Ground flaxseed increased nitric oxide levels in adults with type 2 diabetes: A randomized comparative effectiveness study of supplemental flaxseed and psyllium fiber

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.

Meta-analysis of the anti-oxidative and anti-inflammatory effects of hypoglycaemic plant-derived medicines

BACKGROUND

The pivotal role of oxidative stress and inflammation in the pathophysiology of type 2 diabetes mellitus (T2DM) has been firmly established. However, the evidence concerning hypoglycaemic medicinal plants' antioxidant and anti-inflammatory effects remains inconclusive due to inconsistencies in prior studies. To address this gap, our study aims to perform a comprehensive systematic review and meta-analysis of randomized controlled trials (RCTs) to consolidate previous research findings in this field.

METHODS

We conducted a comprehensive search in the PubMed, Web of Science, Embase, Cochrane Library, and Scopus databases to identify relevant English randomized controlled trials (RCTs). Our study adhered to the Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA) guidelines. All eligible studies that evaluated concurrently the antioxidative and anti-inflammatory effects of hypoglycaemic plant-derived supplements on type 2 diabetes mellitus (T2DM) were included in the meta-analysis. The meta-analysis itself was carried out using both fixed and random effects models to synthesize the findings from the selected studies.

RESULTS

Our study included 47 trials with a total of 2636 participants, both male and female, aged between 20 and 79 years, diagnosed with prediabetes, type 2 diabetes mellitus (T2DM), or metabolic syndrome. The meta-analysis revealed that plant-derived treatments, compared to placebos or other medicines, significantly improved oxidative stress (SMD = - 0.36, 95% CI - 0.64 to - 0.09), inflammation (SMD = - 0.47, 95% CI - 0.63 to - 0.31), total antioxidant capacity (SMD = 0.46, 95% CI 0.16-0.75), and antioxidant enzyme activity (SMD = 1.80, 95% CI 1.26-2.33). The meta-regression analysis showed that treatment duration exceeding 8 weeks significantly impacted the heterogeneity of the oxidative stress data.

CONCLUSIONS

Several hypoglycaemic plant-based treatments appear to positively affect T2DM patients by concurrently lowering oxidative stress and inflammatory indicators and boosting antioxidant enzyme activity.

CLINICAL TRAIL REGISTRY

PROSPERO ID: CRD42021226147.

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.

Effect of flaxseed (Linum usitatissimum) supplementation on glycemic control and insulin resistance in prediabetes and type 2 diabetes: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Prediabetes and type 2 Diabetes Mellitus (T2DM) are characterized by increased blood sugar concentration and insulin resistance. Although there are only a few reports of potential benefits of flaxseed's consumption on different metabolic parameters, there is no evidence of its effect among people with these conditions.

OBJECTIVES

The present systematic review and meta-analysis aimed to assess the effect of flaxseed supplementation on glycemic control variables and insulin resistance in prediabetes and T2DM.

METHODS

A literature search was conducted through PubMed, Cochrane Central Register of Controlled Trials (CENTRAL), and Web of Science, to identify Randomized Control Trials (RCTs) that evaluated the effect of milled or ground flaxseed supplementation on fasting blood glucose, HbA1c, insulin concentrations, or HOMA-IR. The data were analyzed using Comprehensive Meta-Analysis (CMA) software version 3.3 in a fixed-effect model.

RESULTS

Seven studies were included in the systematic review and the meta-analysis, the results showed a significant reduction on fasting blood sugar (SMD: -0.392, 95% CI: -0.596, -0.187, p = <0.001, I² = 64.81%) insulin concentrations, (SMD: -0.287, 95% CI: -0.534, -0.041, p = 0.022, I² = 32.53%), HbA1c (SMD: -0.442, 95% CI: -0.770, -0.114, p = 0.008, I² = 11.058%), and HOMA-IR (SMD: -0.284, 95% CI: -0.530, -0.038, p = 0.024, I² = 0.00%) after flaxseed supplementation.

CONCLUSIONS

Flaxseed supplementation seems to improve glycemic control variables and insulin resistance in prediabetes and T2DM; however, more RCTs are needed to have more decisive evidence about doses, method of supplementation, and the possible effect of synergy with the dietetic treatment.

The Effect of Flaxseed Oil Supplementation on Body Composition and Inflammation Indices in Overweight Adults With Pre-Diabetes

Background:

Flaxseed has rich content of alpha linolenic acid for preventing pro inflammatory process. The aim of present study is exploring the effect of flaxseed oil supplementation on inflammatory biomarkers and body composition in overweight adults with pre-diabetes.

Material and methods:

this double-blind randomized clinical trial conducted with 80 overweight pre-diabetic patients in 2 clusters (flaxseed oil group (2000-mg daily) and control group) across a 14-week period. Anthropometric indices, body composition and inflammatory indices were measured between 2 groups before and after the treatment.

Result:

this study found a significant decrease in visceral fat level in the intervention group (P = .009) and control group (P = .004) at the end of the survey. However, the mean change of it (P = .06) was not significant. Also, this study showed that percentage of body fat (P = .31) and its mean change (P = .6) did not have significantly different between the 2 groups at the 14th week. The skeletal muscle% had a significant rise in the intervention group (P = .005) and control group (P = .003) by the end of 14th week. However, the mean change of it (P = .19) was not significant between the 2 groups. In addition, there was no significant change in the fasting blood glucose (P = . 7), C reactive protein (P = .12) and TNF-α (P = .22) between the 2 groups at the end of study.

