The effect of flaxseed powder on insulin resistance indices and blood pressure in prediabetic individuals: A randomized controlled clinical trial

Estimating the Potential Health Care Cost-Savings from a Flax-Based Treatment for Hypertension

Hypertension contributes to the increase in health care spending in Canada through two primary mechanisms. First, it directly increases costs, as individuals with hypertension require medical care to manage the condition. Second, it indirectly raises expenses by serving as a risk factor for numerous chronic diseases, leading to increased health care utilization among those affected. Therefore, reducing hypertension prevalence could alleviate its resulting strain on the Canadian health care system. Clinical trials have demonstrated that daily flaxseed consumption effectively lowers both systolic and diastolic blood pressure. This study employs a four-step cost-of-illness analysis to estimate the potential health care cost-savings from a flaxseed-based treatment for hypertension. The analysis begins by assessing the proportion of individuals with hypertension likely to adopt the flaxseed regimen. It then evaluates the impact of flaxseed consumption on systolic and diastolic blood pressure. Next, data from the Canadian Health Measures Survey, Cycles 5 and 6, are used to estimate the prevalence of hypertension and the expected reduction in prevalence due to the flaxseed treatment. Finally, the potential reduction in health care spending is calculated. To incorporate uncertainty, partial sensitivity analysis and Monte Carlo simulations were utilized, varying the intake success rate and other model parameters, respectively. The most conservative estimate suggests a potential health care cost-savings of CAD 96,284,344 in Canada for the year 2020.

The Effects of Flaxseed Consumption on Glycemic Control in Native American Postmenopausal Women with Hyperglycemia and Hyperlipidemia

Glucose control in postmenopausal women is influenced by many factors, such as hormones, lifestyle variables, and genetics. Limited data exist on the effect of whole flaxseed on glucose status in postmenopausal Native American women. The aim of this study was to investigate the glucose management effect of a flaxseed dietary intervention on postmenopausal Native American women. In this study, 55 Native American postmenopausal women (aged 47-63 years) with borderline hyperglycemia (>100 and <126 mg/dL) and mild to moderate hypercholestorolemia (≥200 to ≤380 mmol/L), who were not on hormone replacement therapy, were enrolled. Participants were randomly assigned to one of the three dietary regimens (control, flaxseed, and flaxseed + fiber) for three months, receiving interventions in the form of bread, muffins, and flaxseed powder. Despite daily consumption of flaxseed across diverse food formats, no significant changes in glucose (p = 0.3, p = 0.2), insulin levels (p = 0.59, p = 0.9), or HOMA-IR (p = 0.84, p = 0.66) were observed compared to their respective baseline values within the flaxseed and flaxseed + fiber groups, respectively. Conversely, the control group showed a significant rise in final glucose values from baseline (p = 0.01). However, the incorporation of ground flaxseed into low-glycemic foods holds potential for beneficial effects through maintaining glucose status among postmenopausal Native American women. This research provides critical insights into the effects of flaxseed, emphasizing the need for continued exploration to understand its role in supporting glucose management among postmenopausal Native American women. Further exploration is required to investigate the potential long-term impact and the use of flaxseed in managing glucose levels in this demographic.

Tracing the pathways and mechanisms involved in medicinal uses of flaxseed with computational methods and bioinformatics tools

