Effect of whole-grain consumption on changes in fecal microbiota: a review of human intervention trials

The effects of whole grain cereals on tryptophan metabolism and intestinal barrier function: underlying factors of health impact

This review aims to investigate the relationship between the health impact of whole grains mediated via the interaction with intestinal microbiota and intestinal barrier function with special interest on tryptophan metabolism, focusing on the role of the intestinal microbiota and their impact on barrier function. Consuming various types of whole grains can lead to the growth of different microbiota species, which in turn leads to the production of diverse metabolites, including those derived from tryptophan metabolism, although the impact of whole grains on intestinal microbiota composition results remains inconclusive and vary among different studies. Whole grains can exert an influence on tryptophan metabolism through interactions with the intestinal microbiota, and the presence of fibre in whole grains plays a notable role in establishing this connection. The impact of whole grains on intestinal barrier function is closely related to their effects on the composition and activity of intestinal microbiota, and SCFA and tryptophan metabolites serve as potential links connecting whole grains, intestinal microbiota and the intestinal barrier function. Tryptophan metabolites affect various aspects of the intestinal barrier, such as immune balance, mucus and microbial barrier, tight junction complexes and the differentiation and proliferation of epithelial cells. Despite the encouraging discoveries in this area of research, the evidence regarding the effects of whole grain consumption on intestine-related activity remains limited. Hence, we can conclude that we are just starting to understand the actual complexity of the intestinal factors mediating in part the health impacts of whole grain cereals.

Effects of Wholegrain Compared to Refined Grain Intake on Cardiometabolic Risk Markers, Gut Microbiota, and Gastrointestinal Symptoms in Children: A Randomized Crossover Trial

BACKGROUND

Wholegrain intake is associated with lower risk of cardiometabolic diseases in adults, potentially via changes in the gut microbiota. Although cardiometabolic prevention should start early, we lack evidence on the effects in children.

OBJECTIVES

This study investigated the effects of wholegrain oats and rye intake on serum low-density lipoprotein (LDL) cholesterol and plasma insulin (coprimary outcomes), other cardiometabolic markers, body composition, gut microbiota composition and metabolites, and gastrointestinal symptoms in children with high body mass index (BMI).

METHODS

In a randomized crossover trial, 55 healthy Danish 8- to 13-y-olds received wholegrain oats and rye ("WG") or refined grain ("RG") products ad libitum for 8 wk in random order. At 0, 8, and 16 wk, we measured anthropometry, body composition by dual-energy absorptiometry, and blood pressure. Fasting blood and fecal samples were collected for analysis of blood lipids, glucose homeostasis markers, gut microbiota, and short-chain fatty acids. Gut symptoms and stool characteristics were determined by questionnaires. Diet was assessed by 4-d dietary records and compliance by plasma alkylresorcinols (ARs).

RESULTS

Fifty-two children (95%) with a BMI z-score of 1.5 ± 0.6 (mean ± standard deviation) completed the study. They consumed 108 ± 38 and 3 ± 2 g/d wholegrain in the WG and RG period, which was verified by a profound difference in ARs (P < 0.001). Compared with RG, WG reduced LDL cholesterol by 0.14 (95% confidence interval: -0.24, -0.04) mmol/L (P = 0.009) and reduced total:high-density lipoprotein cholesterol (P < 0.001) and triacylglycerol (P = 0.048) without altering body composition or other cardiometabolic markers. WG also modulated the abundance of specific bacterial taxa, increased plasma acetate, propionate, and butyrate and fecal butyrate and reduced fatigue with no other effects on gut symptoms.

CONCLUSION

High intake of wholegrain oats and rye reduced LDL cholesterol and triacylglycerol, modulated bacterial taxa, and increased beneficial metabolites in children. This supports recommendations of exchanging refined grain with wholegrain oats and rye among children. This trial was registered at clinicaltrials.gov as NCT04430465.

