Effects Of Whole Grains Research Articles

Comprehensive modulatory effects of whole grain consumption on immune-mediated inflammation in middle-aged and elderly community residents: A real-world randomized controlled trial

Background and aimsWhole grain consumption is widely recognized as a vital component of a balanced diet. Dietary fiber has been well-documented to play a crucial role in these health benefits attributed to whole grain intake. However, population-based evidence directly linking whole grain consumption to anti-inflammatory effects, especially in the context of immune-mediated inflammation, remains limited. We hypothesized that whole grain consumption promotes health by modulating immune-mediated inflammation. Methods and resultsThis study was designed as a real-world, population-based randomized controlled trial. We compared the effects of whole grain versus refined grain consumption on immune-mediated inflammation through staple food substitution, while participants maintained their usual dietary practices. The results demonstrated that whole grain consumption significantly reduced circulating levels of pro-inflammatory cytokines IL-22 and IL-23 compared to refined grain consumption. These reductions were associated with optimized short-chain fatty acid profiles and changes in CD4+ T cell subset distributions. ConclusionsThe findings suggest that the anti-inflammatory effects of whole grain consumption in middle-aged and elderly populations are mediated by targeting specific CD4+ T cell subsets, in addition to modulating both upstream short-chain fatty acid composition and downstream expression of the pro-inflammatory cytokines IL-22 and IL-23.

Grains in a Modern Time: A Comprehensive Review of Compositions and Understanding Their Role in Type 2 Diabetes and Cancer.

Globally, type 2 diabetes (T2D) and Cancer are the major causes of morbidity and mortality worldwide and are considered to be two of the most significant public health concerns of the 21st century. Over the next two decades, the global burden is expected to increase by approximately 60%. Several observational studies as well as clinical trials have demonstrated the health benefits of consuming whole grains to lower the risk of several chronic non-communicable diseases including T2D and cancer. Cereals grains are the primary source of energy in the human diet. The most widely consumed pseudo cereals include (quinoa, amaranth, and buckwheat) and cereals (wheat, rice, and corn). From a nutritional perspective, both pseudo cereals and cereals are recognized for their complete protein, essential amino acids, dietary fibers, and phenolic acids. The bran layer of the seed contains the majority of these components. Greater intake of whole grains rather than refined grains has been consistently linked to a lower risk of T2D and cancer. Due to their superior nutritional compositions, whole grains make them a preferred choice over refined grains. The modulatory effects of whole grains on T2D and cancer are also likely to be influenced by several mechanisms; some of these effects may be direct while others involve altering the composition of gut microbiota, increasing the abundance of beneficial bacteria, and lowering harmful bacteria, increasing insulin sensitivity, lowering solubility of free bile acids, breaking protein down into peptides and amino acids, producing short-chain fatty acids (SCFAs), and other beneficial metabolites that promote the proliferation in the colon which modulate the antidiabetic and anticancer pathway. Thus, the present review had two aims. First, it summarized the recent knowledge about the nutritional composition and bioactive acids in pseudo cereals (quinoa, amaranth, and buckwheat) and cereals (wheat, rice, and corn); the second section summarized and discussed the progress in recent human studies, such as observational (cross-sectional studies, case-control studies, and cohort studies) and intervention studies to understand their role in T2D and cancer including the potential mechanism. Overall, according to the scientific data, whole grain consumption may reduce the incidence of T2D and cancer. Future studies should carry out randomized controlled trials to validate observational results and establish causality. In addition, the current manuscript encourages researchers to investigate the specific mechanisms by which whole grains exert their beneficial effects on health by examining the effects of different types of specific protein, dietary fibers, and phenolic acids that might help to prevent or treat T2D and cancer.

