Consumption of buckwheat modulates the post-prandial response of selected gastrointestinal satiety hormones in individuals with type 2 diabetes mellitus

Use of ancient grains for the management of diabetes mellitus: A systematic review and meta-analysis

AIMS

A systematic review and meta-analysis of published randomized controlled trials was conducted to collate evidence from studies implementing ancient grains and investigate the impact of ancient grain consumption on health outcomes of patients with Diabetes Mellitus (DM).

DATA SYNTHESIS

Twenty-nine randomized controlled trials were included, and 13 were meta-analyzed. Interventions ranged from 1 day to 24 weeks; most samples were affected by DM type 2 (n = 28 studies) and the ancient grains used were oats (n = 10 studies), brown rice (n = 6 studies), buckwheat (n = 4 studies), chia (n = 3 studies), Job's Tears (n = 2 studies), and barley, Khorasan and millet (n = 1 study). Thirteen studies that used oats, brown rice, and chia provided data for a quantitative synthesis. Four studies using oats showed a small to moderate beneficial effect on health outcomes including LDL-c (n = 717, MD: 0.30 mmol/l, 95% CI: 0.42 to -0.17, Z = 4.61, p < 0.05, I2 = 0%), and TC (n = 717, MD: 0.44 mmol/l, 95% CI: 0.63 to -0.24, Z = 4.40, p < 0.05, I2 = 0%). Pooled analyses of studies using chia and millet did not show significant effects on selected outcomes.

CONCLUSIONS

For adults affected by DM type 2, the use of oats may improve lipidic profile. Further experimental designs are needed in interventional research to better understand the effects of ancient grains on diabetes health outcomes.

PROSPERO REGISTRATION

CRD42023422386.

Assessment of tropane alkaloid levels in Brazilian buckwheat flour products: A novel LC-UHPLC-MS/MS approach using solid-liquid extraction at low temperature

In recent years, the monitoring of tropane alkaloids, specifically hyoscyamine and scopolamine, in food has become a pressing concern. This is due to increasing reports of food contamination with these compounds worldwide, raising awareness about the potential risks associated with their consumption. A novel method is proposed here for the determination of the sum of (+)-hyoscyamine, (-)-hyoscyamine, and (-)-scopolamine in buckwheat-based matrices, using solid-liquid extraction at low temperature and quantification by bidimensional chromatography coupled to tandem mass spectrometry. The validated method presented a linear response in the concentration range of 2.5-15 μg kg-1 (r > 0.99). The precision and accuracy were in the ranges from 0.8 to 11.0 % and from 96 to 103 %, respectively. The limit of quantification (LOQ) was 2.5 μg kg-1. No contamination was found at levels above the LOQ in any of the 18 samples analyzed (buckwheat flour, grains, and gluten-free mix).

Buckwheat: an underutilized crop with attractive sensory qualities and health benefits

The pseudocereal buckwheat is one of the ancient domesticated crops. The aim of the present review was to outline the potential of buckwheat as an agricultural crop and brings studies on buckwheat into a new larger perspective combining current knowledge in agricultural history and practice, nutritional and sensory properties, as well as possible benefits to human health. Historically, buckwheat was an appreciated crop because of its short growth period, moderate requirements for growth conditions, and high adaptability to adverse environments. Nowadays, interest in buckwheat-based food has increased because of its nutritional composition and many beneficial properties for human health. Buckwheat is a rich course of proteins, dietary fibers, vitamins, minerals, and bioactive compounds, including flavonoids. Moreover, it contains no gluten and can be used in the production of gluten-free foods for individuals diagnosed with celiac disease, non-celiac gluten sensitivity, or wheat protein allergies. Buckwheat is traditionally used in the production of various foods and can be successfully incorporated into various new food formulations with positive effects on their nutritional value and attractive sensory properties. Further research is needed to optimize buckwheat-based food development and understand the mechanism of the health effects of buckwheat consumption on human well-being.

