Postprandial Differences in the Amino Acid and Biogenic Amines Profiles of Impaired Fasting Glucose Individuals after Intake of Highland Barley

Refined highland barley ameliorates obesity-associated insulin resistance in high-fat diet-fed mice by targeting the gut microbiota and liver transcriptomics

PURPOSE

It is generally believed that refined grains lack nutritional value compared to whole grains. The objective of this study was to investigate whether refined highland barley (RHB) holds the potential to combat obesity-associated insulin resistance.

METHODS

Thirty-two male 6-week-old C57BL/6J mice were randomly divided into four groups fed with a normal chow diet, a high-fat diet (HFD), a 30% RHB supplemented HFD diet, and a 30% whole-grain highland barley (WGHB) supplemented HFD diet. We examined the anti-obesity and anti-insulin resistance effects of RHB and compared them with WGHB in mice.

RESULTS

RHB intervention effectively improved obesity and insulin resistance, enhanced the intestinal mucosal barrier, and reduced inflammation. Moreover, it promoted the abundance of beneficial gut bacteria such as Akkermansia, Bifidobacterium, Lachnospiraceae_NK4A136_group, Lachnospiraceae_UCG-001, Alloprevotella, and increased the production of short-chain fatty acids (SCFAs) in faeces. Additionally, RHB intervention modulated liver gene transcription, downregulating inflammatory genes like IRF3/7, STAT1/2, NLRP3, and TLR2.

CONCLUSIONS

RHB could effectively alleviate obesity-related insulin resistance by targeting gut microbiota and liver transcriptomics, and its beneficial impacts are comparable to those of WGHB.

Effect of Barley on Postprandial Blood Glucose Response and Appetite in Healthy Individuals: A Randomized, Double-Blind, Placebo-Controlled Trial

Background/Objectives: Barley dietary fiber (BDF), particularly β-glucan, has shown potential in modulating postprandial glycemic responses and improving metabolic health. This study aimed to assess the effects of Saechalssalbori (Hordeum vulgare L.), a glutinous barley variety rich in β-glucan, on postprandial blood glucose, insulin, glucagon, triglycerides, and appetite-related hormones in healthy adults. Methods: In this randomized, double-blind, placebo-controlled, crossover trial, healthy adults (n = 67) with fasting blood glucose levels below 126 mg/dL were assigned to consume either BDF or placebo (rice flour). Fasting and postprandial blood samples were collected at 30, 60, 120, and 180 min after consumption. Blood glucose, insulin, glucagon, triglycerides, and appetite-related hormones (ghrelin, PYY) were measured, and appetite was assessed using the visual analog scale (VAS). The study was approved by the Institutional Review Board (CHAMC 2022-08-040-007) and registered (KCT0009166). Results: BDF consumption significantly delayed the postprandial increase in blood glucose compared with placebo, reduced insulin secretion, and slightly increased glucagon and triglycerides. BDF also lowered hunger and increased satiety, with associated increases in ghrelin and PYY levels. Conclusions: BDF consumption, particularly from β-glucan-rich barley, may improve postprandial glycemic control and suppress appetite, making it a promising dietary intervention for managing metabolic conditions such as diabetes. Further studies are needed to explore its long-term impact on glycemic variability.

Unraveling the Hidden Potential of Barley (Hordeum vulgare): An Important Review

Barley (Hordeum vulgare) is a winter crop well known for its small-seeded grains and self-pollinating characteristics. The flour derived from barley grains plays a crucial role in numerous processed food items, contributing to their taste and nutritional value. Barley consists of complex carbohydrates (80%), proteins (11.5-14.2%), lipids (4.7-6.8%), β-glucans (3.7-7.7%), and ash (1.8-2.4%). Beyond its other nutrients, barley boasts a good reservoir of phenolic compounds (1.2-2.9 mg/g GAE). This abundance of beneficial compounds positions barley as an attractive industrial substrate. In this review, the nutritional composition and bioactive profile of barley are discussed in a systemic manner, emphasizing its potential in the development of innovative barley-based products that promote health and well-being. By incorporating barley into various food formulations, industries can not only boost nutritional content but also offer consumers a wide range of health benefits. In conclusion, barley's diverse applications in food and health highlight its essential role in promoting healthier living.

