Psyllium improves dyslipidaemia, hyperglycaemia and hypertension, while guar gum reduces body weight more rapidly in patients affected by metabolic syndrome following an AHA Step 2 diet

The effect of psyllium on fasting blood sugar, HbA1c, HOMA IR, and insulin control: a GRADE-assessed systematic review and meta-analysis of randomized controlled trials

There is equivocal evidence that psyllium can prevent or attenuate increases in fasting blood sugar. Therefore, this systematic review and meta-analysis sought to investigate the influence of psyllium on hemoglobin A1C (HbA1c), fasting blood sugar (FBS), insulin, and Homeostatic Model Assessment of Insulin Resistance (HOMA IR). We searched PubMed, ISI Web of Science (WOS), and Scopus for eligible publications, up to 15 July 2022, including randomized controlled trials (RCT) assessing the effect of psyllium on HbA1c, FBS, insulin, and HOMA IR levels in adults. Using a random effects model, we report the weighted mean differences (WMD) with 95% confidence intervals (CI). In this article, 19 RCT studies, consisting of 962 participants, were included. Psyllium significantly decreased FBS, HbA1c, and HOMA IR levels, but not insulin levels, as compared to placebo (FBS: WMD): -6.89; 95% CI: -10.62, -3.16; p < .001), HbA1c: (WMD: -0.75; 95% CI: -1.21, -0.29; p < .001), HOMA IR: (WMD: -1.17; 95% CI: -2.11, -0.23; p < .05), and insulin: (WMD: -2.08; 95% CI: -4.21, -0.035; p > .05)). Subgroup analyses illustrated differences in the effects of psyllium on FBS: dosages less than and more than 10 g/d showed significant differences (p value < 0.05). However, it was not significant in intervention durations less than 50 days (p value > 0.05). For HbA1c: psyllium consumption less than 10 g/d (p value > 0.05) was non-significant. For HOMA IR and insulin: no significant changes were noted with psyllium consumption less than vs. more than 10 g/d. In conclusion, we found that psyllium could significantly decrease FBS, HbA1c, and HOMA IR levels, but not insulin levels, as compared to placebo.

Plantago consumption significantly reduces total cholesterol and low-density lipoprotein cholesterol in adults: A systematic review and meta-analysis

Plantago is rich in soluble fiber, known for its beneficial health effects. Given this, we hypothesized that Plantago consumption might positively influence blood lipid in adults. Researchers have conducted numerous randomized controlled trials (RCTs), revealing the impacts of Plantago consumption on various blood lipid parameters. However, findings regarding specific blood lipid parameters have shown variability. This study aimed to comprehensively assess the effect of Plantago consumption on blood lipid parameters. Eligible studies evaluating the effects of Plantago consumption on blood lipid were searched in 5 electronic databases published up to August 2023. Analysis used a random effects model to determine weighted mean difference and 95% confidence intervals. In total, 29 RCTs including 2769 participants were included. Compared with the control group, Plantago consumption significantly reduced total cholesterol (TC) by 0.28 mmol/L and low-density lipoprotein cholesterol (LDL-C) by 0.35 mmol/L, correlating to an estimated 7% decrease in cardiovascular event risk. Conversely, no substantial effects were observed on high-density lipoprotein cholesterol or triglycerides. Subgroup analyses of 29 RCTs revealed that TC concentrations were significantly lowered in studies that included male participants, those who were healthy, or had lipid disorders. Additionally, TC and LDL-C were significantly lower in participants consuming Plantago husk or psyllium, and soluble fiber intake was specifically effective in lowering TC, LDL-C, and triglycerides. In conclusion, Plantago consumption can significantly lower TC and LDL-C concentrations. The findings will provide crucial insights into the potential of Plantago in dietary strategies for blood lipid management.

Psyllium is a natural nonfermented gel-forming fiber that is effective for weight loss: A comprehensive review and meta-analysis

BACKGROUND

Psyllium is a natural, predominantly soluble fiber that forms a viscous gel when hydrated and is not digested or fermented. In the small intestine, psyllium gel increases chyme viscosity, slowing the degradation and absorption of nutrients. Psyllium has a significant effect in patients with metabolic syndrome and type-2 diabetes on glycemic control, while lowering serum cholesterol in hypercholesterolemic patients. Some randomized controlled studies have shown that psyllium also facilitates weight loss in overweight and obese participants.

OBJECTIVES

A comprehensive review and meta-analysis assessing psyllium's impact on body weight, body mass index (BMI), and waist circumference in overweight and obese participants.

DATA SOURCES

A comprehensive search was performed (Medline, Scopus, Cochrane Database) through March 21, 2022, using search terms to identify randomized, controlled, clinical studies designed to assess weight loss in overweight and obese participants over at least 2 months. Data were analyzed using the inverse variance method with random effects models.

CONCLUSIONS

Six studies meeting inclusion criteria were identified (total n = 354). The meta-analysis showed that psyllium, dosed just before meals (mean dose 10.8 g/day, mean duration 4.8 months), was effective for decreasing body weight (MD = -2.1 kg [95% confidence interval [CI]: -2.6 to -1.6]; p < .001), BMI (MD = -0.8 kg/m2 [95% CI: -1.0 to -0.6]; p < .001) and waist circumference (MD = -2.2 cm [95% CI: -2.9 to -1.4]; p < .001) in overweight and obese populations.

IMPLICATIONS FOR PRACTICE

Gel-forming nonfermented psyllium fiber, dosed just before meals, is effective in facilitating weight loss in overweight and obese participants.

The effects of guar gum supplementation on glycemic control, body mass and blood pressure in adults: A GRADE-assessed systematic review and meta-analysis of randomized clinical trials

BACKGROUND

This systematic review and meta-analysis sought to evaluate the effects ofguar gum supplementation on glycemic control, blood pressure, and body mass in adults.

METHODS

Relevant studies were obtained by searching the PubMed, SCOPUS, Embase, and Web of Science databases (from inception to January 2022). Weighted mean differences (WMD) and 95% confidence intervals (CIs) were pooled using a random-effects model. Heterogeneity, sensitivity analysis, and publication bias were reported using standard methods.

RESULTS

Pooled analysis of 14 randomized controlled trials (RCTs) revealed that guar gum supplementation led to significant reductions in hemoglobin A1c (HbA1c) (WMD: -0.47 mg/dL, 95% CI: -0.75, -0.18, p = 0.001). However, there was no effect on fasting blood sugar (FBS), systolic and diastolic blood pressure, and body mass among adults in comparison with the control group. A subgroup analysis demonstrated that intervention in patients with type 2 diabetes (T2DM), and high supplementation dosages (>15 g/d) significantly decreased FBS concentrations, but not in other subgroups.

CONCLUSION

Guar gum supplementation may yield a beneficial effect on glycemic control in T2DM patients. However, the extant clinical trials, thus far, are not sufficient enough to form guidelines for clinical practice.

