Inulin-enriched pasta affects lipid profile and Lp(a) concentrations in Italian young healthy male volunteers

Effects of Yogurt Enriched with Konjac Glucomannan and Inulin on Insulin Sensitivity, Glycemic Control, Lipid Profiles, Anthropometric Measures and Oxidative Stress in Type 2 Diabetes Mellitus: A Randomized Controlled Trial

Type 2 diabetes mellitus (T2DM) is a prevalent metabolic disorder that requires effective dietary strategies for management. In this randomized, double-blind, placebo-controlled clinical trial, the effects of low-fat yogurt enriched with konjac glucomannan (KGM) and inulin on glycemic control, lipid profiles, anthropometric indices, and oxidative stress were investigated in patients with T2DM. Eighty participants were randomly assigned to consume either 150 g of yogurt enriched with 1.5 g of KGM and 1.5 g of inulin (n=40) or plain low-fat yogurt (n=40) daily for 8 weeks. The primary outcomes were fasting blood glucose and fasting insulin levels, insulin sensitivity indices [homeostasis model assessment for insulin resistance (HOMA-IR) and quantitative insulin sensitivity check index (QUICKI)], and glycated hemoglobin. Secondary outcomes included lipid profile [total cholesterol (TC), low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, and triglyceride (TG)], anthropometric indices (weight, body mass index, fat mass, skeletal muscle, and waist circumference), and oxidative stress markers. Compared to control group, the intervention significantly improved fasting insulin levels (-1.85 µIU/mL, P=0.042), HOMA-IR (-0.89, P=0.029), and QUICKI (0.11, P=0.032). Lipid profile analysis revealed reductions in TC (-18.51 mg/dL, P=0.049) and TG levels (-15.0 mg/dL, P=0.041). These findings suggest that daily consumption of yogurt fortified with KGM and inulin significantly enhances insulin sensitivity and lipid profiles in patients with T2DM over an 8-week period. This dietary intervention shows promise as a complementary strategy for T2DM management. Further studies are needed to assess the long-term outcomes, optimize doses, and elucidate the underlying mechanisms of this intervention.

Inulin alleviates atherosclerosis through improving lipid metabolism, inflammation, and gut microbiota in ApoE-knockout mice: the short-chain is more efficacious

Introduction

Atherosclerosis (AS) is considered the underlying cause of many diseases, particularly cardiovascular and cerebrovascular diseases. Inulin, a type of fructan, has shown potential in improving atherosclerosis, although there are conflicting findings. It is hypothesized that the polymerization degree of inulin may largely influence its therapeutic effectiveness. Therefore, this study aimed to investigate the effects and mechanisms of short-chain and long-chain inulin in AS.

Methods

ApoE-/- mice fed a high fat diet (HFD) were used to establish an atherosclerosis model. These mice received daily oral administration of either short-chain or long-chain inulin for 12 weeks. Plasma lipid metabolism-related indices were measured using biochemical analysis, and plasma immunological indices were analyzed via ELISA. The aorta, aortic root regions, liver tissue, adipose tissue, and colon tissue were examined through various staining techniques, including ORO staining, hematoxylin and eosin staining, Alcian blue staining, and immunofluorescent or immunohistochemical assays. Microbiome analysis was conducted in the cecal content.

Results

The results indicated that both short-chain and long-chain inulin substantially reduced the formation of atherosclerotic plaques. Inulin also improved plasma lipid concentrations and hepatic lipid metabolism, and partially alleviated both localized (atherosclerotic lesions) and systemic inflammation. Short-chain inulin was more effective than long-chain inulin in reducing atherosclerotic plaques formation, enhancing lipid metabolism and reducing inflammation. Additionally, both types of inulin showed similar effectiveness in enhancing intestinal epithelial barrier integrity, gut microbiota composition and functionality.

Conclusion

These findings suggest that inulin has a protective role against atherosclerosis by enhancing lipid metabolism, reducing inflammation, and improving intestinal barrier and gut microbiota. As a dietary intervention, short-chain inulin is more effective than long-chain inulin, offering clinical implications for using inulin as a therapeutic agent for atherosclerosis.

From Gut to Eye: Exploring the Role of Microbiome Imbalance in Ocular Diseases

Background: The gut microbiome plays a crucial role in human health, and recent research has highlighted its potential impact on ocular health through the gut-eye axis. Dysbiosis, or an imbalance in the gut microbiota, has been implicated in various ocular diseases. Methods: A comprehensive literature search was conducted using relevant keywords in major electronic databases, prioritizing recent peer-reviewed articles published in English. Results: The gut microbiota influences ocular health through immune modulation, maintenance of the blood-retinal barrier, and production of beneficial metabolites. Dysbiosis can disrupt these mechanisms, contributing to ocular inflammation, tissue damage, and disease progression in conditions such as uveitis, age-related macular degeneration, diabetic retinopathy, dry eye disease, and glaucoma. Therapeutic modulation of the gut microbiome through probiotics, prebiotics, synbiotics, and fecal microbiota transplantation shows promise in preclinical and preliminary human studies. Conclusions: The gut-eye axis represents a dynamic and complex interplay between the gut microbiome and ocular health. Targeting the gut microbiome through innovative therapeutic strategies holds potential for improving the prevention and management of various ocular diseases.