Joint QTL Mapping and Transcriptome Sequencing Analysis Reveal Candidate Seed-Shattering-Related Genes in Common Buckwheat

Common buckwheat (Fagopyrum esculentum M.) is an important traditional miscellaneous grain crop. However, seed-shattering is a significant problem in common buckwheat. To investigate the genetic architecture and genetic regulation of seed-shattering in common buckwheat, we constructed a genetic linkage map using the F₂ population of Gr (green-flower mutant and shattering resistance) and UD (white flower and susceptible to shattering), which included eight linkage groups with 174 loci, and detected seven QTLs of pedicel strength. RNA-seq analysis of pedicel in two parents revealed 214 differentially expressed genes DEGs that play roles in phenylpropanoid biosynthesis, vitamin B6 metabolism, and flavonoid biosynthesis. Weighted gene co-expression network analysis (WGCNA) was performed and screened out 19 core hub genes. Untargeted GC-MS analysis detected 138 different metabolites and conjoint analysis screened out 11 DEGs, which were significantly associated with differential metabolites. Furthermore, we identified 43 genes in the QTLs, of which six genes had high expression levels in the pedicel of common buckwheat. Finally, 21 candidate genes were screened out based on the above analysis and gene function. Our results provided additional knowledge for the identification and functions of causal candidate genes responsible for the variation in seed-shattering and would be an invaluable resource for the genetic dissection of common buckwheat resistance-shattering molecular breeding.

Acute Effects of Dietary Fiber in Starchy Foods on Glycemic and Insulinemic Responses: A Systematic Review of Randomized Controlled Crossover Trials

Dietary fiber (DF) consumption has been associated with improved glycemic control in epidemiological and long-term interventional studies. However, its acute effects are not yet clear. This systematic review aims to elucidate the postprandial effects of DF in starchy products on glycemia and insulinemia. An electronic search of databases was conducted, and forty-one records met the inclusion criteria and underwent a risk-of-bias assessment. It was shown that soluble DF does not clearly affect glycemia in individuals with normal weight, while resistant starch may be more effective in flattening glycemic responses. Concerning insulinemia, both soluble DF and resistant starch have mixed results, with either favorable or no effects. Data on insoluble DF and glucose metabolism are scarce. The same mixed results for glycemia can be seen in healthy volunteers with overweight/obesity, while resistant starch seems to improve insulinemic responses. Finally, more studies need to examine the acute effects of DF in starchy foods on glucose metabolism and insulin secretion in individuals facing glucose abnormalities. Additionally, more studies are needed to prove whether ingesting high-fiber carbohydrate-containing products per se can result in blunted glycemic and insulinemic responses and which DF type and amount are more effective.

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

CONTEXT

Whole grain intake may control help glycemia and reduce food intake by affecting the secretion of glucagon-like peptide 1 (GLP-1) and glucose-dependent insulinotropic peptide (GIP).

OBJECTIVE

This systematic review and meta-analysis aimed to assess the postprandial and long-term effects of whole grains on GLP-1 and GIP levels.

DATA SOURCES

PubMed, Web of Science, and Scopus online databases were searched systematically to identify relevant randomized clinical trials (RCTs) published up to April 2021.

STUDY SELECTION

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.

RESULTS

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.

CONCLUSION

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.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42021256695.

Hypoglycemic Effects and Mechanisms of Buckwheat-Oat-Pea Composite Flour in Diabetic Rats

Nutritional intervention is a basic way to prevent and treat diabetes mellitus. Appropriate whole grain intake daily is recommended. The study aimed to explore the feasibility of a kind of buckwheat-oat-pea composite flour (BOP, quality ratio of buckwheat:oats:peas = 6:1:1) as a stable food substitution and its underlying mechanisms. High-fat food (HFD) and streptozotocin injection were used to induce diabetes in rats, and buckwheat, oats, and three different doses of BOP were added to the HFD separately for diet intervention. The whole study lasted for 10 weeks, and the glucose tolerance test, lipids, liver injury, and gut microbiota were evaluated in the last week. The diabetic rat model was successfully induced. The BOP significantly changed the glucose and lipids metabolism, decreased liver injury, and changed the composition of the gut microbiota of diabetic rats. The outcomes of the current study revealed that BOP is a potential stable food substitution.