The effect of gum consumption on blood pressure as a risk factor for coronary heart disease: A meta-analysis of controlled trials

Guar gum has been used in the management of hypercholesterolemia, constipation, weight loss, type 2 diabetes mellitus and hypertension. Our aim was to verify the hypothesis that Guar gum can be used as an alternative to pharmacological agents in the treatment of mild hypertension. Thus, we conducted a systematic review and meta-analysis to evaluate the effectiveness of Guar gum in reducing blood pressure. We searched the Cochrane Library, PubMed/Medline, Scopus and Google Scholar databases for studies published in the English language up to June 2020 which evaluated the effects of gum consumption on systolic blood pressure (SBP) and diastolic blood pressure (DBP). Nine randomized clinical trials with suitable comparison groups (placebo/control) reported SBP and DBP as outcome measures. These trials involved in total 640 participants. The overall results indicated that the consumption of gum resulted in a significant change in SBP (WMD: -1.190 mmHg, 95% CI: -2.011, -0.370) and DBP (WMD: -1.101 mmHg, 95% CI: -1.597, -0.605). Moreover, the greatest reduction in blood pressure was seen in patients with type 2 diabetes mellitus and metabolic syndrome who consumed Guar gum (WMD: -3.375 mmHg). In addition, there was a significant decrease in SBP if the gum dosage was > 15 g (WMD: -6.637 mmHg) and if the intervention duration was > 12 weeks (WMD: -1.668 mmHg). The results of the present dose-response meta-analysis support the employment of gum consumption in the reduction of SBP and DBP. Based on the sub-group analyses, we highlight that the greatest decrease in SBP was experienced if the gum dosage was > 15 g and when the intervention lasted > 12 weeks.

The role of selected nutraceuticals in management of prediabetes and diabetes: An updated review of the literature

Dysglycemia is a disease state preceding the onset of diabetes and includes impaired fasting glycemia and impaired glucose tolerance. This review aimed to collect and analyze the literature reporting the results of clinical trials evaluating the effects of selected nutraceuticals on glycemia in humans. The results of the analyzed trials, generally, showed the positive effects of the nutraceuticals studied alone or in association with other supplements on fasting plasma glucose and post-prandial plasma glucose as primary outcomes, and their efficacy in improving insulin resistance as a secondary outcome. Some evidences, obtained from clinical trials, suggest a role for some nutraceuticals, and in particular Berberis, Banaba, Curcumin, and Guar gum, in the management of prediabetes and diabetes. However, contradictory results were found on the hypoglycemic effects of Morus, Ilex paraguariensis, Omega-3, Allium cepa, and Trigonella faenum graecum, whereby rigorous long-term clinical trials are needed to confirm these data. More studies are also needed for Eugenia jambolana, as well as for Ascophyllum nodosum and Fucus vesiculosus which glucose-lowering effects were observed when administered in combination, but not alone. Further trials are also needed for quercetin.

Effect of Psyllium husk fiber and lifestyle modification on human body insulin resistance

Insulin resistance is a metabolic disorder that is increasing worldwide and is associated with some of the most common diseases affecting modern societies including diabetes, hypertension, obesity, and coronary heart disease. Changes in diet and physical activity have a profound effect on lowering the risk and cost of managing insulin resistance compared to the pharmacological approach. An interventional study of 16 weeks explored the effect of Psyllium husk fiber in combination with lifestyle modification on insulin resistance among the centrally obese school teachers of district Malakand Khyber Pakhtunkhwa. One Hundred twenty school teachers with central obesity, aged 40-60 years, with no chronic disease history were divided into four subgroups (n = 30) with equal gender bifurcation; a control group, lifestyle modification (LSM) group, psyllium husk fiber (PSH) group, and the combined intervention of LSM & PSH group. Fasting serum was collected to analyze fasting blood glucose, and insulin resistance by using the HOMA-IR method at baseline and post-intervention. A significant effect of the intervention was observed on fasting blood glucose. The combined group of LSM&PSH showed the highest mean change of -7.5 ± 2.6 mg/dl (-9%), followed by the PSH group with a mean change of -6.3 ± 2.1 mg/dl, (-7%). Likewise a significant effect (P < 0.05) on HOMA-IR was observed in the combined group of LSM&PSH with a mean of 1.02 ± 0.14 molar units (-58%), followed by the PSH group with a mean of 1.55 ± 0.14 molar units (-33%). The current study was carried out to assess the effect of regular consumption of Psyllium husk fiber in combination with lifestyle modification on insulin resistance and fasting blood glucose.

Prolonged Isolated Soluble Dietary Fibre Supplementation in Overweight and Obese Patients: A Systematic Review with Meta-Analysis of Randomised Controlled Trials

The prevalence of overweight and obesity is rising rapidly, currently affecting 1.9 billion adults worldwide. Prebiotic dietary fibre supplementation is a promising approach to improve weight loss and reduce metabolic complications in overweight and obese subjects due to modifications of the microbiota composition and function. Previous systematic reviews and meta-analyses addressing similar questions revealed discordant evidence and/or are outdated. We searched MEDLINE, Embase, Google Scholar, and forward and backward citations for randomised controlled trials (RCTs) with isolated soluble dietary fibre supplementation for at least 12 weeks in overweight and obese patients measuring body weight, published through April 2022. We expressed the results as mean differences (MDs) using the random-effects model of the metafor package in R and assessed risk of bias using the Cochrane RoB2 tool. We conducted the study according to the PRISMA guidelines and registered the protocol on PROSPERO (CRD42022295246). The participants with dietary fibre supplementation showed a significantly higher reduction in body weight (MD −1.25 kg, 95% CI −2.24, −0.25; 27 RCTs; 1428 participants) accompanied by a significant decrease in BMI, waist circumference, fasting blood insulin, and HOMA-IR compared to the control group. Certainty of evidence was high, paving the way for the implementation of isolated soluble dietary fibre supplementation into clinical practice.

Multi-Omic Analyses Reveal Bifidogenic Effect and Metabolomic Shifts in Healthy Human Cohort Supplemented With a Prebiotic Dietary Fiber Blend

Dietary fiber, a nutrient derived mainly from whole grains, vegetables, fruits, and legumes, is known to confer a number of health benefits, yet most Americans consume less than half of the daily recommended amount. Convenience and affordability are key factors determining the ability of individuals to incorporate fiber-rich foods into their diet, and many Americans struggle to access, afford, and prepare foods rich in fiber. The objective of this clinical study was to test the changes in microbial community composition, human metabolomics, and general health markers of a convenient, easy to use prebiotic supplement in generally healthy young participants consuming a diet low in fiber. Twenty healthy adults participated in this randomized, placebo-controlled, double-blind, crossover study which was registered at clinicaltrials.gov as NCT03785860. During the study participants consumed 12 g of a prebiotic fiber supplement and 12 g of placebo daily as a powder mixed with water as part of their habitual diet in randomized order for 4 weeks, with a 4-week washout between treatment arms. Fecal microbial DNA was extracted and sequenced by shallow shotgun sequencing on an Illumina NovaSeq. Plasma metabolites were detected using liquid chromatography–mass spectrometry with untargeted analysis. The phylum Actinobacteria, genus Bifidobacterium, and several Bifidobacterium species (B. bifidum, B. adolescentis, B. breve, B. catenulatum, and B. longum) significantly increased after prebiotic supplementation when compared to the placebo. The abundance of genes associated with the utilization of the prebiotic fiber ingredients (sacA, xfp, xpk) and the production of acetate (poxB, ackA) significantly changed with prebiotic supplementation. Additionally, the abundance of genes associated with the prebiotic utilization (xfp, xpk), acetate production (ackA), and choline to betaine oxidation (gbsB) were significantly correlated with changes in the abundance of the genus Bifidobacterium in the prebiotic group. Plasma concentrations of the bacterially produced metabolite indolepropionate significantly increased. The results of this study demonstrate that an easy to consume, low dose (12 g) of a prebiotic powder taken daily increases the abundance of beneficial bifidobacteria and the production of health-promoting bacteria-derived metabolites in healthy individuals with a habitual low-fiber diet.

