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Polyphenol supplementation and executive functioning in overweight and obese adults at risk of cognitive impairment: A systematic review and meta-analysis.
Farag, S, Tsang, C, Murphy, PN
PloS one. 2023;18(5):e0286143
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It is recognised that overweight and obesity pose an increased risk for the development of cardiometabolic disease, and increasing evidence indicates a link to cognitive impairment associated with early onset dementia in such populations. This study's aim was to elaborate on existing knowledge of the effectiveness or otherwise of polyphenols in general to improve executive function (EFs) in an obese/ overweight population at risk of cognitive impairment. This study was a systematic review and meta-analysis of twenty-three randomised controlled trials. Results showed a nonsignificant effect of polyphenols on EFs. Authors concluded that further research should consider investigating polyphenols supplementation in a younger population at risk of cognitive impairment.
Expert Review
Conflicts of interest:
None
Take Home Message:
- Overweight and obesity have increasing evidence that indicates a link to compromised executive functions such as memory and decision-making processes and cognitive impairment
- This meta-analysis revealed a non-significant effect of polyphenol supplementation on executive functions among overweight and/or obese populations with a susceptibility to cognitive impairment.
Evidence Category:
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A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)
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B: Systematic reviews including RCTs of limited number
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C: Non-randomized trials, observational studies, narrative reviews
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D: Case-reports, evidence-based clinical findings
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E: Opinion piece, other
Summary Review:
A systematic review and meta-analysis were undertaken to investigate the impact of polyphenol supplementation on executive functions (cognitive functions which constitute part of the working memory and decision-making processes) among overweight and/or obese populations.
Method:
A comprehensive literature search was conducted using four electronic databases: PubMed/Medline, PsycInfo, Scopus and the Cochrane Trials Library. Inclusion criteria encompassed primary research studies which investigated the impact of polyphenols versus placebo on executive function in overweight or obese adults.
The review comprised a total of 23 randomised controlled trials (RCTs), incorporating a participant pool of N = 1,976 individuals. The mean ages of participants in all 23 studies receiving polyphenol supplementation were 62.92 years (SD = 8.06 years) and the mean BMIs ranged from 25.5 kg/m2 to 33.7 kg/m2. Various dietary polyphenols were investigated in the studies, with the main groups being isoflavones, flavonoids, resveratrol, phenolic acid, curcumin, walnuts and blueberry powder.
- The JADAD scale was employed to assess the methodological quality of the incorporated studies
- Hedges g, accompanied by 95% confidence intervals (CI) for endpoints, was computed utilising a random effects model whenever applicable
- Various statistical methods were considered for potential application in evaluating publication bias
- Sensitivity analysis was conducted to assess the robustness of the obtained results.
Results
- Meta analysis of the 23 primary studies produced a non-significant effect of polyphenol supplementation on executive function (g = 0.076, CI = -0.018 to 0.170)
- A double-blind, randomised, placebo-controlled parallel study reported significant benefits in 60 participants (mean age 67 years) taking 80mg of curcumin over placebo for digital vigilance and serial subtraction tasks (p=0.041)
- A double-blind, randomised, placebo-controlled parallel intervention trial showed significant benefits in 79 patients (mean age of 61 years) taking 150mg of resveratrol for visuospatial working memory double span and trail making test (p= 0.012).
Conclusion:
This meta-analysis revealed a non-significant effect of polyphenol supplementation on executive functions among overweight and/or obese populations.
Clinical practice applications:
- Research has documented the association between compromised executive functions and obesity/overweight, emphasising neuroinflammation and oxidative stress as potential mechanisms
- A plausible intervention involves the utilisation of polyphenols, known for their antioxidant and anti-inflammatory properties
- This systematic review and meta-analysis revealed a non-significant effect of polyphenol supplementation on executive functions
- A potential beneficial impact for 80mg of curcumin and 150mg of resveratrol was revealed in younger populations (mean ages of 67 and 61 years).
Considerations for future research:
- A potential beneficial impact of 80mg of curcumin and 150mg of resveratrol supplementation was revealed in a younger population (mean ages of 67 and 61 years), highlighting the necessity for in-depth exploration in subsequent studies
- The diversity in tasks employed for assessing executive functions and the comprehensive reporting of the phenolic composition of supplements had limitations that warrant consideration in future research
- The exact constituent and dose of supplementation needs to be described as this is necessary for the identification of the potential beneficial compounds for cognitive health and to support clinical practice.
