Low-carbohydrate vegan diets in diabetes for weight loss and sustainability: a randomized controlled trial

BACKGROUND

Low-carbohydrate, high animal fat and protein diets have been promoted for weight loss and diabetes treatment. We therefore tested the effect of a low-carbohydrate vegan diet in diabetes as a potentially healthier and more ecologically sustainable low-carbohydrate option.

OBJECTIVES

We sought to compare the effectiveness of a low-carbohydrate vegan diet with a moderate-carbohydrate vegetarian diet on weight loss and metabolic measures in diabetes.

METHODS

One hundred and sixty-four male and female participants with type 2 diabetes were randomly assigned to advice on either a low-carbohydrate vegan diet, high in canola oil and plant proteins, or a vegetarian therapeutic diet, for 3 mo, with both diets recommended at 60% of calorie requirements. Body weight, fasting blood, blood pressure, and 7-d food records, to estimate potential greenhouse gas emissions, were obtained throughout the study with tests of cholesterol absorption undertaken at baseline and end of study on 50 participants.

RESULTS

Both low-carbohydrate vegan and vegetarian diets similarly but markedly reduced body weight (-5.9 kg; 95% CI: -6.5, -5.28 kg; and -5.23 kg; 95% CI: -5.84, -4.62 kg), glycated hemoglobin (-0.99%; 95% CI: -1.07, -0.9%; and -0.88%; 95% CI: -0.97, -0.8%), systolic blood pressure (-4 mmHg; 95% CI: -7, -2 mmHg; and -6 mmHg; 95% CI: -8, -3 mmHg), and potential greenhouse gas emissions, but only for potential greenhouse gas emissions was there a significant treatment difference of -0.63 kgCO2/d (95% CI: -0.99, -0.27 kgCO2/d) favoring the low-carbohydrate vegan diet.

CONCLUSIONS

Low-carbohydrate vegan and vegetarian diets reduced body weight, improved glycemic control and blood pressure, but the more plant-based diet had greater potential reduction in greenhouse gas emissions.Trial registration number: clinicaltrials.gov identifier NCT02245399.

Are all fibres created equal with respect to lipid lowering? Comparing the effect of viscous dietary fibre to non-viscous fibre from cereal sources: a systematic review and meta-analysis of randomised controlled trials

Although compelling evidence from observational studies supports a positive association between consumption of cereal fibre and CVD risk reduction, randomised controlled trials (RCT) often target viscous fibre type as the prospective contributor to lipid lowering to reduce CVD risk. The objective of our study is to compare the lipids-lowering effects of viscous dietary fibre to non-viscous, cereal-type fibre in clinical studies. RCT that evaluated the effect of viscous dietary fibre compared with non-viscous, cereal fibre on LDL cholesterol and alternative lipid markers, with a duration of ≥ 3 weeks, in adults with or without hypercholesterolaemia were included. Medline, EMBASE, CINAHL and the Cochrane Central Register were searched through October 19, 2021. Data were extracted and assessed by two independent reviewers. The generic inverse variance method with random effects model was utilised to pool the data which were expressed as mean differences (MD) with 95 % CI. Eighty-nine trials met eligibility criteria (n 4755). MD for the effect of viscous dietary fibre compared with non-viscous cereal fibre were LDL cholesterol (MD = -0·26 mmol/l; 95 % CI: -0·30, -0·22 mmol/l; P < 0·01), non-HDL cholesterol (MD = -0·33 mmol/l; 95 % CI: -0·39, -0·28 mmol/l; P < 0·01) and Apo-B (MD = -0·04 g/l; 95 % CI: -0·06, -0·03 g/l; P < 0·01). Viscous dietary fibre reduces LDL cholesterol and alternative lipid markers relative to the fibre from cereal sources, hence may be a preferred type of fibre-based dietary intervention targeting CVD risk reduction.

Effect of coadministration of enriched Korean Red Ginseng (Panax ginseng) and American ginseng (Panax quinquefolius L) on cardiometabolic outcomes in type-2 diabetes: A randomized controlled trial

Background

Diabetes mellitus and hypertension often occur together, amplifying cardiovascular disease (CVD) risk and emphasizing the need for a multitargeted treatment approach. American ginseng (AG) and Korean Red Ginseng (KRG) species could improve glycemic control via complementary mechanisms. Additionally, a KRG-inherent component, ginsenoside Rg3, may moderate blood pressure (BP). Our objective was to investigate the therapeutic potential of coadministration of Rg3-enriched Korean Red Ginseng (Rg3-KRG) and AG, added to standard of care therapy, in the management of hypertension and cardiometabolic risk factors in type-2 diabetes.

Methods

Within a randomized controlled, parallel design of 80 participants with type-2 diabetes (HbA1c: 6.5–8%) and hypertension (systolic BP: 140–160 mmHg or treated), supplementation with either 2.25 g/day of combined Rg3-KRG + AG or wheat-bran control was assessed over a 12-wk intervention period. The primary endpoint was ambulatory 24-h systolic BP. Additional endpoints included further hemodynamic assessment, glycemic control, plasma lipids and safety monitoring.

Results

Combined ginseng intervention generated a mean ± SE decrease in primary endpoint of 24-h systolic BP (−3.98 ± 2.0 mmHg, p = 0.04). Additionally, there was a greater reduction in HbA1c (−0.35 ± 0.1% [–3.8 ± 1.1 mmol/mol], p = 0.02), and change in blood lipids: total cholesterol (−0.50 ± 0.2 mmol/l, p = 0.01), non-HDL-C (−0.54 ± 0.2 mmol/l, p = 0.01), triglycerides (−0.40 ± 0.2 mmol/l, p = 0.02) and LDL-C (−0.35 ± 0.2 mmol/l, p = 0.06) at 12 wks, relative to control. No adverse safety outcomes were observed.

Conclusion

Coadministration of Rg3-KRG + AG is an effective addon for improving BP along with attaining favorable cardiometabolic outcomes in individuals with type 2 diabetes. Ginseng derivatives may offer clinical utility when included in the polypharmacy and lifestyle treatment of diabetes.

Clinical trial registration

Clinicaltrials.gov identifier, NCT01578837;

Co-administration of viscous fiber, Salba-chia and ginseng on glycemic management in type 2 diabetes: a double-blind randomized controlled trial

PURPOSE

Viscous dietary fiber, functional seeds and ginseng roots have individually been proposed for the management of diabetes. We explored whether their co-administration would improve glycemic control in type 2 diabetes beyond conventional therapy.

METHODS

In a randomized, double-blind, controlled trial conducted at two academic centers (Toronto, Canada and Zagreb, Croatia), individuals with type 2 diabetes were assigned to either an active intervention (10 g viscous fiber, 60 g white chia seeds, 1.5 g American and 0.75 g Korean red ginseng extracts), or energy and fiber-matched control (53 g oat bran, 25 g inulin, 25 g maltodextrose and 2.25 g wheat bran) intervention for 24 weeks, while on conventional standard of care. The prespecified primary endpoint was end difference at week 24 in HbA1c, following an intent-to-treat analysis adjusted for center and baseline.