Buckwheat and Cardiometabolic Health: A Systematic Review and Meta-Analysis

Buckwheat (BW) is suggested to have beneficial effects, but evidence on how it affects cardiometabolic health (CMH) is not yet established. We aimed to assess the effects of BW and/or its related bioactive compounds on cardiovascular disease (CVD) risk markers in adults. Five databases were searched for eligible studies. Observational prospective studies, nonrandomized or randomized trials were considered if they assessed BW, rutin or quercetin-3-glucoside intake and CVD risk markers. We adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines for reporting. We selected 16 human studies based on 831 subjects with mild metabolic disturbances, such as hypercholesterolemia, diabetes and/or overweight. Eight studies, investigating primarily grain components, were included in the meta-analyses (n = 464). High study heterogeneity was present across most of our analyses. Weighted mean difference (WMD) for subjects receiving BW supplementation, compared to controls, were - 0.14 mmol/L (95% CI: -0.30; 0.02) for total cholesterol (TC), -0.03 mmol/L (95% CI: -0.22; 0.16) for LDL cholesterol, -0.14 kg (95% CI: -1.50; 1.22) for body weight, -0.04 mmol/L (95% CI: - 0.09;0.02) for HDL cholesterol, -0.02 mmol/L (95% CI: -0.15; 0.11) for triglycerides and -0.18 mmol/L (95% CI: -0.36; 0.003) for glucose. Most of the studies (66.7%) had concerns of risk of bias. Studies investigating other CVD markers were scarce and with inconsistent findings, where available. Evidence on how BW affects CMH is limited. However, the available literature indicates that BW supplementation in mild dyslipidaemia and type 2 diabetes may provide some benefit in lowering TC and glucose, albeit non-significant. Our work highlights the need for more rigorous trials, with better methodological rigor to clarify remaining uncertainties on potential effects of BW on CMH and its utility in clinical nutrition practice.

The role of cereal soluble fiber in the beneficial modulation of glycometabolic gastrointestinal hormones

According to cohort studies, cereal fiber, and whole-grain products might decrease risk for type 2 diabetes (T2DM), inflammatory processes, cancer, and cardiovascular diseases. These associations, mainly affect insoluble, but not soluble cereal fiber. In intervention studies, soluble fiber elicit anti-hyperglycemic and anti-inflammatory short-term effects, partially explained by fermentation to short-chain fatty acids, which acutely counteract insulin resistance and inflammation. ß-glucans lower cholesterol levels and possibly reduce liver fat. Long-term benefits are not yet shown, maybe caused by T2DM heterogeneity, as insulin resistance and fatty liver disease - the glycometabolic points of action of soluble cereal fiber - are not present in every patient. Thus, only some patients might be susceptive to fiber. Also, incretin action in response to fiber could be a relevant factor for variable effects. Thus, this review aims to summarize the current knowledge from human studies on the impact of soluble cereal fiber on glycometabolic gastrointestinal hormones. Effects on GLP-1 appear to be highly contradictory, while these fibers might lower GIP and ghrelin, and increase PYY and CCK. Even though previous results of specific trials support a glycometabolic benefit of soluble fiber, larger acute, and long-term mechanistic studies are needed in order to corroborate the results.

Nanocellulose Prepared from Buckwheat Bran: Physicochemical Characterization, Cytotoxicity Evaluation, and Inhibition Effect on Fat Digestion and Absorption

Cellulose nanocrystal (CNC) is a sustainable biomaterial that has been used in many aspects of the food industry, but its effect on fat digestion and absorption is still underexplored. In this study, three CNCs were prepared from buckwheat bran. Their physicochemical properties were characterized, based on which the acetic acid-hydrolyzed CNC (ACCNC) with high absorption capacity was selected for the cytotoxicity evaluation and as a possible inhibitor for fat digestion and absorption in vitro and in vivo. ACCNC was proved to be nontoxic in the MTT assay and animal feeding tests. Especially, with the addition of ACCNC, the hydrolysis of fat was significantly reduced during the simulated digestion in vitro. In vivo testing also confirmed that ACCNC intake significantly reduced the elevated triglyceride, body weight, and fat accumulation levels. This study highlights the potential role of ACCNC prepared from buckwheat bran as an inhibitor for fat digestion and absorption.

Gluten-Free Cereals and Pseudocereals as a Potential Source of Exposure to Toxic Elements among Polish Residents

BACKGROUND

Nutritional food quality plays a crucial role in maintaining human health. However, food and drinking water, along with occupational exposure, are the main routes of exposure to toxic elements for humans. The main aim of this study was to determine the content of As, Cd, Pb and Hg in naturally gluten-free grains and products made from buckwheat, millet, maize, quinoa and oat. The safety of consumption of the products tested was also assessed.

METHODS

The contents of As, Cd and Pb were determined using inductively coupled plasma mass spectrometry (ICP-MS). To measure Hg, an atomic absorption spectrometry method (AAS) with the amalgamation technique was applied. To assess the level of consumption of the tested products, an online survey was conducted. To estimate health risk, three indicators were used: the target hazard quotient (THQ), cancer risk (CR) and hazard index (HI). The research material obtained 242 different samples without replications.

RESULTS

The highest average content of As, Cd, Pb and Hg were observed for the following groups of products: oat (10.19 µg/kg), buckwheat (48.35 µg/kg), millet (74.52 µg/kg) and buckwheat (1.37 µg/kg), respectively. For six samples, exceedance of established limits was found-three in the case of Cd and three of Pb. Due to the lack of established limits, As and Hg content of the tested products was not compared. Generally, no increased health risks were identified.

