Composition of Whole Grain Dietary Fiber and Phenolics and Their Impact on Markers of Inflammation

Inflammation is an important biological response to any tissue injury. The immune system responds to any stimulus, such as irritation, damage, or infection, by releasing pro-inflammatory cytokines. The overproduction of pro-inflammatory cytokines can lead to several diseases, e.g., cardiovascular diseases, joint disorders, cancer, and allergies. Emerging science suggests that whole grains may lower the markers of inflammation. Whole grains are a significant source of dietary fiber and phenolic acids, which have an inverse association with the risk of inflammation. Both cereals and pseudo-cereals are rich in dietary fiber, e.g., arabinoxylan and β-glucan, and phenolic acids, e.g., hydroxycinnamic acids and hydroxybenzoic acids, which are predominantly present in the bran layer. However, the biological mechanisms underlying the widely reported association between whole grain consumption and a lower risk of disease are not fully understood. The modulatory effects of whole grains on inflammation are likely to be influenced by several mechanisms including the effect of dietary fiber and phenolic acids. While some of these effects are direct, others involve the gut microbiota, which transforms important bioactive substances into more beneficial metabolites that modulate the inflammatory signaling pathways. Therefore, the purpose of this review is twofold: first, it discusses whole grain dietary fiber and phenolic acids and highlights their potential; second, it examines the health benefits of these components and their impacts on subclinical inflammation markers, including the role of the gut microbiota. Overall, while there is promising evidence for the anti-inflammatory properties of whole grains, further research is needed to understand their effects fully.

Exploring a Potential Causal Link Between Dietary Intake and Chronic Obstructive Pulmonary Disease: A Two-Sample Mendelian Randomization Study

Background

Chronic Obstructive Pulmonary Disease (COPD), the most prevalent chronic respiratory condition, significantly impairs patients' quality of life. The pivotal element in disease management lies in prevention, underscoring the paramount importance of employing a scientific approach to investigate early prevention strategies for COPD.

Methods

This study delved into the causal link between 28 dietary intakes and COPD employing two-sample Mendelian randomization. We primarily utilized the Inverse Variance Weighted (IVW) method as the main outcome, complemented by Weighted Median (WM), MR-Egger method, along with several sensitivity analysis techniques, all accompanied by visual representations.

Results

We identified higher odds of COPD following exposure to green beans (OR=1.381, 95% CI=1.119-1.704, P=0.003) and pork intake (OR=2.657, 95% CI=1.203-5.868, P=0.016). In contrast, the odds of developing COPD were lower following exposure to dried fruit (OR=0.481, 95% CI=0.283-0.819, P=0.007), cereal (OR=0.560, 95% CI=0.356-0.880, P=0.012), and whole egg consumption (OR=0.700, 95% CI=0.504-0.972, P=0.033).

Conclusion

In light of our study's findings, we anticipate that strategically modifying dietary choices may offer an avenue for early COPD prevention in the future.

5-Heptadecylresorcinol Ameliorates Obesity-Associated Skeletal Muscle Mitochondrial Dysfunction through SIRT3-Mediated Mitophagy

Skeletal muscle dysfunction caused by obesity is characterized by the decline in mitochondrial content and function. 5-Heptadecylresorcinol (AR-C17) is a specific bioactive component derived from whole wheat and rye, which has been evidenced to improve obesity-associated skeletal muscle dysregulation. However, the mechanism underlying its protective activity requires further exploration. Herein, we found that AR-C17 (5, 10, and 20 μM) intervention reversed PA-induced (0.5 mM) reduction in mitochondrial content, mitochondrial membrane potential, and mitochondrial energy metabolism in C2C12 cells. Meanwhile, AR-C17 evidently alleviated PA-mediated myotube mitochondrial dysfunction via elevating mitochondria autophagy flux and upregulating the expression level of autophagy-related protein, while this effect was abolished by an autophagy inhibitor (3-MA). Further analysis showed that SIRT3-FOXO3A-PINK-Parkin-mediated mitophagy was involved in the modulation of myocyte mitochondrial dysfunction by AR-C17. In addition, AR-C17 administration (30 and 150 mg/kg/day) significantly improved high-fat-diet-induced mitochondrial dysregulation in mice skeletal muscle tissue via SIRT3-dependent mitophagy. Our findings indicate that skeletal muscle cells are responsive to AR-C17, which improves myogenesis and mitophagy in vitro and in vivo.