RESULTS

Between January 2016 and April 2018, 104 participants (60M:44F; mean ± SEM age 59 ± 0.8 years; BMI 29.0 ± 0.4 kg/m²; HbA1c 7.0 ± 0.6%) managed with antihyperglycemic agent(s) (n = 98) or lifestyle (n = 6), were randomized (n = 52 test; n = 52 control). At week 24, HbA1c levels were 0.27 ± 0.1% lower on test compared to control (p = 0.03). There was a tendency towards an interaction by baseline HbA1c (p = 0.07), in which a greater reduction was seen in participants with baseline HbA1c > 7% vs ≤ 7% (- 0.56 ± 0.2% vs 0.03 ± 0.2%). Diet and body weight remained unchanged. The interventions were well tolerated with no related adverse events and with high retention rate of 84%.

CONCLUSIONS

Co-administration of selected dietary and herbal therapies was well-tolerated and may provide greater glycemic control as add-on therapy in type 2 diabetes. Registration: Clinicaltrials.gov NCT02553382 (registered on September 17, 2015).

Relation of Different Fruit and Vegetable Sources With Incident Cardiovascular Outcomes: A Systematic Review and Meta-Analysis of Prospective Cohort Studies

Background Public health policies reflect concerns that certain fruit sources may not have the intended benefits and that vegetables should be preferred to fruit. We assessed the relation of fruit and vegetable sources with cardiovascular outcomes using a systematic review and meta-analysis of prospective cohort studies. Methods and Results MEDLINE, EMBASE, and Cochrane were searched through June 3, 2019. Two independent reviewers extracted data and assessed study quality (Newcastle-Ottawa Scale). Data were pooled (fixed effects), and heterogeneity (Cochrane-Q and I2) and certainty of the evidence (Grading of Recommendations Assessment, Development, and Evaluation) were assessed. Eighty-one cohorts involving 4 031 896 individuals and 125 112 cardiovascular events were included. Total fruit and vegetables, fruit, and vegetables were associated with decreased cardiovascular disease (risk ratio, 0.93 [95% CI, 0.89-0.96]; 0.91 [0.88-0.95]; and 0.94 [0.90-0.97], respectively), coronary heart disease (0.88 [0.83-0.92]; 0.88 [0.84-0.92]; and 0.92 [0.87-0.96], respectively), and stroke (0.82 [0.77-0.88], 0.82 [0.79-0.85]; and 0.88 [0.83-0.93], respectively) incidence. Total fruit and vegetables, fruit, and vegetables were associated with decreased cardiovascular disease (0.89 [0.85-0.93]; 0.88 [0.86-0.91]; and 0.87 [0.85-0.90], respectively), coronary heart disease (0.81 [0.72-0.92]; 0.86 [0.82-0.90]; and 0.86 [0.83-0.89], respectively), and stroke (0.73 [0.65-0.81]; 0.87 [0.84-0.91]; and 0.94 [0.90-0.99], respectively) mortality. There were greater benefits for citrus, 100% fruit juice, and pommes among fruit sources and allium, carrots, cruciferous, and green leafy among vegetable sources. No sources showed an adverse association. The certainty of the evidence was "very low" to "moderate," with the highest for total fruit and/or vegetables, pommes fruit, and green leafy vegetables. Conclusions Fruits and vegetables are associated with cardiovascular benefit, with some sources associated with greater benefit and none showing an adverse association. Registration URL: https://www.clini​caltr​ials.gov; Unique identifier: NCT03394339.

Effect of soluble-viscous dietary fibre on coronary heart disease risk score across 3 population health categories: data from randomized, double-blind, placebo-controlled trials

We applied the Framingham risk equation in healthy, metabolic syndrome, and diabetes populations, following treatment with viscous fibre from konjac-based blend (KBB). KBB yielded reduction in estimated risk score by 16% (1.04 ± 0.03 vs. 0.87 ± 0.04, p < 0.01) in type 2 diabetes, 24% (1.08 ± 0.01 vs. 0.82 ± 0.02, p < 0.01) in metabolic syndrome, and 25% (1.09 ± 0.05 vs. 0.82 ± 0.06, p < 0.01) in healthy individuals. Drivers for decreased risk were improvements in blood cholesterol and systolic blood pressure. The composite coronary heart disease risk across populations was reduced 22% (p < 0.01). Novelty Viscous fibre from konjac-xanthan reduced 10-year relative coronary heart disease using Framingham Risk Score across the glycemic status spectrum.

Effect of viscous fiber supplementation on obesity indicators in individuals consuming calorie-restricted diets: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Dietary fiber has played a consistent role in weight management, with efficacy potentially attributed to increased viscous fiber consumption.

PURPOSE

To summarize the effects of viscous fiber on body weight and other anthropometric parameters, along with a calorie-deficient diet, through a systematic review and meta-analysis.

METHODS

MEDLINE, EMBASE, and the Cochrane library were searched through July 24, 2019 for randomized controlled trials that assessed the effect of viscous fiber supplementation as part of a restricted calorie diet for ≥ 4 weeks relative to comparator diets. Data were pooled using the generic inverse-variance method with random-effects models and expressed as mean differences with 95% confidence intervals. Inter-study heterogeneity was assessed using Cochran's Q and quantified with I². The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach was used to evaluate the overall certainty of evidence.

RESULTS

Findings from 15 studies (n = 1347) showed viscous fiber supplementation significantly decreased body weight (- 0.81 kg [- 1.20, - 0.41]; p < 0.0001), BMI (- 0.25 kg/m² [- 0.46, - 0.05]; p = 0.01), and body fat (- 1.39% [- 2.61, - 0.17]; p = 0.03), compared to control. No effect on waist circumference was found. The certainty of evidence was graded as "moderate" for body weight, BMI, and body fat based on downgrades for imprecision. Waist circumference was graded "low" for downgrades of inconsistency and imprecision.

CONCLUSION

Viscous fiber within a calorie-restricted diet significantly improved body weight and other markers of adiposity in overweight adults and those with additional risk factors for cardiovascular disease. This trial is registered at www.clinicaltrials.gov as NCT03257449.

REGISTRATION

ClinicalTrials.gov identifier: NCT03257449.

Effect of high-carbohydrate or high-monounsaturated fatty acid diets on blood pressure: a systematic review and meta-analysis of randomized controlled trials

Context

Current dietary guidelines for cardiovascular disease risk management recommend restricting intake of saturated fatty acids (SFAs). However, the optimal macronutrient profile, in the context of a low-SFA diet, remains controversial. The blood-pressure effect of replacing SFAs in diets with monounsaturated fatty acids (MUFAs) compared with carbohydrate has not been quantified to date.

Objective

To synthesize the evidence for the effect of substituting a high-carbohydrate (high-CHO) diet for a high-monounsaturated fatty acid (high-MUFA) diet on blood pressure, a systematic review and meta-analysis of randomized clinical trials in a population without health restrictions was conducted.

Data Sources

MEDLINE, EMBASE, and Cochrane Central Register of Controlled Clinical Trials were searched through June 7, 2017. Randomized controlled trials of > 3 weeks duration that assessed the effect of high-MUFA diets in isocaloric substitution for high-CHO diets on systolic blood pressure (SBP) and diastolic blood pressure (DBP) were included.

Data Extraction

Data were pooled using the generic-inverse variance method with random effects models and expressed as mean differences (MDs) with 95% confidence intervals (CIs). Heterogeneity was assessed by Cochran Q statistic and quantified by the I2 statistic. The quality of the evidence was assessed with the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system.

Results

Fourteen trials (n = 980 participants) were included in the analysis. Comparatively, the high-MUFA diets in isocaloric substitution for high-CHO diets did not demonstrate a greater reduction in blood pressure (SBP: MD, -0.08 mmHg [95%CI, -1.01 to 0.84], P = 0.86; DBP: MD = 0.01 mmHg [95%CI, -0.73 to 0.75], P = 0.98). The overall quality of the evidence was assessed as moderate.