Effects of Laser Irradiation at 488, 514, 532, 552, 660, and 785 nm on the Aqueous Extracts of Plantago lanceolata L.: A Comparison on Chemical Content, Antioxidant Activity and Caco-2 Viability

In this study, six laser radiation (488 nm/40 mW, 514 nm/15 mW, 532 nm/20 mW, 552 nm/15 mW, 660 nm/ 75 mW, and at 785 nm/70 mW) were tested on the aqueous extracts of leaves of Plantago lanceolata L. to compare extraction efficacy and antioxidant and cell viability effects in vitro. Briefly, in comparison with the control extract, laser extracts at 488, 514, 532, and 552 nm revealed small acquisitions of total extractible compounds in samples (up to 6.52%; laser extracts at 488 and 532 nm also revealed minerals and micro-elements increases (up to 6.49%); the most prominent results were obtained upon Fe (up to 38%, 488 nm), Cr (up to 307%, 660 nm), and Zn (up to 465%, 532 nm). Laser extracts at 488, 514, 552, and 785 nm proved more intense antioxidant capacity than the control sample, while laser extract at 660 nm indicated clear pro-oxidant effects. Caco-2 cells study indicated stimulatory activity for the extracts at 488 nm, no effects at 532 nm, and the decrease of the cell viability in the case of extracts at 660 nm respectively. Further studies are necessary to understand the pro-oxidant effects observed in the case of extracts exposed to laser radiation at 660 nm.

Effects of guar gum supplementation on the lipid profile: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND AND AIMS

Guar gum can be used as an adjuvant in the treatment of dyslipidemia. However, based on data from different studies, the effectiveness of this product is not uniform. Therefore, we conducted a dose-response meta-analysis between guar gum supplementation and lipid profile.

METHODS AND RESULTS

Five databases (Scopus, Web of Science, PubMed/Medline, Embase, and Google Scholar) were searched to identify relevant articles published up to July 2020. The weighted mean difference (WMD) was derived based on the random-effects model. Overall findings were generated from 25 eligible trials. Patients' conditions included hyperlipidemia, diabetes, metabolic syndrome, hypertension, overweight, carotid endarterectomy, and menopausal women. Prescribed gum dose varied between 100 mg/d and 30 g/d for 1-24 months. Compared with control groups, guar gum supplementation decreased total cholesterol (TC) by -20.41 mg/dL (95% CI: -26.76 to -14.07; P < 0.001) and low-density lipoprotein-cholesterol (LDL-C) by -17.37 mg/dL (95% CI: -23.60 to -11.13; P < 0.001), but did not change triglycerides (TG) (WMD: -6.53 mg/dL, 95% CI: -16.03 to 2.97; P = 0.178) and high-density lipoprotein-cholesterol (HDL-C) (WMD: -0.62 mg/dL, 95% CI: -1.68 to 0.44, P = 0.252).

CONCLUSIONS

Guar gum supplementation significantly reduced serum LDL-C and TC levels in patients with cardiometabolic problems, but had neutral effects on TG and HDL-C levels.

Psyllium husk intake and risk of type 2 diabetes: an evidence-based scientific and regulatory review of a qualified health claim conducted by the US Food and Drug Administration

The US Food and Drug Administration (FDA) received a petition from a company requesting that FDA issue an authorized health claim for the relationship between psyllium husk and a reduced risk of type 2 diabetes. After an initial assessment of the available scientific evidence, FDA determined that significant scientific agreement was lacking for this substance-disease relationship, whereupon the company agreed to have its petition reviewed as a qualified health claim. This article describes the process FDA used in conducting an evidence-based review of the science underpinning the proposed claim and addresses certain safety issues associated with psyllium husk that FDA considered in its review of the petition. Of the 6 studies from which scientific conclusions could be drawn, as identified through FDA's review, psyllium husk significantly improved plasma glucose levels and insulin sensitivity in only 1 study. Therefore, FDA's enforcement discretion letter for this qualified health claim stated: "Psyllium husk may reduce the risk of type 2 diabetes, although the FDA has concluded that there is very little scientific evidence for this claim."

A Guide to Recommending Fiber Supplements for Self-Care

The health benefits of dietary fiber are extensive and wide-ranging, yet most Americans do not consume the recommended amount of fiber from their diet. Fiber supplements may be used as a means to augment a low-fiber diet. But which, if any, of the benefits of dietary fiber are achieved through supplementation? And are all fiber supplements equally effective? An evidence-based approach to recommending fiber supplements for self-care will be discussed.

Can dietary viscous fiber affect body weight independently of an energy-restrictive diet? A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

The role of dietary fiber in obesity management remains debatable. Evidence suggests that intake of viscous fiber may have the potential to facilitate weight loss.

OBJECTIVE

We aimed to summarize and quantify the effects of viscous fiber on body weight, BMI, waist circumference, and body fat, independent of calorie restriction, through a systematic review and meta-analysis of randomized controlled trials.

METHODS

Trials ≥4 wk in duration that assessed the effect of viscous fiber supplemented to an ad libitum diet along with comparator diets were included. MEDLINE, EMBASE, and the Cochrane library were searched through 24 July, 2019. Two independent reviewers extracted relevant data. Data were pooled using the generic inverse variance method and random-effects models and expressed as mean differences with 95% CIs. Interstudy heterogeneity was assessed (Cochran Q statistic) and quantified (I2 statistic). The overall certainty of evidence was explored using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) approach.

RESULTS

Findings from 62 trials (n = 3877) showed that viscous fiber reduced mean body weight (-0.33 kg; 95% CI: -0.51, -0.14 kg; P = 0.004), BMI (in kg/m2) (-0.28; 95% CI: -0.42, -0.14; P = 0.0001), and waist circumference (-0.63 cm; 95% CI: -1.11, -0.16 cm; P = 0.008), with no change in body fat (-0.78%; 95% CI: -1.56%, 0.00%; P = 0.05) when consumed with an ad libitum diet. Greater reductions in body weight were observed in overweight individuals and those with diabetes and metabolic syndrome. The certainty of evidence was graded moderate for body weight, high for waist circumference and body fat, and low for BMI.

CONCLUSIONS

Dietary viscous fiber modestly yet significantly improved body weight and other parameters of adiposity independently of calorie restriction. Future trials are warranted to address the inconsistency and imprecision identified through GRADE and to determine long-term weight-loss sustainability.This systematic review and meta-analysis was registered at clinicaltrials.gov as NCT03257449.

Physical effects of dietary fibre on simulated luminal flow, studied by in vitro dynamic gastrointestinal digestion and fermentation

During the transit through the gastrointestinal tract, fibre undergoes physical changes not usually included in in vitro digestion studies even though they influence nutrient diffusion and might play a role in gut microbiota growth. The aim of this study was to evaluate how physical fibre properties influence the physical properties of gastrointestinal fluids using a gastrointestinal model (stomach, small intestine, ascending colon, transverse colon, and descending colon) (simgi®). Analysis by rheological and particle size characterisation, microbiota composition and short-chain fatty acid (SCFA) determination allows the achievement of this goal. First, the water-holding capacity (WHC), microstructure, and viscosity of eight different fibres plus agar were tested. Based on the results, potato fibre, hydroxypropyl methylcellulose (HPMC), psyllium fibres, and agar (as a control) were selected for addition to a medium growth (GNMF) that was used to feed the stomach/small intestine and colon compartments in the simgi®. During gastrointestinal digestion, GNMF was collected at 5, 30 and 55 minutes of processing at the gastric stage and after the intestinal stage. Then, samples of GNMF with faecal slurry were collected at 0, 24 and 48 h of colonic fermentation. Results showed fibre-dependence on apparent viscosity. Although psyllium was partially broken down in the stomach (decrease in particle size), it was the most viscous at the colonic stage, opposite to the potato fibre, but both led to the highest total SFCA and acetic acid production profile. On a microbiological level, the most relevant increase of bacterial growth was observed in the faecal Lactobacillus species, especially for HPMC and potato fibre, that were not digested until reaching the colon. Besides fibre fermentability, viscosity also influenced microbial growth, and it is necessary to characterise these changes to understand fibre functionality.