Does symbiotic supplementation which contains Bacillus Coagulans Lactobacillus rhamnosus, Lactobacillus acidophilus and fructooligosaccharide has favourite effects in patients with type-2 diabetes? A randomised, double-blind, placebo-controlled trial

This study aimed to determine the effect of Bacillus Coagulans symbiotic supplementation on metabolic factors and inflammation in patients with type-2 diabetes. In this clinical trial, 50 patients with type-2 diabetes were randomly assigned to the symbiotic (containing Bacillus Coagulans + Lactobacillus rhamnosus + Lactobacillus acidophilus and fructooligosaccharide) or placebo groups to receive one sachet daily for 12 weeks. Glycaemic Index, lipid profile, and hs-CRP were measured at the beginning and end of the study. Analysis of covariance demonstrated that fasting blood glucose (FBG), insulin, homeostatic Model Assessment for Insulin Resistance (HOMA-IR), β-cell function (HOMA-β) (p <.05) and hs-CRP (p <.05) significantly declined in the treatment group compared with the placebo group. So, the current study indicated that Bacillus Coagulans symbiotic supplementation could improve metabolic factors and inflammation in patients with type-2 diabetes.

Targeting the Gut-Eye Axis: An Emerging Strategy to Face Ocular Diseases

The human microbiota refers to a large variety of microorganisms (bacteria, viruses, and fungi) that live in different human body sites, including the gut, oral cavity, skin, and eyes. In particular, the presence of an ocular surface microbiota with a crucial role in maintaining ocular surface homeostasis by preventing colonization from pathogen species has been recently demonstrated. Moreover, recent studies underline a potential association between gut microbiota (GM) and ocular health. In this respect, some evidence supports the existence of a gut-eye axis involved in the pathogenesis of several ocular diseases, including age-related macular degeneration, uveitis, diabetic retinopathy, dry eye, and glaucoma. Therefore, understanding the link between the GM and these ocular disorders might be useful for the development of new therapeutic approaches, such as probiotics, prebiotics, symbiotics, or faecal microbiota transplantation through which the GM could be modulated, thus allowing better management of these diseases.

Gastrointestinal Effects and Tolerance of Nondigestible Carbohydrate Consumption

Nondigestible carbohydrates (NDCs) are food components, including nonstarch polysaccharides and resistant starches. Many NDCs are classified as dietary fibers by the US FDA. Because of their beneficial effects on human health and product development, NDCs are widely used in the food supply. Although there are dietary intake recommendations for total dietary fiber, there are no such recommendations for individual NDCs. NDCs are heterogeneous in their chemical composition and physicochemical properties-characteristics that contribute to their tolerable intake levels. Guidance on tolerable intake levels of different NDCs is needed because overconsumption can lead to undesirable gastrointestinal side effects, further widening the gap between actual and suggested fiber intake levels. In this review, we synthesize the literature on gastrointestinal effects of NDCs that the FDA accepts as dietary fibers (β-glucan, pectin, arabinoxylan, guar gum, alginate, psyllium husk, inulin, fructooligosaccharides and oligofructose, galactooligosaccharides, polydextrose, cellulose, soy fiber, resistant maltodextrin/dextrin) and present tolerable intake dose recommendations for their consumption. We summarized the findings from 103 clinical trials in adults without gastrointestinal disease who reported gastrointestinal effects, including tolerance (e.g., bloating, flatulence, borborygmi/rumbling) and function (e.g., transit time, stool frequency, stool consistency). These studies provided doses ranging from 0.75-160 g/d and lasted for durations ranging from a single-meal tolerance test to 28 wk. Tolerance was NDC specific; thus, recommendations ranged from 3.75 g/d for alginate to 25 g/d for soy fiber. Future studies should address gaps in the literature by testing a wider range of NDC doses and consumption forms (solid compared with liquid). Furthermore, future investigations should also adopt a standard protocol to examine tolerance and functional outcomes across studies consistently.

The Prebiotic Potential of Inulin-type Fructans: A Systematic Review

Inulin-type fructans (ITF), including short-chain fructooligosaccharides (scFOS), oligofructose, and inulin, are commonly used fibers that are widely regarded as prebiotic for their ability to be selectively utilized by the intestinal microbiota to confer a health benefit. However, the literature thus far lacks a thorough discussion of the evidence from human clinical trials for the prebiotic effect of ITF, including both effects on the intestinal microbiota composition as well as the intestinal and extraintestinal (e.g., glucose homeostasis, lipids, mineral absorption and bone health, appetite and satiety, inflammation and immune function, and body composition) benefits. Additionally, there is a lack of discussion regarding aspects such as the effect of ITF chain length on its intestinal and extraintestinal effects. The overall objective of this systematic review was to summarize the prebiotic potential of ITF based on the results of human clinical trials in healthy adult populations. Evidence from studies included in the current review suggest that ITF have a prebiotic effect on the intestinal microbiota, promoting the abundances of Bifidobacterium, Lactobacillus, and Faecalibacterium prausnitzii. Beneficial health effects reported following ITF intake include improved intestinal barrier function, improved laxation, increased insulin sensitivity, decreased triglycerides and an improved lipid profile, increased absorption of calcium and magnesium, and increased satiety. While there is some evidence for differing effects of ITF based on chain length, lack of direct comparisons and detailed descriptions of physicochemical properties limit the ability to draw conclusions from human clinical studies. Future research should focus on elucidating the mechanisms by which the intestinal microbiota mediates or modifies the effects of ITF on human health and the contribution of individual factors such as age and metabolic health to move towards personalization of prebiotic application.