Pharmacological drugs targeting specific pathways involved in various diseases have seen recent advancement with newer and more efficient emerging drug targets, but these drugs are limited in terms of their side effects and patient adherence. The potential of plant-based diets in the form of functional foods is increasingly being realized as an option to treat and/or prevent several diseases. In this work, we have selected flaxseed (Linum usitatissimum), also known as linseed, to study its pharmacological efficacy and proposed mechanisms of action for medicinal purposes. The target genes of linseed with Disease Specificity Index (DSI >0.6) are compared to the associated genes of diabetes mellitus, decrease in appetite, addictive behavior, cardiovascular diseases (CVDs), inflammatory bowel diseases (IBDs), and Polycystic Ovary Syndrome (PCOS), and the selected genes are further evaluated using in silico methods. The binding affinity of flaxseed to three common target proteins (CCDC28b, PDCD6IP, and USP34) is assessed by docking and molecular dynamics (MD) simulations. The results show that linseed is safe to use for mutagenic toxicity and other cardiotoxicity measures, but linseed is unsafe for embryotoxicity, hERG toxicity, and cardiac failure. The analysis of the protein-protein interaction (PPI) network, Gene Ontology (GO), and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways indicates that flaxseed can be used as a medicinal herb for treatment of diabetes mellitus, cardiovascular diseases, IBDs, and PCOS.

The Effect of Plant-Derived Low-Ratio Linoleic Acid/α-Linolenic Acid on Markers of Glucose Controls: A Systematic Review and Meta-Analysis

The objective of this meta-analysis was to examine the impact of a low-ratio linoleic acid/α-linolenic acid (LA/ALA) diet on the glycemic profile of adults. A comprehensive search was performed across four databases (Web of Science, Scopus, Embase, and PubMed) to evaluate the influence of the low-ratio LA/ALA. Relevant references were screened up until February 2023. Intervention effects were analyzed by calculating change values as weighted mean differences (WMD) and 95% confidence intervals (CI) using fixed-effects models. Additionally, subgroup analysis and meta-regression were employed to investigate potential sources of heterogeneity. Twenty-one randomized controlled trials (RCTs) were included, and the low-ratio LA/ALA diet had no significant effect on fasting blood sugar (FBS, WMD: 0.00 mmol/L, 95% CI: -0.06, 0.06, p = 0.989, I2 = 0.0%), insulin levels (WMD: 0.20 μIU/mL, 95% CI: -0.23, 0.63, p = 0.360, I2 = 3.2%), homeostatic model assessment insulin resistance (HOMA-IR, WMD: 0.09, 95% CI: -0.06, 0.23, p = 0.243, I2 = 0.0%), and hemoglobin A1c (HbA1c, WMD: -0.01%, 95% CI: -0.07, 0.06, p = 0.836, I2 = 0.0%). Based on subgroup analyses, it was observed that the impact of a low-ratio LA/ALA diet on elevated plasma insulin (WMD: 1.31 μIU/mL, 95% CI: 0.08, 2.54, p = 0.037, I2 = 32.0%) and HOMA-IR (WMD: 0.47, 95% CI: 0.10, 0.84, p = 0.012, I2 = 0.0%) levels exhibited greater prominence in North America compared to Asian and European countries. Publication bias was not detected for FBS, insulin, HOMA-IR, and HbA1c levels according to the Begg and Egger tests. Furthermore, the conducted sensitivity analyses indicated stability, as the effects of the low-ratio LA/ALA diet on various glycemic and related metrics remained unchanged even after removing individual studies. Overall, based on the available studies, it can be concluded that the low-ratio LA/ALA diet has limited impact on blood glucose-related biomarker levels.

Assessing the Highest Level of Evidence from Randomized Controlled Trials in Omega-3 Research

Over the years, there has been heightened interest in the health benefits of n-3 polyunsaturated fatty acids (PUFA) in reducing chronic diseases such as, cardiovascular disease (CVD), cancer, type 2 diabetes, and acute macular degeneration (AMD). Due to inconsistent findings in the evidence, a review to critically examine the plethora of evidence from randomized controlled trials (RCTs) in n-3 PUFA research was undertaken. The aim of this review is to study the highest level of evidence and to identify gaps in n-3 PUFA research. RCTs were originally designed for pharmaceutical research and later adopted for nutrition and food-related research. RCTs with active diseases assume that n-3 PUFA will have "drug" like effects, and this high expectation may have led to the inconsistent evidence in the literature. The inconsistency in the literature may be related to varying doses of n-3 PUFA, sources of n-3 PUFA (food vs. supplement; plant vs. marine), type of n-3 PUFA (mixture vs. purified), trial duration, population characteristics, sample size, and genetic variation. For future research, there is a need to distinguish between primary and secondary prevention, and to focus RCTs on primary prevention of chronic diseases by n-3 PUFA which is lacking in the literature.