Effects of whole grains on glycemic control: a systematic review and dose-response meta-analysis of prospective cohort studies and randomized controlled trials

PurposeWhole grains have recently been promoted as beneficial to diabetes prevention. However, the evidence for the glycemic benefits of whole grains seems to conflict between the cohort studies and randomized control trials (RCTs). To fill the research gap, we conducted a meta-analysis to determine the effects of whole grains on diabetes prevention and to inform recommendations.MethodsWe searched PubMed, Clarivate Web of Science, and Cochrane Library until March 2024. We used the risk ratio (RR) of type 2 diabetes to represent the clinical outcomes for cohort studies, while the biomarkers, including fasting blood glucose and insulin, HbA1C, and HOMA-IR, were utilized to show outcomes for RCTs. Dose-response relationships between whole grain intakes and outcomes were tested with random effects meta-regression models and restricted cubic splines models. This study is registered with PROSPERO, CRD42021281639.ResultsTen prospective cohort studies and 37 RCTs were included. Cohort studies suggested a 50 g/day whole grain intake reduced the risk of type 2 diabetes (RR = 0.761, 95% CI: 0.700 to 0.828, I2 = 72.39%, P < 0.001) and indicated a monotonic inverse relationship between whole grains and type 2 diabetes rate. In RCTs, whole grains significantly reduced fasting blood glucose (Mean difference (MD) = -0.103 mmol/L, 95% CI: -0.178 to -0.028; I2 = 72.99%, P < 0.01) and had modest effects on HbA1C (MD = -0.662 mmol/mol (-0.06%), 95% CI: -1.335 to 0.010; I2 = 64.55%, P = 0.05) and HOMA-IR (MD = -0.164, 95% CI: -0.342 to 0.013; I2 = 33.38%, P = 0.07). The intake of whole grains and FBG, HbA1C, and HOMA-IR were significantly dose-dependent. The restricted spline curves remained flat up to 150 g/day and decreased afterward. Subgroup analysis showed that interventions with multiple whole-grain types were more effective than those with a single type.ConclusionOur study findings suggest that a daily intake of more than 150 g of whole grain ingredients is recommended as a population approach for diabetes prevention.

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.

Effect of whole grain and fiber consumption on chronic liver diseases: a systematic review and meta-analysis.

Objective: The aim of the present study was to conduct a meta-analysis of observational studies to explore the latest evidence on the influence of whole grain and fiber consumption on total chronic liver diseases. Methods: We searched the PubMed and Web of Science online databases and reference lists of eligible articles up to June, 2024. Results: The odds ratio (OR) between whole grain intake and total chronic liver disease risk was 0.90 (95% confidence interval (CI): 0.81 to 0.99, p < 0.001) and indicated an OR of 0.65 (95% CI: 0.57 to 0.74, p < 0.001) between fiber intake and total chronic liver disease risk when comparing the highest and lowest total intake, both indicating a significant negative correlation. Furthermore, subgroup analysis revealed that the protective effect of whole grains on chronic liver diseases was the most significant in cirrhosis (OR = 0.65; 95% CI: 0.57 to 0.74) and mortality (OR = 0.37; 95% CI: 0.29 to 0.47). Conclusion: Whole grain and fiber intake has a protective effect on the risk of chronic liver diseases.

Effects of whole grains on insulin resistance in overweight and obese adults: a Meta-analysis

To conduct a Meta-analysis of the effects of whole grains on insulin resistance in overweight and obese adults in randomize controlled trials. Data were retrieved from PubMed, EMBASE, MEDLINE, Cochrane Library, CBM, CNKI and other databases from the database establishment to August 9, 2021. Randomize controlled trials of the effects of whole grains on insulin resistance in overweight and obese adults were screened out. Data extraction and quality evaluation were conducted for the literatures meeting the inclusion criteria. The Meta-analysis was conducted using R4.1.2 software. A total of 10 randomized controlled trials were included. Among the overweight and obese adults, the whole grains intake decreased their fasting plasma glucose(FPG)(MD=-0.08, 95%CI-0.12, -0.04), homeostasis model assessment of insulin resistance(HOMA-IR)(MD=-0.37, 95%CI-0.60, -0.14) and quantitative insulin sensitivity index(QUICKI)(MD=0.006, 95%CI 0.005, 0.007). However, there were no statistically significant among fasting insulin(FINS), postprandial blood glucose(PG), postprandial insulin(PI), and triglycerides(TG) in overweight and obese adults. In subgroup analysis, FPG was statistically significant in German, quality score 4, 150-200 g intake of whole grain, and health subgroups of each population. There was no statistical significance of the QUICKI group. In sensitivity analysis and publication bias, FINS, PG, PI and TG became significant after one article was removed. However, HOMA-IR result were not statistically significant after the removal of one article. Meanwhile, the publication bias of each index was analyzed by Egger regression. Based on the results of subgroup analysis, a further dose-response analysis was conducted on the whole grains intake. The result showed that the FPG effects scale was better when the daily intake of whole grains was between 140 g and 160 g. Daily intake of 140 g to 160 g of whole grains improves FPG levels in overweight and obese adults.