Abstract
BACKGROUND AND OBJECTIVES Increasing evidence indicates a link between obesity and cognitive impairment. Furthermore, there is limited literature regarding the effect of polyphenols, a plant derived compounds, on executive functioning in an overweight/obese population at-risk of cognitive impairment. The aim of the present systematic review and meta-analysis of randomized controlled trials is to examine the effect of polyphenol supplementation on executive functions in overweight and/or obese populations at risk of cognitive impairment. METHODS A comprehensive literature search was conducted from inception to March 2023 using four electronic databases: PubMed/Medline, PsycInfo, Scopus and Cochrane trials library. Published primary research studies in English that compared the effect of polyphenols with placebo on executive function in overweight/obese adults were considered eligible for the meta-analysis. Jadad scale was used for the methodological quality rating of the included studies. Hedges g with 95% confidence intervals (CI) for endpoints were calculated using random effect model where applicable. Rosenthal's Fail-safe N, funnel plots, the Begg and Mazumdar's rank correlation test (Kendall's S statistic P-Q), Egger's linear regression test, and Duval and Tweedie's trim-and-fill test were identified for potential use as appropriate, to examine publication bias. Sensitivity analysis was conducted to examine the robustness of the results. RESULTS AND CONCLUSION A total of 23 RCT studies involving N = 1,976 participants were included in the review. The results of the meta-analysis revealed a non-significant effect for polyphenol supplementation on executive function (g = 0.076, CI = -0.018 to 0.170). Observations from primary studies within the meta-analysis showed a potential positive effect of polyphenol supplementation in a younger population at-risk of cognitive impairment and it is recommended to investigate this further in future studies. Moreover, the variability of the tasks used to examine executive functions as well as the adequate reporting of supplement's phenolic composition is a limitation that future work should also consider.
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The Effect of Resveratrol on Blood Lipid Profile: A Dose-Response Meta-Analysis of Randomized Controlled Trials.
Cao, X, Liao, W, Xia, H, Wang, S, Sun, G
Nutrients. 2022;14(18)
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It is well known that cardiovascular disease is a leading cause of death. Imbalances in the blood lipid levels, such as elevation of total cholesterol, Triglycerides and LDL cholesterol, may increase the risk of cardiovascular disease. It has been shown that resveratrol, a polyphenol found in grapes, blueberries, mulberries, raspberries, peanuts, and knotweeds, has protective effects against cardiovascular disease. In this meta-analysis, 17 randomised controlled trials were included, with varying durations of 4 to 48 weeks and intervention dosages ranging from 10 to 3000 mg/day. According to the results of this meta-analysis, Resveratrol supplementation significantly reduced total cholesterol, triglycerides, and LDL cholesterol, but not HDL cholesterol. In addition, the reduction in LDL cholesterol was more significant in type 2 diabetic patients when resveratrol was supplemented for 12 weeks or more. A crucial factor in determining the effectiveness of resveratrol supplementation is its dosage. High doses over 500 mg/day were found to have the opposite effect of increasing body mass index and body weight and suppressing the cardioprotective effect. The effects of different dosages and durations of resveratrol supplementation on cardiometabolic health require further robust research. Healthcare professionals may use the results of this study to understand the importance of careful consideration when supplementing resveratrol as a nutraceutical.