The Relationship between Whole-Grain Intake and Measures of Cognitive Decline, Mood, and Anxiety-A Systematic Review

Greater intake of whole grains, compared to refined grains, is consistently associated with a reduced risk of cardiovascular disease and type 2 diabetes, both of which are associated with cognitive decline. To better understand the relationship between whole-grain intake, cognition, mood, and anxiety, a systematic review was conducted to synthesize available evidence linking whole grains to these outcomes. Four electronic databases were searched from inception to August 2021 for potentially relevant observational and interventional studies. Risk of bias (RoB) assessments were performed using the newly developed Nutrition Quality Evaluation Strengthening Tools, and the Grades of Recommendation, Assessment, Development, and Evaluation approach was used to determine the strength of evidence for each outcome. In total, 23 studies [4 randomized controlled trials (RCTs) and 19 observational studies] met the predefined eligibility criteria. Of these,12 studies included analysis of whole-grain intake and cognitive decline, 9 included mood outcomes, and 2 included both cognition and mood outcomes. The overall evidence for an association between whole-grain intake and cognition is inconclusive. With respect to mood outcomes, evidence from RCTs prospective cohort and case-control studies suggest that higher intake is linked to improved outcomes for mood and depression although the evidence is mixed for cross-sectional studies. Reporting of whole-grain intake fell short of suggested standards, and the strength of available evidence was low or very low for all outcomes. A high RoB toward studies reporting results was also noted, complicating both the interpretation of some studies and the combined evidence. Of note, few well-designed RCTs assessing the effect of whole-grain intake on measures of cognition, mood, and anxiety were identified, highlighting the need for more studies in this area. The available, although limited, evidence suggests that greater whole-grain intake is associated with better mood and anxiety-related scores and is inconclusive regarding cognitive outcomes. PROSPERO registration: CRD42021266355.

Serum metabolites associated with wholegrain consumption using nontargeted metabolic profiling: a discovery and reproducibility study

PURPOSE

To identify fasting serum metabolites associated with WG intake in a free-living population adjusted for potential confounders.

METHODS

We selected fasting serum samples at baseline from a subset (n = 364) of the prospective population-based Kuopio Ischaemic Heart Disease Risk Factor Study (KIHD) cohort. The samples were analyzed using nontargeted metabolomics with liquid chromatography coupled with mass spectrometry (LC-MS). Association with WG intake was investigated using both random forest followed by linear regression adjusted for age, BMI, smoking, physical activity, energy and alcohol consumption, and partial Spearman correlation adjusted for the same covariates. Features selected by any of these models were shortlisted for annotation. We then checked if we could replicate the findings in an independent subset from the same cohort (n = 200).

RESULTS

Direct associations were observed between WG intake and pipecolic acid betaine, tetradecanedioic acid, four glucuronidated alkylresorcinols (ARs), and an unknown metabolite both in discovery and replication cohorts. The associations remained significant (FDR<0.05) even after adjustment for the confounders in both cohorts. Sinapyl alcohol was positively correlated with WG intake in both cohorts after adjustment for the confounders but not in linear models in the replication cohort. Some microbial metabolites, such as indolepropionic acid, were positively correlated with WG intake in the discovery cohort, but the correlations were not replicated in the replication cohort.

CONCLUSIONS

The identified associations between WG intake and the seven metabolites after adjusting for confounders in both discovery and replication cohorts suggest the potential of these metabolites as robust biomarkers of WG consumption.

Global, distinctive, and personal changes in molecular and microbial profiles by specific fibers in humans

Dietary fibers act through the microbiome to improve cardiovascular health and prevent metabolic disorders and cancer. To understand the health benefits of dietary fiber supplementation, we investigated two popular purified fibers, arabinoxylan (AX) and long-chain inulin (LCI), and a mixture of five fibers. We present multiomic signatures of metabolomics, lipidomics, proteomics, metagenomics, a cytokine panel, and clinical measurements on healthy and insulin-resistant participants. Each fiber is associated with fiber-dependent biochemical and microbial responses. AX consumption associates with a significant reduction in LDL and an increase in bile acids, contributing to its observed cholesterol reduction. LCI is associated with an increase in Bifidobacterium. However, at the highest LCI dose, there is increased inflammation and elevation in the liver enzyme alanine aminotransferase. This study yields insights into the effects of fiber supplementation and the mechanisms behind fiber-induced cholesterol reduction, and it shows effects of individual, purified fibers on the microbiome.