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.

Effects of whole grain intake on glucagon-like peptide 1 and glucose-dependent insulinotropic peptide: a systematic review and meta-analysis.

Whole grain intake may control help glycemia and reduce food intake by affecting the secretion of glucagon-like peptide1 (GLP-1) and glucose-dependent insulinotropic peptide (GIP). This systematic review and meta-analysis aimed to assess the postprandial and long-term effects of whole grains on GLP-1 and GIP levels. PubMed, Web of Science, and Scopus online databases were searched systematically to identify relevant randomized clinical trials (RCTs) published up to April 2021. RCTs that evaluated the effects of whole grains, compared with refined grains, on the postprandial area under the curve (AUC) value, the postprandial serum concentration of incretins from 0 to 180 minutes, or the fasting level of incretins after at least 14 days of intervention were included. Nineteen studies were included in the meta-analysis. The results showed that acute intake of whole grains could not significantly change the AUC value of GLP-1 or GIP. However, the AUC value of GIP was reduced more significantly in (1) unhealthy participants (standard mean difference [SMD] -1.08; 95%CI, -2.07 to -0.10; I2 = 75.9%) compared with healthy participants, and (2) those with a baseline fasting blood glucose of ≥99 mg/dL (SMD -0.71; 95%CI, -1.30 to -0.11; I2 = 74.4%) compared with those with a baseline value of < 99 mg/dL. On the other hand, the results of time-response evaluation during 0 to 180 minutes after the intake of test meals showed that serum concentrations of GIP decreased significantly from 0 to 30 minutes (coefficient = -44.72; P = 0.005), but increased from 60 to 180 minutes (coefficient = 27.03; P = 0.005). However, long-term studies found no significant effects of whole grains on fasting concentrations of GLP-1 or GIP. Whole grain intake did not affect postprandial levels of GLP-1 but enhanced postprandial levels of GIP from 60 to 180 minutes. Further high-quality trials are required to assess the long-term effects of whole grain intake on serum levels of incretins. PROSPERO registration no. CRD42021256695.

A randomized controlled trial of the effects of whole grains versus refined grains diets on the microbiome in pregnancy

Dietary whole grain consumption has been postulated to have metabolic benefits. The purpose of this study was to compare a pregnancy diet containing 75% of total carbohydrates as refined grains with a diet of 75% of total carbohydrates as whole grains for pregnancy outcomes and effects on the microbiome. Gestational weight gain, glucose tolerance and newborn outcomes were measured on 248 enrolled compliant women from whom a subset of 103 women consented to give 108 vaginal and 109 anal swabs. The data presented here are limited to the patients from whom the vaginal and anal swabs were obtained in order to study the microbiome. A microbiome—16SrRNA survey—was characterized in these samples. Samples and measurements were obtained at the first obstetrical visit, before beginning a prescribed diet (T1—baseline) and after 17–32 weeks on the prescribed diet (T3). Food frequency questionnaires and total plasma alkylresorcinols were used as a measure of whole grain consumption. There were no dietary differences in maternal weight gain, birth weight, or glucose tolerance test. Mothers consuming the whole grains diet showed a trend of gestational decrease in vaginal bacterial alpha diversity, with increasing Lactobacillus-dominance. No significant difference was observed for the anal microbiome. The results suggest that diet modulations of the vaginal microbiome during gestation may have important implications for maternal and neonatal health and in the intergenerational transfer of maternal microbiome. Trial registration: ClinicalTrials.gov Identifier: NCT03232762.