Potential impact of time trend of whole grain intake on burden of major cancers in China

Numerous studies have revealed associations between high intake of whole grains and reduced risk of various cancers. Yet, in recent decades, the traditional Chinese diets have been challenged by reduction in whole grains and increase in refined grains. To assess the impact of this dietary transition on cancer prevention, we analyzed the time trend of whole grain intake using nationally representative sampling data of over 15 thousand individuals from the China Health and Nutrition Survey. We applied the comparative risk assessment method to estimate the population attributable fraction of cancers due to insufficient whole grain intake from 1997 to 2011 and projected the trend of whole grain intake and the associated burden of cancers to 2035. We found a significant decrease of approximately 59% of whole grain intake in the Chinese population from 1997 to 2011. Compared with 1997, insufficient intake of whole grains was responsible for 9940 more cases of breast cancer, 12,903 more cases of colorectal cancer and 434 more cases of pancreatic cancer in 2011. Our projections suggest that if every Chinese would consume 125 g whole grain per day as recommended by the latest Chinese Dietary Guidelines, 0.63% bladder cancer, 8.98% breast cancer, 15.85% colorectal cancer, 3.86% esophageal cancer, 2.52% liver cancer and 2.22% pancreatic cancer (totaling 186,659 incident cases) could theoretically be averted by 2035. Even if everyone maintained the 2011 whole grain intake level, an estimated 8.38% of cancer events could still be prevented by 2035.

Fifty shades of grain - Increasing whole grain consumption through daily messages

Despite numerous health benefits, the majority of consumers, in particular young adults, show low levels of whole grain consumption behaviour (WGCB). In order to increase WGCB, this pre-registered experimental study investigates the effect of a two weeks message intervention. Participants (n = 329) received either information about health benefits, recipe suggestions, a combination of both, or about a control topic. We evaluated WGCB at three time points: prior to, immediately after (post), and one month after the intervention (follow-up). Our findings show that participants read the message on most of the days and on average, evaluate the health-only message most positively. Furthermore, we found that health messages, but not recipe suggestions significantly increase WGCB at the follow-up measure. This effect was serially mediated by attitudes and behavioural intentions at the post-intervention measure, with more positive attitudes and higher intentions leading to more WGCB. Although health messages are an effective tool to influence WGCB, the effect is small in magnitude and consumption levels remain rather low. We discuss implications for future research and for the communication of whole grain related health benefits among different stakeholders in the health sector.

High consumption of whole grain foods decreases the risk of dementia and Alzheimer's disease: Framingham Offspring Cohort

AIMS

To examine the longitudinal associations between total and individual whole grain (WG) food intake and the risk of all-cause dementia and Alzheimer's disease (AD) dementia.

METHODS

This study included 2958 subjects (mean age at baseline was 61 ± 9 years) from the Framingham Offspring Cohort. Standardized interviews, physician examinations, and laboratory tests were collected approximately every 4 years, and the Food Frequency Questionnaire (FFQ) was conducted in cycle 5. Proportional hazards models and cubic spline regression examined associations between WG foods and all-cause dementia and AD dementia.

RESULTS

Over an average of 12.6 years of follow-up, there were 322 dementia cases, of which 247 were AD dementia. After multivariate and dietary adjustments, individuals with the highest category for total WG food consumption had a lower risk of all-cause dementia [HR 0.66, 95% confidence interval (CI) 0.51-0.81] and AD dementia (HR 0.60, 95% CI 0.46-0.78) than individuals with the lowest category. The results remained comparable in different subgroups stratifying for age, sex, education, body mass index, and smoking status without significant interaction. Moreover, these inverse associations were seen for most individual WG foods except popcorn. A nonlinear dose-response association was shown between total WG intake and all-cause dementia and AD dementia, where the rate reduction slightly plateaued at more than one and two servings/day, respectively.