Impact of wheat aleurone on biomarkers of cardiovascular disease, gut microbiota and metabolites in adults with high body mass index: a double-blind, placebo-controlled, randomized clinical trial

Purpose

Aleurone is a cereal bran fraction containing a variety of beneficial nutrients including polyphenols, fibers, minerals and vitamins. Animal and human studies support the beneficial role of aleurone consumption in reducing cardiovascular disease (CVD) risk. Gut microbiota fiber fermentation, polyphenol metabolism and betaine/choline metabolism may in part contribute to the physiological effects of aleurone. As primary objective, this study evaluated whether wheat aleurone supplemented foods could modify plasma homocysteine. Secondary objectives included changes in CVD biomarkers, fecal microbiota composition and plasma/urine metabolite profiles.

Methods

A parallel double-blind, placebo-controlled and randomized trial was carried out in two groups of obese/overweight subjects, matched for age, BMI and gender, consuming foods supplemented with either aleurone (27 g/day) (AL, n = 34) or cellulose (placebo treatment, PL, n = 33) for 4 weeks.

Results

No significant changes in plasma homocysteine or other clinical markers were observed with either treatment. Dietary fiber intake increased after AL and PL, animal protein intake increased after PL treatment. We observed a significant increase in fecal Bifidobacterium spp with AL and Lactobacillus spp with both AL and PL, but overall fecal microbiota community structure changed little according to 16S rRNA metataxonomics. Metabolomics implicated microbial metabolism of aleurone polyphenols and revealed distinctive biomarkers of AL treatment, including alkylresorcinol, cinnamic, benzoic and ferulic acids, folic acid, fatty acids, benzoxazinoid and roasted aroma related metabolites. Correlation analysis highlighted bacterial genera potentially linked to urinary compounds derived from aleurone metabolism and clinical parameters.

Conclusions

Aleurone has potential to modulate the gut microbial metabolic output and increase fecal bifidobacterial abundance. However, in this study, aleurone did not impact on plasma homocysteine or other CVD biomarkers.

Trial Registration

The study was registered at ClinicalTrials.gov (NCT02067026) on the 17th February 2014.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00394-022-02836-9.

Whole Grain Qingke Attenuates High-Fat Diet-Induced Obesity in Mice With Alterations in Gut Microbiota and Metabolite Profile

Whole grain Qingke (WGQK) displays anti-obesity and lipid-lowering properties; however, the underlying mechanism remains elusive. This study investigated the alteration of gut microbiota composition and metabolite profile induced by WGQK intervention in mice through the integration of 16S ribosomal RNA (rRNA) sequencing and an untargeted metabolomics study. C57BL/6J male mice were fed a normal control diet (NC), high-fat diet (HFD), and HFD plus 30% WGQK (HFD+QK) for 16 weeks. The WGQK intervention decreased body weight gain, glucose tolerance, and serum lipid levels, and alleviated liver function damage induced by HFD. Moreover, WGQK changed gut microbiota composition and enriched specific genera such as Akkermansia, Bifidobacterium, and Lactobacillus. Fecal metabolomics analysis indicated that WGQK enhanced the abundance of tryptophan metabolism-related metabolites (indole, 3-indoleacetic acid, indole acetic acid (IAA), 5-hydroxyindole-3-acetic acid), histidine metabolism-related metabolites (histamine), and some unsaturated fatty acids (oleic acid, 9,10-dihydroxy-12Z-octadecenoic acid, and alpha-linolenic acid). Spearman correlation analysis revealed that these metabolites were negatively correlated with obesity-related parameters and positively correlated with the gut genera enriched by WGQK. Moreover, WGQK promoted the expression of Cholesterol 7α-hydroxylase (CYP7A1) responsible for primary bile acids production, accompanied by a decline in intestinal FXR-FGF15 expression levels. The transcript levels of two genes associated with lipogenesis, such as lipid fatty acid synthase (FAS) and acetyl-CoA carboxylase (ACC) were also decreased in the HFD+QK group. Overall, our results suggest interactions between gut microbial shifts and host amino acid/lipid metabolism, and shed light on the mechanisms underlying the anti-obesity effect of WGQK.