Mechanistic and physiological approaches of fecal microbiota transplantation in the management of NAFLD

Non-alcoholic fatty liver disease (NAFLD) is a multifaceted disease allied with various metabolic disorders, obesity and dysbiosis. Gut microbiota plays an influential role in the pathogenesis of NAFLD and other metabolic disorders. However, recent scientific upsurge emphasizes on the utility of beneficial gut microbiota and bacteriotherapy in the management of NAFLD. Fecal microbiota transplantation (FMT) is the contemporary therapeutic approach with state-of-the-art methods for the treatment of NAFLD. Other potential therapies include probiotics and prebiotics supplements which are based on alteration of gut microbes to treat NAFLD. In this review, our major focus is on the pathological association of gut microbiota with progression of NAFLD, historical aspects and recent advances in FMT with possible intervention to combat NAFLD and its associated metabolic dysfunctions.

Whole grain cereals: the potential roles of functional components in human health

Whole grain cereals have been the basis of human diet since ancient times. Due to rich in a variety of unique bioactive ingredients, they play an important role in human health. This review highlights the contents and distribution of primary functional components and their health effects in commonly consumed whole grain cereals, especially dietary fiber, protein, polyphenols, and alkaloids. In general, cereals exert positive effects in the following ways: 1) Restoring intestinal flora diversity and increasing intestinal short-chain fatty acids. 2) Regulating plasma glucose and lipid metabolism, thereby the improvement of obesity, cardiovascular and cerebrovascular diseases, diabetes, and other chronic metabolic diseases. 3) Exhibiting antioxidant activity by scavenging free radicals. 4) Preventing gastrointestinal cancer via the regulation of classical signaling pathways. In summary, this review provides a scientific basis for the formulation of whole-grain cereals-related dietary guidelines, and guides people to form scientific dietary habits, so as to promote the development and utilization of whole-grain cereals.

Effects of short chain fatty acids on metabolic and inflammatory processes in human health

Butyrate, propionate, and acetate are short-chain fatty acids (SCFAs) mainly produced by bacterial metabolism in the human gut after dietary fiber intake. SCFAs are considered important for health maintenance by promoting lipid, glucose, and immune homeostasis with an adequate composition of intestinal microbiota, including other beneficial effects like providing protection against colorectal cancer. Therapies with exogenous SCFAs have been proposed to reduce inflammation in intestinal diseases that result from SCFA dysbiosis and cause mucosal inflammation. The aim of this mini-review was to provide an overview of the importance of SCFAs on metabolic and inflammatory processes as well as their role in treating chronic inflammatory disorders.

Efficacy of inulin supplementation in improving insulin control, HbA1c and HOMA-IR in patients with type 2 diabetes: a systematic review and meta-analysis of randomized controlled trials

Type 2 diabetes mellitus is a chronic disease that occurs among the general population. The insulin-lowering and homeostasis model assessment of insulin resistance-improving effects of inulin are unconfirmed. We conducted this meta-analysis to examine the efficiency and safety of inulin for improving insulin control, homeostasis model assessment of insulin resistance and HbA1c in patients with type 2 diabetes mellitus. We searched the Web of Science, PubMed, Embase and Cochrane Library databases for relevant articles published before June 1, 2019. In total, 225 randomized controlled trials regarding the efficiency of inulin for the treatment of type 2 diabetes mellitus compared to the efficacy of placebo or other treatments were examined. According to the inclusion and exclusion criteria, 9 trials with a total of 661 participants were included. We concluded that inulin supplementation can significantly improve fasting plasma glucose (SMD = -0.55, 95% CI -0.73 to -0.36, p = 0), HOMA-IR (SMD = -0.81, 95% CI -1.59 to -0.03, p = 0.042) and HbA1c (SMD = -0.69, 95% CI -0.92 to -0.46, p = 0). Further subgroup analyses revealed a significant role of inulin supplementation for treatment durations ≥8 weeks (p = 0.038 for insulin, p = 0.002 for HOMA-IR, p = 0.032 for FPG, p = 0 for HbA1c).

