P value = .0006). Estimated gluten doses were found insufficient, however, to affect morphological outcomes, whereas only 1 study had 1 case. Our analysis provides a new perspective with which to view oat safety study conclusions and justifies new clinical trials using today's higher-purity GF oats to settle the oat safety for CD patient debate.

An Overview of Whole Grain Regulations, Recommendations and Research across Southeast Asia

The Association of Southeast Asian Nations (ASEAN) is a diverse region that is experiencing economic growth and increased non-communicable disease burden. This paper aims to evaluate the current regulations, dietary recommendations and research related to whole grains in this region. To do this, a systematic literature review was carried out and information was collected on regulations and dietary recommendations from each member state. The majority of publications on whole grains from the region (99 of 147) were in the area of food science and technology, with few observational studies (n = 13) and human intervention studies (n = 10) related to whole grains being apparent. Information from six countries (Indonesia, Malaysia, The Philippines, Singapore, Thailand and Vietnam) was available. Wholegrain food-labelling regulations were only noted in Malaysia and Singapore. Public health recommendation related to whole grains were apparent in four countries (Indonesia, Malaysia, The Philippines, Singapore), while recent intake data from whole grains was only apparent from Malaysia, The Philippines and Singapore. In all cases, consumption of whole grains appeared to be very low. These findings highlight a need for further monitoring of dietary intake in the region and further strategies targeted at increasing the intake of whole grains.

Processing of oat: the impact on oat's cholesterol lowering effect

Epidemiological and interventional studies have clearly demonstrated the beneficial impact of consuming oat and oat-based products on serum cholesterol and other markers of cardiovascular disease. The cholesterol-lowering effect of oat is thought to be associated with the β-glucan it contains. However, not all food products containing β-glucan seem to lead to the same health outcome. Overall, highly processed β-glucan sources (where the oat tissue is highly disrupted) appear to be less effective at reducing serum cholesterol, but the reasons are not well understood. Therefore, the mechanisms involved still need further clarification. The purpose of this paper is to review current evidence of the cholesterol-lowering effect of oat in the context of the structure and complexity of the oat matrix. The possibility of a synergistic action and interaction between the oat constituents promoting hypocholesterolaemia is also discussed. A review of the literature suggested that for a similar dose of β-glucan, (1) liquid oat-based foods seem to give more consistent, but moderate reductions in cholesterol than semi-solid or solid foods where the results are more variable; (2) the quantity of β-glucan and the molecular weight at expected consumption levels (∼3 g day-1) play a role in cholesterol reduction; and (3) unrefined β-glucan-rich oat-based foods (where some of the plant tissue remains intact) often appear more efficient at lowering cholesterol than purified β-glucan added as an ingredient.

Dietary Fiber Is Beneficial for the Prevention of Cardiovascular Disease: An Umbrella Review of Meta-analyses

Objective

The purpose of this study was to review previously published meta-analyses on the effectiveness of dietary fiber on cardiovascular disease.

Methods

An umbrella review of all published meta-analyses was performed. A PubMed search from January 1, 1980, to January 31, 2017, was conducted using the following search strategy: (fiber OR glucan OR psyllium OR fructans) AND (meta-analysis OR systematic review). Only English-language publications that provided quantitative statistical analysis on cardiovascular disease, lipid concentrations, or blood pressure were retrieved.

Results

Thirty-one meta-analyses were retrieved for inclusion in this umbrella review, and all meta-analyses comparing highest versus lowest dietary fiber intake reported statistically significant reductions in the relative risk (RR) of cardiovascular disease mortality (RR = 0.77-0.83), as well as the incidences of cardiovascular disease (RR = 0.72-0.91), coronary heart disease (RR = 0.76-0.93), and stroke (RR = 0.83-0.93). Meta-analyses on supplementation studies using β-glucan or psyllium fibers also reported statistically significant reductions in both total serum and low-density lipoprotein cholesterol concentrations.

Conclusion

This review suggests that individuals consuming the highest amounts of dietary fiber intake can significantly reduce their incidence and mortality from cardiovascular disease. Mechanistically, these beneficial effects may be due to dietary fibers' actions on reducing total serum and low-density lipoprotein cholesterol concentrations between 9.3 to 14.7 mg/dL and 10.8 to 13.5 mg/dL, respectively.