Abstract
(1) Background: The effects of resveratrol on blood lipids are controversial. Whether there is a dose-response of the lipid profile upon resveratrol supplementation is unknown. (2) Methods: This dose-response meta-analysis of randomized controlled trials (RCTs) was performed to explore the effects of resveratrol supplementation on lipid profile. A systematical and comprehensive search of several databases was conducted by 30 June 2022. (3) Results: The results indicated that the intake of resveratrol could significantly decrease the total cholesterol (TC) (mean difference = -10.28; 95%CI: -13.79, -6.76, p < 0.001), triglyceride (TG) (Mean difference = -856; 95%CI: -12.37, -4.75, p < 0.001) and low-density lipoprotein cholesterol (LDL-C) (mean difference = -5.69; 95%CI: -11.07, -0.31, p = 0.038) level, but did not alter the level of high-density lipoprotein cholesterol (HDL-C). In the non-linear dose-response analysis, we observed a significant effect of the supplementation dosage on the level of LDL-C (p-nonlinearity = 0.002). Results from the sub-group analysis showed that the reduction of LDL-C was more significant in the trials with a duration of ≥12 weeks and in subjects with type 2 diabetes mellitus. (4) Conclusion: Findings from this study suggest that resveratrol may be beneficial to reduce TC, TG, and LDL-C levels in the blood. The dosage of the resveratrol intervention is an essential factor that affects the level of LDL-C.
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Anti-inflammatory effects of resveratrol in patients with cardiovascular disease: A systematic review and meta-analysis of randomized controlled trials.
Teimouri, M, Homayouni-Tabrizi, M, Rajabian, A, Amiri, H, Hosseini, H
Complementary therapies in medicine. 2022;70:102863
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Cardiovascular diseases (CVDs) include various heart or/and blood vessel disorders, such as cerebrovascular disease, congenital heart disease, and coronary artery disease. It is well shown that prolonged or chronic inflammation plays a key role in the pathogenesis of several disorders, especially CVDs. Resveratrol has recently been considered a choice for preventing and treating inflammatory conditions. The aim of this study was to evaluate the impact of resveratrol on serum/plasma concentration of specific inflammatory markers - tumour necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and c-reactive protein (CRP) - in patients with CVDs. This study is a systematic review and meta-analysis of six randomised controlled studies with a total of 415 participants. Results show that resveratrol significantly decreases CRP and TNF-α concentration; however, it did not significantly affect the serum concentration of IL-6 in patients with CVDs. Authors conclude that there is a potential preventive effect of resveratrol supplementation on inflammatory conditions in CVD patients. However, larger randomised clinical trials are needed to further investigate and explore the effects of resveratrol supplementations.
Abstract
BACKGROUND Chronic inflammation is one of the most important factors involved in the development and progression of cardiovascular disease (CVDs). Accumulating evidence has described the effect of resveratrol, a natural polyphenolic compound, on biomarkers of inflammation among patients with CVDs; however, findings are controversial. Here we performed a systematic review and meta-analysis of randomized controlled trials to evaluate the effect of resveratrol supplements on TNF-α, IL-6, and CRP levels in CVDs patients. METHODS Online research was conducted in the following database: MEDLINE, EMBASE, Cochrane Library, Web of Science databases, and Scopus. This systematic review and meta-analysis were conducted to investigate the effects of resveratrol supplements on inflammatory biomarkers among patients with CVDs. The meta-analysis was performed using Comprehensive Meta-Analysis (CMA) V3 software. RESULTS Six RCTs met the inclusion criteria and were selected for the current meta-analysis. Our results demonstrated that resveratrol significantly decreases serum levels of CRP (MD = -0.63, 95 % CI: -0.1.13, -0.12; p = 0.01), and TNF-α (MD = -0.55, 95 % CI: -1.04, -0.06; p = 0.02), however, resveratrol had not significant effect on serum concentration of IL-6 (MD = -0.12, 95 % CI: -0.52, 0.27; p = 0.53), in patients with CVDs. CONCLUSION Our results suggest that resveratrol can be used as a potential treatment in patients with CVD by reducing inflammatory conditions.
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Efficacy and safety of dietary polyphenol supplementation in the treatment of non-alcoholic fatty liver disease: A systematic review and meta-analysis.