CONCLUSIONS

Based on the obtained results, the consumption of gluten-free cereals and pseudocereals available on the Polish market seems to be safe. However, there is a great need to establish maximum levels of the toxic elements, especially As and Hg in cereal products in European legislation.

Whole grain intake, compared to refined grain, improves postprandial glycemia and insulinemia: a systematic review and meta-analysis of randomized controlled trials

Whole grain (WG) intake has been associated with reduced risk of type 2 diabetes (T2D) and may protect against T2D by lowering postprandial glycemia and insulinemia and improving insulin sensitivity. The objective of this systematic review and meta-analysis was to evaluate the effect of WG intake, compared to refined grain (RG) intake, on postprandial glycemia and insulinemia and markers of glycemic control and insulin resistance in randomized controlled trials (RCTs) in adults. A search of PubMed and Scopus yielded 80 relevant RCTs. Compared to RG, WG intake significantly reduced postprandial glycemia (SMD: -0.30; 95% CI: -0.43, -0.18; P < 0.001), insulinemia (SMD: -0.23; 95% CI: -0.35, -0.10; P < 0.001) and glycated hemoglobin (HbA1c) (SMD: -0.21; 95% CI: -0.37, -0.06; P = 0.007). There was no effect of WG on fasting glucose, fasting insulin, or homeostatic model assessment of insulin resistance (HOMA-IR). These results suggest WG foods improve short-term glycemia and insulinemia, which may improve HbA1c, a marker of long-term glycemic control. This may partially explain the inverse association between WG intake and risk of T2D, but further investigations are needed to understand if short-term reductions in glycemia translate to longer term benefits in reducing the risk of T2D.Systematic Review Registration: PROSPERO Registration CRD42020180069.

Pseudocereal grains: Nutritional value, health benefits and current applications for the development of gluten-free foods

Nowadays, consumers are more conscious of the environmental and nutritional benefits of foods. Pseudocereals grains, edible seeds belonging to dicotyledonous plant species, are becoming a current trend in human diets as gluten-free (GF) grains with excellent nutritional and nutraceutical value. Pseudocereals are a good source of starch, fiber, proteins, minerals, vitamins, and phytochemicals such as saponins, polyphenols, phytosterols, phytosteroids, and betalains with potential health benefits. The present review aims to summarize the nutritional quality and phytochemical profile of the three main pseudocereal grains: quinoa, amaranth and buckwheat. In addition, current evidence about their health benefits in animal models and human studies is also provided in detail. Based on the accumulating research supporting the inclusion of pseudocereals grains in the diet of celiac persons, this review discusses the recent advances in their application for the development of new GF products. Future directions for a wider cultivation and commercial exploitation of these crops are also highlighted.

Buckwheat: A Useful Food and Its Effects on Human Health

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Buckwheat is a plant used for many purposes, such as consumed as a food and used in the treatment of diseases. It is a good source of many vitamins and minerals and has balanced nutritional value. Because of its nutrient content and many positive effects on human health, buckwheat has become a functional food, recently. Main effects of buckwheat on human health are its hypotensive, hypoglycemic, hypocholesterolemic, neuroprotective and antioxidant effects. Thus, it is considered an alternative food component in dietary treatment for chronic and metabolic diseases, such as diabetes, hypertension and celiac disease. Also, its rich nutrient content supports daily diet and provides a better eating profile. As a result, buckwheat is accepted as a functional food, suggested to improve human health and is used in the treatment of diseases. The aim of this review is to explain some positive effects of buckwheat on human health.

Recombinant buckwheat trypsin inhibitor decreases fat accumulation via the IIS pathway in Caenorhabditis elegans

Buckwheat trypsin inhibitor (BTI) is a low molecular weight polypeptide that can help to prevent metabolic diseases such as obesity, hyperglycemia and hyperlipidemia. Herein, the effects of recombinant BTI (rBTI) on fat accumulation in Caenorhabditis elegans were studied. rBTI prevented fat accumulation under normal and high glucose conditions, and led to significantly shorter body widths without affecting C. elegans feeding behavior. Results also indicate that rBTI altered fat breakdown, synthesis, and accumulation by altering the transcription, expression and activity of key enzymes in lipolysis and fat synthesis. In daf-2 and daf-16 mutants, rBTI did not prevent fat accumulation, indicating that rBTI activity relies on the insulin/insulin-like growth factor (IIS) pathway. Overall rBTI may regulate changes in lipolysis and fat synthesis by down-regulating the IIS pathway, which can affect fat accumulation. These findings support the application of rBTI in preventing obesity, hyperglycemia and hyperlipemia.