The Role of Flaxseed in Improving Human Health

Flaxseed contains high amounts of biologically active components such as α-linolenic acid, lignans, and dietary fiber. Due to its numerous nutritional properties, flaxseed has been classified as a "superfood", that is, a food of natural origin with various bioactive components and many health-promoting benefits. Flaxseed consumption can be an important factor in the prevention of diseases, particularly related to nutrition. The regular consumption of flaxseed may help to improve lipid profile and lower blood pressure, fasting glucose, and insulin resistance index (HOMA-IR). Moreover, flaxseed is characterized by anticancer and antioxidant properties and can significantly reduce the intensity of symptoms associated with menopause, constipation, and mental fatigue, improve skin condition, and accelerate wound healing. In addition to its bioactive compounds, flaxseed also contains antinutrients such as cyanogenic glycosides (CGs), cadmium, trypsin inhibitors, and phytic acid that can reduce the bioavailability of essential nutrients and/or limit its health-promoting effects. Three common forms of flaxseed available for human consumption include whole flaxseed, ground flaxseed, and flaxseed oil. The bioavailability of ALA and lignans is also dependent on the form of flaxseed consumed. To ensure high bioavailability of its bioactive components, flaxseed should be consumed in the ground form.

Effect of flaxseed supplementation on blood pressure: a systematic review, and dose-response meta-analysis of randomized clinical trials

Many clinical trials have revealed that flaxseed supplementation might exert a potent antihypertensive influence, but the findings are inconsistent. In this regard, a meta-analysis was carried out to provide a more accurate estimate of the impact of flaxseed supplementation on blood pressure. We searched international databases including PubMed, Cochrane Library, Web of Science, Scopus, Embase, and Google Scholar till July 2022. A random-effects model was used to calculate weighted mean differences (WMDs). Non-linear dose-response analysis and meta-regression were performed. Meta-analysis of 33 trials (comprising 43 treatment arms) with 2427 participants revealed significant reductions in both systolic (WMD: -3.19 mmHg; 95% CI: -4.15 to -2.24, p < 0.001; I² = 92.5%, p < 0.001) and diastolic blood pressure (WMD = -2.61 mmHg; 95% CI: -3.27, -1.94, p < 0.001; I² = 94.1%, p < 0.001) following flaxseed supplementation. Greater effects on SBP and DBP were found in trials with an intervention duration of >20 weeks, ≥30 g day^-1 of flaxseed, subjects with BMI 25-30 kg m^-2, and in patients with hypertension. Supplementation with various flaxseed products significantly reduced SBP and DBP levels, confirming the hypothesis that flaxseed could be used as an effective supplement for blood pressure management, alongside routine medications.

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.

Effect of dietary chia supplementation on glucose metabolism and adipose tissue function markers in non-alcoholic fatty liver disease subjects