Lipid Lowering with Soluble Dietary Fiber

Consumption of dietary soluble fibers has been associated with health benefits such as reduced lipid levels, lower blood pressure, improved blood glucose control, weight loss, improved immune function, and reduced inflammation. Many of these health benefits relate to a reduced risk of developing cardiovascular disease. In this paper, we have reviewed recent studies on the hypocholesterolemic effects of dietary soluble fibers as well as fiber-rich foods. Findings include the following: (a) consumption of water-soluble, viscous-forming fibers can reduce total and low-density lipoprotein cholesterol levels by about 5-10 %; (b) minimal changes of high-density lipoprotein cholesterol or triglyceride levels were observed; (c) cholesterol-lowering properties of soluble fibers depend on their physical and chemical properties; and (d) medium to high molecular weight fibers are more effective in reducing lipid levels. Hypocholesterolemic benefits were also observed with some fiber-rich foods, such as whole oats, whole barley, legumes, peas, beans, flax seeds, apples, and citrus foods.

Phenolics from Whole Grain Oat Products as Modifiers of Starch Digestion and Intestinal Glucose Transport

Four oat varieties and three product forms (porridge, cereal, and snack bar) were assessed to determine the impact of oat phenolics on starch digestibility and intestinal glucose transport. α-Amylase activity was enhanced by 20 GAE μM (gallic acid equivalent) of phenolics extracted from oat (96.7-118%, p < 0.05), while it was modestly inhibited at 500 GAE μM (83.0-95.4%). Maltose hydrolysis was reduced (49.6-82.4%, p < 0.05), albeit with high IC₅₀ values (500-940 GAE μM). Free and bound oat phenolic extracts dose-dependently attenuated transport of d-glucose-1,2,3,4,5,6,6-d₇ by Caco-2 monolayers over 60 min. Oat foods were then subjected to a coupled in vitro digestion/Caco-2 intestinal cell model to determine relevance to whole food systems. Digestive release of glucose was similar among products; however, glucose transport was significantly reduced from digesta of GMI 423 porridge and puffed cereal by 34% ± 12% and 20% ± 10% (p < 0.05) at 60 min. Results suggest phenolics might be a factor modulating glycemic response of oat products.

Effects of 3 g of soluble fiber from oats on lipid levels of Asian Indians - a randomized controlled, parallel arm study

Background

Cardiovascular diseases are more prevalent and severe in Asian Indians. Simple diet-based strategies are important for prevention of cardiovascular diseases.The aim of the present study was to evaluate the effects of oats consumption on lipid parameters in mildly hypercholesterolemic Asian Indians living in India.

Methods

A short-term, prospective, open-labeled, randomized controlled, parallel group study was conducted. Mildly hypercholesterolemic (total cholesterol >200 mg/dL and <240 mg/dL) subjects (n = 80) were randomized into two groups: intervention (n = 40) and usual diet (n = 40). Sample size was calculated for a two-group parallel superiority randomized control trial. Out of 80 enrolled subjects 69 subjects completed the study; 33 in the control group and 36 in the intervention group. In the intervention group, patients were served 70 g of oats twice a day in the form of porridge and upma (A thick porridge from oats with seasonings and vegetables) under observation at the study site. Lipid parameters were assessed at baseline and after 4 weeks of intervention.

Results

There was a reduction of 3.1% in total cholesterol levels in the control group as against 8.1% reduction in the intervention group (p < 0.02). Greater reductions were also seen in low-density lipoprotein cholesterol in the intervention group (11.6%) as compared to control group (4.1%, p < 0.04) over a period of 28 days.

Conclusion

Daily consumption of 3 g of soluble fiber from 70 g of oats leads to beneficial effects on the lipid parameters, specifically total cholesterol and low-density lipoprotein cholesterol in hypercholesterolemic Asian Indians. Large scale studies over a longer period of intervention are required to further establish the cholesterol-lowering effect of oat fiber.

Trial registration

The study was retrospectively registered at clinicaltrials.gov (dated: 25th Februrary.2015) with registration number NCT02376660.