De novo transcriptome assembly and identification of genes related to seed size in common buckwheat (Fagopyrum esculentum M.)

Common buckwheat (Fagopyrum esculentum M.) belongs to the eudicot family Polygonaceae, Fagopyrum Mill, and its seeds have high nutritional value. The mechanism of seed development of common buckwheat remains unclear at the molecular level and no genes related to seed size have been identified. In this study, we performed genome-wide transcriptome sequencing and analysis using common buckwheat seeds at 5 days post anthesis (DPA) and 10 DPA from two cultivars (large-seeded and small-seeded). A total of 259,895 transcripts were assembled, resulting in 187,034 unigenes with average length of 1097 bp and N50 of 1538 bp. Based on gene expression profiles, 9127 differentially expressed genes (DEGs) were identified and analyzed in GO enrichment and KEGG analysis. In addition, genes related to seed size in the IKU pathway, ubiquitin-proteasome pathway, MAPK signaling pathway, TFs and phytohormones were identified and analyzed. AP2 and bZIP transcription factors, BR-signal and ABA were considered to be important regulators of seed size. This study provides a valuable genetic resource for future identification and functional analysis of candidate genes regulating seed size in common buckwheat and will be useful for improving seed yield in common buckwheat through molecular breeding in the future.

Fibre-enriched buckwheat pasta modifies blood glucose response compared to corn pasta in individuals with type 1 diabetes and celiac disease: Acute randomized controlled trial

AIM

People with type 1 diabetes and celiac disease (T1D&CD) have high blood glucose variability. Processed gluten-free foods have shown to induce a worse metabolic profile whereas naturally gluten-free foods may represent healthier options. On the other hand, dietary fibre has shown to reduce postprandial glycemic excursions in individuals with diabetes. Thus, we evaluated the acute effect of fibre-enriched buckwheat (FBP) and corn pasta (CP) on postprandial blood glucose response (PP-BGR).

METHODS

Ten adult patients with T1D&CD consumed two meals with the same amount of carbohydrate while differing only for pasta type (FBP or CP) preceded by the same insulin bolus. Participants utilized continuous glucose monitoring (CGM) and data over 6 h after meal were analyzed.

RESULTS

PP-BGR differed between the two meals, being significantly lower in the first period (0-3 h) after the CP than the FBP meal (iAUC: -38 ± 158 vs. 305 ± 209 mmol/L · 180 min, p = 0.040), whereas significantly higher in the second period (3-6 h) after the CP than the FBP meal (iAUC: 432 ± 153 vs. 308 ± 252 mmol/L · 180 min, p = 0.030). Overall, a less variable postprandial profile was observed after FBP than CP consumption.

CONCLUSIONS

In individuals with T1D&CD, the acute consumption of FBP induces significant differences in PP-BGR compared with CP that may be clinically relevant.

Evaluating Whole Grain Intervention Study Designs and Reporting Practices Using Evidence Mapping Methodology

Consumption of whole grains have been associated with reduced risk of chronic diseases in many observational studies; yet, results of intervention studies are mixed. We aimed to use evidence mapping to capture the methodological and reporting variability in whole grain intervention studies that may contribute to this inconsistency. We conducted a reproducible search in OVID Medline for whole grain human intervention studies (published 1946 to February 2018). After screening based on a priori criteria, we identified 202 publications describing a total of 213 unique trials. Over half (55%) were acute trials, lasting ≤1 day, 30% were moderate duration studies (up to 6 weeks) and 15% were of longer duration (more than 6 weeks). The majority of acute trials (75%) examined measures of glycaemia and/or insulinemia, while most of the longer trials included measures of cardiometabolic health (71%), appetite/satiety (57%) and weight/adiposity (56%). Among the moderate and long duration trials, there was a wide range of how whole grains were described but only 10 publications referenced an established definition. Only 55% of trials reported the actual amount of whole grains (in grams or servings), while 36% reported the amount of food/product and 9% did not report a dose at all. Of the interventions that provided a mixture of whole grains, less than half (46%) reported the distribution of the different grain types. Reporting of subject compliance also varied and only 22% used independent biomarkers of whole grain intake. This evidence map highlights the need to standardize both study protocols and reporting practices to support effective synthesis of study results and provide a stronger foundation to better inform nutrition scientists and public health policy.