Effect of pearling on nutritional value of highland barley flour and processing characteristics of noodles

Highland barley is increasingly recognized as its nutritional benefits but its structure restricts the development and utilization in the food industry. The quality of highland barley products may be impacted by pearling, an essential step before the hull bran is consumed or further processed. The nutrition, function and edible qualities of three highland barley flour (HBF) with different pearling rates were assessed in this study. The content of resistant starch was the highest when the pearling rate of QB27 and BHB was 4%, while 8% of QB13. Un-pearled HBF showed higher DPPH, ABTS and superoxide radicals inhibition rates. The break rates of QB13, QB27 and BHB obviously decreased from 51.7%, 53.3% and 38.3% to 35.0%, 15.0% and 6.7% respectively at 12% pearling rate. PLS-DA model further attributed the improvement of pearling on noodles quality to the alteration of resilience, hardness, tension distance, breaking rate and water absorption of noodles.

Beneficial Effects of Partly Milled Highland Barley on the Prevention of High-Fat Diet-Induced Glycometabolic Disorder and the Modulation of Gut Microbiota in Mice

The nutritional functions of highland barley (HB) are superior to those of regular cereals and have attracted increasing attention in recent years. The objective of this study was to investigate whether partly milled highland barley (PHB) can regulate the serum glucose and lipid disorders of mice fed a high-fat diet (HFD) and to further explore their potential gut microbiota modulatory effect. Our results showed that PHB supplementation significantly reduced fasting blood glucose (FBG) and improved oral glucose tolerance. Histological observations confirmed the ability of PHB to alleviate liver and intestine damage. Furthermore, the results of 16S amplicon sequencing revealed that PHB prevented a HFD-induced gut microbiota dysbiosis, enriching some beneficial bacteria, such as Lactobacillus, Bifidobacterium, and Ileibacterium, and reducing several HFD-dependent taxa (norank_f_Desulfovibrionaceae, Blautia, norank_f_Lachnospiraceae, unclassified_f_Lachnospiraceae, and Colidextribacter). In addition, the increase of Lactobacillus and Bifidobacterium presence has a slightly dose-dependent relationship with the amount of the added PHB. Spearman correlation analysis revealed that Lactobacillus and Bifidobacterium were negatively correlated with the blood glucose level of the oral glucose tolerance test. Overall, our results provide important information about the processing of highland barley to retain its hypoglycemic effect and improve its acceptability and biosafety.

Four features of temporal patterns characterize similarity among individuals and molecules by glucose ingestion in humans

Oral glucose ingestion induces systemic changes of many blood metabolites related not only to glucose, but also other metabolites such as amino acids and lipids through many blood hormones. However, the detailed temporal changes in the concentrations of comprehensive metabolites and hormones over a long time by oral glucose ingestion are uncharacterized. We measured 83 metabolites and 7 hormones in 20 healthy human subjects in response to glucose ingestion. We characterized temporal patterns of blood molecules by four features: (i) the decomposability into “amplitude” and “rate” components, (ii) the similarity of temporal patterns among individuals, (iii) the relation of molecules over time among individuals, and (iv) the similarity of temporal patterns among molecules. Glucose and glucose metabolism-related hormones indicated a rapid increase, and citrulline and lipids, which indicated a rapid decrease, returned to fasting levels faster than amino acids. Compared to glucose metabolism-related molecules and lipids, amino acids showed similar temporal patterns among individuals. The four features of temporal patterns of blood molecules by oral glucose ingestion characterize the differences among individuals and among molecules.

Chlorogenic acid and β-glucan from highland barley grain ameliorate β-cell dysfunction via inhibiting apoptosis and improving cell proliferation

Recent studies have reported that highland barley as a whole grain diet has anti-hyperglycemic effects, however little information is available about the active compounds that ameliorate pancreatic β-cell dysfunction and the related mechanisms. In this study, chlorogenic acid (CA) and β-glucan (BG) were identified as the active compounds that ameliorated β-cell dysfunction. CA ameliorated β-cell dysfunction by inhibiting cell apoptosis and improving glucose-stimulated insulin secretion via targeting G protein-coupled receptor 40 (GPR40) and regulating the phospholipase C β (PLCβ) pathway. BG ameliorated β-cell dysfunction by improving cell proliferation via targeting mammalian target of rapamycin (mTOR) and regulating the protein kinase B (Akt)/glycogen synthase kinase-3β (GSK-3β) pathway. Furthermore, CA and BG improved β-cell sensitivity and pancreatic insulin secretion, and inhibited β-cell apoptosis in impaired glucose tolerance (IGT) mice. Notably, CA restored homeostasis model assessment (HOMA)-β values and Ca²⁺-ATP and K⁺-ATP levels back to normal levels, and BG at 300 mg per kg BW restored β-cell insulin contents back to normal levels in IGT mice. Additionally, the combination of CA and BG had an additive effect on ameliorating β-cell dysfunction. These results help develop whole highland barley grain as a functional food for preventing type 2 diabetes by ameliorating pancreatic β-cell damage.