Yang, K, Chen, J, Zhang, T, Yuan, X, Ge, A, Wang, S, Xu, H, Zeng, L, Ge, J
Frontiers in immunology. 2022;13:949746
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Non-alcoholic fatty liver disease (NAFLD) is characterised by fat accumulation in the liver that can result in liver damage. NAFLD affects approximately 25% of the global population. There is evidence that dietary polyphenols can improve metabolism and insulin resistance and reduce inflammation and oxidative stress, which are the mechanisms that lead to liver damage in NAFLD. This systematic review and meta-analysis aimed to assess the effectiveness of dietary polyphenols in the treatment of non-alcoholic fatty liver disease (NAFLD). Eight dietary polyphenols, such as curcumin, resveratrol, naringenin, anthocyanin, hesperidin, catechin, silymarin, and genistein, were evaluated for their efficacy and safety. The administration of 80-3,000 mg of Curcumin for an 8-12 week duration is effective and safe for reducing body mass index, aspartate aminotransferase (AST), alanine aminotransferase (ALT), triglycerides (TG), total cholesterol (TC), and insulin resistance (HOMA-IR). Compared with the placebo, Naringenin reduced the percentage of NAFLD grade, TG, TC, and low-density lipoprotein cholesterol and increased high-density lipoprotein cholesterol. Hesperidin may potentially decrease body mass index (BMI), AST, ALT, TG, TC, and HOMA-IR. Catechin is safe, and 500-1000 mg supplementation for 12 weeks may reduce BMI, HOMA-IR, and TG. NAFLD patients who received silymarin showed improvements in ALT and AST, as well as reductions in hepatic fat accumulation and liver stiffness. 94–2100 mg of Silymarin supplementation for 8–48 weeks may reduce liver enzyme levels. Researchers can use the results of this study to understand the clinical utility of different polyphenol supplements in the treatment of NAFLD. Because the current evidence is highly heterogeneous in nature and limited in scope, further robust research is required on various classes of polyphenols and their effectiveness in reducing the severity of NAFLD.
Abstract
Background: Dietary polyphenol treatment of non-alcoholic fatty liver disease (NAFLD) is a novel direction, and the existing clinical studies have little effective evidence for its therapeutic effect, and some studies have inconsistent results. The effectiveness of dietary polyphenols in the treatment of NAFLD is still controversial. The aim of this study was to evaluate the therapeutic efficacy of oral dietary polyphenols in patients with NAFLD. Methods: The literature (both Chinese and English) published before 30 April 2022 in PubMed, Cochrane, Medline, CNKI, and other databases on the treatment of NAFLD with dietary polyphenols was searched. Manual screening, quality assessment, and data extraction of search results were conducted strictly according to the inclusion and exclusion criteria. RevMan 5.3 software was used to perform the meta-analysis. Results: The RCTs included in this study involved dietary supplementation with eight polyphenols (curcumin, resveratrol, naringenin, anthocyanin, hesperidin, catechin, silymarin, and genistein) and 2,173 participants. This systematic review and meta-analysis found that 1) curcumin may decrease body mass index (BMI), Aspartate aminotransferase (AST), Alanine aminotransferase (ALT), Triglycerides (TG) total cholesterol (TC), and Homeostasis Model Assessment-Insulin Resistance (HOMA-IR) compared to placebo; and curcumin does not increase the occurrence of adverse events. 2) Although the meta-analysis results of all randomized controlled trials (RCTs) did not reveal significant positive changes, individual RCTs showed meaningful results. 3) Naringenin significantly decreased the percentage of NAFLD grade, TG, TC, and low-density lipoprotein cholesterol (LDL-C) and increased high-density lipoprotein cholesterol (HDL-C) but had no significant effect on AST and ALT, and it is a safe supplementation. 4) Only one team presents a protocol about anthocyanin (from Cornus mas L. fruit extract) in the treatment of NAFLD. 5) Hesperidin may decrease BMI, AST, ALT, TG, TC, HOMA-IR, and so on. 6) Catechin may decrease BMI, HOMA-IR, and TG level, and it was well tolerated by the patients. 7) Silymarin was effective in improving ALT and AST and reducing hepatic fat accumulation and liver stiffness in NAFLD patients. Conclusion: Based on current evidence, curcumin can reduce BMI, TG, TC, liver enzymes, and insulin resistance; catechin can reduce BMI, insulin resistance, and TG effectively; silymarin can reduce liver enzymes. For resveratrol, naringenin, anthocyanin, hesperidin, and catechin, more RCTs are needed to further evaluate their efficacy and safety.
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Exploring the Therapeutic Potential of Phytochemicals in Alzheimer's Disease: Focus on Polyphenols and Monoterpenes.