Mice Microbiota Composition Changes by Inulin Feeding with a Long Fasting Period under a Two-Meals-Per-Day Schedule

Water-soluble dietary fiber is known to modulate fecal microbiota. Although there are a few reports investigating the effects of fiber intake timing on metabolism, there are none on the effect of intake timing on microbiota. Therefore, in this study, we examined the timing effects of inulin-containing food on fecal microbiota. Mice were housed under conditions with a two-meals-per-day schedule, with a long fasting period in the morning and a short fasting period in the evening. Then, 10-14 days after inulin intake, cecal content and feces were collected, and cecal pH and short-chain fatty acids (SCFAs) were measured. The microbiome was determined using 16S rDNA sequencing. Inulin feeding in the morning rather than the evening decreased the cecal pH, increased SCFAs, and changed the microbiome composition. These data suggest that inulin is more easily digested by fecal microbiota during the active period than the inactive period. Furthermore, to confirm the effect of fasting length, mice were housed under a one-meal-per-day schedule. When the duration of fasting was equal, the difference between morning and evening nearly disappeared. Thus, our study demonstrates that consuming inulin at breakfast, which is generally after a longer fasting period, has a greater effect on the microbiota.

Prebiotics: Definition, Types, Sources, Mechanisms, and Clinical Applications

Prebiotics are a group of nutrients that are degraded by gut microbiota. Their relationship with human overall health has been an area of increasing interest in recent years. They can feed the intestinal microbiota, and their degradation products are short-chain fatty acids that are released into blood circulation, consequently, affecting not only the gastrointestinal tracts but also other distant organs. Fructo-oligosaccharides and galacto-oligosaccharides are the two important groups of prebiotics with beneficial effects on human health. Since low quantities of fructo-oligosaccharides and galacto-oligosaccharides naturally exist in foods, scientists are attempting to produce prebiotics on an industrial scale. Considering the health benefits of prebiotics and their safety, as well as their production and storage advantages compared to probiotics, they seem to be fascinating candidates for promoting human health condition as a replacement or in association with probiotics. This review discusses different aspects of prebiotics, including their crucial role in human well-being.

Milk Powder Co-Supplemented with Inulin and Resistant Dextrin Improves Glycemic Control and Insulin Resistance in Elderly Type 2 Diabetes Mellitus: A 12-Week Randomized, Double-Blind, Placebo-Controlled Trial

SCOPE

The objective of the present study is to evaluate the effects of milk powder co-supplemented with inulin and resistant dextrin (MPCIR) on elderly patients with type 2 diabetes mellitus (T2DM).

METHODS AND RESULTS

A randomized, double-blind, placebo-controlled clinical trial is carried out among elderly T2DM patients. The subjects recruited from the community are randomly assigned to either the MPCIR group or placebo group for 12 weeks intervention. Each group receives 45 g milk powder with or without inulin and resistant dextrin. Anthropometric and metabolic variables are measured. For the MPCIR group, systolic blood pressure (BP) and diastolic BP are reduced significantly by 5.45 and 4.56 mm Hg (p < 0.001, vs placebo group), respectively. Compared with the placebo group, the fasting and 2-h postprandial plasma glucose levels, glycosylated serum protein, and insulin resistance index of the MPCIR group are significantly decreased by 0.96 mmol L^-1 , 1.47 mmol L^-1 , 16.33 μmol L^-1 , and 0.65 respectively (p < 0.001). The MPCIR group shows an increase by 7.09 μIU mL^-1 and 20.43 in 2-h postprandial insulin (p = 0.016) and β-cell function index (p < 0.001), respectively.

CONCLUSION

MPCIR supplementation helps to improve glycemic control, insulin resistance, and blood pressure.

The prebiotic inulin improves substrate metabolism and promotes short-chain fatty acid production in overweight to obese men

BACKGROUND AND AIMS

Human gut microbiota play an important role in maintaining human health. Dietary fibers, i.e. prebiotics, are fermented by human gut microbiota into the short-chain fatty acids (SCFAs) acetate, propionate, and butyrate. SCFAs promote fat oxidation and improve metabolic health. Therefore, the prebiotic inulin might be an effective dietary strategy to improve human metabolism. We aimed to investigate the acute metabolic effects of ingesting inulin compared with digestible carbohydrates and to trace inulin-derived SCFAs using stable isotope tracer methodology.

METHODS

In a double-blind, randomized, placebo-controlled crossover design, 14 healthy, overweight to obese men consumed a high-fat milkshake containing A) 24 g inulin of which 0.5 g was U-¹³C-inulin (INU) or B) 24 g maltodextrin placebo (PLA), with a wash-out period of at least five days. Fat oxidation was measured via an open-circuit ventilated hood and blood samples were collected up to 7 h after ingestion. Plasma, breath, and fecal samples were collected, and appetite and satiety scores were assessed.

RESULTS

Fat oxidation increased in the early postprandial phase (0-3 h), and both plasma glucose and insulin were lower after INU ingestion compared with PLA (all P < 0.05). Plasma free fatty acids were higher in the early, and lower in the late postprandial period after INU ingestion. Inulin was fermented into SCFAs as indicated by higher plasma acetate concentrations after INU compared with PLA (P < 0.05). In addition, we found continuous increases in plasma ¹³C-SCFA enrichments (P < 0.05 from t = 120 onwards) and breath ¹³CO₂ enrichments after INU intake. There were no effects on plasma triglycerides, free glycerol, satiety hormones GLP-1 and PYY, and appetite and satiety scores.