The composition of the human fecal microbiota might be significantly associated with fecal SCFA levels under hyperbaric conditions

The fecal microbiota and short-chain fatty acids (SCFAs) play important roles in the human body. This study examined how hyperbaric conditions affect the fecal microbiota and fecal SCFAs. Fecal samples were obtained from 12 divers at three points during deep-diving training (before the diving training, at 2.1 MPa, and after decompression). At 2.1 MPa, the changes in the frequency of Clostridium cluster IV and fecal iso-valerate levels were positively correlated, and the changes in the frequencies of Bacteroides and Clostridium subcluster XIVa were inversely correlated. After decompression, positive correlations were detected between the changes in the frequency of Bifidobacterium and fecal n-valerate levels and between the changes in the fecal levels of iso-butyrate and iso-valerate. On the other hand, inverse correlations were detected between the changes in the frequency of Clostridium cluster IX and fecal iso-butyrate levels, between the changes in the frequency of Clostridium cluster IX and fecal iso-valerate levels, and between the changes in the frequencies of Bacteroides and Clostridium cluster IV plus subcluster XIVa. During the study period, the changes in fecal iso-butyrate and iso-valerate levels were positively correlated, and inverse correlations were seen between the changes in the frequency of Clostridium cluster IV and fecal propionate levels and between the changes in the frequencies of Prevotella and Clostridium subcluster XIVa. These findings suggest that hyperbaric conditions affect the fecal microbiota and fecal SCFA levels and that intestinal conditions reversibly deteriorate under hyperbaric conditions.

Mediterranean Diet to Prevent the Development of Colon Diseases: A Meta-Analysis of Gut Microbiota Studies

Gut microbiota dysbiosis is a common feature in colorectal cancer (CRC) and inflammatory bowel diseases (IBD). Adoption of the Mediterranean diet (MD) has been proposed as a therapeutic approach for the prevention of multiple diseases, and one of its mechanisms of action is the modulation of the microbiota. We aimed to determine whether MD can be used as a preventive measure against cancer and inflammation-related diseases of the gut, based on its capacity to modulate the local microbiota. A joint meta-analysis of publicly available 16S data derived from subjects following MD or other diets and from patients with CRC, IBD, or other gut-related diseases was conducted. We observed that the microbiota associated with MD was enriched in bacteria that promote an anti-inflammatory environment but low in taxa with pro-inflammatory properties capable of altering intestinal barrier functions. We found an opposite trend in patients with intestinal diseases, including cancer. Some of these differences were maintained even when MD was compared to healthy controls without a defined diet. Our findings highlight the unique effects of MD on the gut microbiota and suggest that integrating MD principles into a person’s lifestyle may serve as a preventive method against cancer and other gut-related diseases.

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%.

Effect of arabinogalactan on the gut microbiome: A randomized, double-blind, placebo-controlled, crossover trial in healthy adults

OBJECTIVE

Promising evidence suggests beneficial health effects of arabinogalactan, but little is known about the effect of this non-digestible carbohydrate on the gut microbiota, a crucial mediator of human health. The objective of this study was to investigate the effect of an arabinogalactan product (ResistAid) on the fecal microbiome and short-chain fatty acids and gastrointestinal tolerance in healthy adults in a randomized, double-blind, crossover trial.

METHODS

Thirty adults were randomly assigned to consume 15 g/d maltodextrin (control) or ResistAid for 6 wk.