Piccialli, I, Tedeschi, V, Caputo, L, D'Errico, S, Ciccone, R, De Feo, V, Secondo, A, Pannaccione, A
Frontiers in pharmacology. 2022;13:876614
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Alzheimer’s disease (AD) is a complex chronic neurodegenerative disorder characterized by the irreversible loss of memory and brain functions. Many different hypotheses are circulating to explain the underlying cause of the disease, yet therapeutic strategies to treat the degenerative processes have been unsuccessful to date. In recent years research has broadened its focus, viewing the pathology of AD more as an interplay of many factors whilst also taking into account other comorbidities associated with AD, such as insulin resistance and low energy production in the brain. One of the big challenges for clinical treatment is that by the time symptoms present and the diagnosis is made, irreversible brain loss has already occurred. Many lifestyle interventions can influence the modifiable risk factors of ageing and hence present a promising preventative strategy for AD. Plant-derived compounds found in foods and medicinal herbs have received much interest due to their versatile action potential. This review specifically looked at compounds in the polyphenols and monoterpenes category and summarized the current evidence, possible mechanisms of action and how this could aid AD management. An overview of the various hypothesis believed to contribute to the development of AD is presented. These include Aβ aggregation and toxicity, Tau hyperphosphorylation and toxicity, oxidative stress and mitochondrial dysfunction, neuroinflammation and brain insulin resistance. A synopsis of the current state of treatments and treatment development is provided, before exploring the potential of plant-derived compounds, in particular polyphenols and monoterpenes and their potential from various sources. Concluding remarks discuss the challenges that come with turning plant-derived compounds into drug treatments. Many studies on mechanisms of action show therapeutic potential, clinical trials in humans have not yet managed to mirror those effects sufficiently. There is a need to advance the field further and assess more thoroughly the clinical relevance of these findings. This review yields a comprehensive and detailed summary of aspects of AD, the proposed mechanisms and the potential of some nutrition related management options.
Abstract
Alzheimer's disease (AD) is a chronic, complex neurodegenerative disorder mainly characterized by the irreversible loss of memory and cognitive functions. Different hypotheses have been proposed thus far to explain the etiology of this devastating disorder, including those centered on the Amyloid-β (Aβ) peptide aggregation, Tau hyperphosphorylation, neuroinflammation and oxidative stress. Nonetheless, the therapeutic strategies conceived thus far to treat AD neurodegeneration have proven unsuccessful, probably due to the use of single-target drugs unable to arrest the progressive deterioration of brain functions. For this reason, the theoretical description of the AD etiology has recently switched from over-emphasizing a single deleterious process to considering AD neurodegeneration as the result of different pathogenic mechanisms and their interplay. Moreover, much relevance has recently been conferred to several comorbidities inducing insulin resistance and brain energy hypometabolism, including diabetes and obesity. As consequence, much interest is currently accorded in AD treatment to a multi-target approach interfering with different pathways at the same time, and to life-style interventions aimed at preventing the modifiable risk-factors strictly associated with aging. In this context, phytochemical compounds are emerging as an enormous source to draw on in the search for multi-target agents completing or assisting the traditional pharmacological medicine. Intriguingly, many plant-derived compounds have proven their efficacy in counteracting several pathogenic processes such as the Aβ aggregation, neuroinflammation, oxidative stress and insulin resistance. Many strategies have also been conceived to overcome the limitations of some promising phytochemicals related to their poor pharmacokinetic profiles, including nanotechnology and synthetic routes. Considering the emerging therapeutic potential of natural medicine, the aim of the present review is therefore to highlight the most promising phytochemical compounds belonging to two major classes, polyphenols and monoterpenes, and to report the main findings about their mechanisms of action relating to the AD pathogenesis.
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Potential Adverse Effects of Resveratrol: A Literature Review.