CONCLUSIONS

Ingestion of the prebiotic inulin improves fat oxidation and promotes SCFA production in overweight to obese men. Overall, replacing digestible carbohydrates with the fermentable inulin may favor human substrate metabolism.

CLINICAL TRIAL REGISTRY

The trial was registered at clinicaltrials.gov under number NCT02009670.

Assessing the Effect of High Performance Inulin Supplementation via KLF5 mRNA Expression in Adults with Type 2 Diabetes: A Randomized Placebo Controlled Clinical Trail

Purpose: The worldwide prevalence of metabolic disorders such as diabetes is increasing rapidly. Currently, the complications of diabetes are the major health concern. The aim of this study was to investigate the effect of high performance (HP) inulin supplementation on glucose homeostasis via KLF5 mRNA expression in adults with type 2 diabetes.

Methods: In the present clinical trial conducted for a duration of 6 weeks, 46 volunteers diabetic patients referring to diabetes clinic in Tabriz, Iran, were randomly assigned into intervention (n= 23, consuming 10 gr/d HP inulin) and control groups (n= 23, consuming 10 gr/ d starch). We assessed glycemic and anthropometric indices, blood lipids and plasmatic level of miR-375 as well as KLF5 mRNA expression before and after the intervention.

Results: Findings indicated that inulin supplementation significantly decreased fasting plasma glucose (FPG) in comparison to the placebo group (P<0.001). Also Intra-group and between group results showed that inulin supplementation resulted in significant decrease in KLF5 mRNA expression in peripheral blood mononuclear cells (PBMCs) (Fold change: 0.61± 0.11; P-value= 0.001) and significant increase in plasmatic level of miR-375 (Fold change: 3.75± 0.70; P-value=0.004).

Conclusion: Considering the improvements of FPG level in diabetic patients, it seems that HP inulin supplementation may be beneficial in controlling diabetes via the expression of some genes. However, further studies are needed to achieve concise conclusions.

A systematic review on the relations between pasta consumption and cardio-metabolic risk factors

AIMS

The traditional Italian dish pasta is a major food source of starch with low glycemic index (GI) and an important low-GI component of the Mediterranean diet. This systematic review aimed at assessing comprehensively and in-depth the potential benefit of pasta on cardio-metabolic disease risk factors.

DATA SYNTHESIS

Following a standard protocol, we conducted a systematic literature search of PubMed, CINAHL, and Cochrane Central Register of Controlled Trials for prospective cohort studies and randomized controlled dietary intervention trials that examined pasta and pasta-related fiber and grain intake in relation to cardio-metabolic risk factors of interest. Studies comparing postprandial glucose response to pasta with that to bread or potato were quantitatively summarized using meta-analysis of standardized mean difference. Evidence from studies with pasta as part of low-GI dietary intervention and studies investigating different types of pasta were qualitatively summarized.

CONCLUSIONS

Pasta meals have significantly lower postprandial glucose response than bread or potato meals, but evidence was lacking in terms of how the intake of pasta can influence cardio-metabolic disease risk. More long-term randomized controlled trials are needed where investigators directly contrast the cardio-metabolic effects of pasta and bread or potato. Long-term prospective cohort studies with required data available should also be analyzed regarding the effect of pasta intake on disease endpoints.

Significance of Microbiota in Obesity and Metabolic Diseases and the Modulatory Potential by Medicinal Plant and Food Ingredients

Metabolic syndrome is a cluster of three or more metabolic disorders including insulin resistance, obesity, and hyperlipidemia. Obesity has become the epidemic of the twenty-first century with more than 1.6 billion overweight adults. Due to the strong connection between obesity and type 2 diabetes, obesity has received wide attention with subsequent coining of the term "diabesity." Recent studies have identified unique contributions of the immensely diverse gut microbiota in the pathogenesis of obesity and diabetes. Several mechanisms have been proposed including altered glucose and fatty acid metabolism, hepatic fatty acid storage, and modulation of glucagon-like peptide (GLP)-1. Importantly, the relationship between unhealthy diet and a modified gut microbiota composition observed in diabetic or obese subjects has been recognized. Similarly, the role of diet rich in polyphenols and plant polysaccharides in modulating gut bacteria and its impact on diabetes and obesity have been the subject of investigation by several research groups. Gut microbiota are also responsible for the extensive metabolism of polyphenols thus modulating their biological activities. The aim of this review is to shed light on the composition of gut microbes, their health importance and how they can contribute to diseases as well as their modulation by polyphenols and polysaccharides to control obesity and diabetes. In addition, the role of microbiota in improving the oral bioavailability of polyphenols and hence in shaping their antidiabetic and antiobesity activities will be discussed.