Conclusion:

It showed that flaxseed oil supplementation cannot improve body composition and inflammation.

Effectiveness and Safety of Ayurvedic Medicines in Type 2 Diabetes Mellitus Management: A Systematic Review and Meta-Analysis

Introduction: Many Ayurvedic medicines have the potential for managing type 2 diabetes mellitus (T2DM), with previous systematic reviews demonstrating effectiveness and safety for specific Ayurvedic medicines. However, many of the reviews need updating and none provide a comprehensive summary of all the Ayurvedic medicines evaluated for managing T2DM.

Objective: The objective of this systematic review was to evaluate and synthesize evidence on the effectiveness and safety of Ayurvedic medicines for managing T2DM.

Inclusion criteria: Published and unpublished RCTs assessing the effectiveness and safety of Ayurvedic medicines for managing T2DM in adults.

Methods: The JBI systematic review methodology was followed. A comprehensive search of sources (including 18 electronic databases) from inception to 16 January 2021 was made. No language restrictions were applied. Data synthesis was conducted using narrative synthesis and random effects meta-analyses, where appropriate. Pooled results are reported as mean differences (MD) with 95% confidence intervals (CI).

Results: Out of 32,519 records identified from the searches, 219 articles were included in the systematic review representing 199 RCTs (21,191 participants) of 98 Ayurvedic medicines. Overall, in the studies reviewed the methodology was not adequately reported, resulting in poorer methodological quality scoring. Glycated hemoglobin (HbA1c) was reduced using Aegle marmelos (L.) Corrêa (MD -1.6%; 95% CI −3 to −0.3), Boswellia serrata Roxb. (−0.5; −0.7 to −0.4), Gynostemma pentaphyllum (Thunb.) Makino (−1; −1.5 to −0.6), Momordica charantia L. (−0.3; −0.4 to −0.1), Nigella sativa L. (−0.4; −0.6 to −0.1), Plantago ovata Forssk. (−0.9; −1.4 to −0.3), Tinospora cordifolia (Willd.) Hook.f. and Thomson (−0.5; −0.6 to −0.5), Trigonella foenum-graecum L. (−0.6; −0.9 to −0.4), and Urtica dioica L. (−1.3; −2.4 to −0.2) compared to control. Similarly, fasting blood glucose (FBG) was reduced by 4–56 mg/dl for a range of Ayurvedic medicines. Very few studies assessed health-related quality of life (HRQoL). Adverse events were not reported in many studies, and if reported, these were mostly none to mild and predominately related to the gastrointestinal tract.

Conclusion: The current evidence suggests the benefit of a range of Ayurvedic medicines in improving glycemic control in T2DM patients. Given the limitations of the available evidence and to strengthen the evidence base, high-quality RCTs should be conducted and reported.

Current Research on the Effects of Non-Digestible Carbohydrates on Metabolic Disease

Metabolic diseases (MDs), including cardiovascular diseases (CVDs) and diabetes, occur when the body’s normal metabolic processes are disrupted. Behavioral risk factors such as obesity, physical inactivity, and dietary habits are strongly associated with a higher risk of MD. However, scientific evidence strongly suggests that balanced, healthy diets containing non-digestible carbohydrates (NDCs), such as dietary fiber and resistant starch, can reduce the risk of developing MD. In particular, major properties of NDCs, such as water retention, fecal bulking, viscosity, and fermentation in the gut, have been found to be important for reducing the risk of MD by decreasing blood glucose and lipid levels, increasing satiety and insulin sensitivity, and modifying the gut microbiome. Short chain fatty acids produced during the fermentation of NDCs in the gut are mainly responsible for improvement in MD. However, the effects of NDCs are dependent on the type, source, dose, and duration of NDC intake, and some of the mechanisms underlying the efficacy of NDCs on MD remain unclear. In this review, we briefly summarize current studies on the effects of NDCs on MD and discuss potential mechanisms that might contribute to further understanding these effects.

Effects of Flaxseed Interventions on Circulating Inflammatory Biomarkers: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

There have been various clinical studies on the effect of flaxseed-derived products on circulating inflammatory biomarkers, but the findings from these are contradictory. The aim of the present study was to clarify any association. A comprehensive literature search was conducted from inception to May 2018. From the eligible trials, 32 articles describing studies conducted on adults aged 18-70 y were selected for the meta-analysis. Meta-analyses using the random-effects model were performed to investigate the data and results showed significant effects of flaxseed intake on circulating high-sensitivity CRP (hs-CRP) [weighted mean difference (WMD) = -0.75; 95% CI: -1.19, -0.30; P < 0.001] and TNFα (WMD = -0.38; 95% CI: -0.75,-0.01; P = 0.04). However, no significant changes were found in IL6 concentration (WMD = -0.24; 95% CI: -0.70, 0.21; P = 0.28) and C-reactive protein (CRP) (WMD = -0.34; 95% CI:-0.89, 0.20; P = 0.22). Moreover, by eliminating 1 of the studies from the sensitivity analysis, changes in IL6 concentration were significant (WMD = -0.44; 95% CI: -0.81, -0.08). The changes in inflammatory biomarkers were dependent on study design (parallel or crossover), supplement type (flaxseed, flaxseed oil, or lignan), study quality (high or low), and participants' age and BMI. According to this meta-analysis, flaxseed significantly reduced circulating concentrations of hs-CRP and TNFα, but did not affect IL6 and CRP. Further research is needed to examine the effect of different doses and long-term benefits of flaxseed and its derivatives on inflammatory factors.

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.