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.

Physiological Effects of Bioactive Compounds Derived from Whole Grains on Cardiovascular and Metabolic Diseases

Cardiovascular diseases are a global health burden with an increasing prevalence. In addition, various metabolic diseases, such as obesity, diabetes, and hypertension are associated with a higher risk of cardiovascular diseases. Dietary strategies based on healthy foods have been suggested for the prevention or improvement of cardiovascular and metabolic diseases. Grains are the most widely consumed food worldwide, and the preventive effects of whole grains (e.g., oats, barley, and buckwheat) on metabolic diseases have been reported. The germ and bran of grains are rich in compounds, including phytochemicals, vitamins, minerals, and dietary fiber, and these compounds are effective in preventing and improving cardiovascular and metabolic diseases. Thus, this review describes the characteristics and functions of bioactive ingredients in whole grains, focusing on mechanisms by which polyphenols, antioxidants, and dietary fiber contribute to cardiovascular and metabolic diseases, based on preclinical and clinical studies. There is clear evidence for the broad preventive and therapeutic effects of whole grains, supporting the value of early dietary intervention.

Whole grains and legumes consumption in association with neuromyelitis optica spectrum disorder odds

Background: The environmental risk factors of neuromyelitis optica spectrum disorder (NMOSD) are not fully specified. Regarding the evidence on the possible protective effects of whole grains and legumes against inflammatory disorders, we examined the association between the mentioned dietary components and NMOSD. Methods: 70 patients with NMOSD with definite diagnosis and 164 hospital-based controls were included in this case-control investigation. Data on demographic, clinical, and anthropometric characteristics were collected. Dietary habits of participants were assessed using a previously validated food frequency questionnaire (FFQ) containing 168 food items. Daily intakes of whole grains and legumes were calculated and classified in quartiles. The odds of suffering from NMOSD according to the quartiles of whole grains and legumes were measured in the form of logistic regression models. Results: The mean amount of whole grains (115.29 vs. 44.14 g) and legumes (59.43 vs. 34.50 g) consumption was significantly higher in the control group versus the case group. There was a reverse association between whole grains or legumes and NMOSD odds in both models [P < 0.05, odds ratio (OR) < 1]. In the fully-adjusted model, 90% [95% confidence interval (CI): 0.02-0.39] and 92% (95% CI: 0.01-0.52) reduction in NMOSD odds was observed in the third and fourth quartiles of whole grains intake, respectively. Higher intake of legumes in the third and fourth quartiles led to 81% (95% CI: 0.05-0.71) and 95% (95% CI: 0.01-0.27) reduction in the odds of NMOSD, respectively. Conclusion: Aligned with the results of other investigations on inflammatory disorders, our results suggested a negative association between whole grains and legumes and NMOSD odds.

Effects of Whole-Grain and Sugar Content in Infant Cereals on Gut Microbiota at Weaning: A Randomized Trial.

The introduction of complementary foods during infancy marks an important step in the development of the infant gut microbiome. Infant cereals are popular weaning foods but consistent evidence on their effect on the intestinal microbiota, especially when differing in nutritional quality, is lacking. Fecal samples from 4–7-month-old Spanish infants who consumed infant cereals differing in whole grain and sugar content as first weaning foods were analyzed on changes in microbial composition by massively parallel sequencing of the 16S ribosomal RNA gene at baseline and after 7 weeks of intervention. Samples were obtained from a previous trial conducted in Spain demonstrating whole-grain cereal acceptability. In total, samples of 18 infants consuming 0% whole grain cereals with 24 g sugar (0-WG) and 25 infants consuming 50% whole grain cereals with 12 g sugar (50-WG) were analyzed. Microbial composition changed significantly over time (p = 0.001), per intervention group (p = 0.029) and per infant (p = 0.001). Abundance of genus Veillonella increased in both groups while Enterococcus decreased. Within the 0-WG group, phylum Actinobacteria decreased along with genus Bifidobacterium. In the 50-WG, we observed an increase in Lachnoclostridium and Bacteroides. In addition, 50-WG decreased Proteobacteria and Escherichia to levels lower than 0-WG. Although weaning itself appeared to be responsible for most changes, the increased presence of anaerobic fermenters together with inhibition of pathogenic Escherichia may indicate a supporting effect of infant cereals with 50% whole grains and a reduced sugar content over infant cereals manufactured with refined hydrolyzed flours on the infant microbiota. In fact, using a novel methodology for the identification of microbial signatures, we found two groups of microbial taxa predictive of infants consuming enriched whole-grain infant cereals with a high predictive value of about 93%.