CONCLUSIONS

Higher consumption of total and several common individual WG foods was strongly associated with a lower risk of all-cause dementia and AD dementia.

Health Effects of Whole Grains: A Bibliometric Analysis

Whole grains have been recommended in the diet in most countries, with numerous publications focusing on their health effect. A systematic analysis of these publications on different research methods, regions and perspectives will contribute to an understanding of the innovation pattern in this field. This bibliometric study analyzes the global publication characteristics, hotspots and frontiers of whole grain health benefit research, and discusses the trends and prospects of this topic. The overall number of publications is on the rise, with the United States contributing the most publications. The most cited literature shows that observational studies, systematic reviews and meta-analysis are the most widely used methods. The main focus in this area is on dietary fiber and bioactive substances, while the latter has received increased attention in recent years in particular. With the increasingly prominent problems of hidden hunger and chronic disease, the development of whole grain foods and their optimum intake have gradually become hot topics. In addition to the need to reveal the mechanism of whole grain health effects, consensus needs to be reached on standards and definitions for whole grain foods, and attention should be paid to the retention of taste and healthy nutrients in processing.

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.

Consumption of whole grains and risk of type 2 diabetes: A comprehensive systematic review and dose-response meta-analysis of prospective cohort studies

This study aimed to quantitatively summarize earlier findings on the association between whole grain (WG) intake and type 2 diabetes (T2D) risk. We searched related keywords on PubMed/Medline, Scopus, and Google Scholar up to October 2021. Prospective observational studies investigating the association between WG intake and risk of T2D were included. The random‐effects model calculates the summary relative risks by contrasting categories and linear and nonlinear dose–response associations. Eleven prospective cohort studies, including 463,282 participants and 37,249 type 2 diabetes incidents, were analyzed. The pooled relative risk (RR) for the highest versus the lowest WG intake category indicated a 21% decrease in T2D risk (95% confidence interval (CI): 0.73–0.85, I² = 77%). Each additional 50 grams WG consumption per day was associated with a 23% reduced risk of T2D. The nonlinear association of WG and T2D revealed that 60 grams WG intake per day would give the highest benefit to prevent T2D (Pnonlinearity < 0.001). The findings were not affected by any individual study. No evidence of publication bias was documented. In conclusion, a high intake of WG was associated with a lower risk of T2D. Randomized controlled trials are needed to confirm our results.

Relationship Between Dietary Fiber and Vitamin C Intake and Oral Cancer

Background

Dietary fiber and vitamin C has been reported to play a possible role in tumorigenesis. However, few studies have estimated their association with oral cancer risk. In this project, we investigated the relationship between dietary fiber and vitamin C and oral cancer risk in adults in Southern China.

Methods

382 patients newly diagnosed with oral cancer were matched to 382 hospital derived controls by frequency matching in age and sex. Pre-diagnostic consumption of dietary fiber and vitamin C intake were measured through food frequency questionnaire. Association between nutrients intake and oral cancer risk were evaluated by logistic regression. OR value and 95% confidence interval was calculated.

Results

Intake of dietary fiber and vitamin C was significantly lower in oral cancer patients (8.15 g/day) than in control participants (8.88 g/day). Increased dietary fiber or vitamin C intake was linked to a decreased incidence of OC after adjustment of age, marital status, residence, BMI, occupation, education, tobacco smoking, alcohol consumption and family history of cancer P_trend< 0.001). Compared with the lowest tertile, the adjusted OR of the top tertile of dietary fiber was 0.47 (95 % CI 0.32, 0.68). While the adjusted OR of the highest tertile was 0.60 (95 % CI 0.42, 0.87) compared with the lowest tertile of vitamin C.

Conclusions

Dietary intake of fiber and vitamin C were lower in oral cancer patients than in control participants. Dietary fiber and vitamin C were inversely related to risk of oral cancer risk.

