Effect of Nigella sativa (black seed) supplementation on glycemic control: A systematic review and meta‐analysis of clinical trials

Endothelial Function Responses to Nigella sativa (Black Seed) Supplementation: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Nigella sativa (NS), commonly known as black cumin or black seed, is a medicinal plant with a rich history of traditional use in various cultures. Recent research has shed light on its potential therapeutic properties, particularly its effects on endothelial markers involved in inflammatory processes. This systematic review and meta-analysis evaluated the endothelial function responses, including intercellular adhesion molecule (ICAM) and vascular cell adhesion molecule (VCAM), to NS supplementation. We systematically searched Medline via PubMed, Scopus, Web of Science, and Embase databases from inception until August 5, 2023. Comparative randomized controlled trials (RCTs) were included. Pairwise meta-analysis was conducted using RevMan version 5.4 for Windows. Pooled data were reported as mean difference (MD), with their 95% confidence interval (CI). The present meta-analysis included three RCTs, which included 146 patients. The pooled random-effect size showed no difference between the NS group and the control group in terms of ICAM (MD = -59.32, 95% CI: -137.18 to 18.54; p = 0.14) and VCAM (MD = -200.1, 95% CI: -429.9 to 29.69; p = 0.09). The pooled data were severely heterogeneous. In conclusion, NS supplementation does not have a significant impact on the endothelial function of patients with CVD or the risks of CVD. Further comparative RCTs with larger sample sizes and more diverse populations are needed to establish the efficacy and safety of NS in different clinical settings.

A Scoping Review of the Clinical Evidence for the Health Benefits of Culinary Doses of Herbs and Spices for the Prevention and Treatment of Metabolic Syndrome

Metabolic syndrome (MetS) is a growing global health problem. Evidence suggests that diets rich in phytochemical-containing herbs and spices can contribute to reducing the risk of chronic diseases. This review assesses the scope of evidence supporting the use of herbs and spices in the diet for the prevention or treatment of MetS and its associated health conditions. A search of the PubMed, Scopus and Google Scholar databases was carried out to assess the available clinical evidence for culinary doses of commonly used herbs and spices. Trials that were measuring health factors related to metabolic disorders in healthy individuals, or the health of individuals with MetS or associated diseases, were included. Out of a total of 1738 papers identified, there were 142 relevant studies on black pepper, chilli, cardamom, cinnamon, coriander, cumin, fennel, fenugreek, garlic, ginger, nigella seed, rosemary, sage and turmeric. No relevant research was found for cloves, mint, oregano, parsley or thyme. Cinnamon, fenugreek and ginger were the herbs/spices with the most published trials on them and that showed promise for glycaemic control. Cardamom appears to have potential to reduce inflammatory markers, and cinnamon, ginger and turmeric to reduce blood lipids. Patients with type 2 diabetes were the population most likely to be included in studies, but the preventative benefits of herbs/spices in healthy populations were also investigated, particularly for chilli, ginger and cinnamon. There is evidence for the beneficial effect of culinary doses of many common herbs/spices in the prevention and treatment of MetS and associated disorders.

Mechanism of the antidiabetic action of Nigella sativa and Thymoquinone: a review

Introduction

Long used in traditional medicine, Nigella sativa (NS; Ranunculaceae) has shown significant efficacy as an adjuvant therapy for diabetes mellitus (DM) management by improving glucose tolerance, decreasing hepatic gluconeogenesis, normalizing blood sugar and lipid imbalance, and stimulating insulin secretion from pancreatic cells. In this review, the pharmacological and pharmacokinetic properties of NS as a herbal diabetes medication are examined in depth, demonstrating how it counteracts oxidative stress and the onset and progression of DM.

Methods

This literature review drew on databases such as Google Scholar and PubMed and various gray literature sources using search terms like the etiology of diabetes, conventional versus herbal therapy, subclinical pharmacology, pharmacokinetics, physiology, behavior, and clinical outcomes.

Results

The efficiency and safety of NS in diabetes, notably its thymoquinone (TQ) rich volatile oil, have drawn great attention from researchers in recent years; the specific therapeutic dose has eluded determination so far. TQ has anti-diabetic, anti-inflammatory, antioxidant, and immunomodulatory properties but has not proved druggable. DM's intimate link with oxidative stress, makes NS therapy relevant since it is a potent antioxidant that energizes the cell's endogenous arsenal of antioxidant enzymes. NS attenuates insulin resistance, enhances insulin signaling, suppresses cyclooxygenase-2, upregulates insulin-like growth factor-1, and prevents endothelial dysfunction in DM.