Buckwheat and CVD Risk Markers: A Systematic Review and Meta-Analysis

The effects of buckwheat intake on cardiovascular diseases (CVDs) have not been systematically investigated. The aim of the present study was to comprehensively summarize studies in humans and animals, evaluating the impact of buckwheat consumption on CVD risk markers and to conduct a meta-analysis of relevant data. Thirteen randomized, controlled human studies, two cross-sectional human studies and twenty-one animal studies were identified. Using random-effects models, the weighted mean difference of post-intervention concentrations of blood glucose, total cholesterol and triglycerides were significantly decreased following buckwheat intervention compared with controls [differences in blood glucose: -0.85 mmol/L (95% CI: -1.31, -0.39), total cholesterol: 0.50 mmol/L (95% CI: -0.80, -0.20) and triglycerides: 0.25 mmol/L (95% CI: -0.49, -0.02)]. Responses of a similar magnitude were seen in two cross-sectional studies. For animal studies, nineteen of twenty-one studies showed a significant reduction in total cholesterol of between 12% and 54%, and fourteen of twenty studies showed a significant reduction in triglycerides of between 2% and 74%. All exhibited high unexplained heterogeneity. There was inconsistency in HDL cholesterol outcomes in both human and animal studies. It remains unclear whether increased buckwheat intake significantly benefits other markers of CVD risk, such as weight, blood pressure, insulin, and LDL-cholesterol, and underlying mechanisms responsible for any effects are unclear.

A randomized, controlled, crossover study of appetite-related sensations after consuming snacks made from buckwheat

With the rising incidence of overweight and obesity in developed countries, there is an interest in developing food products that may aid in satiety and reduce energy intake. Buckwheat (Fagopyrum esculentum) is a gluten-free edible seed that has been previously shown to induce changes in postprandial concentrations of satiety hormones; however, subjective measures of appetite-related sensations and objective measures of energy intake at subsequent meals following buckwheat consumption have not been measured. Thirty-eight healthy adults were recruited to participate in a randomized, controlled, crossover trial with the main objective to determine if consuming snacks made from buckwheat would increase satiety and reduce energy intake compared with snacks comparable in serving size, physical characteristics, and nutrient composition. Water was included as a no-kilocalorie control. Participants received each of the treatments once separated by at least 7 days. Appetite related sensations were assessed using visual analog scales at fasting and after consuming the snack at 30-min intervals for 180 min. Lunch was provided at the clinic and the amount of food consumed was weighed. Participants recorded food intake for the rest of the day. Consuming buckwheat groats (32 g serving; 141 kcal) or pita bread made from buckwheat flour (50 g serving; 135 kcal) was not associated with changes in appetite related sensations or energy consumption compared with reference snack products made from corn or rice flour. Sensory questionnaires revealed that snacks made from buckwheat were liked to a similar degree or more as reference snack products, which shows commercial promise for developing buckwheat-containing snacks.

rBTI reduced β-amyloid-induced toxicity by promoting autophagy-lysosomal degradation via DAF-16 in Caenorhabditis elegans

Alzheimer's disease (AD) is an age-related neurodegenerative disease, of which β-amyloid (Aβ) induced toxicity was suggested as a main cause. Some substances with prolongevity effects have been shown to be protective against AD. In a previous study we demonstrated that a recombinant buckwheat trypsin inhibitor (rBTI) could prolonge the lifespan in Caenorhabditis elegans (C. elegans). Here, we investigated whether rBTI may benefit to mitigate the AD symptom by feeding the AD model C. elegans CL4176. CL4176 is a transgenic C. elegans expressing human Aβ_3-42 in muscle tissue. The results showed that rBTI not only could extend lifespan but also could reduce Aβ toxicity-triggered body paralysis in AD worms. Further study found the accumulation of Aβ was decreased and autophagy-lysosomal degradation pathway was activated in AD worms treated with rBTI. Moreover, the inhibition of autophagy reduced rBTI-mediated paralysis delay. Genetic analyses showed rBTI increased the transcriptional activity of dauer formation abnormal-16 (DAF-16) and the disruption of daf-16 abolished rBTI-mediated protective effect in AD worms. Taken together, these data indicated that rBTI promoted the autophagy-lysosomal degradation pathway to reduce the Aβ-induced toxicity via DAF-16 in an AD model C. elegans, implying that BTI has the potential to protect against AD.