Introduction

Background: adipose tissue dysfunction is a key factor for diabetes and non-alcoholic fatty liver disease (NAFLD) development. Chia (Salvia hispanica) is an abundant source of omega-3 fatty acids, antioxidants, and fiber which could improve adipose tissue functionality. Aim: to analyze the effect of an isocaloric chia-supplemented diet on glucose metabolism, adipose tissue inflammation, and endothelial function markers in patients with NAFLD and early stages of diabetes. Methods: in 32 patients with previous NAFLD diagnosis, without known diabetes, the effect of a diet supplemented with ground chia (25 g/day/8 weeks) was evaluated. Visceral (VAF) and liver fat, plasma lipids, fatty acids, and cytokine profiles, oral glucose tolerance test (OGTT), insulinogenic index (IGI30), insulin disposition index (DIO), and endothelial progenitor cells (EPC) were analyzed. Before and after eight weeks of diet supplementation. Results: chia supplementation promoted increases in plasma alpha-linolenic acid (75 %) and fiber consumption (55 %), and a higher number of EPC (+126 %). Basal OGTT showed that nine patients had normal OGTT, 17 pre-diabetes, and six newly diagnosed diabetes. In patients with diabetes, chia favored a healthier adipose tissue (VAF -7 %, NAFLD -100 %, adiponectin +47 %, resistin -30 %, IL-6 -44 %, IL-1β -22 %) and upturn glucose metabolism through the improvement of beta-cell function (IGI30 +50 %, DIO +66 %). Conclusions: dietary supplementation with 25 g/day of ground chia may promote a healthier adipose tissue and improve pancreatic β-cell and endothelial function. Among patients with early metabolic abnormalities, phytochemical properties of chia may retard diabetes progression and advanced stages of liver damage.

Therapeutic Effect of Sunflower Seeds and Flax Seeds on Diabetes

Diabetes mellitus (DM) is a metabolic syndrome that is spreading like an epidemic throughout the world without any differentiation of races and ethnic groups and has become the cause of death worldwide. It is characterized by high levels of glucose in the blood and has different types classified on the basis of varying pathophysiology. Type 1 diabetes or insulin-dependent diabetes is characterized by insulin insufficiency due to autoimmune dysfunction. Type 2 diabetes or non-insulin-dependent diabetes results from the combination of resistance to insulin action or/and inadequate insulin secretion. Gestational diabetes (GDM) is defined as hyperglycemia due to insulin resistance during pregnancy. Other types include the monogenic type of DM such as neonatal diabetes mellitus (NDM), maturity-onset diabetes of young (MODY), and diabetes in metabolic syndrome. Diabetes is diagnosed by criteria given by American Diabetes Association (ADA) for different tests like fasting plasma glucose test and hemoglobin A1c test. It is characterized by polydipsia, polyphagia, hyperglycemia, and glucosuria. Diabetes mellitus is managed through medications but many studies have proven that consumption of particular foods leads to decreased glucose levels in diabetic patients. Seeds like sunflower and flax seeds have a role in the reduction of glucose levels and can be used to treat type 2 diabetes. The bioactive components in these seeds like chlorogenic acid in sunflower seeds and secoisolariciresinol diglucosoid are involved in the treatment of insulin resistance or insulin production. In different studies, different amounts of these seed extracts were consumed by rats and humans and it resulted in better glycemic control, which provides information that these seeds have anti-diabetic properties.

Effects of nut and seed consumption on markers of glucose metabolism in adults with prediabetes: a systematic review of randomised controlled trials

The primary aim was to investigate the effects of nut and seed consumption on markers of glucose metabolism in adults with prediabetes. Studies with a randomised controlled trial (RCT) design, comparing the effects of a diet containing nuts or seeds against a diet without nuts or seeds in adults with prediabetes, were considered eligible. Primary outcome measures included fasting plasma glucose (FPG), 2-h plasma glucose during oral glucose tolerance test and glycated Hb (HbA1c) concentrations. Studies were identified by searching PubMed and Scopus electronic databases and by checking full texts and reference lists of relevant records. Risk of bias was assessed using the Cochrane Collaboration's tool. We included five RCT involving 371 adults with prediabetes or at risk of diabetes; three RCT investigated the effects of whole nut consumption and two the effects of ground flaxseed consumption. Consumption of 57 g/d pistachios or mean intake of 60 g/d almonds for 4 months improved FPG and fasting plasma insulin (FPI) concentrations, insulin resistance, cellular glucose uptake in lymphocytes and β-cell function. Consumption of 56 g/d walnuts for 6 months was not found to affect FPG or HbA1c concentrations. Consumption of 13 g/d flaxseed for 3 months improved FPG and FPI concentrations and insulin resistance. In a second study, however, flaxseed consumption was not found to affect markers of glucose metabolism. The risk of bias was generally low, thus the reported results could be reliable. Further investigation of nut and seed consumption effects in the field of prediabetes is warranted.