Conclusion

The interaction of NS with mainstream drugs, gut microbiota, and probiotics opens new possibilities for innovative therapies. Despite its strong potential to treat DM, NS and TQ must be examined in more inclusive clinical studies targeting underrepresented patient populations.

Therapeutic role of kaempferol and myricetin in streptozotocin-induced diabetes synergistically via modulation in pancreatic amylase, glycogen storage and insulin secretion

Kaempferol and Myricetin alone have promising benefits on diabetes and related complications, yet the effectiveness of cotreating the two compounds on diabetes have not been studied. The existing investigation was to study the combined anti-diabetic effect of kaempferol and myricetin in Streptozotocin (STZ)-activated diabetes in rats. To evaluate the anti-diabetic activity, 36 Wistar rats were segregated into six groups; Normal, 50 mg/kg STZ-induced diabetes, and four (50 mg/kg kaempferol, 50 mg/kg myricetin, 25 mg/kg kaempferol + myricetin, and 5 mg/kg glibenclamide) compound-treated diabetic groups. The effects of co-treatment on parameters, glucose, insulin, lipid profile, liver enzymes, antioxidant biomarkers, and inflammatory cytokines were measured. The study revealed that combined treatment restored the assessed parameters including glucose levels, inflammatory cytokines, oxidative markers, and lipid and liver enzymes in diabetic rats. The results indicate that cotreatment of kaempferol and myricetin has a beneficial role against diabetes suggesting that cotreatment of these compounds can be used therapeutically in treating diabetes.

Consumption of Nuts and Seeds and Health Outcomes Including Cardiovascular Disease, Diabetes and Metabolic Disease, Cancer, and Mortality: An Umbrella Review

Consumption of nuts and seeds is associated with a range of health outcomes. Summarizing the best evidence on essential health outcomes from the consumption of nuts is essential to provide optimal recommendations. Our objective is to comprehensively assess health outcome associations related to the consumption of nuts and seeds, using a culinary definition including tree nuts and peanuts (registered in PROSPERO: CRD42021258300). Health outcomes of interest include cardiovascular disease, cancer, diabetes, obesity, respiratory disease, mortality, and their disease biomarkers. We present associations for high compared with low consumption, per serving, and dose-response relations. MEDLINE, Embase, Cochrane, and Epistemonikos were searched and screened for systematic reviews and meta-analyses. Evidence was extracted from 89 articles on the consumption of nuts and relevant health outcomes, including 23 articles with meta-analysis on disease and mortality, 66 articles on biomarkers for disease, and 9 articles on allergy/adverse outcomes. Intake of nuts was associated with reduced risk of cardiovascular diseases and related risk factors, with moderate quality of evidence. An intake of 28 g/d nuts compared with not eating nuts was associated with a 21% RR reduction of cardiovascular disease (including coronary heart disease incidence and mortality, atrial fibrillation, and stroke mortality), an 11% risk reduction of cancer deaths, and 22% reduction in all-cause mortality. Nut consumption was also inversely associated with mortality from respiratory diseases, infectious diseases, and diabetes; however, associations between nut consumption and diabetes incidence were mixed. Meta-analyses of trials on biomarkers for disease generally mirrored meta-analyses from observational studies on cardiovascular disease, cancers, and diabetes. Allergy and related adverse reactions to nuts were observed in 1-2% of adult populations, with substantial heterogeneity between studies. Overall, the current evidence supports dietary recommendations to consume a handful of nuts and seeds per day for people without allergies to these foods.