Conclusions

In the context of low SFAs, high-MUFA diets in isocaloric substitution for high-CHO diets did not affect blood pressure in individuals with and without hypertension. Large-scale trials achieving higher MUFA targets are required to support these findings.

ClinicalTrials.gov ID

NCT02626325.

Vascular effects of combined enriched Korean Red ginseng (Panax Ginseng) and American ginseng (Panax Quinquefolius) administration in individuals with hypertension and type 2 diabetes: A randomized controlled trial

BACKGROUND

Type 2 diabetes is known to abrogate the vascular response. Combination of two commonly consumed ginseng species, American ginseng (AG) and a Korean Red ginseng (KRG), enriched with ginsensoide Rg3, was shown to concomitantly improve glucemic control and blood pressure. We evaluated the hypothesis that improvements in central hemodynamics, vascular function and stiffness markers are involved in observed benefits of co-administration.

METHODS

In this randomized, placebo controlled, two-center trial, patients with type 2 diabetes and hypertension were assigned to either 2.25 g ginsenoside Rg3-enriched KRG&AG co-administration or a control 3 times daily for 12-weeks, treated by standard of care. The effects on central hemodynamics, pulse wave velocity (PWV) and endothelial function over the 12-week administration were analyzed.

RESULTS

In intent-to-treat analysis of 80 individuals, a reduction in central systolic BP (-4.69 ± 2.24 mmHg, p = 0.04) was observed with co-administration of Rg3-KRG + AG relative to control at 12-weeks, which was characterized by a decrease in end-systolic pressure (-6.60 ± 2.5 mmHg, p = 0.01) and area under the systolic/diastolic BP curve (-132.80 ± 65.1, p = 0.04, 220.90 ± 91.1, p = 0.02, respectively). There was no significant change in reactive hyperemia index (0.09 ± 0.11, p = 0.44), PWV (-0.40 ± 0.28 %, p = 0.17), and other related pulse wave analysis components.

CONCLUSION

Co-administration of complementary ginseng species improved central systolic BP and components of pulse waveform without a direct effect on endothelial function, when added to background pharmacotherapy in individuals with diabetes. These data support potential utility of ginseng for modest blood pressure benefit to broaden its role in diabetes management.

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.

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.

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.

Acute effect of equicaloric meals varying in glycemic index and glycemic load on arterial stiffness and glycemia in healthy adults: a randomized crossover trial

BACKGROUND/OBJECTIVES

Dietary carbohydrate quality and quantity fluctuate but it is unknown which attribute takes precedence in vascular health preservation. We investigated all four permutations of glycemic index (GI) and glycemic load (GL) on acute vascular and glycemic responses.

SUBJECTS/METHODS

Twenty-one healthy adults were screened for this crossover trial. Seventeen (8 M:9 F; 26.7 ± 12.3 y; BMI 22.2 ± 2.8 kg/m²) entered randomization and completed the study, receiving four isocaloric meals, varying in GI and GL, in random order at least 3 days apart. The four meals included either chickpeas (GI = 28, GL = 14, 50 g available carbohydrates (CHO)), a small potato portion (GI = 85, GL = 14, CHO = 17 g), pasta (GI = 45, GL = 42, CHO = 94 g) or a large potato portion (GI = 85, GL = 42, CHO = 50 g) as the source of carbohydrate. Augmentation index (AIx) and central and peripheral blood pressure were measured fasting, 1, 2, 3, and 4 h post-consumption. Capillary blood glucose was analyzed fasting, 15, 30, 45, 60, 90, 120, 180, and 240 min.

RESULTS

A reduction in AIx from baseline was observed 4 h following the chickpeas (low GI-low GL) (p = 0.046). The incremental area under blood glucose curves were significantly higher 2 h post-consumption following high compared with low GL meals (p < 0.001). Despite doubling carbohydrates, there was no difference in glycemic response between the large potato (high GI-high GL) and the pasta (low GI-high GL) meals. No significant differences in AIx or blood pressure were seen between meals.

CONCLUSIONS

Low GI, low-carbohydrate meals may support a healthy vascular tone. Varying meal GI and GL results in different glycemic profiles, which are not necessarily predicted by carbohydrate content. Further investigations on cardiometabolic profiles to meals varying in GI and GL are warranted.

The effect of viscous soluble fiber on blood pressure: A systematic review and meta-analysis of randomized controlled trials

AIMS

Dietary fiber intake, especially viscous soluble fiber, has been established as a means to reduce cardiometabolic risk factors. Whether this is true for blood pressure remains controversial. A systematic review and meta-analysis of randomized controlled trials (RCTs) was conducted to investigate the effects of viscous soluble fiber supplementation on blood pressure and quantify the effect of individual fibers.

DATA SYNTHESIS

MEDLINE, Embase, and Cochrane databases were searched. We included RCTs of ≥4-weeks in duration assessing viscous fiber supplementation from five types: β-glucan from oats and barley, guar gum, konjac, pectin and psyllium, on systolic blood pressure (SBP) and diastolic blood pressure (DBP). Study data were pooled using the generic inverse variance method with random effects models and expressed as mean differences (MD) with 95% confidence intervals (CIs). Twenty-two (N = 1430) and twenty-one RCTs (N = 1343) were included in the final analysis for SBP and DBP, respectively. Viscous fiber reduced SBP (MD = -1.59 mmHg [95% CI: -2.72,-0.46]) and DBP (MD = -0.39 mmHg [95% CI: -0.76,-0.01]) at a median dose of 8.7 g/day (1.45-30 g/day) over a median follow-up of 7-weeks. Substantial heterogeneity in SBP (I² = 72%, P < 0.01) and DBP (I² = 67%, P < 0.01) analysis occurred. Within the five fiber types, SBP reductions were observed only for supplementation using psyllium fiber (MD = -2.39 mmHg [95% CI: -4.62,-0.17]).

CONCLUSION

Viscous soluble fiber has an overall lowering effect on SBP and DBP. Inclusion of viscous fiber to habitual diets may have additional value in reducing CVD risk via improvement in blood pressure.

PROTOCOL REGISTRATION

ClinicalTrials.gov identifier-NCT02670967.

Co-administration of a konjac-based fibre blend and American ginseng (Panax quinquefolius L.) on glycaemic control and serum lipids in type 2 diabetes: a randomized controlled, cross-over clinical trial

PURPOSE

Use of polypharmacy in the treatment of diabetes is the norm; nonetheless, optimal control is often not achieved. Konjac-glucomannan-based fibre blend (KGB) and American ginseng (AG) have individually been shown to improve glycaemia and CVD risk factors in type 2 diabetes. The aim of this study was to determine whether co-administration of KGB and AG could improve diabetes control beyond conventional treatment.

METHOD

Thirty-nine participants with type 2 diabetes (6.5 > A1c < 8.4%) were enrolled between January 2002 and May 2003 at the Risk Factor Modification Centre at St Michaels Hospital in a randomized, placebo-controlled, crossover trial with each intervention lasting 12-weeks. Medications, diet and lifestyle were kept constant. Interventions consisted of 6 g of fibre from KGB together with 3 g of AG (KGB and AG) or wheat bran-based, fibre-matched control. Primary endpoint was the difference in HbA1c levels at week 12.