The effect of omega-3 and vitamin D co-supplementation on glycemic control and lipid profiles in reproductive-aged women with pre-diabetes and hypovitaminosis D: a randomized controlled trial

BACKGROUND

Prediabetes can predispose the individual to type 2 diabetes in the long-term. The present study was conducted to determine the effectiveness of vitamin D and omega-3 co-supplementation on glycemic control and serum lipid profiles in women of reproductive age with prediabetes and hypovitaminosis D.

METHODS

The present factorial, triple-blind, clinical trial was conducted on 168 women of reproductive age with prediabetes and hypovitaminosis D. The participants were assigned to four groups based on block randomization method: the placebo group received omega-3 and vitamin D placebos; the omega-3 group took omega-3 supplements and vitamin D placebos; the vitamin D group received omega-3 placebos and vitamin D supplements and the co-supplementation group. The groups received every 2 weeks 50,000 IU pearls of vitamin D and twice-daily doses of 1000-mg omega-3 tablets or placebos for 8 weeks. Dietary intake, physical activity, anthropometric indices and blood biochemical tests were measured at the beginning and end of the study. Analysis was performed using two-way mixed ANOVA.

RESULTS

A significant reduction was observed in fasting glucose, insulin, homeostasis model assessment-beta cell function, weight and waist circumference in the co-supplementation group compared to the other three groups (P < 0.05). Moreover, high-density lipoprotein-cholesterol levels increased significantly in the co-supplementation group compared to the other three groups (P < 0.05). Despite the fact that homeostasis model assessment-insulin resistance, total cholesterol, triglyceride and low-density lipoprotein-cholesterol levels decreased after intervention in the co-supplementation group, there was no significant difference between the groups in these outcomes.

CONCLUSION

Vitamin D and omega-3 co-supplementation improved fasting serum glucose, insulin, high-density lipoprotein-cholesterol level, homeostasis model assessment-beta cell function, weight and waist circumference in women of reproductive age with prediabetes and hypovitaminosis D. This co-supplementation can therefore be recommended for glycemic control in these women.Trial registration Iranian Registry of Clinical Trials Code: IRCT20100130003226N17. Registered on 9 Feb. 2019.

Seeds

A wide variety of plant species provide edible seeds. Seeds are the dominant source of human calories and protein. The most important and popular seed food sources are cereals, followed by legumes and nuts. Their nutritional content of fiber, protein, and monounsaturated/polyunsaturated fats make them extremely nutritious. They are important additions to our daily food consumption. When consumed as part of a healthy diet, seeds can help reduce blood sugar, cholesterol, and blood pressure.

The effect of co supplementation of omega-3 and vitamin D on cardio metabolic risk factors and psychological distress in reproductive-aged women with prediabetes and hypovitaminosis D: a study protocol for a randomized controlled trial

BACKGROUND

A prediabetic state is a risk factor for type 2 diabetes. There are no approved drugs to manage prediabetes. Among the supplements routinely used by individuals, vitamin D and omega-3 have been studied to reduce fasting blood sugar. However, their co-supplementation has not been studied in individuals with prediabetes. This randomized controlled trial is designed to determine the effects of these two supplements on fasting blood sugar, other cardio metabolic risk factors, and psychological distress in reproductive-aged women with prediabetes and hypovitaminosis D.