RESULTS

At week 6, compared to placebo, ResistAid supplementation led to a significant decrease in the ratio of fecal Firmicutes to Bacteroidetes, driven by an increase in Bacteroidetes and a decrease in Firmicutes. Moreover, the relative abundance of Bifidobacterium tended to increase with ResistAid supplementation. Additionally, ResistAid significantly decreased the α-diversity of the fecal microbiome. Predicted functional abundances based on 16S rRNA sequences showed that ResistAid supplementation increased the gene abundance of the gut microbiome for α-l-rhamnosidase, β-fructosidase, and levanase, as well as tricarboxylic acid and vitamin B₆ biosynthesis pathways. Fecal isovaleric, valeric, and hexanoic acids were significantly lower after ResistAid consumption. There were no statistically significant changes in bowel habit, stool consistency, gastrointestinal tolerance symptoms, chemistry profile, metabolic panel, or vitals, suggesting that consumption of 15 g daily ResistAid over 6 wk is safe.

CONCLUSION

These results demonstrate that the gut microbiome composition and predicted functions can be modulated by ResistAid consumption, perhaps suggesting a mechanistic explanation on its reported benefits in metabolic parameters and the immune system.

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.

Perspective: Why Whole Grains Should Be Incorporated into Nutrient-Profile Models to Better Capture Nutrient Density

Healthy eating patterns, as described by dietary guidelines, typically favor whole grains, low-fat dairy, vegetables, fruit, legumes, and nuts and seeds. Nutrient-profiling (NP) models capture nutrient density of individual foods and can inform healthier food choices. Although whole grains are prominently featured in most dietary guidelines, they are not included in most NP models. Healthy foods, as identified by most NP models, are those that contain limited amounts of energy, saturated fat, total or added sugar, and sodium. As global dietary guidance turns to foods and food groups as opposed to individual nutrients, future nutrient-density metrics may need to do the same. Potential methods to incorporate whole grains into the overall concept of nutrient density and into selected NP models are outlined in this review. Incorporating whole grains into the Nutri-Score, Health Star Rating, or the Nutrient Rich Food index will require further analyses of dietary nutrient density in relation to health outcomes across diverse population subgroups. We present the rationale for how the inclusion of whole grains in NP models can assist in the implementation of dietary guidance.

Dietary fibers reduce obesity-related disorders: mechanisms of action

PURPOSE OF REVIEW

Dietary fibers decrease risk of cardiovascular disease and obesity, but the most important mechanisms for fiber's protective properties are debated. The purpose of the review is to summarize the recent human studies that examine mechanisms how dietary fiber decreases risk of obesity-related disorders.

RECENT FINDINGS

Dietary fiber has effects throughout the digestive tract that decrease risk of obesity-related diseases. Soluble, viscous fibers slow absorption of and decrease serum cholesterol. Intake of dietary fiber enhances satiety and reduces food intake at future meals. The importance of gut fermentation and changes in the gut microbiota and metabolites are linked to decrease risk for obesity-related disorders. Dietary fibers alter the gut microbiota and produce metabolites such as short-chain fatty acids that may explain fiber's role in obesity prevention and treatment. Dietary fiber encompasses many plant compounds, so conclusions that dietary fiber reduces or treats obesity-related disorders must be considered by the fiber was fed in the study.

SUMMARY

Dietary fiber prevents and treats obesity-related disorders. Mechanisms for this protection include decreased absorption of macronutrients and enhanced satiety. Changes in the gut microbiota and short-chain fatty acids are emerging mechanisms to explain why high fiber diets protect against obesity and have a role in obesity treatment.