Effects of Whole Grain, Compared to Refined Grain, Intake on Subjective Measures of Appetite: A Systematic Review and Meta-Analysis

Abstract Objectives Results from observational studies indicate that whole grain intake is inversely associated with BMI and risk of weight gain. Whole grain intake may influence energy balance and body composition through effects on appetite and thus, energy intake. To evaluate the impact of whole grain food consumption on appetite, we performed a systematic review and meta-analysis of randomized controlled trials (RCTs) assessing whole grain food intake and subjective measures of appetite in adults. Methods A search of PubMed, Scopus and Food Science and Technology abstracts yielded 34 RCTs measuring hunger ratings after consuming whole grain foods compared to refined grain controls. Seventeen of these studies (598 subjects), with a total of 33 unique whole grain treatments, reported areas under the curve (AUC) for subjective hunger and were included in the meta-analysis. Pooled estimates from meta-analyses are expressed as standardized mean differences (SMD). Results Intake of whole grain foods resulted in significantly lower subjective hunger AUC (range for AUC times ranged from 120 to 270 min) compared to refined grain foods [SMD −0.36, P &amp;lt; 0.001, 95% CI (−0.48, −0.24)]. Sensitivity analyses were also completed in which studies with AUC values for &amp;lt; and ≥ 180 min were evaluated separately, as well as hunger ratings at the 180 min timepoint alone, and the results were similar to those for the main analysis (SMDs −0.33 to −0.54, all P ≤ 0.03). Conclusions These results support the view that consumption of whole grain foods, compared to refined grain controls, significantly reduces subjective hunger, and this may provide at least part of the explanation for the inverse associations between whole grain food intake and risks for overweight, obesity and weight gain over time. Funding Sources This study was funded by the Bell Institute of Health and Nutrition, General Mills, Minneapolis, MN and registered with PROSPERO.

Effects of different varieties and processing degree grains on blood glucose and blood lipid in rats

To investigate the effects of whole grains(WG) and refined grains(RG) on blood glucose, blood lipid and inflammatory factors in normal rats, and the common effects of different whole grains. 2×2 factorial experiments were designed according to grain sources(rice &amp; wheat) and processing precision(whole grain &amp; refined grain). According to the initial body weight and fasting blood glucose, 48 male SD rats were randomly divided into four groups: RG rice group, WG rice group, RG wheat group and WG wheat group. They were fed with 45% refined rice, whole grain rice, refined wheat and whole grain wheat respectively for 18 weeks. The formula was in accordance with AIN-93 G. Food intake and body weight were monitored weekly. Fasting blood glucose, lipid, inflammatory factors and organ pathology were detected at the end of the experiment. During the experiment, the body weight growth and food intake of rats in each group were basically the same. At the end of the experiment, fatty liver appeared in varying degrees, while the kidney of rats in RG rice group and RG wheat group showed epithelial steatosis. Biochemical indexes showed that blood urea nitrogen(UN), fasting blood glucose(FBG), total cholesterol(TC), triglyceride(TG), low density lipoprotein(LDL)and monocyte chemoattractant protein-1(MCP-1)in RG wheat group were significantly higher than those in WG wheat group(P&lt;0. 05), while high density lipoprotein(HDL)level in RG wheat group was significantly lower than that in WG wheat group(P&lt;0. 05), and there was no significant difference in other indexes. The result of factorial analysis showed that the differences of FBG, serum insulin, homeostasis model assessment of insulin resistance(HOMA-IR)and C-reactive protein(CRP)caused by different grain processing degree were significant, but there was no significant difference between rice and wheat varieties(P&gt;0. 05). Studies have shown that long-term feeding of refined grains can lead to fasting blood glucose, blood lipid abnormality and renal pathological changes in rats, and proper feeding of whole grains can delay the development of adverse symptoms.