METHODS/DESIGN

This 2 × 2 factorial, triple-blind, randomized, placebo-controlled, clinical trial will be done on 168 women of reproductive age diagnosed with prediabetes and hypovitaminosis D. Participants will be randomly assigned equally to four groups: (1) 1000 mg omega-3 fatty acid twice a day + vitamin D placebo every two weeks; (2) omega-3 fatty acid placebo twice a day + 50,000 IU vitamin D every two weeks; (3) 1000 mg omega-3 fatty acid twice a day + 50,000 IU vitamin D every two weeks; (4) omega-3 fatty acid placebo twice a day + vitamin D placebo every two weeks for eight weeks. At the beginning, participants will provide a self-reported questionnaire on the sociodemographic characteristics. At baseline and post-intervention visits, physical activity, Depression Anxiety Stress Scale 21 and Pittsburgh Sleep Quality Index, and a three-day food record will be collected for each individual. Blood pressure, weight, height, and waist circumference will also be measured. At the beginning and at the end, a blood sample will be used for estimating serum glucose indices (fasting blood sugar and insulin, homeostasis model assessment-insulin resistance, homeostasis model assessment-beta cell function), lipids (triglyceride, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, total cholesterol), and vitamin D status. Data analysis using Kolmogorov-Smirnov test, paired t-test, one-way analysis of variance, and repeated measures analysis of variance will be conducted through SPSS-24 software.

DISCUSSION

The primary aim of the present trial is to determine the effect of vitamin D and/or omega-3 on glycemic indices, lipid profiles, psychological distress, blood pressure, and anthropometric indices in prediabetic women with hypovitaminosis D. The results from this trial will provide evidence on the efficacy of these two supplements for preventing or delaying the onset of type 2 diabetes in high-risk individuals.

TRIAL REGISTRATION

Iran Clinical Trials Registry, IRCT20100130003226N17. Registered on 9 February 2019.

Effect of Flaxseed Powder on Cardiovascular Risk Factor in Dyslipidemic and Hypertensive Patients

Background:

Hyperlipidemia and hypertension are the most important causes of ischemic heart disease. There is evidence that flaxseed powder can improve lipid profile and blood pressure. In this study, we want to investigate the effects of flaxseed powder consumption on patients with hyperlipidemia and hypertension.

Methods:

This randomized double-blind placebo-controlled clinical trial was performed on 80 hyperlipidemic and hypertensive patients (men and women between 20 and 60 years old). In this study, participants were recruited from Imam Khomeini hospital clinics of Shiraz University of Medical Sciences in 2017 randomly allocated to flaxseed powder group and placebo group. The intervention group received 36 g of flaxseed sachet (n = 40), and control group received 12 g placebo sachet (n = 40) for 8 weeks. Serum lipid profiles, blood pressure, fasting blood sugar, and anthropometric indices were measured. Data were analyzed by using SPSS.

Results:

We found significant reduction (P < 0.001) in anthropometric indices (waist circumference and waist-to-hip ratio) and lipid profiles (triglycerides [P = 0.015], total cholesterol [P = 0.018], and low-density lipoprotein [P < 0.001]) within flaxseed group in comparison with placebo group.

Conclusions:

Based on beneficial effects of flaxseed on cardiovascular risk factors, it seems that flaxseed consumption can be considered as a useful therapeutic approach for reducing lipid profile and anthropometric indices.

An evaluation of randomized controlled trials on nutraceuticals containing traditional Chinese medicines for diabetes management: a systematic review

BACKGROUND

Nutraceuticals containing traditional Chinese medicine (TCM) are promoted for use in the management of diabetes. The evidence to support such use is largely unknown. This study aimed to summarise and evaluate the literature reporting the results of randomized controlled trials (RCTs) investigating the effects of nutraceuticals in people living with diabetes.

METHODS

Literature from four electronic databases (PubMed, Scopus, CINAHL and Web of Science) was searched following PRISMA guidelines to yield RCT publications on nutraceutical for diabetes management published since 2009. The quality of reporting was assessed using the CONSORT 2010 checklist statement. Risk-of-bias for each study was assessed using the Cochrane risk of bias tool.