Shaito, A, Posadino, AM, Younes, N, Hasan, H, Halabi, S, Alhababi, D, Al-Mohannadi, A, Abdel-Rahman, WM, Eid, AH, Nasrallah, GK, et al
International journal of molecular sciences. 2020;21(6)
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Resveratrol is a polyphenol compound found naturally in plant foods. It has several therapeutic effects including antioxidant, anti-inflammatory and cardio protective properties. This review focuses however on the potential adverse effects of resveratrol to better understand the nutrient and its use in therapy. Evidence suggests that dosage is important with low doses of resveratrol having beneficial effects, whilst high doses can be associated with toxicity. However, many studies also report poor bioavailability of resveratrol meaning the body is unable to absorb it efficiently. This may also be influenced by differences in gut bacteria. So, toxicity will differ from one patient to the next. It is also noted that most studies focus on short-term usage and outcomes whilst more data may be required to understand the effects of longer-term usage. The differences in studies, and usage of resveratrol, means the characteristics of patients and symptoms reported vary greatly. This makes it hard to rigorously evaluate adverse effects as there is a high level of variability between one study and another. The review concludes that if there was more uniformity in study designs it would be easier to evaluate both beneficial and adverse effects.
Abstract
Due to its health benefits, resveratrol (RE) is one of the most researched natural polyphenols. Resveratrol's health benefits were first highlighted in the early 1990s in the French paradox study, which opened extensive research activity into this compound. Ever since, several pharmacological activities including antioxidant, anti-aging, anti-inflammatory, anti-cancerous, anti-diabetic, cardioprotective, and neuroprotective properties, were attributed to RE. However, results from the available human clinical trials were controversial concerning the protective effects of RE against diseases and their sequelae. The reason for these conflicting findings is varied but differences in the characteristics of the enrolled patients, RE doses used, and duration of RE supplementation were proposed, at least in part, as possible causes. In particular, the optimal RE dosage capable of maximizing its health benefits without raising toxicity issues remains an area of extensive research. In this context, while there is a consistent body of literature on the protective effects of RE against diseases, there are relatively few reports investigating its possible toxicity. Indeed, toxicity and adverse effects were reported following consumption of RE; therefore, extensive future studies on the long-term effects, as well as the in vivo adverse effects, of RE supplementation in humans are needed. Furthermore, data on the interactions of RE when combined with other therapies are still lacking, as well as results related to its absorption and bioavailability in the human body. In this review, we collect and summarize the available literature about RE toxicity and side effects. In this process, we analyze in vitro and in vivo studies that have addressed this stilbenoid. These studies suggest that RE still has an unexplored side. Finally, we discuss the new delivery methods that are being employed to overcome the low bioavailability of RE.
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Effects of resveratrol on VEGF & HIF1 genes expression in granulosa cells in the angiogenesis pathway and laboratory parameters of polycystic ovary syndrome: a triple-blind randomized clinical trial.
Bahramrezaie, M, Amidi, F, Aleyasin, A, Saremi, A, Aghahoseini, M, Brenjian, S, Khodarahmian, M, Pooladi, A
Journal of assisted reproduction and genetics. 2019;36(8):1701-1712
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Polycystic ovary syndrome (PCOS) is a condition in women characterised by disruptions in the ovulation cycle and hormonal imbalances causing infertility. There are several biological mechanisms involved in the development of PCOS, including hormonal imbalance. Recently, high levels of a protein known as VEGF, which stimulates the formation of new blood vessels, has been detected in the ovaries of women with PCOS and is thought to be involved in its development. Resveratrol is a herbal supplement, which has been shown in animal studies to reduce VEGF. This randomised control trial of 61 women with PCOS aimed to determine if there was a similar effect in humans. The results showed that VEGF was decreased following the supplementation of resveratrol, and that it also helped to achieve a more normal hormonal balance. As a result, this improved the quality of embryos, but did not increase the rate of fertility. It was concluded that resveratrol may be of benefit to women with PCOS by decreasing the production of VEGF and helping to achieve a better hormonal balance in women with PCOS.