Efficacy of nigella sativa oil on endothelial function and atherogenic indices in patients with coronary artery diseases: A randomized, double-blind, placebo-control clinical trial

A therapeutic compound with antioxidant and anti-inflammatory effects might be a practical approach in endothelial dysfunction caused by oxidation and inflammation associated with atherosclerosis. Therefore, we aim to examine the efficacy of Nigella sativa (NS) oil supplementation on endothelial function and atherogenic indices in coronary artery disease (CAD) patients. Sixty individuals aged between 35 to 65 years old were recruited and divided into two groups, receiving either 2 g/daily of NS oil or sunflower oil as the placebo for 8 weeks. Serum levels of adhesion molecules, oxidative markers, and atherogenic parameters were evaluated at the starting point and the end of supplementation. Serum levels of vascular cell adhesion protein 1 (sVCAM-1) [-264.44 95% C, (156.83, 372.04)], intercellular adhesion molecule 1 (sICAM-1) [-132.38 95% C, (40.64, 224.1)], and malondialdehyde (MDA) [-0.21 95% C, (0.03, 0.40)] declined significantly following NS supplementation, while total antioxidant capacity increased [0.03 95% C, (0.03, 0.16)]. NS oil supplementation demonstrated a potential beneficial effect on endothelial function by reducing ICAM-1, VCAM-1 levels and affecting oxidative markers. However, further studies are necessary to elucidate NS oil as a therapeutic agent and complementary therapy in patients with stable CAD.

Nigella sativa L. and Its Active Compound Thymoquinone in the Clinical Management of Diabetes: A Systematic Review

Despite existing conventional hypoglycemic drugs to manage diabetes, their non-availability and cost in low-income countries coupled with the associated side effects remain a major concern. Consequently, exploring for alternative treatments to manage diabetes has been a continuous priority. Nigella sativa L. (NS) (Family: Ranunculaceae) is regarded as a valuable traditional remedy in diabetes management and extensively studied for its biological properties. This systematic review provides a comprehensive and critical analysis of clinical studies on the efficacy, safety, and mechanism of action of NS and its compound thymoquinone (TQ) in diabetes management. The main scientific databases which were scrutinised were Scopus, PubMed, Google Scholar, and Web of Science. Data search was conducted from inception to January 2022. A total of 17 clinical studies were obtained; 16 studies on Nigella sativa L. and 1 study on its compound TQ. N. sativa was found to be highly potent in terms of its hypoglycemic activity when compared to placebo based on improvement in parameters including fasting blood glucose (FBG), postprandial blood glucose (PPBG), Hemoglobin A1C (HbA1c), homeostatic model assessment for insulin resistance (HOMA-IR), and homeostatic model assessment for assessment of beta-cell functionality (HOMA-β). The compound TQ in combination with a daily dose of metformin demonstrated a greater reduction in the levels of HbA1c and blood glucose compared to metformin alone. The bioavailability of TQ can be enhanced by using nanoparticulate drug delivery systems. Considering the findings of the clinical studies along with negligible adverse effects, NS has strong potential application in bioproduct development for the management of diabetes. Further investigations should explore the detailed mechanism of actions by which TQ exerts its therapeutic antidiabetic effects to provide more insights into its clinical use in the management of diabetes.

A Phase II, Randomized, Double-Blind, Double-Dummy, Active-Controlled Clinical Trial to Investigate the Efficacy and Safety of NW Low-Glu® in Patients Newly Diagnosed with Type 2 Diabetes Mellitus

Background

Medicinal plants have long been used for the treatment of type 2 diabetes mellitus (T2DM). This study aimed to investigate the hypoglycemic efficacy and safety of NW Low-Glu® (contents of one capsule are 300 mg Mas Cotek + 100 mg Cinnamomum cassia L. + 250 mg Nigella sativa L. powdered extracts) in treatment-naïve, newly diagnosed T2DM patients.

Methods

This was a 12-week, double-blind, double-dummy, randomized, phase 2 clinical trial. A total of 232 male and female patients aged ≥18 and ≤65 years who were newly diagnosed with T2DM and have not received any antidiabetic drugs before and were equally randomized to receive metformin (2000 mg per day), low-dose NW Low-Glu® (content of four capsules per day), or high-dose NW Low-Glu® (content of five capsules per day). Our primary objective was to measure the mean change in HbA1c between each of the experimental arms and the metformin arm.

Results

There was a significant reduction in mean HbA1c at 12 weeks compared to baseline in the low-dose (0.6 (1.4)%; p=0.002) and high-dose arms (0.8 (1.7)%; p=0.004). There was also a significant reduction in 2 hr PPG at 12 weeks in the low-dose (35.4 (74.9) mg/dL, p=0.001) and high-dose arms (24.7 (100.8) mg/dL, p=0.04). Weight reduction was significantly higher with both high-dose (1.1 (−1.7) Kg; p=0.005) and low-dose arms (0.9 (−1.5) Kg; p=0.023) compared to metformin (0.8 (−1.8) Kg). No serious AEs or deaths were reported.