Protein Digestion-Derived Peptides and the Peripheral Regulation of Food Intake

The gut plays a central role in energy homeostasis. Food intake regulation strongly relies on the gut-brain axis, and numerous studies have pointed out the significant role played by gut hormones released from enteroendocrine cells. It is well known that digestive products of dietary protein possess a high satiating effect compared to carbohydrates and fat. Nevertheless, the processes occurring in the gut during protein digestion involved in the short-term regulation of food intake are still not totally unraveled. This review provides a concise overview of the current data concerning the implication of food-derived peptides in the peripheral regulation of food intake with a focus on the gut hormones cholecystokinin and glucagon-like peptide 1 regulation and the relationship with some aspects of glucose homeostasis.

Dipeptidyl Peptidase IV Inhibitory Peptides Derived from Oat (Avena sativa L.), Buckwheat (Fagopyrum esculentum), and Highland Barley (Hordeum vulgare trifurcatum (L.) Trofim) Proteins

Peptides released from oat, buckwheat, and highland barley proteins were examined for their in vitro inhibitory effects on dipeptidyl peptidase IV (DPP4), an enzyme that deactivates incretin hormones involved in insulin secretion. All of the hydrolysates exhibited DPP4 inhibitory activities, with IC50 values ranging from 0.13 mg/mL (oat glutelin alcalase digestion) to 8.15 mg/mL (highland barley albumin tryptic digestion). The lowest IC50 values in gastrointestinal, alcalase, and tryptic digestions were 0.99 mg/mL (oat flour), 0.13 mg/mL (oat glutelin), and 1.83 mg/mL (highland barley glutelin). In all, 35 peptides of more than seven residues were identified in the tryptic hydrolysates of oat globulin using liquid chromatography-mass spectroscopy. Peptides LQAFEPLR and EFLLAGNNK were synthesized and their DPP4 inhibitory activities determined. LQAFEPLR showed high in vitro DPP4 inhibitory activity with an IC50 value of 103.5 μM.

Buckwheat as a Functional Food and Its Effects on Health

Buckwheat (BW) is a gluten-free pseudocereal that belongs to the Polygonaceae family. BW grain is a highly nutritional food component that has been shown to provide a wide range of beneficial effects. Health benefits attributed to BW include plasma cholesterol level reduction, neuroprotection, anticancer, anti-inflammatory, antidiabetic effects, and improvement of hypertension conditions. In addition, BW has been reported to possess prebiotic and antioxidant activities. In vitro and animal studies suggest that BW's bioactive compounds, such as D-chiro-inositol (DCI), BW proteins (BWP), and BW flavonoids (mainly rutin and quercetin) may be partially responsible for the observed effects. The purpose of this paper is to review the recent research regarding the health benefits of BW, in vitro and in vivo, focusing on the specific role of its bioactive compounds and on the mechanisms by which these effects are exerted.

An enriched, cereal-based bread affects appetite ratings and glycemic, insulinemic, and gastrointestinal hormone responses in healthy adults in a randomized, controlled trial

BACKGROUND

Bread can contribute to the regulation of appetite.

OBJECTIVE

The objective of this study was to investigate the appetite ratings and postprandial glucose, insulin, and gastrointestinal hormone responses related to hunger and satiety after the intake of a cereal-based bread.

METHODS

A randomized, controlled crossover trial was conducted in 30 healthy adults (17 men and 13 women) aged 19-32 y with body mass index of 19.2-28.5. Each volunteer consumed the cereal-based bread and the control bread 2 times, with a 1-wk wash-out period, over a total of 4 sessions. The cereal-based bread contained a variety of cereal flours (wheat, oat, and spelt) and consisted of 22% dried fruits (figs, apricots, raisins, and prunes). It was also enriched with both fiber (7% from wheat cross-linked maltodextrins and pea) and protein (10-11% from wheat gluten and hydrolyzed wheat proteins). The control bread consisted of white bread with margarine and jam to control for energy density, fat, and sugar content. We measured appetite ratings using standardized visual analogue scales and glucose, insulin, and gastrointestinal hormone responses over a postprandial time of 4 h after the ingestion of each bread. Linear mixed-effects models were used to compare the areas under the curve (AUCs) for different variables.

RESULTS

Consuming the cereal-based bread decreased prospective consumption more than consumption of the control bread (-5.3 ± 0.6 m · min and -4.4 ± 0.6 m · min, respectively; P = 0.02) and increased satiety more (6.2 ± 0.7 m · min and 5.2 ± 0.6 m · min, respectively; P = 0.04), although subsequent ad libitum energy intake 4 h later did not differ. Postprandial blood glucose, insulin, ghrelin, glucagon-like peptide 1 and gastric inhibitory polypeptide AUCs were lower after the ingestion of the cereal-based bread, whereas the pancreatic polypeptide AUC was higher than with the control bread (P < 0.05).