RESULTS

Thirty participants (18M:12F; age: 64 ± 7 years; BMI: 28 ± 5 kg/m²; HbA1c: 7.0 ± 1.0%) completed the study, and consumed 5.5 and 4.9 g/day of fibre from KGB and wheat bran control, respectively, and 2.7 g/day of AG. At week 12, HbA1c levels were 0.31% lower on the KGB and AG compared to control (p = 0.011). Mean (±SEM) plasma lipids decreased on the KGB and AG vs control by 8.3 ± 3.1% in LDL-C (p = 0.002), 7.5 ± 2.4% in non-HDL-C (p = 0.013), 5.7 ± 1.9% in total-C (p = 0.012), 4.1 ± 2.1% in total-C:HDL-C ratio (p = 0.042), 9.0 ± 2.3% in ApoB (p = 0.0005) and 14.6 ± 4.2% in ApoB:ApoA1 ratio (p = 0.049).

CONCLUSIONS

Co-administration of KGB and AG increases the effectiveness of conventional therapy through a moderate but clinically meaningful reduction in HbA1c and lipid concentrations over 12 weeks in patients with type 2 diabetes.

CLINICAL TRIALS REGISTRATION

NCT02806349 ( https://clinicaltrials.gov/ ).

The effect of alpha-linolenic acid on glycemic control in individuals with type 2 diabetes: A systematic review and meta-analysis of randomized controlled clinical trials

BACKGROUND

Polyunsaturated fats (PUFAs) have been shown to reduce type 2 diabetes (T2DM) risk and improve insulin responsiveness in T2DM subjects, but whether the plant sources of omega-3 PUFA (alpha-linolenic acid [ALA]) have an effect on glycemic control requires further investigation.

METHODS

The parameters of interest were glycated hemoglobin (HbA1c), fasting blood glucose (FBG), fasting blood insulin (FBI), homeostatic model assessment for insulin resistance (HOMA-IR), fructosamine, and glycated albumin. A comprehensive search was conducted with MEDLINE, Embase, CINAHL, and Cochrane. Eligible studies included randomized controlled trials (RCTs) ≥1 month in duration that compared diets enriched in ALA with usual diets on glycemic parameters. For each study, the risk of bias as well as the study quality was assessed. Using the statistical software RevMan (v5.3), data were pooled using the generic inverse method with random effects model, and final results were expressed as mean differences (MD) with 95% confidence intervals (CI). Heterogeneity was assessed by the Cochran Q statistic and quantified by the I statistic.

RESULTS

A total of 8 trials (N = 212) were included in the meta-analysis. Compared to a control diet, a median dose of 4.4 g/day of ALA intake for a median duration of 3 months did not affect HbA1c (%) (MD = -.01; [95%: -.32, .31], P = .96). A median ALA dose of 5.4 g/day did not lower FBG (MD = .07; [95% CI: -.61, .76], P = .84) or FBI (MD = 7.03, [95% CI: -5.84, 19.89], P = .28). Summary effect estimates were generally compromised by considerable and unexplained heterogeneity (I ≥75%). In the subgroup analysis of continuous predictors, a reduction in HbA1c (%) and FBG (mmol/L) was significantly associated with an increased intake of ALA. Further adjustment for Publication Bias using Duval and Tweedie's trim-and-fill analysis provided an adjusted, significant MD of -.25 (95% CI: -.38, -.12; P <.001) for HbA1c (%).

CONCLUSIONS

ALA-enriched diets did not affect HbA1c, FBG, or FBI. The scarce number of existing RCTs and the presence of heterogeneity in our meta-analysis limit the ability to make firm conclusions about ALA in T2DM management. The potential for ALA to have dose-dependent effects warrants further research in this area.

A systematic review and meta-analysis of randomized controlled trials of the effect of konjac glucomannan, a viscous soluble fiber, on LDL cholesterol and the new lipid targets non-HDL cholesterol and apolipoprotein B

Background: Evidence from randomized controlled trials (RCTs) suggests the consumption of konjac glucomannan (KJM), a viscous soluble fiber, for improving LDL-cholesterol concentrations. It has also been suggested that the cholesterol-lowering potential of KJM may be greater than that of other fibers. However, trials have been relatively scarce and limited in sample size and duration, and the effect estimates have been inconsistent. The effect of KJM on new lipid targets of cardiovascular disease (CVD) risk is also unknown.Objective: This systematic review and meta-analysis aimed to assess the effect of KJM on LDL cholesterol, non-HDL cholesterol, and apolipoprotein B.Design: Medline, Embase, CINAHL, and the Cochrane Central databases were searched. We included RCTs with a follow-up of ≥3 wk that assessed the effect of KJM on LDL cholesterol, non-HDL cholesterol, or apolipoprotein B. 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 the Cochran Q statistic and quantified by the I² statistic.Results: Twelve studies (n = 370), 8 in adults and 4 in children, met the inclusion criteria. KJM significantly lowered LDL cholesterol (MD: -0.35 mmol/L; 95% CI: -0.46, -0.25 mmol/L) and non-HDL cholesterol (MD: -0.32 mmol/L; 95% CI: -0.46, -0.19 mmol/L). Data from 6 trials suggested no impact of KJM on apolipoprotein B.Conclusions: Our findings support the intake of ∼3 g KJM/d for reductions in LDL cholesterol and non-HDL cholesterol of 10% and 7%, respectively. The information may be of interest to health agencies in crafting future dietary recommendations related to reduction in CVD risk. This study was registered at clinicaltrials.gov as NCT02068248.

Salba-chia (Salvia hispanica L.) in the treatment of overweight and obese patients with type 2 diabetes: A double-blind randomized controlled trial

BACKGROUND AND AIM

Preliminary findings indicate that consumption of Salba-chia (Salvia hispanica L.), an ancient seed, improves management of type 2 diabetes and suppresses appetite. The aim of this study was to assesse the effect of Salba-chia on body weight, visceral obesity and obesity-related risk factors in overweight and obese adults with type 2 diabetes.

METHODS

A double-blind, randomized, controlled trial with two parallel groups involved 77 overweight or obese patients with type 2 diabetes (HbA_1c: 6.5-8.0%; BMI: 25-40 kg/m²). Both groups followed a 6-month calorie-restricted diet; one group received 30 g/1000 kcal/day of Salba-chia, the other 36 g/1000 kcal/day of an oat bran-based control. Primary endpoint was change in body weight over 6-months. Secondary endpoints included changes in waist circumference, body composition, glycemic control, C-reactive protein, and obesity-related satiety hormones.

RESULTS

At 6-months, participants on Salba-chia had lost more weight than those on control (1.9 ± 0.5 kg and 0.3 ± 0.4 kg, respectively; P = 0.020), accompanied by a greater reduction in waist circumference (3.5 ± 0.7 cm and 1.1 ± 0.7 cm, respectively; P = 0.027). C-reactive protein was reduced by 1.1 ± 0.5 mg/L (39 ± 17%) on Salba-chia, compared to 0.2 ± 0.4 mg/L (7 ± 20%) on control (P = 0.045). Plasma adiponectin on the test intervention increased by 6.5 ± 0.7%, with no change observed on control (P = 0.022).

CONCLUSIONS

The results of this study, support the beneficial role of Salba-chia seeds in promoting weight loss and improvements of obesity related risk factors, while maintaining good glycemic control. Supplementation of Salba-chia may be a useful dietary addition to conventional therapy in the management of obesity in diabetes. REGISTRATION: clinicaltrials.gov identifier: NCT01403571.