Conclusions

After 3 months of treatment, NW Low-Glu® was noninferior to metformin in reducing HbA1c and 2 hr PPG, while leading to significantly higher weight reduction in newly diagnosed T2DM patients. It was also safe and well tolerated.

Nigella sativa supplementation improves cardiometabolic indicators in population with prediabetes and type 2 diabetes mellitus: A systematic review and meta-analysis of randomized controlled trials

Objective

Nigella sativa (N. sativa) from the family Ranunculaceae has medicinal properties. Previous studies have reported promising findings showing that N. sativa may benefit cardiometabolic health; however, current evidence on its cardiometabolic effects on those with prediabetes and type 2 diabetes mellitus (T2DM) is still unclear. Hence, we conducted a systematic review and meta-analysis to assess the efficacy of N. sativa on cardiometabolic parameters in population with prediabetes and T2DM.

Methods

PubMed/Medline, ISI Web of Science, Scopus, and Cochrane library were systematically searched up to June 20, 2022. Meta-analyses using random-effects models were used.

Results

Eleven randomized controlled trials (RCTs) were included in the meta-analysis. N. sativa intervention resulted in significant changes in fasting plasma glucose (FPG), hemoglobin A1c (HbA1c), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), c-reactive protein (CRP), and malondialdehyde (MDA), without overall changes in glucose levels after oral glucose tolerance test (OGTT), fasting insulin, homeostatic model assessment of insulin resistance (HOMA-IR), triglyceride, high-density lipoprotein cholesterol (HDL-C), and body mass index (BMI) when compared with the control group. In subgroup analyses, N. sativa supplementation enhanced serum levels of HDL-C in subjects with baseline HDL-C lower than 40 mg/dL. Furthermore, HOMA-IR and BMI values decreased in the N. sativa-supplemented group compared with the control group, when the length of follow-up was more than 8 weeks and the dose was more than 1 g/day for N. sativa supplementation, respectively.

Conclusion

Our findings indicate that N. sativa supplementation may effectively improve cardiometabolic profiles in individuals with prediabetes and T2DM.

Effect of Nigella sativa supplementation on kidney function, glycemic control, oxidative stress, inflammation, quality of life, and depression in diabetic hemodialysis patients: study protocol for a double-blind, randomized controlled trial

Background and objectives

The kidney is probably the most crucial target of microvascular damage in diabetes, which can ultimately eventuate end-stage renal disease (ESRD). Hemodialysis is the most usual way of renal replacement therapy in ESRD. Patients receiving hemodialysis are susceptible to many complications like hyperglycemia, inflammation, depression, anxiety, and poor quality of life. So, they are constrained to consume many drugs. Medicinal herbs are used in different cultures as a reliable source of natural remedies. This study aims to determine the efficacy of Nigella sativa (NS) oil supplementation on blood glucose, kidney function tests, inflammation, oxidative stress, quality of life, and depression in hemodialysis patients.

Methods and analysis

This double-blind, randomized controlled trial will enroll 46 patients with diabetes mellitus who give hemodialysis thrice a week. Patients who have an inflammatory or infectious disease and who are receiving nonsteroidal anti-inflammatory drugs will be excluded. Patients will be randomized to the treatment and control group, which will be recommended using two soft gels of NS and paraffin oil, respectively. Laboratory tests will be assessed at baseline and end of the study, including fasting blood sugar, glycated albumin, insulin, creatinine, blood urea nitrogen, urea, uric acid, superoxide dismutase, malondialdehyde, total antioxidant capacity, high sensitive C reactive protein, and 24-h urine volume. Also, the kidney disease and quality of life and hospital anxiety and depression scale questionnaires will be evaluated.

Discussion

Previous studies have reported a positive effect of Nigella sativa supplementation in chronic kidney disease, but there is no evidence that this plant is safe in hemodialysis patients. The results of this study can be helpful in better control of blood sugar and kidney function and reduce complications in diabetic hemodialysis patients.

Trial registration

Iranian Registry of Clinical Trials . Registered on 31 May 2020

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-021-05917-y.