A Randomized Controlled Trial of a Herbal Compound for Improving Metabolic Parameters in Diabetic Patients with Uncontrolled Dyslipidemia

Objective:

The aim of this randomized controlled trial was to investigate the effects of a polyherbal compound consisting of Aloe vera, black seed, fenugreek, garlic, milk thistle, and psyllium on diabetic patients with uncontrolled dyslipidemia.

Methods:

Fifty patients with type 2 diabetes who had dyslipidemia in spite of statin therapy were randomly allocated to two groups: control group (n = 25) receiving a conventional therapy with hypolipidemic and hypoglycemic drugs and intervention group (n = 25) receiving both the conventional therapy and the herbal compound (one sachet twice daily) for 12 weeks. Each sachet contained 300 mg of Aloe vera leaf gel, 1.8 g of black seed, 300 mg of garlic, 2.5 g of fenugreek seed, 1 g of psyllium seed, and 500 mg of milk thistle seed.

Results:

The levels of serum triglyceride, total cholesterol, low-density lipoprotein, and HbA1c showed a significant in-group improvement in the intervention group. However, the effects of the herbal compound on fasting blood glucose remained insignificant. The compound had no unwanted effect on the kidney function parameters (urea, creatinine) and serum liver enzymes (alanine aminotransferase and aspartate transaminase).

Conclusion:

The tested herbal compound, as an add-on to statin therapy, was effective in lowering the serum lipids in diabetic patients with uncontrolled dyslipidemia.

Should Viscous Fiber Supplements Be Considered in Diabetes Control? Results From a Systematic Review and Meta-analysis of Randomized Controlled Trials

OBJECTIVE

Evidence from randomized controlled trials (RCTs) suggests that viscous dietary fiber may offer beneficial effects on glycemic control and, thus, an improved cardiovascular disease risk profile. Our purpose was to conduct a systematic review and meta-analysis of RCTs to synthesize the therapeutic effect of viscous fiber supplementation on glycemic control in type 2 diabetes.

RESEARCH DESIGN AND METHODS

MEDLINE, Embase, and Cochrane Central Register of Controlled Trials were searched through 15 June 2018. We included RCTs ≥3 weeks in duration that assessed the effects of viscous fiber on markers of glycemic control in type 2 diabetes. Two independent reviewers extracted data. Data were pooled using the generic inverse variance method and expressed as mean differences (MD) with 95% CIs. Heterogeneity was assessed (Cochran Q statistic) and quantified (I ² statistic). The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach was used to evaluate the overall certainty of the evidence.

RESULTS

We identified 28 eligible trial comparisons (n = 1,394). Viscous fiber at a median dose of ∼13.1 g/day significantly reduced HbA_1c (MD -0.58% [95% CI -0.88, -0.28]; P = 0.0002), fasting blood glucose (MD -0.82 mmol/L [95% CI -1.32, -0.31]; P = 0.001), and HOMA-insulin resistance (IR) (MD -1.89 [95% CI -3.45, -0.33]; P = 0.02) compared with control and in addition to standard of care. The certainty of evidence was graded moderate for HbA_1c, fasting glucose, fasting insulin, and HOMA-IR and low for fructosamine.

CONCLUSIONS

Viscous fiber supplements improve conventional markers of glycemic control beyond usual care and should be considered in the management of type 2 diabetes.

The effects of psyllium supplementation on body weight, body mass index and waist circumference in adults: A systematic review and dose-response meta-analysis of randomized controlled trials

Background: Previous studies reported inconsistent findings regarding the effects of psyllium supplementation on obesity measures. This systematic review and meta-analysis was performed to summarize data from available randomized clinical trials (RCTs) on the effect of psyllium supplementation on body weight, body mass index (BMI), and waist circumference (WC) in adults.Methods: PubMed, SCOPUS, Cochrane Library, and Google Scholar were searched to identify relevant articles up to August 2018. The effect sizes were presented as weighted mean difference (WMD) and 95% confidence intervals (CI) by using random effects model. To detect dose-response relationships, we used fractional polynomial modeling.Results: A total of 22 RCTs were included. Meta-analysis did not find any significant effect of psyllium supplementation on body weight (MD: -0.28 kg, 95% CI: -0.78, 0.21, p = 0.268), BMI (MD: -0.19 kg/m², 95% CI: -0.55, 0.15, p = 0.27) and WC (MD: -1.2 cm, 95% CI: -2.6, 0.2, p = 0.09). Subgroup analysis showed that psyllium dosage, kind of psyllium administration, duration of trial, study design, sample size, and gender were potential sources of heterogeneity. Moreover, there was nonlinear association between duration of psyllium consumption, BMI and WC.Conclusion: Psyllium supplementation does not reduce body weight, BMI, and WC significantly.

Dietary Fiber Is Independently Related to Blood Triglycerides Among Adults with Overweight and Obesity

BACKGROUND

Metabolic syndrome (MetS), a cluster of visceral adiposity-related risk factors, affects approximately 35% of the United States population. Although improvement in diet quality is an important approach to reducing MetS risk, the role of particular dietary components remains unclear, especially among younger adults. Individual dietary components have been implicated in ameliorating or exacerbating MetS risk; however, the extent to which these factors contribute to MetS prevention has received little attention.

OBJECTIVE

This cross-sectional study aimed to assess relations between diet and individual MetS components in young to middle-aged adults who are overweight and/or obese.

METHODS

Participants aged 25-45 y (N = 117) with overweight and obesity, but no other diagnosed metabolic disease, recorded dietary intake over 7 d. MetS components (waist circumference, blood pressure, glucose, triglycerides [TGs], and high-density lipoprotein cholesterol [HDL]) were measured. Visceral adipose tissue was measured by dual-energy X-ray absorptiometry. Linear regression was used to assess relations between diet and MetS risk factors, adjusting for age, sex, and visceral adipose tissue.

RESULTS

MetS prevalence in this sample was 32%. Energy-adjusted total fiber intake (β = -0.21, P = 0.02) was inversely associated with TG concentrations. No significant relations were observed between other dietary factors and MetS components. These findings indicate that among MetS components, TG concentrations are potentially sensitive to fiber consumption.

CONCLUSIONS

These results provide cross-sectional evidence supporting the protective influence of dietary fiber on MetS components among young to middle-aged adults. Additional, well-designed clinical trials are needed to assess the causal relations between various types of dietary fiber and metabolic disease.

Effect of psyllium (Plantago ovata) fiber on LDL cholesterol and alternative lipid targets, non-HDL cholesterol and apolipoprotein B: a systematic review and meta-analysis of randomized controlled trials

Background

Studies have identified viscous dietary fiber as potentially attenuating cholesterol, including psyllium, which reduces LDL cholesterol and thus may complement cardiovascular disease (CVD) treatment.

Objectives

The aims of this study were to update evidence on the effect of psyllium on LDL cholesterol and to provide an assessment of its impact on alternate markers: non-HDL cholesterol and apolipoprotein B (apoB).