Abstract
OBJECTIVES Management options for PCOS, as the most prevalent endocrine disorder in women of reproductive age, using natural supplements have a high priority for physicians, especially based on the etiological pathways. Therefore, this study was conducted to describe the effect of resveratrol on the angiogenesis pathway, for management of PCOS through assessing VEGF, HIF1 gene expression, and laboratory parameters. METHODS In this triple-blind RCT, PCOS was confirmed in ICSI candidates based on the Rotterdam criteria. Sixty-two patients that met the inclusion criteria were randomly assigned to two groups. All patients took resveratrol 800 mg/day or placebo for 40 days orally from the beginning of their previous menstruation cycle until the oocyte retrieval day. The serum levels of different hormones were measured, and the expression of HIF1 & VEGF genes was quantified by real-time PCR. RESULTS As for the laboratory hormone assay in 61 PCOS patients, a significant mean difference was seen in the FSH, LH, TSH, and testosterone between the two groups (P < 0.05). The results showed a reduction in the expression of VEGF & HIF1 genes under the effect of resveratrol in the granulosa cells (P = 0.0001). The number of mature oocytes, cleavage rate, fertilization rate, and fertility rate were not significantly different between the two groups (P > 0.05), but the high-quality oocyte rate and high-quality embryo rate were higher in the resveratrol group (P < 0.05). CONCLUSIONS Based on the results, resveratrol may improve some outcomes of PCOS patients, probably through changing the serum levels of some sex hormones and expression of VEGF & HIF1 genes in the angiogenesis pathway of granulosa cells.
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The occurrence of resveratrol in foodstuffs and its potential for supporting cancer prevention and treatment. A review
Dybkowska, E, Sadowska, A, Świderski, F, Rakowska, R, Wysocka, K
Roczniki Panstwowego Zakladu Higieny. 2018;69(1):5-14
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There has been increasing interest in plant-based substances that show potential for preventing cancer development. Resveratrol is among these and is found in the skin of grapes, tomatoes and in red wine. Resveratrol displays anti-carcinogenic capacity by neutralising reactive oxygen species and modulating cell proliferation, differentiation and apoptosis. The purpose of this review was to present the characteristics of resveratrol as a bioactive compound and assess the mechanism of its anti-cancer properties. According to many in vitro and in vivo studies, resveratrol is able to inhibit all stages of carcinogenesis in several types of cancer. Based on these findings, the authors conclude there is a need to promote knowledge of the beneficial effects of resveratrol, and that conventional cancer treatment should be supported by an increase of this substance from both foodstuffs and supplements.
Abstract
Over recent years, there has been increasing interest noted in those active substances derived from plants that show potential for preventing cancer development. The most promising candidate is resveratrol which can be found in large amounts in the skin of grapes, tomatoes and in red wine. Its beneficial effects on the human body are seen both in prevention and therapy. The anti-carcinogenic action of resveratrol is linked with its ability to neutralise reactive oxygen species and to modulate cellular processes such as apoptosis, and both cancerous cell proliferation and differentiation. This article presents the characteristics of resveratrol as a bioactive compound derived from natural sources exhibiting anti-cancer properties, which, because of a wide spectrum of biological activities may be used in the prevention of cancer. Many in vitro and animal-based studies have demonstrated such preventative anti-cancer action in the colon, prostate, breast and lungs. The beneficial effects of resveratrol are also presented when adopted as a support to conventional treatments of cancer using chemo- and radio-therapy.
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Dietary phytochemicals in breast cancer research: anticancer effects and potential utility for effective chemoprevention.
Kapinova, A, Kubatka, P, Golubnitschaja, O, Kello, M, Zubor, P, Solar, P, Pec, M
Environmental health and preventive medicine. 2018;23(1):36
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Bioactive phytochemicals are continually being studied for their role in cancer prevention with increasing evidence for flavonoids, carotenoids, phenolic acids, and organosulfur compounds (found in cruciferous vegetables). This 2018 review explores the protective effects of a broad spectrum of plant-derived substances. In total, more than 5000 individual phytochemicals have been identified in plant-derived foods, such as fruits, vegetables, and grains. These bioactive compounds have been shown to have antitumor activity, reduce inflammation, induce apoptosis (cell death), inhibit the proliferation of aggressive tumour cells, and impact on metastasis (migration of cancer cells). Specifically, in breast cancer, a few studies have examined phytochemicals on cancer stem cells (the originating tumour cells) and found that curcumin, genistein, indol-3-carbinol, c-phycocyanin, resveratrol, and quercetin downregulated their activity. Systematic reviews of dietary patterns and breast cancer show vegetables, and especially fibre, to be consistently protective against reduced risk of mammary carcinogenesis. Dietary polyphenols are considered a cost-effective approach to cancer care however there is still a lack of evidence due to the complex nature of combined phytochemicals versus isolated agents. Wholefood consumption is considered to improve bioavailability compared to supplementation however phytochemicals are a low-dose component of foods. There is also concern that some phytochemicals may act as carcinogens or tumour promoters (for example, beta-carotene). More clinical trials are required to fully understand phytochemicals and breast cancer care.