The Role of Bioactive Compounds of Nigella sativa in Rheumatoid Arthritis Therapy-Current Reports

Black cumin (Nigella sativa, NS) is included in the Ranunculaceae family and is classified as a medicinal plant due to very high levels of various bioactive compounds. They determine its therapeutic effects, including anti-inflammatory, anti-allergic, anti-cancer, hypoglycemic, antioxidant, hypotensive, hypolipidemic, and immunomodulating properties. The results of scientific studies indicate a supporting role of black cumin in the treatment of autoimmune diseases, including rheumatoid arthritis, due to the health-promoting properties of its bioactive ingredients. The aim of the current article is to analyze the results of scientific publications on the role of bioactive ingredients contained in black cumin in the treatment of rheumatoid arthritis.

Effects of Nigella sativa oil supplementation on selected metabolic parameters and anthropometric indices in patients with coronary artery disease: A randomized, double-blind, placebo-controlled clinical trial

Various metabolic parameters are risk factors related to the amplified risk of atherosclerotic cardiovascular disease. A wide variety of data exist on Nigella sativa (NS) and metabolic parameters. The current study is designed to examine NS supplementation on lipid profile, blood pressure, glycemic control, anthropometric indices, and insulin resistance in individuals with coronary artery disease (CAD). In a randomized, double-blind, placebo-controlled clinical trial, 60 patients with CAD received either 2 g of NS oil or sunflower oil as a placebo for 8 weeks. Biochemical and anthropometric measurements were assessed. NS significantly reduced weight (-1.82 Kg; 95% C, [2.72, 4.13]), body mass index (-0.67 kg/m² ; 95% C, [0.33, 1.01]), waist circumference (-2.15 cm; 95% C, [1.06, 3.23]), hip circumference (-1.26 cm; 95% C, [0.61, 1.910]), waist-to-hip ratio (0.008; 95%C, [0.001, 0.01]), systolic (-9.52 mmHg; 95% C, [7.14, 11.9]), diastolic blood pressure (-8.26 mmHg; 95% C, [4.89, 11.62]), and fasting blood glucose (FBS) (-4.32 mg/dl; 95% C, [-0.51, 9.15]) as compared with the placebo group. The results indicate a potential beneficiary effect of NS on the metabolic parameters in CAD patients including improvements in anthropometric indices, blood pressure, and FBS.

Phytonutrient supplements and metabolic biomarkers of cardiovascular disease: An umbrella review of meta-analyses of clinical trials

Phytonutrients exert several pharmacological effects on humans. In this study, we performed an umbrella review of the association of phytonutrient supplements (PNSs) with biomarkers of cardiovascular disease. Relevant published systematic reviews and meta-analyses of clinical trials were identified by searching PubMed, Embase, and Cochrane Library until July 4, 2020. Weighted mean differences (WMDs) and 95% confidence intervals (CIs) for summarized effects and I² statistics of heterogeneity were extracted from individual studies or reanalyzed using a random-effects model. Of the 50 included studies, pooled effects of PNSs on blood pressure, lipid profiles, and glycemic control were reported in 16, 25, and 14 articles, respectively. The findings appeared to be highly heterogeneous among individual trials of included systematic reviews and meta-analyses. Ginger (WMD = -6.36 mmHg, 95% CI = -11.27, -1.46) and Hibiscus sabdariffa (WMD = -7.58 mmHg, 95% CI = -9.69, -5.46) were associated with lowered systolic blood pressure, whereas Aloe vera, Nigella sativa, and spirulina were associated with beneficial effects on both lipid profiles and glycemic control. In summary, this umbrella review has provided up-to-date evidence for the effect of PNSs on biomarkers related to hypertension, dyslipidemia, and diabetes. The results must be interpreted with caution due to potential heterogeneity.

Therapeutic perspective of thymoquinone: A mechanistic treatise

The higher utilization of fruits and vegetables is well known to cure human maladies due to the presence of bioactive components. Among these compounds, thymoquinone, a monoterpene and significant constituent in the essential oil of Nigella sativa L., has attained attention by the researchers due to their pharmacologies perspectives such as prevention from cancer, antidiabetic and antiobesity, prevention from oxidative stress and cardioprotective disorder. Thymoquinone has been found to work as anticancer agent against different human and animal cancer stages including propagation, migration, and invasion. Thymoquinone as phytochemical also downregulated the Rac1 expression, mediated the miR-34a upregulation, and increased the levels of miR-34a through p53, as well as also regulated the pro- and antiapoptotic genes and decreased the phosphorylation of NF-κB and IKKα/β. In addition, thymoquinone also lowered the metastasis and ERK1/2 and PI3K activities. The present review article has been piled by adapting narrative review method and highlights the diverse aspects of thymoquinone such as hepatoprotective, anti-inflammatory, and antiaging through various pathways, and further utilization of this compound in diet has been proven effective against different types of cancers.