Design

Medline, EMBASE, CINAHL, and the Cochrane Central Register of Controlled Trials were searched through 3 October 2017. Independent reviewers extracted relevant data and assessed risk of bias. We included randomized controlled trials with a duration of ≥3 wk that assessed the effect of psyllium on blood lipids in individuals with or without hypercholesterolemia. Data were pooled by using the generic inverse variance method with random-effects models and expressed as mean differences (MDs) with 95% CIs. Heterogeneity was assessed by Cochran's Q statistic and quantified by the I2 statistic. Overall quality of the evidence was assessed by using the GRADE (Grading of Recommendations Assessment, Development, and Evaluation) approach.

Results

We included 28 trials in our analysis (n = 1924). Supplementation of a median dose of ∼10.2 g psyllium significantly reduced LDL cholesterol (MD = -0.33 mmol/L; 95% CI: -0.38, -0.27 mmol/L; P < 0.00001), non-HDL cholesterol (MD = -0.39 mmol/L; 95% CI: -0.50, -0.27 mmol/L; P < 0.00001), and apoB (MD = -0.05 g/L; 95% CI: -0.08, -0.03 g/L; P < 0.0001). Effect estimates for LDL cholesterol and non-HDL cholesterol were graded as moderate quality on the basis of downgrades for inconsistency and graded as high quality for apoB.

Conclusion

Psyllium fiber effectively improves conventional and alternative lipids markers, potentially delaying the process of atherosclerosis-associated CVD risk in those with or without hypercholesterolemia. This trial is registered at www.clinicaltrials.gov as NCT03346733.

Effects of psyllium vs. placebo on constipation, weight, glycemia, and lipids: A randomized trial in patients with type 2 diabetes and chronic constipation

OBJECTIVE

To compare the effects of baked psyllium supplementation versus those who received a placebo on constipation symptoms, body weight, glycemic and lipids control in patients with type 2 diabetes (T2D) and chronic constipation.

METHODS

In a single-blinded, randomized controlled trial, 51 patients with T2D and chronic constipation with body mass index (BMI) 20-47 kg/m² received either 10 g of psyllium pre-mixed in cookies twice per day or placebo cookies for 12 weeks. Constipation symptoms, body mass index (BMI), fasting plasma glucose (FPG), glycosylated hemoglobin (HbA1c), and lipid profile were determined at the beginning and end of 4, 8, and 12-week period. Constipation was evaluated with a stool diary (ROME III).

RESULTS

The psyllium group showed improvement in constipation symptoms, body weight, glucose and lipid values compared with the baseline and the placebo group. Body weight and FPG decreased from baseline in the psyllium group (P < 0.001 and P = 0.056, respectively). The differences (95% CI) of absolute change of body weight (-2.0 (-3.0, -1.0) kg; P < 0.001), FPG (-13.6 (-24.3, -2.9) mg/dl; P = .040), and HbA1c (-1.7 (-2.9, -0.5)); P = 0.002) between the groups were statistically significant. Cholesterol (-21.5 (-25.6, -14.4); P < 0.001), triglycerides (-20.0 (-32.3, -7.7); P = 0.021) and constipation symptoms (1.5 (0.4, 2.3); P < 0.001) decreased in the psyllium group. The compliance was good and no adverse effects were observed.

CONCLUSION

In patients with T2D and chronic constipation, psyllium supplementation decreased constipation symptoms, body weight, glycemic, cholesterol, and increased HDLC levels.

Effects on oral fat load of a nutraceutical combination of fermented red rice, sterol esters and stanols, curcumin, and olive polyphenols: A randomized, placebo controlled trial

BACKGROUND

In literature, there are several studies about the effects of nutraceutical combinations at fasting, but data in post-prandial phase are lacking.

PURPOSE

We planned a study to evaluate the efficacy and safety of a nutraceutical agent containing fermented red rice, phytosterols and olive polyphenols compared to placebo in a sample of Caucasian patients with low cardiovascular risk, both at fasting and after an oral fat load.

STUDY DESIGN

Eighty patients were randomized to receive, as addition to diet and physical activity, a nutraceutical combination containing fermented red rice, sterol esters and stanols, curcumin, and olive polyphenols or placebo (control group), once a day.

METHODS

We evaluated at baseline, and after 3 months: body mass index, fasting plasma glucose, lipid profile, soluble intercellular adhesion molecule-1, soluble vascular cell adhesion molecule-1, and soluble endothelial-leukocyte adhesion molecule-1. We evaluated these parameters both at fasting, and after an oral fat load.

RESULTS

Nutraceutical combination gave a reduction of total cholesterol, triglycerides, and low-density lipoprotein cholesterol, both compared to baseline (p < 0.05 for all), and to placebo (p < 0.05 for all). We recorded a reduction of soluble intercellular adhesion molecule-1, soluble vascular cell adhesion molecule-1, and sE-selectin in the group treated with nutraceutical combination, both compared to baseline (p < 0.05 for all), and to placebo (p < 0.05 for all). Parameters recorded during oral fat load improved compared to the oral fat load performed at baseline with the nutraceutical combination.

CONCLUSIONS

The nutraceutical combination of fermented red rice, sterol esters and stanols, curcumin, and olive polyphenols seems to be effective in improving lipid profile and markers of endothelial damage in dyslipidemic patients in primary prevention at low risk for developing cardiovascular disease. The true novelty of this study, however, is the improvement of endothelial damage after an oral fat load compared to placebo.

Comparison of Two Calorie-Reduced Diets of Different Carbohydrate and Fiber Contents and a Simple Dietary Advice Aimed to Modify Carbohydrate Intake on Glycemic Control and Inflammatory Markers in Type 2 Diabetes: A Randomized Trial

OBJECTIVES

The aim of this study was to compare the effect of a simple dietary advice with two energy-restricted diets with different carbohydrate and fiber contents on anthropometric, biochemical, and inflammatory markers over an 8-wk intervention period in individuals with diabetes.

METHODS

Forty-seven patients with type 2 diabetes (31 women and 16 men; age: 52.9 ± 8.0 years, body mass index: 29.5 ± 4.9 kg.m^-2) completed an 8-wk randomized intervention trial that compared a simple dietary advice aimed to modulate carbohydrate intake (n = 13) with the two calorie-restricted (CR) diets (25% caloric restriction from total energy requirements) differing with regard to carbohydrate and fiber content, one with higher fiber (CRHF) containing 55% energy from carbohydrate plus a tablespoon of psyllium powder (n = 18) and the other with lower carbohydrate (CRLC) containing 40% energy from carbohydrate plus placebo powder (n = 16). Weight, plasma concentrations of glucose, insulin, lipids, interleukin-6 (IL-6), and tumor necrosis factor alpha (TNF-α) were determined at baseline and after 8 weeks.

RESULTS

The mean change of body weight and plasma lipids were not different between the groups. Fasting plasma insulin and the homeostasis model assessment of insulin resistance (HOMA-IR) were significantly lower in the CRHF group (changes from baseline values in simple advice, CRHF, and CRLC were 1.3 ± 1.9, -1.0 ± 1.2, and 0.3 ± 3.1 µIL/mL for insulin and 0.5 ± 0.7, -0.3 ± 0.6, and 0.2 ± 0.9 for HOMA-IR, respectively). The levels of IL-6 significantly decreased in the CRHF and CRLC groups (changes from baseline values in simple advice, CRHF, and CRLC were 7.5 ± 6.8, -1.2 ± 4.7, and -4.2 ± 5.6 pg/mL, respectively). TNF-α levels were significantly lower only in the CRHF compared to the advice group (P < 0.05).

CONCLUSIONS

Our results suggest that in comparison with simple advice to modify carbohydrate intake, a calorie-restricted, moderate carbohydrate diet supplemented with psyllium has better effects on plasma insulin and pro-inflammatory cytokines in patients with type 2 diabetes.