The effect of ginseng (genus Panax) on blood pressure: a systematic review and meta-analysis of randomized controlled clinical trials

Pre-clinical evidence indicates the potential for ginseng to reduce cardiovascular disease risk and acutely aid in blood pressure (BP) control. Clinical evidence evaluating repeated ginseng exposure, however, is controversial, triggering consumer and clinician concern. A systematic review and meta-analysis were conducted to assess whether ginseng has an effect on BP. MEDLINE, EMBASE, Cochrane and CINAHL were searched for relevant randomized controlled trials ⩾4 weeks that compared the effect of ginseng on systolic (SBP), diastolic (DBP) and/or mean arterial (MAP) BPs to control. Two independent reviewers extracted data and assessed methodological quality and risk of bias. Data were pooled using random-effects models and expressed as mean differences (MD) with 95% confidence intervals (CIs). Heterogeneity was assessed and quantified. Seventeen studies satisfied eligibility criteria (n=1381). No significant effect of ginseng on SBP, DBP and MAP was found. Stratified analysis, although not significant, appears to favour systolic BP improvement in diabetes, metabolic syndrome and obesity (MD=-2.76 mm Hg (95% CI=-6.40, 0.87); P=0.14). A priori subgroup analyses revealed significant association between body mass index and treatment differences (β=-0.95 mm Hg (95% CI=-1.56, -0.34); P=0.007). Ginseng appears to have neutral vascular affects; therefore, should not be discouraged for concern of increased BP. More high-quality, randomized, controlled trials assessing BP as a primary end point, and use of standardized ginseng root or extracts are warranted to limit evidence of heterogeneity in ginseng research and to better understand its cardiovascular health potential.

Effect of Spinach, a High Dietary Nitrate Source, on Arterial Stiffness and Related Hemodynamic Measures: A Randomized, Controlled Trial in Healthy Adults

Diets rich in fruits and vegetables reduce risk of adverse cardiovascular events. However, the constituents responsible for this effect have not been well established. Lately, the attention has been brought to vegetables with high nitrate content with evidence that this might represent a source of vasoprotective nitric oxide. We hypothesized that short-term consumption of spinach, a vegetable having high dietary nitrate content, can affect the arterial waveform indicative of arterial stiffness, as well as central and peripheral blood pressure (BP). Using a placebo-controlled, crossover design, 27 healthy participants were randomly assigned to receive either a high-nitrate (spinach; 845 mg nitrate/day) or low-nitrate soup (asparagus; 0.6 mg nitrate/day) for 7 days with a 1-week washout period. On days 1 and 7, profiles of augmentation index, central, and brachial BP were obtained over 180 min post-consumption in 4 fasted visits. A postprandial reduction in augmentation index was observed at 180 min on high-nitrate compared to low-nitrate intervention (-6.54 ± 9.7% vs. -0.82 ± 8.0%, p = 0.01) on Day 1, and from baseline on Day 7 (-6.93 ± 8.7%, p < 0.001; high vs. low: -2.28 ± 12.5%, p = 0.35), suggesting that the nitrate intervention is not associated with the development of tolerance for at least 7 days of continued supplementation. High vs. low-nitrate intervention also reduced central systolic (-3.39 ± 5.6 mmHg, p = 0.004) and diastolic BP (-2.60 ± 5.8 mmHg, p = 0.028) and brachial systolic BP (-3.48 ± 7.4 mmHg, p = 0.022) at 180 min following 7-day supplementation only. These findings suggest that dietary nitrate from spinach may contribute to beneficial hemodynamic effects of vegetable-rich diets and highlights the potential of developing a targeted dietary approach in the management of elevated BP.

Carbohydrates and endothelial function: is a low-carbohydrate diet or a low-glycemic index diet favourable for vascular health?

Low-carbohydrate diets have become increasingly popular in both media and clinical research settings. Although they may improve some metabolic markers, their effects on arterial function remain unclear. Endothelial dysfunction is the well-established response to cardiovascular risk factors and a pivotal feature that precedes atherosclerotic diseases. It has been demonstrated that a high carbohydrate-induced hyperglycemia and subsequent oxidative stress acutely worsen the efficacy of the endothelial vasodilatory system. Thus, in theory, a carbohydrate restricted diet may preserve the integrity of the arterial system. This review attempts to provide insight on whether low-carbohydrate diets have a favorable or detrimental impact on vascular function, or it is perhaps the quality of carbohydrate that should direct dietary recommendations. Research to date suggests that diets low in carbohydrate amount may negatively impact vascular endothelial function. Conversely, it appears that maintaining recommended carbohydrate intake with utilization of low glycemic index foods generates a more favorable vascular profile. Understanding these relationships will aid in deciphering the diverging role of modulating quantity and quality of carbohydrates on cardiovascular risk.

Modulation of endothelial function by Korean red ginseng (Panax ginseng C.A. Meyer) and its components in healthy individuals: a randomized controlled trial

AIMS

Ginseng root and its derivatives remain atop the most widely used medicinal herbs in cardiovascular disease, despite inadequate substantiation of efficacy. We previously reported the potential of Korean red ginseng (KRG) to affect vascular tone by decreasing arterial wave reflection via an unknown mechanism. Given the preclinical link between ginseng intake and vasoactivity related to nitric oxide (NO) production, we sought to directly evaluate the effects of KRG root and its major root components, on an established noninvasive measure of endothelial function.

METHODS

In an acute, randomized, placebo-controlled, double-blind, crossover design, 16 healthy participants (9M:7F, age:30 ± 9y, BMI: 24 kg ±3 kg/m(2) , systolicBP/diastolicBP: 109 ± 11/66 ± 8 mmHg) on four occasions were administered: KRG root (3 g), KRG ginsenosides extract, KRG polysaccharides extract, and cornstarch control. Extracted fractions were delivered at doses bioequivalent to those found in 3 g of KRG. Flow-mediated vasodilatation (FMD) assessment, preceding a brachial blood pressure measurement, was performed at baseline and at 90 and 180 min posttreatment to assess endothelial function.

RESULTS

KRG significantly improved FMD posttreatment. Maximal vasodilatation of Δ2.57 ± 2.8% occurred at 180 min compared with control (Δ-0.83 ± 2.7%, P = 0.003 for all comparisons). The ginsenoside extract produced a comparable response (Δ1.75 ± 2.6%), but not the polysaccharide fraction (Δ0.10 ± 2.7%). Brachial blood pressure remained unchanged for all treatments (P = 0.45).

CONCLUSIONS

KRG acutely improved endothelial function in healthy individuals, which appears to be attributable to its ginsenoside containing fraction. Our data confirm preclinical data and support the potential for these compounds as targets for therapeutic strategies in disorders involving endothelial dysfunction.

Ethanol extraction preparation of American ginseng (Panax quinquefolius L) and Korean red ginseng (Panax ginseng C.A. Meyer): differential effects on postprandial insulinemia in healthy individuals

ETHNOPHARMACOLOGICAL RELEVANCE

Ginsenosides are the proposed bioactive constituent of ginseng, especially for the attenuation of postprandial glycemia (PPG). The efficacious proportion of total and specific ginsenosides, remains unknown. Alcohol extraction of whole ginseng root can be used to selectively manipulate the ginsenoside profile with increasing alcohol concentrations producing high yields of total ginsenosides and varying their individual proportions.

AIM OF THE STUDY

We aimed to compare the acute efficacy of different ethanol-extraction preparations of American ginseng (AG) and Korean red ginseng (KRG), with their whole-root origins, on PPG and insulin parameters in healthy adults.