The effect of nigella sativa on biomarkers of inflammation and oxidative stress: A systematic review and meta-analysis of randomized controlled trials

Inflammation and oxidative stress are involved in the pathogenesis of a myriad of chronic disorders. This systematic review and meta-analysis was designed to determine the effects of Nigella Sativa (NS) seed and seed oil consumption on several biomarkers of inflammation and oxidative stress. The Scopus, Web of Science, and PubMed-MEDLINE databases were systematically searched until August 2019. The quality assessment and heterogeneity of the selected randomized clinical trials (RCTs) were measured using the Jadad checklist, and Q and I² tests, respectively. Finally, a total of 10 clinical RCTs were found to be eligible for this meta-analysis. The pooled findings showed that NS consumption significantly reduced serum high-sensitivity C-reactive protein (hs-CRP; WMD: -0.67, 95% CI: -1.29, -0.05, I²  = 95.7%), tumor necrosis factor-alpha (TNF-α; WMD: -2.29, 95% CI: -4.48, -0.11, I²  = 93%), and malondialdehyde (MDA; WMD: -1.18, 95% CI: -2.24, -0.12, I²  = 85.4%), and significantly increased total antioxidant capacity (TAC; WMD: 0.35, 95% CI: 0.10, 0.59, I²  = 77.1%), and superoxide dismutase (SOD; WMD: 66.30, 95% CI: 1.03, 131.57, I²  = 99.4%) levels. Overall, the results of this systematic review and meta-analysis imply that NS consumption may decrease inflammatory response and oxidative stress markers. PRACTICAL APPLICATIONS: Overall, the evidence supports the consumption of NS to reduce hs-CRP, TNF-α, and MDA, and to increase SOD and TAC levels. In addition, the subgroup analyses findings concluded that lower dosages of NS, longer durations of the intervention, and the use of NS seed oil may result in more effective action on inflammatory markers, but because of the limited number of trials, the results must be analyzed with caution, especially for the subgroup analysis. However, further prospective studies regarding the effect of NS consumption on biomarkers of inflammation and oxidative stress, with larger sample sizes, from various countries and longer follow-up periods, are required to confirm whether NS possesses veritable anti-inflammatory and antioxidant effects.

A polyphenol-rich dietary pattern improves intestinal permeability, evaluated as serum zonulin levels, in older subjects: The MaPLE randomised controlled trial

BACKGROUND & AIM

Increased intestinal permeability (IP) can occur in older people and contribute to the activation of the immune system and inflammation. Dietary interventions may represent a potential strategy to reduce IP. In this regard, specific food bioactives such as polyphenols have been proposed as potential IP modulator due to their ability to affect several critical targets and pathways that control IP. The trial aimed to test the hypothesis that a polyphenol-rich dietary pattern can decrease serum zonulin levels, an IP surrogate marker involved in tight junction modulation, and can beneficially alter the intestinal microbiota, and IP-associated biochemical and clinical markers in older subjects.

METHODS

A randomised, controlled, cross-over intervention trial was performed. Sixty-six subjects (aged ≥ 60 y) with increased IP based on serum zonulin levels, were randomly allocated to one of the two arms of the intervention consisting of a control diet (C-diet) vs. a polyphenol-rich diet (PR-diet). Each intervention was 8-week long and separated by an 8-week wash out period. At the beginning and at the end of each intervention period, serum samples were collected for the quantification of zonulin and other biological markers. Faecal samples were also collected to investigate the intestinal microbial ecosystem. In addition, anthropometrical/physical/biochemical parameters and food intake were evaluated.