Influence of Plantago ovata husk (dietary fiber) on the bioavailability and other pharmacokinetic parameters of metformin in diabetic rabbits

Background

Metformin is an oral hypoglycemic agent frequently used in patients with type 2 diabetes. In this study, we have investigated the influence of the dietary fiber Plantago ovata husk on the pharmacokinetics of this drug when included in the diet, as well as when administered at the same time as metformin.

Methods

Six groups of 6 rabbits were used. Groups 1 to 3 were fed with standard chow and groups 4 to 6 with chow supplemented with fiber (3.5 mg/kg/day). Groups 1 and 4 received metformin intravenously (30 mg/kg). Groups 2 and 5 received metfomin orally (30 mg/kg), and number 3 and 6 were treated orally with metformin (30 mg/kg) and fiber (300 mg/kg).

Results

The changes caused by the inclusion of fiber in the feeding were more important in groups that received oral metformin. In this way, metformin oral bioavailability showed an increase of 34.42% when rabbits were fed with supplemented chow.

Conclusions

Plantago ovata husk increased the amount of absorbed metformin when included in the diet (significant increase in AUC), and delayed its absorption when administered at the same time (significant increase in t_max).

Effects of Higher Dietary Protein and Fiber Intakes at Breakfast on Postprandial Glucose, Insulin, and 24-h Interstitial Glucose in Overweight Adults

Dietary protein and fiber independently influence insulin-mediated glucose control. However, potential additive effects are not well-known. Men and women (n = 20; age: 26 ± 5 years; body mass index: 26.1 ± 0.2 kg/m²; mean ± standard deviation) consumed normal protein and fiber (NPNF; NP = 12.5 g, NF = 2 g), normal protein and high fiber (NPHF; NP = 12.5 g, HF = 8 g), high protein and normal fiber (HPNF; HP = 25 g, NF = 2 g), or high protein and fiber (HPHF; HP = 25 g, HF = 8 g) breakfast treatments during four 2-week interventions in a randomized crossover fashion. On the last day of each intervention, meal tolerance tests were completed to assess postprandial (every 60 min for 240 min) serum glucose and insulin concentrations. Continuous glucose monitoring was used to measure 24-h interstitial glucose during five days of the second week of each intervention. Repeated-measures ANOVA was applied for data analyses. The HPHF treatment did not affect postprandial glucose and insulin responses or 24-h glucose total area under the curve (AUC). Higher fiber intake reduced 240-min insulin AUC. Doubling the amount of protein from 12.5 g to 25 g/meal and quadrupling fiber from 2 to 8 g/meal at breakfast was not an effective strategy for modulating insulin-mediated glucose responses in these young, overweight adults.

Fiber supplements and clinically proven health benefits: How to recognize and recommend an effective fiber therapy

BACKGROUND

Only 5% of adults consume the recommended level of dietary fiber. Fiber supplements appear to be a convenient and concentrated source of fiber, but most do not provide the health benefits associated with dietary fiber.

PURPOSE

This review will summarize the physical effects of isolated fibers in small and large intestines, which drive clinically meaningful health benefits.

DATA SOURCES

A comprehensive literature review was conducted (Scopus and PubMed) without limits to year of publication (latest date included: October 31, 2016).

CONCLUSIONS

The physical effects of fiber in the small intestine drive metabolic health effects (e.g., cholesterol lowering, improved glycemic control), and efficacy is a function of the viscosity of gel-forming fibers (e.g., psyllium, β-glucan). In the large intestine, fiber can provide a laxative effect if (a) it resists fermentation to remain intact throughout the large intestine, and (b) it increases percentage of water content to soften/bulk stool (e.g., wheat bran and psyllium).

IMPLICATIONS FOR PRACTICE

It is important for nurse practitioners to understand the underlying mechanisms that drive specific fiber-related health benefits, and which fiber supplements have rigorous clinical data to support a recommendation.

CLINICAL PEARL

For most fiber-related beneficial effects, "Fiber needs to gel to keep your patients well."

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.

Role of phytochemicals in the management of metabolic syndrome

BACKGROUND

The World Health Organization (WHO) for some years has been focusing on what is now commonly referred to as an "epidemic of obesity and diabetes" ("diabesity"): behind this outbreak, there are several risk factors grouped in what is called "metabolic syndrome" (MetS). The basis of this "epidemic" is either a diet too often characterized by excessive consumption of saturated and trans-esterified fatty acids, simple sugars and salt, either a sedentary lifestyle.

PURPOSE

The aim of this review is to focus on the phytochemicals that have a more positive effect on the treatment and/or prevention of MetS.

CHAPTERS

Treatment strategies for MetS include pharmacologic and non-pharmacologic options, with varying degrees of success rate. The first is indicated for patients with high cardiovascular risk, while the second one is the most cost-effective preventive approach for subjects with borderline parameters and for patients intolerant to pharmacological therapy. MetS non-pharmacological treatments could involve the use of nutraceuticals, most of which has plant origins (phytochemicals), associated with lifestyle improvement. The chapter will discuss the available evidence on soluble fibres from psyllium and other sources, cinnamaldehyde, cinnamic acid and other cinnamon phytochemicals, berberine, corosolic acid from banaba, charantin from bitter gourd, catechins and flavonols from green tea and cocoa. Vegetable omega-3 polyunsaturated fatty acids, alliin from garlic, soy peptides, and curcumin from curcuma longa.

CONCLUSION

Some nutraceuticals, when adequately dosed, should improve a number of the MetS components.

Soluble fibers from psyllium improve glycemic response and body weight among diabetes type 2 patients (randomized control trial)

BACKGROUND

Water-soluble dietary fibers intake may help control blood glucose and body weight.

OBJECTIVE

The objective of the study was to determine whether soluble fiber supplementation from psyllium improves glycemic control indicators and body weight in type 2 diabetic patients.

METHOD

Forty type 2 diabetes patients, non-smoker, aged >35 years were stratified to different strata according to sex, age, body mass index (BMI) and fasting blood sugar level (FBS) and randomly assigned into two groups; The intervention group which consists of 20 participants was on soluble fiber (10.5 g daily), and the control group which consist of 20 participants continued on their regular diet for eight weeks duration.

RESULTS

After 8 weeks of intervention, soluble fiber supplementation showed significant reduction in the intervention group in BMI (p < 0.001) when compared with the control group. Moreover, water soluble fiber supplementation proven to improve FBS (163 to 119 mg/dl), HbA1c (8.5 to 7.5 %), insulin level (27.9 to 19.7 μIU/mL), C-peptide (5.8 to 3.8 ng/ml), HOMA.IR (11.3 to 5.8) and HOMA-β % (103 to 141 %).

CONCLUSION

The reduction in glycemic response was enhanced by combining soluble fiber to the normal diet. Consumption of foods containing moderate amounts of these fibers may improve glucose metabolism and lipid profile in type 2 diabetes patients.

TRIAL REGISTRATION

Current Controlled Trials PHRC/HC/28/15 .

Dietary fibre for the primary prevention of cardiovascular disease

BACKGROUND

The prevention of cardiovascular disease (CVD) is a key public health priority. A number of dietary factors have been associated with modifying CVD risk factors. One such factor is dietary fibre which may have a beneficial association with CVD risk factors. There is a need to review the current evidence from randomised controlled trials (RCTs) in this area.