Understanding the Physics of Functional Fibers in the Gastrointestinal Tract: An Evidence-Based Approach to Resolving Enduring Misconceptions about Insoluble and Soluble Fiber

Enduring misconceptions about the physical effects of fiber in the gut have led to misunderstandings about the health benefits attributable to insoluble and soluble fiber. This review will focus on isolated functional fibers (eg, fiber supplements) whose effects on clinical outcomes have been readily assessed in well-controlled clinical studies. This review will also focus on three health benefits (cholesterol lowering, improved glycemic control, and normalizing stool form [constipation and diarrhea]) for which reproducible evidence of clinical efficacy has been published. In the small bowel, clinically meaningful health benefits (eg, cholesterol lowering and improved glycemic control) are highly correlated with the viscosity of soluble fibers: high viscosity fibers (eg, gel-forming fibers such as b-glucan, psyllium, and raw guar gum) exhibit a significant effect on cholesterol lowering and improved glycemic control, whereas nonviscous soluble fibers (eg, inulin, fructooligosaccharides, and wheat dextrin) and insoluble fibers (eg, wheat bran) do not provide these viscosity-dependent health benefits. In the large bowel, there are only two mechanisms that drive a laxative effect: large/coarse insoluble fiber particles (eg, wheat bran) mechanically irritate the gut mucosa stimulating water and mucous secretion, and the high water-holding capacity of gel-forming soluble fiber (eg, psyllium) resists dehydration. Both mechanisms require that the fiber resist fermentation and remain relatively intact throughout the large bowel (ie, the fiber must be present in stool), and both mechanisms lead to increased stool water content, resulting in bulky/soft/easy-to-pass stools. Soluble fermentable fibers (eg, inulin, fructooligosaccharide, and wheat dextrin) do not provide a laxative effect, and some fibers can be constipating (eg, wheat dextrin and fine/smooth insoluble wheat bran particles). When making recommendations for a fiber supplement, it is essential to recognize which fibers possess the physical characteristics required to provide a beneficial health effect, and which fiber supplements are supported by reproducible, rigorous evidence of one or more clinically meaningful health benefits.

Effect of inulin-type fructans on blood lipid profile and glucose level: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND/OBJECTIVES

This systematic review and meta-analysis was performed to assess the effects of inulin-type fructans (ITF) on human blood lipids and glucose homeostasis associated with metabolic abnormalities, including dyslipidemia, overweight or obesity, and type-2 diabetes mellitus (T2DM).

SUBJECTS/METHODS

The MEDLINE, EMBASE and Cochrane Library databases were systematically searched for randomized controlled trials (RCTs) before January 2016. Human trials that investigated the effects of ITF supplementation on the lipid profile, fasting glucose and insulin were included using Review Manager 5.3.

RESULTS

Twenty RCTs with 607 adult participants were included in this systematic review and meta-analysis. In the overall analysis, the supplementation of ITF reduced only the low density lipoprotein-cholesterol (LDL-c) (mean difference (MD): -0.15; 95% confidence interval (CI): -0.29, -0.02; P=0.03) without affecting the other endpoints. Within the T2DM subgroup analysis, ITF supplementation was positively associated with a decreased fasting insulin concentration (MD: -4.01; 95% CI: -5.92, -2.09; P<0.0001) and increased high density lipoprotein-cholesterol (HDL-c) (MD: 0.07; 95% CI: 0, 0.14; P=0.05). Moreover, a reduced fasting glucose tendency was identified only in the T2DM subgroup (MD: -0.42; 95% CI: -0.90, 0.06; P=0.09). There was a potential publication bias, and few trials were available for the T2DM subgroup analysis.

CONCLUSIONS

In summary, the use of ITF may have benefits for LDL-c reduction across all study populations, whereas HDL-c improvement and glucose control were demonstrated only in the T2DM subgroup. Thus, additional, well-powered, long-term, randomized clinical trials are required for a definitive conclusion. Overall, ITF supplementation may provide a novel direction for improving the lipid profile and glucose metabolism.

Distant Site Effects of Ingested Prebiotics

The gut microbiome is being more widely recognized for its association with positive health outcomes, including those distant to the gastrointestinal system. This has given the ability to maintain and restore microbial homeostasis a new significance. Prebiotic compounds are appealing for this purpose as they are generally food-grade substances only degraded by microbes, such as bifidobacteria and lactobacilli, from which beneficial short-chain fatty acids are produced. Saccharides such as inulin and other fructo-oligosaccharides, galactooligosaccharides, and polydextrose have been widely used to improve gastrointestinal outcomes, but they appear to also influence distant sites. This review examined the effects of prebiotics on bone strength, neural and cognitive processes, immune functioning, skin, and serum lipid profile. The mode of action is in part affected by intestinal permeability and by fermentation products reaching target cells. As the types of prebiotics available diversify, so too will our understanding of the range of microbes able to degrade them, and the extent to which body sites can be impacted by their consumption.

Relationship between the Peroxidation of Leukocytes Index Ratio and the Improvement of Postprandial Metabolic Stress by a Functional Food

For the first time, we investigated the relationship between postprandial dysmetabolism and the Peroxidation of Leukocytes Index Ratio (PLIR), a test that measures the resistance of leukocytes to exogenous oxidative stress and their functional capacity of oxidative burst upon activation. Following a blind, placebo controlled, randomized, crossover design, ten healthy subjects ingested, in two different occasions, a high fat and high carbohydrates meal with Snello cookie (HFHCM-S) or with control cookies (HFHCM-C). Snello cookie, a functional food covered by dark chocolate and containing glucomannan, inulin, fructooligosaccharides, and Bacillus coagulans strain GanedenBC30, significantly improved postprandial metabolic stress (insulin, glucose, and triglycerides) and reduced the postprandial increase of uric acid. HFHCM-S improved PLIR of lymphocytes, but not of monocytes and granulocytes. Both meals increased granulocytes' count and reduced the lipoperoxidation induced by both exogenous free radicals and reactive oxygen species (ROS) produced by oxidative burst. Our results suggest that the healthy status of the subjects could be a limitation of this pilot study for PLIR evaluation on cells that produce ROS by oxidative burst. In conclusion, the relationship between PLIR and postprandial dysmetabolism requires further investigations.