MATERIALS AND METHODS

Following an overnight fast, 13 healthy individuals (Gender: 5M:8F, with mean ± SD, age: 28.9 ± 9.2 years, BMI: 26.3 ± 2.7 kg/m(2) and fasting plasma glucose: 4.21 ± 0.04 mmol/L) randomly received 3g of each of the following 10 different ginseng treatments on separate visits: whole root KRG and AG; 30%, 50% or 70% ethanol extracts of KRG and AG and 2 cornstarch placebos. Treatments were consumed 40 min prior to a 50 g oral glucose challenge test with capillary blood samples collected at baseline, 15, 30, 45, 60, 90 and 120 min. Insulin samples were collected at 0, 30, 60 and 120 min.

RESULTS

There was no difference in attenuation of PPG among the tested ginseng preparations. Measures of Insulin Sensitivity Index (ISI) showed increased insulin sensitivity (IS) with KRG-30% and AG-50% extracts compared to placebo (p<0.05).

CONCLUSIONS

The insulin sensitizing effects of KRG-30% and AG-50% extracts suggest that other root parts, including other ginsenosides not typically measured, may influence PPG and insulin parameters. There is potential for AG and KRG extracts to modulate IS, an independent predictor of type 2 diabetes.

Randomized clinical trial in healthy individuals on the effect of viscous fiber blend on glucose tolerance when incorporated in capsules or into the carbohydrate or fat component of the meal

BACKGROUND/OBJECTIVE

Addition of viscous fiber to foods has been shown to significantly reduce postprandial glucose excursions. However, palatability issues and the variability in effectiveness due to different methods of administration in food limits it use. This study explores the effectiveness of a viscous fiber blend (VFB) in lowering postprandial glycemia using different methods of incorporation.

METHODS

Two acute, randomized, controlled studies were undertaken: Study 1: Twelve healthy individuals (mean ± SD, age: 36 ± 13 years, body mass index [BMI]: 27 ± 4 kg/m(2)) consumed 8 different breakfasts. All meals consisted of 50 g of available carbohydrate from white bread (WB) and 10 g margarine. Zero, 1, 2, or 4 g of the VFB was baked into WB or mixed with the margarine. Study 2: Thirteen healthy individuals (mean ± SD, age: 39 ± 17 years, BMI: 25 ± 5 kg/m(2)) consumed 6 test meals, consisting of 50 g of available carbohydrate from WB. Six capsules containing either cornstarch or VFB were taken at 4 different time points during the glucose tolerance test. After obtaining a fasting finger-prick blood sample, volunteers consumed the test meal over a 10-minute period. Additional blood samples were taken at 15, 30, 45, 60, 90, and 120 minutes from the start of the meal. For study 2, an additional fasting sample was obtained at -30 minutes.

RESULTS

Study 1: Irrespective of VFB dose, glucose levels were lower at 30 and 45 minutes when VFB was mixed into the margarine compared to the control (p < 0.05). Incremental areas under the curve were significantly lower compared to control when 4 g of VFB was mixed into the margarine. Study 2: There was no effect of the VFB on postprandial glucose levels when administered in capsules.

CONCLUSION

Incorporation of VFB into margarine was more effective in lowering postprandial glycemia than when the VFB was baked into bread and no effect when given in capsules.

Glycemic effect of oat and barley beta-glucan when incorporated into a snack bar: a dose escalation study

BACKGROUND

The blood glucose-lowering effects of β-glucan from oats and barley depend on the amounts consumed and their rheological properties. This has been recently challenged with growing evidence that the food matrix may also be an important factor in predicting its physiological response.

OBJECTIVE

The objective of this study was to examine the effects of varying doses of β-glucan from oats and barley and added to a snack bar on postprandial glycemia.

DESIGN

In a randomized crossover study, 12 healthy males and females consumed one of 8 snack bars containing 0 (control), 1.5, 3, and 6 g of β-glucan derived from oats or barley or 3 white bread controls. All treatments contained 50 g of available carbohydrate. Blood glucose concentrations were measured after ingestion of the treatments over 2 hours.

RESULTS

Incorporation of 1.5 to 6 g of β-glucan into snack bars had no additional glucose-lowering benefits irrespective of dose and source compared to the control bars (0 g β-glucan), suggesting that both the solid food matrix and composition of the bars may play a role in their effects on glycemic response. All bars reduced blood glucose area under the curve (AUC) by an average of 25% (p < 0.05) compared to the mean of the 3 white bread controls.

CONCLUSION

Adding β-glucan from oats and barley to the snack bar formulation used in this study did not yield any additional benefits beyond the glucose-lowering effects of the snack bars themselves.

Effect of Rg3-enriched Korean red ginseng (Panax ginseng) on arterial stiffness and blood pressure in healthy individuals: a randomized controlled trial

Ginsenoside Rg3, present in steamed ginseng (Panax Ginseng C.A. Meyer), is thought to be a potent modulator of vascular function. Our objective was to clinically evaluate acute effects of ginsenoside Rg3-enriched Korean red ginseng (Rg3-KRG) on measures of arterial stiffness and peripheral and central blood pressure (BP) parameters in healthy volunteers. Using a double-blind, randomized, crossover design, 23 individuals (9 males:14 females; age, 25 ± 2 years; body mass index, 22 ± 0.6 kg/m(2); systolic BP/diastolic BP, 113 ± 3/70 ± 2 mm Hg) were administered 400-mg Rg3-KRG extract or 400-mg wheat bran control on two separate visits with a 7-day washout period. Aortic augmentation index and central BP were measured using applanation tonometry by radial pulse wave analysis, and peripheral BP was evaluated oscillometrically. Measurements were taken at baseline and at 1, 2, and 3 hours after intervention. Compared with control, there were significant reductions in augmentation index (-4.3 ± 8.9%, P = .03), central (-4.8 ± 6.8 mm Hg, P = .01) and brachial mean arterial pressure (-4.4 ± 6.6 mm Hg, P = .01), central systolic (-5.0 ± 7.9 mm Hg, P = .01) and diastolic BP (-3.9 ± 6.6 mm Hg, P = .01), and brachial systolic (-4.4 ± 10.0 mm Hg, P = .048) and diastolic BP (-3.6 ± 6.4 mm Hg, P = .01) at 3 hours after intervention compared with control. This study is the first to demonstrate Rg3-KRG extract acutely lowers central and peripheral arterial pressures in healthy adults. Further clinical evaluation is desired to quantify efficacy in higher risk individuals and in long-term settings.