OBJECTIVES

The primary objective of this systematic review was to determine the effectiveness of dietary fibre for the primary prevention of CVD.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, Ovid MEDLINE (1946 to January 2015), Ovid EMBASE (1947 to January 2015) and Science Citation Index Expanded (1970 to January 2015) as well as two clinical trial registers in January 2015. We also checked reference lists of relevant articles. No language restrictions were applied.

SELECTION CRITERIA

We selected RCTs that assessed the effects of dietary fibre compared with no intervention or a minimal intervention on CVD and related risk factors. Participants included adults who are at risk of CVD or those from the general population.

DATA COLLECTION AND ANALYSIS

Two authors independently selected studies, extracted data and assessed risk of bias; a third author checked any differences. A different author checked analyses.

MAIN RESULTS

We included 23 RCTs (1513 participants randomised) examining the effect of dietary fibre. The risk of bias was unclear for most studies and studies had small sample sizes. Few studies had an intervention duration of longer than 12 weeks. There was a wide variety of fibre sources used, with little similarity between groups in the choice of intervention.None of the studies reported on mortality (total or cardiovascular) or cardiovascular events. Results on lipids suggest there is a significant beneficial effect of increased fibre on total cholesterol levels (17 trials (20 comparisons), 1067 participants randomised, mean difference -0.23 mmol/L, 95% CI -0.40 to -0.06), and LDL cholesterol levels (mean difference -0.14 mmol/L, 95% CI -0.22 to -0.06) but not on triglyceride levels (mean difference 0.00 mmol/L, 95% CI -0.04 to 0.05), and there was a very small but statistically significant decrease rather than increase in HDL levels with increased fibre intake (mean difference -0.03 mmol/L, 95% CI -0.06 to -0.01). Fewer studies (10 trials, 661 participants randomised) reported blood pressure outcomes where there is a significant effect of increased fibre consumption on diastolic blood pressure (mean difference -1.77 mmHg, 95% CI -2.61 to -0.92) whilst there is a reduction in systolic blood pressure with fibre but this does not reach statistical significance (mean difference -1.92 mmHg, 95% CI -4.02 to 0.19). There did not appear to be any subgroup effects by the nature of the type of intervention (fibre supplements or provision of foods/advice to increase fibre consumption) or the type of fibre (soluble/insoluble) although the number of studies contributing to each subgroup were small. All analyses need to be viewed with caution given the risks of bias observed for total cholesterol and the statistical heterogeneity observed for systolic blood pressure. Adverse events, where reported, appeared to mostly reflect mild to moderate gastrointestinal side-effects and these were generally reported more in the fibre intervention groups than the control groups.

AUTHORS' CONCLUSIONS

Studies were short term and therefore did not report on our primary outcomes, CVD clinical events. The pooled analyses for CVD risk factors suggest reductions in total cholesterol and LDL cholesterol with increased fibre intake, and reductions in diastolic blood pressure. There were no obvious effects of subgroup analyses by type of intervention or fibre type but the number of studies included in each of these analyses were small. Risk of bias was unclear in the majority of studies and high for some quality domains so results need to be interpreted cautiously. There is a need for longer term, well-conducted RCTs to determine the effects of fibre type (soluble versus insoluble) and administration (supplements versus foods) on CVD events and risk factors for the primary prevention of CVD.

Psyllium fiber improves glycemic control proportional to loss of glycemic control: a meta-analysis of data in euglycemic subjects, patients at risk of type 2 diabetes mellitus, and patients being treated for type 2 diabetes mellitus

BACKGROUND

A number of health benefits are associated with intake of soluble, viscous, gel-forming fibers, including reduced serum cholesterol and the attenuation of postprandial glucose excursions.

OBJECTIVE

We assess the effects of psyllium, which is a soluble, gel-forming, nonfermented fiber supplement, on glycemic control in patients who were being treated for type 2 diabetes mellitus (T2DM) and in patients who were at risk of developing T2DM.

DESIGN

A comprehensive search was performed of available published literature (Scopus scientific database) and clinical records stored by Procter & Gamble with the use of key search terms to identify clinical studies that assessed the glycemic effects of psyllium in nondiabetic, pre-T2DM, and T2DM patients.

RESULTS

We identified 35 randomized, controlled, clinical studies that spanned 3 decades and 3 continents. These data were assessed in 8 meta-analyses. In patients with T2DM, multiweek studies (psyllium dosed before meals) showed significant improvement in both the fasting blood glucose (FBG) concentration (-37.0 mg/dL; P < 0.001) and glycated hemoglobin (HbA1c) [-0.97% (-10.6 mmol/mol); P = 0.048]. Glycemic effects were proportional to baseline FBG; no significant glucose lowering was observed in euglycemic subjects, a modest improvement was observed in subjects with pre-T2DM, and the greatest improvement was observed in subjects who were being treated for T2DM.

CONCLUSIONS

These data indicate that psyllium would be an effective addition to a lifestyle-intervention program. The degree of psyllium's glycemic benefit was commensurate with the loss of glycemic control. Because the greatest effect was seen in patients who were being treated for T2DM, additional studies are needed to determine how best to incorporate psyllium into existing prevention and treatment algorithms with concomitant hypoglycemic medications.

Protection against the Metabolic Syndrome by Guar Gum-Derived Short-Chain Fatty Acids Depends on Peroxisome Proliferator-Activated Receptor γ and Glucagon-Like Peptide-1

The dietary fiber guar gum has beneficial effects on obesity, hyperglycemia and hypercholesterolemia in both humans and rodents. The major products of colonic fermentation of dietary fiber, the short-chain fatty acids (SCFAs), have been suggested to play an important role. Recently, we showed that SCFAs protect against the metabolic syndrome via a signaling cascade that involves peroxisome proliferator-activated receptor (PPAR) γ repression and AMP-activated protein kinase (AMPK) activation. In this study we investigated the molecular mechanism via which the dietary fiber guar gum protects against the metabolic syndrome. C57Bl/6J mice were fed a high-fat diet supplemented with 0% or 10% of the fiber guar gum for 12 weeks and effects on lipid and glucose metabolism were studied. We demonstrate that, like SCFAs, also guar gum protects against high-fat diet-induced metabolic abnormalities by PPARγ repression, subsequently increasing mitochondrial uncoupling protein 2 expression and AMP/ATP ratio, leading to the activation of AMPK and culminating in enhanced oxidative metabolism in both liver and adipose tissue. Moreover, guar gum markedly increased peripheral glucose clearance, possibly mediated by the SCFA-induced colonic hormone glucagon-like peptide-1. Overall, this study provides novel molecular insights into the beneficial effects of guar gum on the metabolic syndrome and strengthens the potential role of guar gum as a dietary-fiber intervention.

Nutraceuticals for the treatment of metabolic diseases: evidence from clinical practice

The aim of this review is to describe some types of supplements that have been shown to be good co-adjuvants along with diet and drug treatment in improving insulin resistance and dyslipidemia. We can conclude that some nutraceuticals, such as l-carnitine, berberine, omega-3 polyunsaturated fatty acids, krill oil and red yeast rice, can be helpful in reducing hypercholesterolemia or insulin resistance, as reported in clinical trials. Nutraceuticals can be associated with conventional pharmacological treatments to achieve an improved lipid profile without increasing statin dosage. Similarly, although nutraceuticals cannot replace conventional antidiabetic treatments, they may be useful as an adjuvant to standard therapy, improving insulin resistance. However, not all nutraceuticals are the same and their natural origin does not mean that everyone can take them or that they cannot be dangerous; nutraceuticals should be used only under medical prescription and should be combined with a well-balanced diet.