Procyanidin B1 and p-Coumaric Acid from Highland Barley Grain Showed Synergistic Effect on Modulating Glucose Metabolism via IRS-1/PI3K/Akt Pathway

INTRODUCTION

Phenolic extract in highland barley grain has showed hypoglycemic effect, while little information is available about the active compounds and whether there exist additive or synergistic effect on modulating glucose metabolism.

METHODS AND RESULTS

Procyanidin B1 (PB) and p-coumaric acid (CA) are the active compounds in highland barley grain and show synergistic effect on improving glucose uptake and glycogen synthesis by upregulating glucose transporter (GLUT4) and downregulating glycogen synthase kinase-3β (GSK-3β) protein expression, respectively. The mechanism may be attributed to target insulin receptor (IRβ) and regulate insulin receptor substrate-1 (IRS-1)/phosphatidylinositol 3-kinase (PI3K)/ protein kinase B (Akt) pathway. Furthermore, PB + CA exhibits synergistic effect on restoring glucose intolerance and insulin resistance, and improving hepatic glycogen synthesis in impaired glucose tolerance (IGT) mice. The postprandial blood glucose (PBG), homeostasis model assessment (HOMA)-IR values and serum insulin contents in PB + CA-treated IGT mice with dosage of 300 mg kg^-1 BW are reversed to normal levels. Additionally, PC + CA shows additive effect on inhibiting gluconeogenesis in vitro and in vivo.

CONCLUSION

PB + CA in highland barley grain synergistically modulate glucose metabolism. These results may provide evidence of whole highland barley grain diet achieve superior effect on restoring IGT than isolated components.

Integrated multi-omics uncovers reliable potential biomarkers and adverse effects of zinc deficiency

BACKGROUND

Zinc deficiency is a worldwide public health problem. Currently, there are no established biomarkers available for the accurate diagnosis of zinc-deficiency in individuals. Additionally, a comprehensive view of the adverse effects of zinc deficiency is lacking. Our aim was to identify superior biomarkers of zinc deficiency and uncover the adverse effects of zinc deficiency.

METHODS

We performed multi-omics analysis using serum proteomics-metabolomics and liver proteomics on zinc-deficient rats to identify candidate biomarkers and reveal the associated adverse effects of zinc deficiency. Secondly, the candidate biomarkers were validated in two zinc-deficient populations and an RCT zinc supplementation trial on a zinc-deficient population.

RESULTS

Our integrated multi-omics approach revealed numerous biomarkers (>2000) and glutathione metabolism as the most important changed pathway in zinc deficiency. Three candidate biomarkers from glutathione metabolism were validated in repeated zinc-deficient rats by quantitative analysis. Only glutathione sulfotransferase omega-1 (GSTO1) (among 3 candidate biomarkers) was validated in the two zinc-deficient populations and zinc-supplemented population. Compared with serum zinc, serum GSTO1 yielded a better response to zinc supplementation and a higher correlation coefficient with zinc intake and the AUC value and has the potential for diagnosing zinc deficiency. By integrated multi-omics, we identified both established and novel adverse effects of zinc deficiency.

CONCLUSIONS

Our integrated multi-omics analysis revealed more complete information about zinc deficiency; GSTO1 was found to be a reliable potential biomarker for diagnosis of zinc deficiency. This trial is registered at http://www.chictr.org.cn/registry.aspx as ChiCTR1900028162.

Molecular Mechanism of Functional Ingredients in Barley to Combat Human Chronic Diseases

Barley plays an important role in health and civilization of human migration from Africa to Asia, later to Eurasia. We demonstrated the systematic mechanism of functional ingredients in barley to combat chronic diseases, based on PubMed, CNKI, and ISI Web of Science databases from 2004 to 2020. Barley and its extracts are rich in 30 ingredients to combat more than 20 chronic diseases, which include the 14 similar and 9 different chronic diseases between grains and grass, due to the major molecular mechanism of six functional ingredients of barley grass (GABA, flavonoids, SOD, K-Ca, vitamins, and tryptophan) and grains (β-glucans, polyphenols, arabinoxylan, phytosterols, tocols, and resistant starch). The antioxidant activity of barley grass and grain has the same and different functional components. These results support findings that barley grain and its grass are the best functional food, promoting ancient Babylonian and Egyptian civilizations, and further show the depending functional ingredients for diet from Pliocene hominids in Africa and Neanderthals in Europe to modern humans in the world. This review paper not only reveals the formation and action mechanism of barley diet overcoming human chronic diseases, but also provides scientific basis for the development of health products and drugs for the prevention and treatment of human chronic diseases.