The effects of beta-glucan rich oat bread on serum nitric oxide and vascular endothelial function in patients with hypercholesterolemia

INTRODUCTION

Oats are high in soluble fibers and effective in reducing the risk of cardiovascular diseases (CVD). We assessed the effects of beta-glucan from oat bran on serum nitric oxide (NO) endothelial function in patients with hypercholesterolemia.

METHOD

Sixty hypercholesterolemic patients were randomly divided to receive an experimental bread rich in beta-glucan from oat bran (intervention) or bread rich in wheat fiber (control) for four weeks. All subjects had the same diet for two-week baseline period and hypocaloric diet for four weeks of intervention. Serum NO concentration and flow-mediated dilation (FMD) were determined before and after the experiment.

RESULTS

Mean age of the participants was 51.1 ± 9.3 years and 65% (n = 39) were female. After intervention, serum NO concentration increased by 50.2 ± 19.8 μmol/lit in the intervention group (P = 0.017), but no change was observed in the control group (17.5 ± 27.5 μmol/lit; P = 0.530). No change of FMD was observed in the intervention (0.48 ± 0.78%; P = 0.546) or in the control group (0.59 ± 0.92%; P = 0.533).

CONCLUSION

Consumption of oat bread for four weeks increases serum NO concentration but has no effect on FMD. Further studies are warranted in this regard.

The effects of a diet rich in inulin or wheat fibre on markers of cardiovascular disease in overweight male subjects

BACKGROUND

Previous studies suggest that the beneficial health effects of a diet rich in whole grains could be a result of the individual fibres found in the grain. The present study aimed to investigate the influence of a diet high in either wheat fibre (as an example of an insoluble fibre) or inulin (a nondigestible carbohydrate) on markers of cardiovascular disease.

METHODS

Ten male participants classified as at higher risk of cardiovascular disease [mean (SD) body mass index 30.2 (3) kg m(-2) , mean (SD) waist circumference 106.4 (7) cm, mean (SD) age 39.8 (9) years] were recruited to a randomised, controlled, cross-over study comparing the consumption of bespoke bread rolls containing either inulin, wheat germ or refined grain (control) (15 g day(-1) ) for 4 weeks with a 4-week washout period between each regime. At the end of each regime, participants underwent an oral glucose tolerance test (OGTT), measures of pulse wave velocity (PWV), 24-h ambulatory blood pressure (AMBP), plasma lipid status and markers of glucose control.

RESULTS

There was no difference in measures of glucose control, lipid status, 24-h AMBP or PWV after the intervention periods and no changes compared to baseline. There was no significant difference between OGTT glucose and insulin time profiles; however, there was a significant difference in area under the curves between the wheat fibre and control interventions when comparing change from baseline (control +10.2%, inulin +4.3%, wheat fibre -2.5%; P = 0.03).

CONCLUSIONS

Only limited differences between the interventions were identified, perhaps as a consequence of the amount of fibre used and intervention length. The wheat germ intervention resulted in a significant reduction in glucose area under the curve, suggesting that this fibre may aid glucose control.

'The way to a man's heart is through his gut microbiota'--dietary pro- and prebiotics for the management of cardiovascular risk

The human gut microbiota has been identified as a possible novel CVD risk factor. This review aims to summarise recent insights connecting human gut microbiome activities with CVD and how such activities may be modulated by diet. Aberrant gut microbiota profiles have been associated with obesity, type 1 and type 2 diabetes and non-alcoholic fatty liver disease. Transfer of microbiota from obese animals induces metabolic disease and obesity in germ-free animals. Conversely, transfer of pathogen-free microbiota from lean healthy human donors to patients with metabolic disease can increase insulin sensitivity. Not only are aberrant microbiota profiles associated with metabolic disease, but the flux of metabolites derived from gut microbial metabolism of choline, phosphatidylcholine and l-carnitine has been shown to contribute directly to CVD pathology, providing one explanation for increased disease risk of eating too much red meat. Diet, especially high intake of fermentable fibres and plant polyphenols, appears to regulate microbial activities within the gut, supporting regulatory guidelines encouraging increased consumption of whole-plant foods (fruit, vegetables and whole-grain cereals), and providing the scientific rationale for the design of efficacious prebiotics. Similarly, recent human studies with carefully selected probiotic strains show that ingestion of viable microorganisms with the ability to hydrolyse bile salts can lower blood cholesterol, a recognised risk factor in CVD. Taken together such observations raise the intriguing possibility that gut microbiome modulation by whole-plant foods, probiotics and prebiotics may be at the base of healthy eating pyramids advised by regulatory agencies across the globe. In conclusion, dietary strategies which modulate the gut microbiota or their metabolic activities are emerging as efficacious tools for reducing CVD risk and indicate that indeed, the way to a healthy heart may be through a healthy gut microbiota.