Whole grain oats, more than just a fiber: Role of unique phytochemicals

Oats are a good source of soluble dietary fiber, especially β-glucan, which has outstanding functional and nutritional properties. β-Glucan is considered to be the major active component of oats because of its cholesterol-lowering and antidiabetic effects. However, the nutritional benefits of oats appear to go beyond fiber to bioactive phytochemicals with strong antioxidant and anti-inflammatory effects. In this review, we summarize current knowledge on the chemistry, stability, bioavailability, and health effects of two unique phytochemicals in oats, avenanthramides, and avenacosides A and B. We conclude that studies on the beneficial effects of avenanthramides and avenacosides A and B are still in their infancy, and additional health benefits of these unique oat components may yet be identified.

Evaluation of a high nutritional quality snack based on oat flakes and inulin: effects on postprandial glucose, insulin and ghrelin responses of healthy subjects

A low GI snack with satiety promoting effects.

Evaluation of a high nutritional quality snack based on oat flakes and inulin: effects on postprandial glucose, insulin and ghrelin responses of healthy subjects

A low GI snack with satiety promoting effects.

Evaluation of a high nutritional quality snack based on oat flakes and inulin: effects on postprandial glucose, insulin and ghrelin responses of healthy subjects

A low GI snack with satiety promoting effects.

Evaluation of a high nutritional quality snack based on oat flakes and inulin: effects on postprandial glucose, insulin and ghrelin responses of healthy subjects

A low GI snack with satiety promoting effects.

Evaluation of a high nutritional quality snack based on oat flakes and inulin: effects on postprandial glucose, insulin and ghrelin responses of healthy subjects

A low GI snack with satiety promoting effects.

Evaluation of a high nutritional quality snack based on oat flakes and inulin: effects on postprandial glucose, insulin and ghrelin responses of healthy subjects

A low GI snack with satiety promoting effects.

Evaluation of a high nutritional quality snack based on oat flakes and inulin: effects on postprandial glucose, insulin and ghrelin responses of healthy subjects

A low GI snack with satiety promoting effects.

Evaluation of a high nutritional quality snack based on oat flakes and inulin: effects on postprandial glucose, insulin and ghrelin responses of healthy subjects

A low GI snack with satiety promoting effects.

Evaluation of a high nutritional quality snack based on oat flakes and inulin: effects on postprandial glucose, insulin and ghrelin responses of healthy subjects

A low GI snack with satiety promoting effects.

Evaluation of a high nutritional quality snack based on oat flakes and inulin: effects on postprandial glucose, insulin and ghrelin responses of healthy subjects

A low GI snack with satiety promoting effects.

Evaluation of a high nutritional quality snack based on oat flakes and inulin: effects on postprandial glucose, insulin and ghrelin responses of healthy subjects

A low GI snack with satiety promoting effects.

The Metabolic Effects of Oats Intake in Patients with Type 2 Diabetes: A Systematic Review and Meta-Analysis

The present study aimed to comprehensively assess if oats intake is beneficial for diabetic patients. The literature search was conducted in PubMed database up to 23 August 2015. Fourteen controlled trials and two uncontrolled observational studies were included. Compared with the controls, oats intake significantly reduced the concentrations of glycosylated hemoglobin A1c (HbA1c) (MD, −0.42%; 95% CI, −0.61% to −0.23%), fasting blood glucose (FBG) (MD, −0.39 mmol/L; 95% CI, −0.58 to −0.19 mmol/L), total cholesterol (TC) (MD, −0.49 mmol/L; 95% CI, −0.86 to −0.12 mmol/L), low-density lipoprotein cholesterol (LDL-C) (MD, −0.29 mmol/L; 95% CI, −0.48 to −0.09 mmol/L). Oatmeal significantly reduced the acute postprandial glucose and insulin responses compared with the control meal. The present study has revealed a beneficial effect of oats intake on glucose control and lipid profiles in type 2 diabetic patients. Further investigations of oats intake in patients with type 1 diabetes and the safety of oats consumption are required.

Whole-grain and blood lipid changes in apparently healthy adults: a systematic review and meta-analysis of randomized controlled studies

BACKGROUND

Whole grains are recognized for their potential role in preventing cardiovascular diseases; however, results from randomized controlled studies on blood lipids are inconsistent, potentially because of compositional differences between individual grain types for some nutrients, including dietary fiber.