Effects of Korean White Ginseng (Panax Ginseng C.A. Meyer) on Vascular and Glycemic Health in Type 2 Diabetes: Results of a Randomized, Double Blind, Placebo-controlled, Multiple-crossover, Acute Dose Escalation Trial

Korean red ginseng (steam treated Panax ginseng C.A. Meyer), among most prized traditional herbal remedies, has been clinically shown to improve cardiovascular disease (CVD) risk factors. Whether this holds true for the dried non-steamed variety, known as Korean white ginseng (KWG) is unclear. This study therefore, investigated the efficacy and safety of escalating doses of KWG on vascular and glycemic parameters in type 2 diabetes (T2DM). Using an acute, randomized, placebo-controlled, double-blind, crossover design, 25 participants with well-controlled T2DM (12-males: 13-females, age: 63 ± 9 years, A1c: 6.9 ± 0.7%, BMI: 29.3 ± 4.3 kg/m²) underwent five visits during which they received 1 g, 3 g, or 6 g KWG or 3 g wheat-bran control (twice) together with 50 g-glucose load. For the duration of 240 minutes, augmentation index (AI), and central blood pressure were measured at baseline and at 60 min-intervals, and ambulatory blood pressure was assessed at baseline and at 10 min-intervals. Additionally, capillary blood was collected at time zero and at 15, 30, 45, 60, 90, 120, and 180 minutes post-treatment. A symptoms questionnaire was used to assess safety and adverse events. Two-way ANOVA demonstrated a significant time-treatment interaction effect on AI (p = 0.01) with one-way ANOVA showing significant reductions in AI with 3 g KWG relative to control (p = 0.04). Compared to control, acute administration of KWG appeared to be safe, but did not affect any other postprandial, vascular or glycemic parameters. KWG might have a beneficial effect on AI, a cumulative indicator of arterial health. However, these results are preliminary and highlight the need for long-term investigation with a focus on its accountable components. Clinical Trial Registration: NCT01699074

Effect of Rg3-enriched Korean red ginseng (Panax ginseng) on arterial stiffness and blood pressure in healthy individuals: a randomized controlled trial

Ginsenoside Rg3, present in steamed ginseng (Panax Ginseng C.A. Meyer), is thought to be a potent modulator of vascular function. Our objective was to clinically evaluate acute effects of ginsenoside Rg3-enriched Korean red ginseng (Rg3-KRG) on measures of arterial stiffness and peripheral and central blood pressure (BP) parameters in healthy volunteers. Using a double-blind, randomized, crossover design, 23 individuals (9 males:14 females; age, 25 ± 2 years; body mass index, 22 ± 0.6 kg/m(2); systolic BP/diastolic BP, 113 ± 3/70 ± 2 mm Hg) were administered 400-mg Rg3-KRG extract or 400-mg wheat bran control on two separate visits with a 7-day washout period. Aortic augmentation index and central BP were measured using applanation tonometry by radial pulse wave analysis, and peripheral BP was evaluated oscillometrically. Measurements were taken at baseline and at 1, 2, and 3 hours after intervention. Compared with control, there were significant reductions in augmentation index (-4.3 ± 8.9%, P = .03), central (-4.8 ± 6.8 mm Hg, P = .01) and brachial mean arterial pressure (-4.4 ± 6.6 mm Hg, P = .01), central systolic (-5.0 ± 7.9 mm Hg, P = .01) and diastolic BP (-3.9 ± 6.6 mm Hg, P = .01), and brachial systolic (-4.4 ± 10.0 mm Hg, P = .048) and diastolic BP (-3.6 ± 6.4 mm Hg, P = .01) at 3 hours after intervention compared with control. This study is the first to demonstrate Rg3-KRG extract acutely lowers central and peripheral arterial pressures in healthy adults. Further clinical evaluation is desired to quantify efficacy in higher risk individuals and in long-term settings.

Effect of American ginseng (Panax quinquefolius L.) on arterial stiffness in subjects with type-2 diabetes and concomitant hypertension

ETHNOPHARMACOLOGICAL RELEVANCE

Substantial pre-clinical and some clinical data are available showing that Asian ginseng (Panax ginseng C.A. Meyer) varieties or its particular ginsenosides exert a vasodilatating effect, thus may modulate vascular function. However, the clinical evidence for American ginseng (Panax quinquefolius L.) is scarce. Therefore, this study evaluates the effect of American ginseng (AG) on arterial stiffness, as measured by augmentation index (AI), and blood pressure (BP), in type 2 diabetes patients with concomitant hypertension.

MATERIALS AND METHODS

Using a double-blind, placebo-controlled, parallel design, each participant was randomized to either the selected AG extract or placebo at daily dose of 3g for 12 weeks as an adjunct to their usual antihypertensive and anti-diabetic therapy (diet and/or medications). AI and BP were measured by applanation tonometry at baseline and after 12 weeks of treatment.

RESULTS

A total of 64 individuals with well-controlled essential hypertension and type 2 diabetes (gender: 22 M:42 F, age:63 ± 9.3 years, BP: 145 ± 10.8/84 ± 8.0 mmHg, HbA1c: 7.0 ± 1.3%, fasting blood glucose (FBG): 8.1 ± 2.3 mmol/L) completed the study. Compared to placebo, 3g of AG significantly lowered radial AI by 5.3% (P=0.041) and systolic BP by 11.7% (P<0.001) at 12 weeks. No effect was observed with diastolic BP.

CONCLUSIONS

Addition of AG extract to conventional therapy in diabetes with concomitant hypertension improved arterial stiffness and attenuated systolic BP, thus warrants further investigation on long-term endothelial parameters before recommended as an adjunct treatment.

Effect of American ginseng (Panax quinquefolius L.) on glycemic control in type 2 diabetes

Since diabetes tends to progressively worsen over time, glycemic control often deteriorates in spite of taking regular therapy. Therefore, numerous research studies are by and large focused on finding more efficient therapy, both new medicines for treating type 2 diabetes mellitus, as well as supplements that could serve as an addition to conventional treatment modalities. A variety of herbal preparations have been shown to have modest short-term beneficial effects on glycemia, but of these, the best studied is American ginseng (AG). AG has been shown to be effective in improving glycemic control in type 2 diabetes through increasing post-prandial insulin levels and decreasing postprandial glycemic response. However, high variability in ginsenosides may result in just as high variability in antidiabetic efficacy of over-the-counter ginseng products. Therefore, the availability of standardized extracts of AG could assist greatly in advancing our knowledge on the role of this traditionally used herb and result in a wider application of ginseng product in diabetes management. The aim of this review is to outline the efficacy and safety of American ginseng for AG preparations on glycemic control in patients with type 2 diabetes as well as to increase awareness of the evidence supporting the use of these therapies in diabetes care.

Korean red ginseng (Panax ginseng C.A. Meyer) root fractions: differential effects on postprandial glycemia in healthy individuals

ETHNOPHARMACOLOGICAL RELEVANCE

Variations in ginsenoside profile may predict the postprandial glucose (PPG)-lowering efficacy of ginseng. Previously we reported differential PPG-lowering effects with two Korean red ginseng (KRG) root. FRACTIONS: body and rootlets, of variable ginsenoside profiles. Whether this effect is reproducible with a different KRG source is unclear. We therefore tested two root fractions from a KRG source with elevated ginsenoside levels to assess its effect on PPG.

MATERIALS AND METHODS

After a 12-h overnight fast, 13 healthy individuals (6M:7F; age=28 ± 10 y; BMI=24.1 ± 3 kg/m2; FBG=4.77 ± 0.04 mmol/L) randomly received either 3g of KRG-body, rootlets or placebo, on three separate visits. Treatments were consumed 60 min prior to a standard test meal with capillary blood samples at -60, 0, 15, 30, 45, 60, 90 and 120 min.

RESULTS

The KRGrootlets had>6 fold total ginsensosides than the KRG-body but did not significantly affect PPG. Despite a reduced ginsenoside profile, KRG-body lowered PPG levels at 45, 60, 90 and 120 min during the test (p<0.05), rendering an overall reduction of 27% in incremental area under the glucose curve compared to the control (p<0.05).

CONCLUSIONS

Comparing the results with a previously studied batch of KRG suggests a potential therapeutic dose range for ginsenosides. This observation should be clinically verified with acute screening and ginsenoside composition analysis.