Abstract
Cancerous tissue transformation developing usually over years or even decades of life is a highly complex process involving strong stressors damaging DNA, chronic inflammation, comprehensive interaction between relevant molecular pathways, and cellular cross-talk within the neighboring tissues. Only the minor part of all cancer cases are caused by inborn predisposition; the absolute majority carry a sporadic character based on modifiable risk factors which play a central role in cancer prevention. Amongst most promising candidates for dietary supplements are bioactive phytochemicals demonstrating strong anticancer effects. Abundant evidence has been collected for beneficial effects of flavonoids, carotenoids, phenolic acids, and organosulfur compounds affecting a number of cancer-related pathways. Phytochemicals may positively affect processes of cell signaling, cell cycle regulation, oxidative stress response, and inflammation. They can modulate non-coding RNAs, upregulate tumor suppressive miRNAs, and downregulate oncogenic miRNAs that synergically inhibits cancer cell growth and cancer stem cell self-renewal. Potential clinical utility of the phytochemicals is discussed providing examples for chemoprevention against and therapy for human breast cancer. Expert recommendations are provided in the context of preventive medicine.
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Phytochemicals in Skin Cancer Prevention and Treatment: An Updated Review.
Ng, CY, Yen, H, Hsiao, HY, Su, SC
International journal of molecular sciences. 2018;19(4)
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This 2018 review discusses the anti-oxidative, anti-inflammatory, anti-proliferative, and anti-angiogenic effects of phytochemicals for the management of skin cancer. Melanoma and non-melanoma skin cancers are caused by cellular DNA damage, and as the skin is the body’s largest organ, it is most exposed to environmental stimulus. There are several promising phytochemicals in cancer chemoprevention including Epigallocatechin-3-gallate, resveratrol, curcumin, proanthocyanidins, silymarin, apigenin, capsaicin, genistein, indole-3-carbinol, and luteolin. Additionally, Gingerol has been applied topically to improve chemical stability in the skin. Caffeic Acid Phenethyl Ester (CAPE) is derived from bee propolis was shown to inhibit skin papilloma in animal studies. Capsaicin from red chillies induced apoptosis (cell death) in melanoma cells. Curcumin has been shown to modify numerous inflammatory markers including C-reactive protein and COX-2 whilst topically can promote remarkable symptomatic relief and reduce external cancer lesion size. Caffeic Acid exerts a protective effect towards skin cancer migration and invasion. EGCG has been shown to sensitize melanoma cells to inhibit growth, promote cell death and decrease cell proliferation. Genistein from soy has been shown to exert anti-angiogenesis properties, reduce tumour proliferation and metastasis. Resveratrol has a synergistic effect with other phytochemicals to suppress tumours. What all the studies reviewed show is the potential for phytochemicals in cancer treatment. They are widely available, cost effective and highly tolerated. They appear to have anti-carcinogenic effects through regulation of multiple different signalling pathways which help alter the typical progression of skin cancer.
Abstract
Skin is the largest human organ, our protection against various environmental assaults and noxious agents. Accumulation of these stress events may lead to the formation of skin cancers, including both melanoma and non-melanoma skin cancers. Although modern targeted therapies have ameliorated the management of cutaneous malignancies, a safer, more affordable, and more effective strategy for chemoprevention and treatment is clearly needed for the improvement of skin cancer care. Phytochemicals are biologically active compounds derived from plants and herbal products. These agents appear to be beneficial in the battle against cancer as they exert anti-carcinogenic effects and are widely available, highly tolerated, and cost-effective. Evidence has indicated that the anti-carcinogenic properties of phytochemicals are due to their anti-oxidative, anti-inflammatory, anti-proliferative, and anti-angiogenic effects. In this review, we discuss the preventive potential, therapeutic effects, bioavailability, and structure-activity relationship of these selected phytochemicals for the management of skin cancers. The knowledge compiled here will provide clues for future investigations on novel oncostatic phytochemicals and additional anti-skin cancer mechanisms.