Effects of insoluble and soluble fibers isolated from barley on blood glucose, serum lipids, liver function and caecal short-chain fatty acids in type 2 diabetic and normal rats

Large prospective cohort studies suggested an important role of cereal insoluble fiber in the prevention and management of type 2 diabetes, which challenge the traditional view that viscosity and solubility are the main driving factors for these beneficial effects of dietary fiber. To evaluate the anti-diabetic effects of insoluble- (BIF) and soluble fibers (BSF) enzymatically isolated from barley, a conventional rat model and a type 2 diabetes rat model were used. Our results showed that 4-week treatment of BIF or BSF effectively reduced FBG in the diabetic condition, with caecal level of propionic acid and minor SCFAs increased by BIF and that of butyric acid and insulin sensitivity improved by BSF, respectively. The two treatments further ameliorated liver function, judged by the recovered serum level of ALT, albumin and total protein levels. BIF and BSF also increased HDL-C and decreased serum MDA. In normal rats, BIF and BSF showed a hypolipidaemic effect in triglycerides and LDL-C, reduced body weight and enhanced the caecal production of minor SCFAs. Furthermore, the two treatments reduced the caecal level of butyric acid while BSF increased that of propionic acid. In conclusion, BIF could exert anti-diabetic effects that might via a different mechanism from BSF.

Postprandial metabolomics: GC-MS analysis reveals differences in organic acid profiles of impaired fasting glucose individuals in response to highland barley loads

The aim of our work was to use a targeted GC-MS approach to investigate the difference in organic acid profiles between individuals with impaired fasting glucose (IFG) and healthy controls and then to investigate the alterations in postprandial organic acid profiles after a meal of highland barley (HB) in IFG individuals. Firstly, 30 IFG and 30 healthy individuals were recruited and 26 organic acids were detected to characterize the organic acid profiles in the fasting serum metabolome. Secondly, 15 participants of the IFG group received three different loads: glucose (GL), white rice (WR) and HB. Serum was collected at time zero, 30, 60, 90 and 120 min after the test load. The results showed fasting organic acid profiles were different between the IFG group and the controls. For the postprandial changes in organic acids after the three test loads, six organic acids related to the tricarboxylic acid (TCA) cycle, namely citrate, cis-aconitic acid, fumarate, succinate, pyruvate and malate, had a significant test load effect (p < 0.01) and a significant time × test load interaction effect (p < 0.01). The AUC0-120 min values for citrate, fumarate and malate after WR and HB loads were significantly lower (p < 0.05) compared to the GL load. In addition, the AUC0-120 min value for pyroglutamic acid after WR and HB loads was significantly higher (p < 0.05) compared to the GL load, whereas the AUC0-120 min for malonic acid after WR and HB loads was significantly lower (p < 0.05) compared to the GL load. Altogether, these findings suggest that the HB load producing low postprandial glucose and insulin responses brings about several alterations in organic acids.

Abnormal circulating amino acid profiles in multiple metabolic disorders

AIM

To evaluate circulating amino acids (AA) profiles in obesity, type 2 diabetes (T2D) and metabolic syndrome (MetS).

METHODS

Serum AA were profiled among 200; healthy, obese, T2D and MetS subjects matched by sex, age and BMI using ultra-high performance liquid chromatography tandem quadruple mass spectrometry (UPLC-TQ-MS). A meta-analysis, including 47 case-control studies (including the current study) on serum AA in obesity, T2D and MetS searched through October 2016 was conducted to explore the AA differences in obesity, T2D and MetS.