Effects of prebiotic dietary fibers and probiotics on human health: With special focus on recent advancement in their encapsulated formulations

Background

Dietary fibers (DFs) are known as potential formulations in human health due to their beneficial effects in control of life-threatening chronic diseases including cardiovascular disease (CVD), diabetes mellitus, obesity and cancer. In recent decades scientists around the globe have shown tremendous interest to evaluate the interplay between DFs and gastrointestinal (GIT) microbiota. Evidences from various epidemiological and clinical trials have revealed that DFs modulate formation and metabolic activities of the microbial communities residing in the human GIT which in turn play significant roles in maintaining health and well-being. Furthermore, interestingly, a rapidly growing literature indicates success of DFs being prebiotics in immunomodulation, namely the stimulation of innate, cellular and humoral immune response, which could also be linked with their significant roles in modulation of the probiotics (live beneficial microorganisms).

Scope and approach

The main focus of the current review is to expressively highlight the importance of DFs being prebiotics in human health in association with their influence on gut microbiota. Now in order to significantly achieve the promising health benefits from these prebiotics, it is aimed to develop novel formulations to enhance and scale up their efficacy. Therefore, finally, herein unlike previously published articles, we highlighted different kinds of prebiotic and probiotic formulations which are being regarded as hot research topics among the scientific community now a days.

Conclusion

The information in this article will specifically provide a platform for the development of novel functional foods the demands for which has risen drastically in recent years.

Weight loss induced by whole grain-rich diet is through a gut microbiota-independent mechanism

The prevalence of overweight and obesity has increased worldwide. Obesity is a well-known risk factor of type 2 diabetes mellitus and cardiovascular disease and raises public health concerns. Many dietary guidelines encourage the replacement of refined grains with whole grains (WGs) to enhance body weight management. Current evidence regarding interrelationships among WGs, body weight, and gut microbiota is limited and inconclusive. In this editorial, we comment on the article by Roager et al published in the recent issue of the Gut 2019; 68(1): 83-93. In the study, obese patients (25 < body mass index < 35 kg/m²) were randomly assigned to receive two 8-wk dietary controlling periods with WGs and refined grain-rich diet. The results showed significantly decreased body weight in the WG group. Either the composition of gut microbiota or short-chain fatty acids, the leading end product of fermentation of non-digestible carbohydrate by gut microbiota, did not differ between the two groups. The study highly indicated that a WG-rich diet reduced body weight independent of gut microbiota. We then raised some plausible mechanisms of how WGs might influence body weight and demonstrated more literature in line with WGs enhance body weight control through a microbiota-independent pathway. Possible mechanisms include: (1) The abundant dietary fiber contents of WGs increase satiety, satiation, energy excretion from stool, and energy expenditure simultaneously decreasing energy absorption and fat storage; (2) The plentiful amount of polyphenols of WGs improve energy expenditure by hampering adipocyte maturation and function; (3) The sufficient magnesium and zinc of WGs guarantee lean body mass growth and decrease fat mass; (4) The effect of WGs on brown adipose tissue is a key component of non-shivering thermogenesis; and (5) The increase of adiponectin by WGs enhances glucose utilization, lipid oxidation, and energy expenditure.

Differential Physiological Responses Elicited by Ancient and Heritage Wheat Cultivars Compared to Modern Ones

Although ancient, heritage, and modern wheat varieties appear rather similar from a nutritional point of view, having a similar gluten content and a comparable toxicity linked to their undigested gluten peptide, whenever the role of ancient end heritage wheat grains has been investigated in animal studies or in clinical trials, more anti-inflammatory effects have been associated with the older wheat varieties. This review provides a critical overview of existing data on the differential physiological responses that could be elicited in the human body by ancient and heritage grains compared to modern ones. The methodology used was that of analyzing the results of relevant studies conducted from 2010 through PubMed search, by using as keywords “ancient or heritage wheat”, “immune wheat” (protein or peptides), and immune gluten (protein or peptides). Our conclusion is that, even if we do not know exactly which molecular mechanisms are involved, ancient and heritage wheat varieties have different anti-inflammatory and antioxidant proprieties with respect to modern cultivars. It is, therefore, reasonable to assume that the health proprieties attributed to older cultivars could be related to wheat components which have positive roles in the modulation of intestinal inflammation and/or permeability.