Metabolic benefits of dietary prebiotics in human subjects: a systematic review of randomised controlled trials

Complex relationships exist between the gut microflora and their human hosts. Emerging evidence suggests that bacterial dysbiosis within the colon may be involved in the pathogenesis of the metabolic syndrome, type 2 diabetes and CVD. The use of dietary prebiotic supplements to restore an optimal balance of intestinal flora may positively affect host metabolism, representing a potential treatment strategy for individuals with cardiometabolic disorders. The present review aimed to examine the current evidence supporting that dietary prebiotic supplementation in adults has beneficial effects on biochemical parameters associated with the development of metabolic abnormalities including obesity, glucose intolerance, dyslipidaemia, hepatic steatosis and low-grade chronic inflammation. Between January 2000 and September 2013, eight computer databases were searched for randomised controlled trials published in English. Human trials were included if at least one group received a dietary prebiotic intervention. In the present review, twenty-six randomised controlled trials involving 831 participants were included. Evidence indicated that dietary prebiotic supplementation increased self-reported feelings of satiety in healthy adults (standardised mean difference -0.57, 95% CI -1.13, -0.01). Prebiotic supplementation also significantly reduced postprandial glucose (-0.76, 95% CI -1.41, -0.12) and insulin (-0.77, 95% CI -1.50, -0.04) concentrations. The effects of dietary prebiotics on total energy intake, body weight, peptide YY and glucagon-like peptide-1 concentrations, gastric emptying times, insulin sensitivity, lipids, inflammatory markers and immune function were contradictory. Dietary prebiotic consumption was found to be associated with subjective improvements in satiety and reductions in postprandial glucose and insulin concentrations. Additional evidence is required before recommending prebiotic supplements to individuals with metabolic abnormalities. Large-scale trials of longer duration evaluating gut microbial growth and activity are required.

Improvement of biochemical parameters in type 1 diabetic rats after the roots aqueous extract of yacon [Smallanthus sonchifolius (Poepp.& Endl.)] treatment

The aim of this study was to evaluate the effect of yacon (Smallanthus sonchifolius) (Poepp.& Endl.) on clinical parameters under diabetic conditions. The aqueous extract of yacon tuberous roots (YRAE; 0.76 g fructan kg⁻¹ body weight) was prepared at the moment of each administration. Thirty-two male rats were divided into four groups (n=8): control group (C); group that received YRAE (Y); untreated diabetic group (DM1); and diabetic group treated with YRAE (Y-DM1). The diabetes mellitus was induced by streptozotocin (60 mg kg⁻¹ body weight). The animals from Y2 and Y-DM1 received YRAE by gavage, at 7-day intervals, for 30 days. The aqueous extract of yacon roots decreased (p<0.05) the water and food intake in diabetic rats (Y-DM1). YRAE treatment reduced (p<0.05) glycaemia, total cholesterol, VLDL-c, LDL-c and triacylglycerol levels in diabetic rats (YRAE). HDL, urea and creatinine levels did not differ (p>0.05) between the Y and Y-DM1 groups. YRAE normalised alanine aminotransferase (ALT) activity, when comparing DM1 and Y-DM1 rats, but had no effect on lactate dehydrogenase activity (LDH). In conclusion, YRAE was sufficient for controlling water and food consumption, hyperglycaemia and dyslipidaemia, and promote the reduction of the ALT, suggesting a hepatoprotective effect in rats with STZ-induced DM1.

Effects of a diet with inulin-enriched pasta on gut peptides and gastric emptying rates in healthy young volunteers

AIM

Our group has previously shown that the administration of pasta enriched along with the prebiotic inulin induces a significant reduction in triglyceride and glucose levels with a significant delay in gastric emptying (GE) rates. This protective effect may occur by affecting the release of a number of gut peptides involved in the control of gastrointestinal motility. The aim of the present study was to evaluate the effects of inulin-enriched pasta on the circulating levels of neurotensin (NT), somatostatin (SS), and corticotropin-releasing factor (CRF) in relation to the GE time in young healthy subjects.

METHODS

Twenty healthy young male volunteers completed a randomized double-blind crossover study consisting of a 2-week run-in period and two 5-week study periods (11% inulin-enriched/control pasta), with an 8-week wash-out period in between. Gut peptide concentrations were evaluated by radioimmunoassay. GE time was evaluated by ultrasonography.

RESULTS

The prebiotic treatment significantly increased the area under the curve (AUC) values of both NT and SS (p < 0.05 Dunn's post-test). With regard to gastric motility, along with a significant delay in both the final time and T (1/2) gastric emptying time, a positive correlation was found between T (1/2) and SS AUC values (r = 0.57, p = 0.009) in the inulin-enriched pasta group.

CONCLUSION

These results support the hypothesis that inulin plays an active role in mechanisms affecting the release of these gut peptides, which may modulate the gastric emptying of digesta.