RESULTS

Out of 1978 records identified in the initial search, 24 randomized, double/triple-blinded, controlled trials that investigated the effect of nutraceuticals covering 17 different TCM herbs for diabetes management were selected. Participants included people who were diabetic (n = 16), pre-diabetic (n = 3) or predisposed to diabetes (n = 5). Sample sizes ranged between 23 and 117 for 2 arms, or 99-165 for 3 arms. Comparisons were made against placebo (n = 22), conventional medicine (n = 1), or regular diet (n = 1) for a duration between 4 and 24 weeks. All but one study tested the effect on fasting blood glucose levels (n = 23) or glycated haemoglobin levels (n = 18), and/or postprandial 2-h blood glucose levels (n = 4) as the primary outcomes. Nineteen studies reported some statistically significant reductions in the respective measures while 5 studies showed no effect on primary or secondary outcomes. None of the included studies met all the criteria for the CONSORT guidelines. Incomplete reporting about randomization and blinding, and a lack of ancillary analyses to explore other influential factors and potential harms associated with the use were repeatedly noted. Based on the Cochrane risk-of-bias tool, 19 studies were deemed to have a high risk of bias mainly attributed to sponsor bias.

CONCLUSIONS

There is some evidence to suggest positive clinical outcomes in response to the administration of a range of nutraceuticals containing TCM in the management of diabetes. However, these results must be interpreted with caution due to the overall low quality of the trials.

Flaxseed Lignans as Important Dietary Polyphenols for Cancer Prevention and Treatment: Chemistry, Pharmacokinetics, and Molecular Targets

Cancer causes considerable morbidity and mortality across the world. Socioeconomic, environmental, and lifestyle factors contribute to the increasing cancer prevalence, bespeaking a need for effective prevention and treatment strategies. Phytochemicals like plant polyphenols are generally considered to have anticancer, anti-inflammatory, antiviral, antimicrobial, and immunomodulatory effects, which explain their promotion for human health. The past several decades have contributed to a growing evidence base in the literature that demonstrate ability of polyphenols to modulate multiple targets of carcinogenesis linking models of cancer characteristics (i.e., hallmarks and nutraceutical-based targeting of cancer) via direct or indirect interaction or modulation of cellular and molecular targets. This evidence is particularly relevant for the lignans, an ubiquitous, important class of dietary polyphenols present in high levels in food sources such as flaxseed. Literature evidence on lignans suggests potential benefit in cancer prevention and treatment. This review summarizes the relevant chemical and pharmacokinetic properties of dietary polyphenols and specifically focuses on the biological targets of flaxseed lignans. The consolidation of the considerable body of data on the diverse targets of the lignans will aid continued research into their potential for use in combination with other cancer chemotherapies, utilizing flaxseed lignan-enriched natural products.

Dietary Polyphenols, Mediterranean Diet, Prediabetes, and Type 2 Diabetes: A Narrative Review of the Evidence

Dietary polyphenols come mainly from plant-based foods including fruits, vegetables, whole grains, coffee, tea, and nuts. Polyphenols may influence glycemia and type 2 diabetes (T2D) through different mechanisms, such as promoting the uptake of glucose in tissues, and therefore improving insulin sensitivity. This review aims to summarize the evidence from clinical trials and observational prospective studies linking dietary polyphenols to prediabetes and T2D, with a focus on polyphenol-rich foods characteristic of the Mediterranean diet. We aimed to describe the metabolic biomarkers related to polyphenol intake and genotype-polyphenol interactions modulating the effects on T2D. Intakes of polyphenols, especially flavan-3-ols, and their food sources have demonstrated beneficial effects on insulin resistance and other cardiometabolic risk factors. Several prospective studies have shown inverse associations between polyphenol intake and T2D. The Mediterranean diet and its key components, olive oil, nuts, and red wine, have been inversely associated with insulin resistance and T2D. To some extent, these associations may be attributed to the high amount of polyphenols and bioactive compounds in typical foods conforming this traditional dietary pattern. Few studies have suggested that genetic predisposition can modulate the relationship between polyphenols and T2D risk. In conclusion, the intake of polyphenols may be beneficial for both insulin resistance and T2D risk.