RESULTS

In comparison with healthy controls, 14 AA (10 increased and 4 decreased) were significantly altered (P<0.05) in all non-healthy subjects. Also, mean differences of valine (obese: 34.13 [27.70, 40.56]µmol/L, P<0.001, T2D: 19.49 [3.31, 35.68]µmol/L, P<0.05, MetS: 29.18 [16.04, 42.33]µmol/L, P<0.001), glutamic acid (obese: 18.62 [11.64, 25.61]µmol/L, P<0.001, T2D: 19.94 [0.28, 39.61]µmol/L, P<0.05, MetS: 12.45 [3.98, 20.91]µmol/L, P<0.001), proline (obese: 16.72 [6.20, 27.24]µmol/L, P<0.001, T2D: 20.72 [15.82, 25.61]µmol/L, P<0.001, MetS: 29.95 [25.18, 34.71]µmol/L, P<0.001) and isoleucine (obese: 11.39 [8.54, 14.24]µmol/L, P<0.001, T2D: 7.37 [1.52, 13.22]µmol/L, P<0.05, MetS: 10.40 [4.90, 15.89]µmol/L, P<0.001) were significantly higher compared to healthy controls. Similarly, mean differences of glycine (obese: -30.99 [-39.69, -22.29]µmol/L, P<0.001, T2D: -30.37 [-41.80, -18.94]µmol/L, P<0.001 and MetS: -35.24 [-39.28, -31.21]µmol/L, P<0.001) were significantly lower compared to healthy controls.

CONCLUSION

In both the case-control study and meta-analysis, obesity was related to the most circulating AA changes, followed by MetS and T2D. Valine, isoleucine, glutamic acid and proline increased, while Glycine decreased in all metabolic disorders.

Effects of Histidine Supplementation on Global Serum and Urine 1H NMR-based Metabolomics and Serum Amino Acid Profiles in Obese Women from a Randomized Controlled Study

The aim of current study was to investigate the metabolic changes associated with histidine supplementation in serum and urine metabolic signatures and serum amino acid (AA) profiles. Serum and urine 1H NMR-based metabolomics and serum AA profiles were employed in 32 and 37 obese women with metabolic syndrome (MetS) intervened with placebo or histidine for 12 weeks. Multivariable statistical analysis were conducted to define characteristic metabolites. In serum 1H NMR metabolic profiles, increases in histidine, glutamine, aspartate, glycine, choline, and trimethylamine-N-oxide (TMAO) were observed; meanwhile, decreases in cholesterol, triglycerides, fatty acids and unsaturated lipids, acetone, and α/β-glucose were exhibited after histidine supplement. In urine 1H NMR metabolic profiles, citrate, creatinine/creatine, methylguanidine, and betaine + TMAO were higher, while hippurate was lower in histidine supplement group. In serum AA profiles, 10 AAs changed after histidine supplementation, including increased histidine, glycine, alanine, lysine, asparagine, and tyrosine and decreased leucine, isoleucine, ornithine, and citrulline. The study showed a systemic metabolic response in serum and urine metabolomics and AA profiles to histidine supplementation, showing significantly changed metabolism in AAs, lipid, and glucose in obese women with MetS.

Targeted metabolomics reveals differences in the extended postprandial plasma metabolome of healthy subjects after intake of whole-grain rye porridges versus refined wheat bread

SCOPE

We previously found that whole-grain (WG) rye porridges suppressed appetite and improved glucose metabolism. This study aimed to investigate potential plasma metabolites that may be related to differences in those appetite and glucose responses.

METHODS AND RESULTS

Twenty-one health subjects consumed six isocaloric breakfasts in a randomized cross-over study. Plain WG rye porridges (40 and 55 g), rye porridge enriched with different inulin: gluten proportions (9:3 g; 6:6 g; 3:9 g), and a 55 g refined wheat bread (control) were served as part of complete breakfast, followed by a standardized lunch. NMR metabolomics assessed 36 plasma metabolites and short chain fatty acids were measured by GC-MS from baseline up to 8 h. Pre-lunch plasma essential amino acids reflected protein composition and post-lunch plasma short chain fatty acids varied with fiber content in breakfasts. No correlations were observed between measured metabolites and glucose, insulin, or appetite responses.

CONCLUSIONS

Differences in protein and fiber contents in breakfasts altered postprandial plasma amino acids and short chain fatty acids, respectively, but were unrelated to appetite and glucose responses. Further studies are warrant to identify the underlying mechanisms for the beneficial effects on appetite and second meal glucose responses after rye-based foods.

Dietary Components and Metabolic Dysfunction: Translating Preclinical Studies into Clinical Practice

The importance of diet in the pathophysiology of metabolic syndrome is well acknowledged [1-3] and may be crucial in the determination of cardiovascular risk and the development of cardiovascular complications [4-7].[...].