Whole grain intake compared with cereal fibre intake in association to CVD risk factors: a cross-sectional analysis of the National Diet and Nutrition Survey (UK).

To investigate how intakes of whole grains and cereal fibre were associated to risk factors for CVD in UK adults. Cross-sectional analyses examined associations between whole grain and cereal fibre intakes and adiposity measurements, serum lipid concentrations, C-reactive protein, systolic blood pressure, fasting glucose, HbA1c, homocysteine and a combined CVD relative risk score. The National Diet and Nutrition Survey (NDNS) Rolling Programme 2008-2014. A nationally representative sample of 2689 adults. Participants in the highest quartile (Q4) of whole grain intake had lower waist-hip ratio (Q1 0·872; Q4 0·857; P = 0·04), HbA1c (Q1 5·66 %; Q4 5·47 %; P = 0·01) and homocysteine (Q1 9·95 µmol/l; Q4 8·76 µmol/l; P = 0·01) compared with participants in the lowest quartile (Q1), after adjusting for dietary and lifestyle factors, including cereal fibre intake. Whole grain intake was inversely associated with C-reactive protein using multivariate analysis (P = 0·02), but this was not significant after final adjustment for cereal fibre. Cereal fibre intake was also inversely associated with waist-hip ratio (P = 0·03) and homocysteine (P = 0·002) in multivariate analysis. Similar inverse associations between whole grain and cereal fibre intakes to CVD risk factors suggest the relevance of cereal fibre in the protective effects of whole grains. However, whole grain associations often remained significant after adjusting for cereal fibre intake, suggesting additional constituents may be relevant. Intervention studies are needed to compare cereal fibre intake from non-whole grain sources to whole grain intake.

Effects of dietary whole grain, fruit, and vegetables on weight and inflammatory biomarkers in overweight and obese women.

The separate effects of whole grain (WG) and fruit and vegetable (F&V) diets on inflammatory biomarkers have not been assessed. Therefore, we evaluated these two high-fiber diets in relation to inflammation indices in obese and overweight women. Parallel randomized clinical trial. In the present study, 75 women were recruited and randomly assigned to three diet groups: a whole grain diet (WG-D) group, F&V group, and a combined whole grain and F&V diet group (WGFV-D) for 10weeks. As a "feeding trial" all participants were asked to visit the clinic daily and eat prescribed foods in the presence of a nutritionist. Anthropometric indices and biochemical biomarkers were measured at baseline and after 10weeks of the trial. Each of the three diet groups showed significant changes in serum biomarkers (CRP, TNF-α, IL-6, D-dimer, and serum fibrinogen) after following the diet for 10weeks (P = 0.01). In adjusted models, significant changes were observed for CRP, TNF-α, IL-6, D-dimer, and serum fibrinogen (P = 0.01). In a model adjusted for malondialdehyde (MDA) level, a trend toward significance was observed (P = 0.05). Consumption of all three different diets for 10weeks showed statistically significant change for all biomarkers (P < 0.05) the most notable changes in inflammatory indices were observed among participants following the WG diet. Study results indicate that consumption of high-fiber diets, especially the WG diet, can help lower inflammatory levels and prevent subsequent adverse health consequences. Level I, randomized controlled trial.