Plant Polysaccharides Modulate Immune Function via the Gut Microbiome and May Have Potential in COVID-19 Therapy

Plant polysaccharides can increase the number and variety of beneficial bacteria in the gut and produce a variety of active substances, including short-chain fatty acids (SCFAs). Gut microbes and their specific metabolites have the effects of promoting anti-inflammatory activity, enhancing the intestinal barrier, and activating and regulating immune cells, which are beneficial for improving immunity. A strong immune system reduces inflammation caused by external viruses and other pathogens. Coronavirus disease 2019 (COVID-19) is still spreading globally, and patients with COVID-19 often have intestinal disease and weakened immune systems. This article mainly evaluates how polysaccharides in plants can improve the immune system barrier by improving the intestinal microecological balance, which may have potential in the prevention and treatment of COVID-19.

Plasma Alkylresorcinol Metabolite, a Biomarker for Whole-Grain Intake, Is Inversely Associated with Risk of Nonalcoholic Fatty Liver Disease in a Case-Control Study of Chinese Adults

Background

Epidemiological studies consistently find associations between whole-grain intake and reduced risk of obesity and related metabolic diseases, yet data on the potential of whole grains to prevent fatty liver diseases are scarce.

Objectives

To examine whether plasma 3-(3, 5-dihydroxyphenyl)-1-propanoic acid (DHPPA), a biomarker of whole-grain wheat and rye intake, is associated with nonalcoholic fatty liver disease (NAFLD).

Methods

This case-control study of Chinese adults enrolled 940 NAFLD cases and 940 age- and sex-matched non-NAFLD controls (mean age: 55.2 years; 65% males). NAFLD diagnosis was defined as individuals whose hepatic ultrasound disclosed hepatic steatosis at any stage, after the exclusion of alcohol abuse and other liver diseases. Fasting plasma DHPPA concentration was measured by high-performance liquid chromatography-tandem mass spectrometry. Multivariate adjusted odds ratios (ORs) and 95% confidence intervals (CI) were estimated to assess the association between plasma DHPPA and NAFLD using conditional logistic regression.

Results

Plasma concentration of DHPPA was significantly lower in NAFLD patients compared to controls (median: 9.86 nmol/L vs. 10.9 nmol/L, P = 0.002). In multivariable logistic regression models, the ORs (95% CI) for NAFLD across increasing tertiles of plasma DHPPA were 1 (referent), 0.76 (0.54, 1.05) and 0.65 (0.45, 0.93), respectively (P for trend = 0.026). In addition, the inverse associations persisted in subgroups stratified by sex, age, BMI, abdominal adiposity, smoking status, physical activity, diabetes, hypertension, and hyperlipidemia.

Conclusions

These results indicate that increased plasma DHPPA concentration is associated with lower risk of NAFLD in Chinese adults, independently of well-known risk factors. Our finding provides evidence to support health benefits of whole-grain consumption on NAFLD. This trial was registered at clinicaltrials.gov as NCT03845868.

Whole Grain Consumption and Inflammatory Markers: A Systematic Literature Review of Randomized Control Trials

Whole grain foods are rich in nutrients, dietary fibre, a range of antioxidants, and phytochemicals, and may have potential to act in an anti-inflammatory manner, which could help impact chronic disease risk. This systematic literature review aimed to examine the specific effects of whole grains on selected inflammatory markers from human clinical trials in adults. As per the Preferred Reporting Items for Systematic Reviews (PRISMA) protocol, the online databases MEDLINE, Embase, Cochrane, CINAHL, and Scopus were searched from inception through to 31 August 2021. Randomized control trials (RCTs) ≥ 4 weeks in duration, reporting ≥1 of the following: C-reactive protein (CRP), interleukin-6 (IL-6), and tumor necrosis factor (TNF), were included. A total of 31 RCTs were included, of which 16 studies recruited overweight/obese individuals, 12 had pre-existing conditions, two were in a healthy population, and one study included participants with prostate cancer. Of these 31 RCTs, three included studies with two intervention arms. A total of 32 individual studies measured CRP (10/32 were significant), 18 individual studies measured IL-6 (2/18 were significant), and 13 individual studies measured TNF (5/13 were significant). Most often, the overweight/obese population and those with pre-existing conditions showed significant reductions in inflammatory markers, mainly CRP (34% of studies). Overall, consumption of whole grain foods had a significant effect in reducing at least one inflammatory marker as demonstrated in 12/31 RCTs.