Effects of Korean red ginseng (Panax ginseng C.A. Mayer) and its isolated ginsenosides and polysaccharides on arterial stiffness in healthy individuals

BACKGROUND

Preclinical studies indicate a role of Korean red ginseng (KRG) in the modulation of vascular function; however, clinical evidence is scarce. Therefore, the objective of this study was to investigate the effect of KRG root on peripheral blood pressure (BP) and augmentation index (AI), an emerging method to assess cardiovascular risk beyond conventional BP measurements. Furthermore, in an attempt to elucidate which of the major components of KRG is responsible for these effects, the ginsenoside and polysaccharide fractions isolated from the same KRG root were also investigated.

METHODS

The study was designed as an acute randomized, controlled, double blind, crossover trial. A total of 17 healthy fasted individuals (gender: 9 males:8 females, age: 30 +/- 9 years, body mass index: 25 +/- 3 kg/m(2), systolic BP (SBP): 110 +/- 10.1, diastolic BP (DBP): 65 +/- 7 mm Hg) received, on separate occasions, four treatments consisting of: 3 g of either placebo, KRG root, or a KRG root bioequivalent dose of ginsenoside or polysaccharide fractions. BP and AI were measured by applanation tonometry at baseline, 1, 2, and 3 h post-treatment.

RESULTS

Compared to placebo, 3 g of KRG significantly lowered radial AI by 4.6% (P = 0.045), whereas the ginsenoside fraction comparably decreased AI by 4.8% (P = 0.057), and no effect was observed with the polysaccharides. There were no differences in BP between treatments.

CONCLUSION

Although preliminary, this study is the first to demonstrate that KRG may improve arterial stiffness as measured by AI. In addition, it appears that ginsenosides may be the principal pharmacologically active component of the root, rather than the polysaccharide fraction. This study supports the results seen with KRG in the preclinical studies and warrants further investigation on acute and long-term endothelial parameters.

Fiber facts: benefits and recommendations for individuals with type 2 diabetes

In randomized controlled trials, viscous soluble fibers have demonstrated acute and long-term metabolic improvements in type 2 diabetes, such as reductions in hemoglobin A1c, fasting and post-prandial glycemia, insulinemia, and cardiovascular risk factors. In addition, they may be helpful in weight control through promoting feelings of fullness. Increasing consumption of foods containing fiber or use of fiber supplements could play an important role in managing diabetes with positive outcomes on vascular complications and reduced cardio-vascular disease risk.

Comparable postprandial glucose reductions with viscous fiber blend enriched biscuits in healthy subjects and patients with diabetes mellitus: acute randomized controlled clinical trial

AIM

To compare the blood glucose-lowering effect of a highly viscous fiber blend (VFB) added to a starchy snack on postprandial glycemia between healthy participants and participants with diabetes mellitus.

METHODS

Ten healthy participants (4 men and 6 women, aged 28+/-2.6 years, body mass index [BMI], 24.3+/-0.8 kg/m(2)) and 9 participants with diabetes mellitus type 2 (3 men and 6 women, aged 68+/-3.8 years, BMI 28.8+/-1.2 kg/m(2)) on four separate occasions took either 50 g available carbohydrates as control biscuits, biscuits with 10 g of highly viscous fiber blend, white bread with 12 g of margarine, or white bread alone. Postprandial blood glucose response, glycemic index (GI), and palatability were determined.

RESULTS

Mean (95% confidence interval) GI values of the viscous fiber blend biscuits were 26 (16-36) and 37 (27-47) GI units for healthy participants and participants with diabetes mellitus, respectively. These values were significantly lower than those of white bread, white bread with 12 g of margarine, and control biscuits (P<0.001, paired t test) both in healthy participants (GI 100, 108 [57-159], and 101 [44-158], respectively) and participants with diabetes mellitus (GI 100, 103 [79-127], and 94 [78-110], respectively). Viscous fiber blend significantly reduced the glycemic index by 74% (7.4 GI units/g of fiber) in healthy participants and by 63% (6.3 GI units/g of fiber) in participants with diabetes. The GI did not differ between control meals in both healthy participants and participants with diabetes. There were no significant differences in palatability among the types of meals, although participants with diabetes found the viscous fiber blend biscuits more palatable (P=0.002, t test).

CONCLUSION

Viscous fiber blend is a very potent and palatable soluble fiber addition to a starchy snack, which is able to reduce the glycemic response to a similar extent in both healthy participants and individuals with diabetes mellitus. Biscuits with low GI, and possibly other viscous fiber blend fortified starchy foods, may potentially be a useful replacement of high GI snack foods in the diet.

Using cereal to increase dietary fiber intake to the recommended level and the effect of fiber on bowel function in healthy persons consuming North American diets

BACKGROUND

Dietary fiber intake remains low despite increasing evidence for its health benefits, including laxation.

OBJECTIVE

We aimed to assess the effects of increasing fiber intake on bowel habits and gastrointestinal tolerance in healthy persons consuming a typical Canadian or US diet.

DESIGN

Under a randomized crossover design, 23 free-living participants consumed a typical Canadian or US diet (35% fat, 12 g fiber/d) and received 25.0-28.7 g fiber/d from each of 5 breakfast cereals: All-Bran (AB), Bran Buds with Corn (BBC), Bran Buds with Psyllium (BBP), BBC with viscous fiber blend (VFB), or a low-fiber control for 3 wk, with each study arm separated by a washout of >/=1 wk. Seven-day stool collections and a symptom diary were obtained during the last week of each study arm.

RESULTS

All study cereals induced significant (P < 0.05) increases in fecal bulk from the control diet at 128 +/- 38 g to 199 +/- 56, 199 +/- 57, 247 +/- 87, and 197 +/- 63 g with consumption of AB, BBC, BBP, and VFB, respectively; less intestinal transit time; and significantly (P < 0.05) greater bowel movement frequency. Despite the increased activity of the bowel, a positive level of comfort was maintained. BBP was more effective than other cereals in terms of increasing fecal wet weight (P < 0.05).

CONCLUSION

Water-insoluble dietary fibers (ie, AB and BBC) and their mixtures with water-soluble fibers (ie, BBP and VFB) in the form of breakfast cereals (2.5 servings/d) proved to be a practical way of increasing fiber intake to recommended levels, while maintaining a good level of tolerance.

Fetal safety of loratadine use in the first trimester of pregnancy: a multicenter study

BACKGROUND

Women in their childbearing years often require drug therapy for allergic conditions. Loratadine, a newer nonsedating antihistamine, is often used because of its preferred side effect profile. To date no published data exist on the safety of loratadine use in pregnancy.

OBJECTIVE

We sought to determine whether the use of loratadine in the first trimester of pregnancy was associated with an increased risk for major malformations. Secondary outcomes included rates of miscarriage, birth weights, and gestational age at delivery.

METHODS

All women were prospectively enrolled from 4 participating centers. Detailed maternal medical history and drug exposures were collected at intake, whereas pregnancy complications and outcomes were collected at follow-up. A group of unexposed control subjects were recruited and followed up in a similar manner.

RESULTS

This report includes follow-up on 161 loratadine exposed pregnancies and an equal number of unexposed control subjects. Maternal characteristics (age, pregnancy history, alcohol consumption, and smoking habits) were not different between the 2 groups. There were 5 malformations observed in the exposed group and 6 in the control group, which was not significantly different (P =.9) Similarly, the live birth rate, gestational age at delivery, and birth weights were not different between the 2 groups.

CONCLUSION

These results suggest that loratadine use in pregnancy is not associated with a large risk for major malformations. Further studies are warranted to confirm these findings and to increase study power.