CONCLUSIONS

Consumption of the cereal-based bread contributed to appetite control by reducing hunger and enhancing satiety. In addition, consumption of this bread improved glycemic, insulinemic, and gastrointestinal hormone responses in healthy adults. This trial was registered at clinicaltrials.gov as NCT02090049.

Postprandial effects of polydextrose on satiety hormone responses and subjective feelings of appetite in obese participants

Background

Dietary fibers are associated with enhanced satiety. However, the mechanism of different dietary fibers contributing to satiety-related gastrointestinal (GI) peptide release, especially in an obese population, is still poorly understood. Polydextrose (PDX), a water-soluble glucose polymer, has demonstrated its ability to reduce energy intake at a subsequent meal, but its mechanism of action requires further research. Also, there is limited evidence on its capacity to regulate subjective feelings of appetite. This study examines the effects of PDX on postprandial secretion of satiety-related GI peptides, short chain fatty acids (SCFAs), lactic acid, and subjective appetite ratings in obese participants.

Methods

18 non-diabetic, obese participants (42.0 y, 33.6 kg/m²) consumed a high-fat meal (4293 kJ, 36% from fat) with or without PDX (15 g) in an acute, multicenter, randomized, double-blind, placebo-controlled and crossover trial. Postprandial plasma concentrations of satiety-related peptides, namely ghrelin, cholecystokinin (CCK), glucagon-like peptide 1 (GLP-1), and peptide YY (PYY), as well as SCFAs and lactic acid were assessed. GI peptide, SCFA and lactate concentrations were then modeled using a linear mixed-effects model.

The subjective feelings of hunger, satisfaction, and desire to eat were evaluated using visual analogue scales (VAS), which were analyzed as incremental areas under the curve (iAUC) during the satiation and satiety periods.

Results

We found that PDX supplementation increased plasma GLP-1 levels more than the placebo treatment (P = 0.02). In the whole group, GLP-1 concentrations found in participants older than 40 years old were significantly lower (P = 0.01) as compared to those aged 40 years or less. There were no statistically significant differences in postprandial ghrelin, CCK, or PYY responses. The lactic acid concentrations were significantly (P = 0.01) decreased in the PDX group, while no significant changes in SCFAs were found. PDX reduced iAUC for hunger by 40% (P = 0.03) and marginally increased satisfaction by 22.5% (P = 0.08) during the post-meal satiety period.

Conclusion

Polydextrose increased the postprandial secretion of the satiety hormone GLP-1 and reduced hunger after a high-fat meal. PDX also reduced the elevated postprandial lactic acid levels in plasma. Therefore, PDX may offer an additional means to regulate inter-meal satiety and improve postprandial metabolism in obese participants.

Comparative analysis of flavonoids and polar metabolite profiling of Tanno-original and Tanno-high rutin buckwheat

Rutin is an important indicator for evaluating the quality of buckwheat. In this study, flavonoid biosynthesis was compared between two common cultivars (an original and a high-rutin line) of buckwheat, Fagopyrum esculentum Moench. Transcriptional levels of the main flavonoid biosynthetic genes were analyzed by real-time PCR, and main flavonoid metabolites were detected by high-performance liquid chromatography (HPLC); levels of gene expression varied among organs of the two cultivars. Significantly higher transcription levels of most flavonoid biosynthetic genes, except FeFLS1, were detected in stems of the high-rutin line than in stems of the original line. FeCHI and FeFLS2 genes also showed higher expression levels in seeds of the high-rutin cultivar. In contrast, FePAL, FeC4H, Fe4CL1, FeCHS, FeF3H, FeF3'H, FeFLS2, and FeDFR were highly detected in the roots of the original line. The HPLC results indicated 1.73-, 1.62-, and 1.77-fold higher accumulation of rutin (the primary flavonoid compound) in leaves, stems, and mature seeds of the high-rutin cultivar (24.86, 1.46, and 1.36 μg/mg, respectively) compared with the original cultivar (14.40, 0.90, and 0.77 μg/mg, respectively). A total of 46 metabolites were identified from seeds by gas chromatography-time-of-flight mass spectrometry. The metabolite profiles were subjected to principal component analysis (PCA). PCA could clearly differentiate the original and high-rutin cultivars. Our results indicate that the high-rutin cultivar could be an excellent alternative for buckwheat culture, and we provide useful information for obtaining this cultivar.