Effects of Different Pilot-Scale Milling Methods on Bioactive Components and End-Use Properties of Whole Wheat Flour

The health benefits from consumption of whole wheat products are widely recognized. This study investigated the effects of different pilot-scale milling methods on physicochemical properties, bioactive components, Chinese steamed bread (CSB), and Chinese leavened pancakes (CLP) qualities of whole wheat flour (WWF). The results indicated that WWF-1 from the reconstitution of brans processed by a hammer mill had the best CSB and CLP quality overall. WWF from entire grain grinding by a jet mill (65 Hz) contained the highest concentration of bioactive components including dietary fibers (DF) and phenolic acids. A finer particle size did not necessarily result in a higher content of phenolic antioxidants in WWF. DF contents and damaged starch were negatively correlated with CSB and CLP quality. Compromised reduced quality observed in CLP made from WWF indicated its potentially higher acceptance as a whole-grain product.

Health benefits of whole grain: effects on dietary carbohydrate quality, the gut microbiome, and consequences of processing

Grains are important sources of carbohydrates in global dietary patterns. The majority of these carbohydrates, especially in refined-grain products, are digestible. Most carbohydrate digestion takes place in the small intestine where monosaccharides (predominantly glucose) are absorbed, delivering energy to the body. However, a considerable part of the carbohydrates, especially in whole grains, is indigestible dietary fibers. These impact gut motility and transit and are useful substrates for the gut microbiota affecting its composition and quality. For the most part, the profile of digestible and indigestible carbohydrates and their complexity determine the nutritional quality of carbohydrates. Whole grains are more complex than refined grains and are promoted as part of a healthy and sustainable diet mainly because the contribution of indigestible carbohydrates, and their co-passenger nutrients, is significantly higher. Higher consumption of whole grain is recommended because it is associated with lower incidence of, and mortality from, CVD, type 2 diabetes, and some cancers. This may be due in part to effects on the gut microbiota. Although processing of cereals during milling and food manufacturing is necessary to make them edible, it also offers the opportunity to still further improve the nutritional quality of whole-grain flours and foods made from them. Changing the composition and availability of grain carbohydrates and phytochemicals during processing may positively affect the gut microbiota and improve health.

Effect of breakfast cereal type on portion size and nutritional implications

OBJECTIVE

The present study aimed to assess the effect of different types of breakfast cereal (BC) on portion size and the nutritional implications of potential under or overserving.

DESIGN

A cross-sectional analysis was performed using one BC from the seven established BC manufacturing methods (flaking (F), gun puffed (GP), oven puffed (OP), extruded gun puffed (EGP), shredded wholegrain (SW), biscuit formed (BF) and granola). Participants were asked to pour cereal as if they were serving themselves (freepour). Difference between the freepour and recommended serving size (RSS) was calculated (DFR). The Friedman test followed by Dunn's multiple comparison test was used to test for a significant differences between cereal categories.

SETTING

City of Chester, North West of the UK.

PARTICIPANTS

Adults (n 169; n 110 female, 32 (sd 18) years).

RESULTS

Freepour values were greater than RSS for all categories of BC. Median values for denser cereals such as SW, granola and oats were significantly (P < 0·001) greater than all other categories with granola having the highest median freepour value of 95 g. Median (and range of) DFR weight values for granola were significantly higher than other BC (50·0 g (-24·0 to 267·0 g), P < 0·001). BC with the lowest median DFR were F1 (7·0 g (-20 to 63·0 g)), GP (6·0 g (-26·0 to 69·0 g)), EGP (6·0 g (-26·0 to 56·0 g)), OP (5·0 g (-27·0 to 53·0 g)) and BF (0·0 g (-28·2 to 56·4 g)).

CONCLUSIONS

The degree of overserving may be related to the type of BC with denser cereals more readily overserved. Encouraging manufacturers to reformulate cereals and improving their nutritional properties may have benefit in reducing excess energy intake.