Evidence-Based Approach to Fiber Supplements and Clinically Meaningful Health Benefits, Part 1: What to Look for and How to Recommend an Effective Fiber Therapy

Dietary fiber that is intrinsic and intact in fiber-rich foods (eg, fruits, vegetables, legumes, whole grains) is widely recognized to have beneficial effects on health when consumed at recommended levels (25 g/d for adult women, 38 g/d for adult men). Most (90%) of the US population does not consume this level of dietary fiber, averaging only 15 g/d. In an attempt to bridge this “fiber gap,” many consumers are turning to fiber supplements, which are typically isolated from a single source. Fiber supplements cannot be presumed to provide the health benefits that are associated with dietary fiber from whole foods. Of the fiber supplements on the market today, only a minority possess the physical characteristics that underlie the mechanisms driving clinically meaningful health benefits. The first part (current issue) of this 2-part series will focus on the 4 main characteristics of fiber supplements that drive clinical efficacy (solubility, degree/rate of fermentation, viscosity, and gel formation), the 4 clinically meaningful designations that identify which health benefits are associated with specific fibers, and the gel-dependent mechanisms in the small bowel that drive specific health benefits (eg, cholesterol lowering, improved glycemic control). The second part (next issue) of this 2-part series will focus on the effects of fiber supplements in the large bowel, including the 2 mechanisms by which fiber prevents/relieves constipation (insoluble mechanical irritant and soluble gel-dependent water-holding capacity), the gel-dependent mechanism for attenuating diarrhea and normalizing stool form in irritable bowel syndrome, and the combined large bowel/small bowel fiber effects for weight loss/maintenance. The second part will also discuss how processing for marketed products can attenuate efficacy, why fiber supplements can cause gastrointestinal symptoms, and how to avoid symptoms for better long-term compliance.

Evidence-Based Approach to Fiber Supplements and Clinically Meaningful Health Benefits, Part 2: What to Look for and How to Recommend an Effective Fiber Therapy

Dietary fiber that is intrinsic and intact in fiber-rich foods (eg, fruits, vegetables, legumes, whole grains) is widely recognized to have beneficial effects on health when consumed at recommended levels (25 g/d for adult women, 38 g/d for adult men). Most (90%) of the US population does not consume this level of dietary fiber, averaging only 15 g/d. In an attempt to bridge this “fiber gap,” many consumers are turning to fiber supplements, which are typically isolated from a single source. Fiber supplements cannot be presumed to provide the health benefits that are associated with dietary fiber from whole foods. Of the fiber supplements on the market today, only a minority possess the physical characteristics that underlie the mechanisms driving clinically meaningful health benefits. In this 2-part series, the first part (previous issue) described the 4 main characteristics of fiber supplements that drive clinical efficacy (solubility, degree/rate of fermentation, viscosity, and gel formation), the 4 clinically meaningful designations that identify which health benefits are associated with specific fibers, and the gel-dependent mechanisms in the small bowel that drive specific health benefits (eg, cholesterol lowering, improved glycemic control). The second part (current issue) of this 2-part series will focus on the effects of fiber supplements in the large bowel, including the 2 mechanisms by which fiber prevents/relieves constipation (insoluble mechanical irritant and soluble gel-dependent water-holding capacity), the gel-dependent mechanism for attenuating diarrhea and normalizing stool form in irritable bowel syndrome, and the combined large bowel/small bowel fiber effects for weight loss/maintenance. The second part will also discuss how processing for marketed products can attenuate efficacy, why fiber supplements can cause gastrointestinal symptoms, and how to avoid symptoms for better long-term compliance.

The short-chain fatty acid uptake fluxes by mice on a guar gum supplemented diet associate with amelioration of major biomarkers of the metabolic syndrome

Studies with dietary supplementation of various types of fibers have shown beneficial effects on symptoms of the metabolic syndrome. Short-chain fatty acids (SCFAs), the main products of intestinal bacterial fermentation of dietary fiber, have been suggested to play a key role. Whether the concentration of SCFAs or their metabolism drives these beneficial effects is not yet clear. In this study we investigated the SCFA concentrations and in vivo host uptake fluxes in the absence or presence of the dietary fiber guar gum. C57Bl/6J mice were fed a high-fat diet supplemented with 0%, 5%, 7.5% or 10% of the fiber guar gum. To determine the effect on SCFA metabolism, ¹³C-labeled acetate, propionate or butyrate were infused into the cecum of mice for 6 h and the isotopic enrichment of cecal SCFAs was measured. The in vivo production, uptake and bacterial interconversion of acetate, propionate and butyrate were calculated by combining the data from the three infusion experiments in a single steady-state isotope model. Guar gum treatment decreased markers of the metabolic syndrome (body weight, adipose weight, triglycerides, glucose and insulin levels and HOMA-IR) in a dose-dependent manner. In addition, hepatic mRNA expression of genes involved in gluconeogenesis and fatty acid synthesis decreased dose-dependently by guar gum treatment. Cecal SCFA concentrations were increased compared to the control group, but no differences were observed between the different guar gum doses. Thus, no significant correlation was found between cecal SCFA concentrations and metabolic markers. In contrast, in vivo SCFA uptake fluxes by the host correlated linearly with metabolic markers. We argue that in vivo SCFA fluxes, and not concentrations, govern the protection from the metabolic syndrome by dietary fibers.

Effects of berberine on lipid profile in subjects with low cardiovascular risk

OBJECTIVE

To evaluate the efficacy as antihypercholesterolemic agent of berberine in patients with low cardiovascular risk.

RESEARCH DESIGN AND METHODS

144 Caucasian subjects were enrolled. After a 6-month run-in period following diet and practicing physical activity, patients were randomized to take placebo or berberine 500 mg twice a day, for 3 months, in a double-blind, placebo-controlled design. Berberine and placebo were then interrupted for 2 months (washout period), and all patients continued with only diet and physical activity. At the end of the washout period, patients restarted berberine or placebo twice a day for further 3 months. Anthropometric and metabolic parameters were assessed during the run-in period, at randomization, before and after the washout period.

RESULTS

A decrease of body weight and BMI was observed after the run-in period. Berberine reduced total cholesterol, triglycerides and LDL cholesterol and increased HDL cholesterol after 3 months from randomization and compared with placebo. After the washout period, lipid profile worsened; afterward, when berberine was reintroduced, lipid profile improved again both compared with the washout period, and with placebo.

CONCLUSIONS

Berberine is effective and safe to mildly improve lipid profile in subjects with low risk for cardiovascular disease.

Viscous versus nonviscous soluble fiber supplements: mechanisms and evidence for fiber-specific health benefits

PURPOSE

This review focuses on the health benefits of viscous versus nonviscous soluble fibers, why symptoms can occur with increased fiber consumption, and how to avoid symptoms to improve adherence with a high-fiber diet.

DATA SOURCES

Review of scientific literature as well as evidence-based guidelines and resources.

CONCLUSIONS

While it is generally known that "fiber is good for you," it is less well known that specific health benefits are associated with specific fiber characteristics. Many of the health benefits of fiber can be directly correlated with the viscosity of soluble fibers when hydrated (i.e., gel-forming). A reduction in viscosity of a given fiber will attenuate these health benefits, and a nonviscous fiber does not exhibit these health benefits.

IMPLICATIONS FOR PRACTICE

Increasing the viscosity of chyme with a viscous soluble fiber has been shown clinically to lower cholesterol for cardiovascular health, improve glycemic control in type 2 diabetes, normalize stool form in both constipation (softens hard stool) and diarrhea (firms loose/liquid stool), and improve the objective clinical measures of metabolic syndrome (glycemic control, lipoprotein profile, body mass index/weight loss, and blood pressure).