OBJECTIVE

Using a meta-analytic approach, we assessed the effect of whole-grain compared with non-whole-grain foods on changes in total cholesterol (TC), LDL cholesterol, HDL cholesterol, and triglycerides.

DESIGN

We conducted a systematic literature search in selected databases. Studies were included if they were randomized controlled comparisons between whole-grain foods and a non-whole-grain control in adults. A total of 6069 articles were screened for eligibility, and data were extracted from 24 studies. Weighted mean differences were calculated, and meta-regression analyses were performed for whole-grain dose, study duration, and baseline TC concentration.

RESULTS

Overall, whole-grain intake lowered LDL cholesterol (weighted difference: -0.09 mmol/L; 95% CI: -0.15, -0.03 mmol/L; P < 0.01) and TC (weighted difference: -0.12 mmol/L; 95% CI: -0.19, -0.05 mmol/L; P < 0.001) compared with the control. Whole-grain oat had the greatest effect on TC (weighted difference: -0.17 mmol/L; 95% CI: -0.10, -0.25 mmol/L; P < 0.001). No effect of whole-grain foods on HDL cholesterol was seen, whereas whole-grain foods tended to lower triglycerides compared with the control (weighted difference: -0.04 mmol/L; 95% CI: -0.08, 0.01; P = 0.10). No association was found between whole-grain dose or baseline TC concentration and any of the outcomes, whereas study duration was positively associated with changes in TC and LDL cholesterol.

CONCLUSIONS

Consumption of whole-grain diets lowers LDL cholesterol and TC, but not HDL cholesterol or triglycerides, compared with consumption of non-whole-grain control diets. Whole-grain oat appears to be the most effective whole grain for lowering cholesterol.

Oat (Avena sativa L.): Oil and Nutriment Compounds Valorization for Potential Use in Industrial Applications

Oat is a promising plant for the future. It is edible and beneficial thanks to its nutritional, medicinal and pharmaceutical uses and, hence, recognized to be useful for a healthier world. The assessment of the vital functions of oat components is important for industries requiring correct health labelling, valid during the shelf life of any product. Oil, enzymes and other biomolecules of nutraceutic or dietary usage from oats would be valorized for this purpose. Although oats have a unique and versatile composition including antioxidants and biomolecules indispensable for health, they are undervalued in comparison with other staple cereals such as wheat, barley and rice. Furthermore, oats, apart from maize, comprise a high oil content used for a wide range of beneficial purposes. In addition, they contain beta glucan that has proven to be very helpful in reducing blood cholesterol levels and other cardiovascular diseases risks. In fact, there is diversity in the composition and content of the beneficial oat components within their genotypes and the different environmental conditions and, thus, oats are amenable to be enhanced by agronomic practices and genetic approaches.

Oat agriculture, cultivation and breeding targets: implications for human nutrition and health

Oats are undervalued in comparison with wheat, rice and barley, despite their unique composition that includes many of the nutrients required for health and a reduced risk of degenerative disease incidence. Furthermore, oats as whole grain and some of their associated products also contain β-glucan, a complex polysaccharide that has an approved health claim to reduce blood cholesterol levels and reduce the risk of CHD incidence if consumed at ≥ 3 g/d. At the agronomic level, oats exhibit optimal growth in regions of moderate temperature and long day length. In addition, they can tolerate wet weather and acidic soils more effectively than other cereals, such as wheat. Studies have shown that there is diversity in the content and composition of nutrients and health-beneficial components within the available wild and cultivated germplasm and that these are amenable to be enhanced by different agronomic practices as well as are susceptible to climatic variation. The advances in modern plant genetics, developed in sister cereals such as wheat, rice and barley, mean that oat development and exploitation should see an acceleration in the coming decade as they are adopted and applied. These advances include approaches such as genome sequencing, genotyping by sequencing and the allied next-level analytical approaches of RNA sequencing, transcriptome profiling and metabolomics. The collation and coordination of these approaches should lead to the generation of new, tailored oat varieties that are nutritionally enhanced and contain a greater proportion of health-beneficial components that can be translated through into a wide(r) range of consumer products with the ultimate hope of associated benefits to human health and nutrition.