RESULTS

Fifty-one subjects successfully completed the intervention and a high compliance to the dietary protocols was demonstrated. Overall, polyphenol intake significantly increased from a mean of 812 mg/day in the C diet to 1391 mg/day in the PR-diet. Two-way analysis of variance showed a significant effect of treatment (p = 0.008) and treatment × time interaction (p = 0.025) on serum zonulin levels, which decreased after the 8-week PR-diet. In addition, a treatment × time interaction was observed showing a reduction of diastolic blood pressure (p = 0.028) following the PR-diet, which was strongest in those not using antihypertensive drugs. A decrease in both diastolic (p = 0.043) and systolic blood pressure (p = 0.042) was observed in women. Interestingly, a significant increase in fibre-fermenting and butyrate-producing bacteria such as the family Ruminococcaceae and members of the genus Faecalibacterium was observed following the PR intervention. The efficacy of this dietary intervention was greater in subjects with higher serum zonulin at baseline, who showed more pronounced alterations in the markers under study. Furthermore, zonulin reduction was also stronger among subjects with higher body mass index and with insulin resistance at baseline, thus demonstrating the close interplay between IP and metabolic features.

CONCLUSIONS

These data show, for the first time, that a PR-diet can reduce serum zonulin levels, an indirect marker of IP. In addition, PR-diet reduced blood pressure and increased fibre-fermenting and butyrate-producing bacteria. These findings may represent an initial breakthrough for further intervention studies evaluating possible dietary treatments for the management of IP, inflammation and gut function in different target populations. THIS STUDY WAS REGISTERED AT WWW.ISRCTN.

ORG AS

ISRCTN10214981.

Effects of Nigella sativa on glycemic control, lipid profiles, and biomarkers of inflammatory and oxidative stress: A systematic review and meta-analysis of randomized controlled clinical trials

The aim of this systematic review and meta-analysis was to evaluate the effects of Nigella sativa (N. sativa) on glycemic control, lipid profiles, and biomarkers of inflammatory and oxidative stress. Two independent authors systematically examined online databases consisting of, EMBASE, Scopus, PubMed, Cochrane Library, and Web of Science from inception until October 30, 2019. Cochrane Collaboration risk of bias tool was applied to assess the methodological quality of the studied trials. The heterogeneity among the included studies were assessed using the Cochrane's Q test and I-square (I² ) statistic. Data were pooled using a random-effects model and weighted mean difference (WMD) was considered as the overall effect size. A total of 50 trials were included in this meta-analysis. We found a significant reduction in total cholesterol (WMD: -16.80; 95% CI: -21.04, -12.55), triglycerides (WMD: -15.73; 95% CI: -20.77, -10.69), LDL-cholesterol (WMD: -18.45; 95% CI: -22.44, -14.94) and VLDL-cholesterol (WMD: -3.72; 95% CI: -7.27, -0.18) following supplementation with N. sativa. In addition, there was significant reductive effect observed with N. sativa on fasting glucose (WMD: -15.18; 95% CI: -19.82, -10.55) and HbA1C levels (WMD: -0.45; 95% CI: -0.66, -0.23). Effects of N. sativa on CRP (WMD: -3.61; 95% CI: -9.23, 2.01), TNF-α (WMD: -1.18; 95% CI: -3.23, 0.86), TAC (WMD: 0.31; 95% CI: 0.00, 0.63), and MDA levels (WMD: -0.95; 95% CI: -2.18, 0.27) were insignificant. This meta-analysis demonstrated the beneficial effects of N. sativa on fasting glucose, HbA1c, triglycerides, total-, VLDL-, LDL-cholesterol levels.

Trends in use, pharmacology, and clinical applications of emerging herbal nutraceuticals

The nutraceuticals market is vast, encompassing many different products with inconsistent levels of evidence available to support their use. This overview represents a Western perspective of the nutraceuticals market, with a brief comparison with that in China, as an illustration of how individual health supplements increase and decrease in popularity in regional terms. Recent changes in sales patterns, mainly taken from the US market, are summarized and a selection of five newer products, which have not been subject to extensive recent review are profiled: astaxanthin, a carotenoid found in red algae, seafood, salmon and trout, as an antioxidant; cannabidiol, a non-euphoric marijuana ingredient used as mood enhancer and for painful/inflammatory conditions; modified extracts of ginseng used in new indications including dementia and space travel; monk fruit, a non-sugar high intensity sweetener and nigella seed, a popular food ingredient and Asian medicine, which has experienced an extraordinary rise in sales recently. LINKED ARTICLES: This article is part of a themed section on The Pharmacology of Nutraceuticals. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v177.6/issuetoc.