Contribution of gut microbiota to metabolism of dietary glycine betaine in mice and in vitro colonic fermentation

BackgroundAccumulating evidence is supporting the protective effect of whole grains against several chronic diseases. Simultaneously, our knowledge is increasing on the impact of gut microbiota on our health and on how diet can modify the composition of our bacterial cohabitants. Herein, we studied C57BL/6 J mice fed with diets enriched with rye bran and wheat aleurone, conventional and germ-free C57BL/6NTac mice on a basal diet, and the colonic fermentation of rye bran in an in vitro model of the human gastrointestinal system. We performed 16S rRNA gene sequencing and metabolomics on the study samples to determine the effect of bran-enriched diets on the gut microbial composition and the potential contribution of microbiota to the metabolism of a novel group of betainized compounds.ResultsThe bran-enriched study diets elevated the levels of betainized compounds in the colon contents of C57BL/6 J mice. The composition of microbiota changed, and the bran-enriched diets induced an increase in the relative abundance of several bacterial taxa, including Akkermansia, Bifidobacterium, Coriobacteriaceae, Lactobacillus, Parasutterella, and Ruminococcus, many of which are associated with improved health status or the metabolism of plant-based molecules. The levels of betainized compounds in the gut tissues of germ-free mice were significantly lower compared to conventional mice. In the in vitro model of the human gut, the production of betainized compounds was observed throughout the incubation, while the levels of glycine betaine decreased. In cereal samples, only low levels or trace amounts of other betaines than glycine betaine were observed.ConclusionsOur findings provide evidence that the bacterial taxa increased in relative abundance by the bran-based diet are also involved in the metabolism of glycine betaine into other betainized compounds, adding another potential compound group acting as a mediator of the synergistic metabolic effect of diet and colonic microbiota.

Functional Properties of Polyphenols in Grains and Effects of Physicochemical Processing on Polyphenols

Phenolic compounds are important products of secondary metabolism in plants. They cannot be synthesized in the human body and are mainly taken from food. Cereals, especially whole grains, are important sources of dietary polyphenols. Compared with vegetables and fruits, the content and biological activities of polyphenols in cereals have long been underestimated. Polyphenols in whole grains are non-nutritive compounds, which are distributed in all structural areas of cereal substances, mainly phenolic acids, flavonoids, and lignans. In recent years, the health effects of whole grains are closely related to their phenolic compounds and their antioxidant activities. Now, different physicochemical processing treatments and their effects have been summarized in order to provide the basis for promoting the development and utilization of food. The various functions of whole grains are closely related to the antioxidant effect of polyphenols. As the basic research on evaluating the antioxidant effect of active substances, in vitro antioxidant tests are faster and more convenient.

A Whole-Grain Diet Increases Glucose-Stimulated Insulin Secretion Independent of Gut Hormones in Adults at Risk for Type 2 Diabetes.

The effect of whole-grain (WG) versus refined-grain (RG) diets on glucose-stimulated insulin secretion (GSIS) and β-cell function is unclear. In a double-blind crossover randomized controlled trial, 13 prediabetic adults (37.2±1.8 y, BMI: 33.6±1.4 kg m-2 , 2h glucose: 146.9±11.6 mg dL-1 ) are provided isocaloric-matched WG and RG diets for 8-weeks each, with an 8-10 week washout between diets. Glucose, insulin, and C-peptide are studied over 240 min following a 75g OGTT. Incretins (GLP-1 and GIP), PYY, and total ghrelin are assessed at 0, 30, and 60 min. Mixed-meal diets for carbohydrate (54%), fat (28%), and protein (18%) contain either WG (50g/1000 kcal) or equivalent RG. Both diets induce fat loss (≈2 kg). While neither diet impacts early phase GSIS, the WG diet increases total GSIS (iAUC of C-peptide0-240 /Glc0-240 , p = 0.02) and β-cell function (disposition index; GSIS × insulin sensitivity, p = 0.02). GIP and PYY are unaltered by either diet, but GLP-1 is higher at 30 min following RG versus WG (p = 0.04). Ghrelin levels are higher at 60 min of the OGTT following both interventions (p = 0.01). A WG-rich diet increases β-cell function independent of gut hormones in adults with prediabetes.