What is the effect of resveratrol on obesity? A systematic review and meta-analysis

Multidimensional biological activities of resveratrol and its prospects and challenges in the health field

Resveratrol (RES) is a naturally occurring polyphenolic compound. Recent studies have identified multiple potential health benefits of RES, including antioxidant, anti-inflammatory, anti-obesity, anticancer, anti-diabetic, cardiovascular, and neuroprotective properties. The objective of this review is to summarize and analyze the studies on the biological activities of RES in disease prevention and treatment, as well as its metabolism and bioavailability. It also discusses the challenges in its clinical application and future research directions. RES exhibits significant potential in the prevention and treatment of many diseases. The future direction of RES research should focus on improving its bioavailability, conducting more clinical trials to determine its effectiveness in humans, and investigating its mechanism of action. Once these challenges have been overcome, RES is expected to become an effective health intervention.

Sleep deprivation induced fat accumulation in the visceral white adipose tissue by suppressing SIRT1/FOXO1/ATGL pathway activation

Sleep is critical for maintaining overall health. Insufficient sleep duration and poor sleep quality are associated with various physical and mental health risks and chronic diseases. To date, plenty of epidemiological research has shown that sleep disorders are associated with the risk of obesity, which is usually featured by the expansion of adipose tissue. However, the underlying mechanism of increased fat accumulation upon sleep disorders remains unclear. Here we demonstrated that sleep deprivation (SD) caused triglycerides (TG) accumulation in the visceral white adipose tissue (vWAT), accompanied by a remarkable decrease in the expression of adipose triglyceride lipase (ATGL) and other two rate-limiting lipolytic enzymes. Due to the key role of ATGL in initiating and controlling lipolysis, we focused on investigating the signaling pathway leading to attenuated ATGL expression in vWAT upon SD in the following study. We observed that ATGL downregulation resulted from the suppression of ATGL transcription, which was mediated by the reduction of the transcriptional factor FOXO1 and its upstream regulator SIRT1 expression in vWAT after SD. Furthermore, impairment of SIRT1/FOXO1/ATGL pathway activation and lipolysis induced by SIRT1 inhibitor EX527 in the 3 T3-L1 adipocytes were efficiently rescued by the SIRT1 activator resveratrol. Most notably, resveratrol administration in SD mice revitalized the SIRT1/FOXO1/ATGL pathway activation and lipid mobilization in vWAT. These findings suggest that targeting the SIRT1/FOXO1/ATGL pathway may offer a promising strategy to mitigate fat accumulation in vWAT and reduce obesity risk associated with sleep disorders.

Polyphenols in obesity and weight management: Are they worth further research? An umbrella review

Polyphenols are widely known for their putative antioxidant and anti-inflammatory effects and their potential protective role in several diseases such as type 2 diabetes, cardiovascular disease and cancer. They have also attracted significant interest as 'anti-obesity' agents, although with mechanisms of action that have been exclusively demonstrated in animal and in vitro studies. This umbrella review aims to evaluate current evidence surrounding the role of polyphenols in obesity and weight management and to establish the usefulness of these agents in combatting obesity. A search of systematic reviews and meta-analyses of randomised controlled trials was carried out. Nine systematic reviews (of which eight included a meta-analysis) were included. Evidence of polyphenols' effects on reducing bodyweight is mixed, and where the effects are significant, they are numerically small and unlikely to be of help in reducing bodyweight or preventing weight gain. Future research should focus on establishing the anti-inflammatory and antioxidant effects of polyphenols through well-designed randomised controlled trials. Such research could be more valuable and cost-effective since it has shown potential to improve human health.

Clinically Effective Molecules of Natural Origin for Obesity Prevention or Treatment

The prevalence and incidence of obesity and the comorbidities linked to it are increasing worldwide. Current therapies for obesity and associated pathologies have proven to cause a broad number of adverse effects, and often, they are overpriced or not affordable for all patients. Among the alternatives currently available, natural bioactive compounds stand out. These are frequently contained in pharmaceutical presentations, nutraceutical products, supplements, or functional foods. The clinical evidence for these molecules is increasingly solid, among which epigallocatechin-3-gallate, ellagic acid, resveratrol, berberine, anthocyanins, probiotics, carotenoids, curcumin, silymarin, hydroxy citric acid, and α-lipoic acid stand out. The molecular mechanisms and signaling pathways of these molecules have been shown to interact with the endocrine, nervous, and gastroenteric systems. They can regulate the expression of multiple genes and proteins involved in starvation-satiety processes, activate the brown adipose tissue, decrease lipogenesis and inflammation, increase lipolysis, and improve insulin sensitivity. This review provides a comprehensive view of nature-based therapeutic options to address the increasing prevalence of obesity. It offers a valuable perspective for future research and subsequent clinical practice, addressing everything from the molecular, genetic, and physiological bases to the clinical study of bioactive compounds.

Anthropometric and cardiometabolic effects of polyphenols in people with overweight and obesity: an umbrella review

CONTEXT

Polyphenols are plant-based compounds with potential anti-inflammatory, antioxidant, and anti-obesogenic properties. However, their effects on health outcomes remain unclear.

OBJECTIVE

To evaluate the effects of polyphenols on anthropometric and cardiometabolic markers.

DATA SOURCES

Six electronic databases-namely, EMBASE, CINAHL, PubMed, Scopus, The Cochrane Library (reviews only), and Web of Science-were searched for relevant systematic reviews with meta-analyses (SRMAs).

DATA EXTRACTION

Three reviewers performed the data extraction via a data-extraction Microsoft Excel spreadsheet.

DATA ANALYSIS

An umbrella review and meta-analysis of existing SRMAs was conducted. Eighteen SRMAs published from 2015 to 2023, representing 445 primary studies and 838 unique effect sizes, were identified. Meta-analyses were conducted using random-effects models with general inverse variance. Polyphenol-containing foods were found to significantly improve weight (-0.36 kg; 95% confidence interval [CI]: -0.62, 0.77 kg; P < 0.01, I2 = 64.9%), body mass index (-0.25 kg/m2; 95% CI: -0.34, -0.17 kg/m2; P < 0.001, I2 = 82.4%), waist circumference (-0.74 cm; 95% CI: -1.34, -0.15 cm; P < 0.01, I2 = 99.3%), low-density-lipoprotein cholesterol (-1.75 mg/dL; 95% CI: -2.56, -0.94; P < 0.001, I2 = 98.6%), total cholesterol (-1.23 mg/dL; 95% CI: -2.00, -0.46; P = 0.002, I2 = 94.6%), systolic blood pressure (-1.77 mmHg; 95% CI: -1.77, -0.93 mmHg; P < 0.001, I2 = 72.4%), diastolic blood pressure (-1.45 mmHg; 95% CI: -2.09, -0.80 mmHg; P < 0.001, I2 = 61.0%), fat percentage (-0.70%; 95% CI: -1.03, -0.36%; P < 0.001, I2 = 52.6%), fasting blood glucose (-0.18 mg/dL; 95% CI: -0.35, -0.01 mg/dL; P = 0.04, I2 = 62.0%), and C-reactive protein (CRP; including high-sensitivity-CRP [hs-CRP]) (-0.2972 mg/dL; 95% CI: -0.52, -0.08 mg/dL; P = 0.01, I2 = 87.9%). No significant changes were found for high-density-lipoprotein cholesterol (-0.12 mg/dL; 95% CI: -1.44, 0.69; P = 0.67, I2 = 89.4%) and triglycerides (-1.29 mg/dL; 95% CI: -2.74, 0.16; P = 0.08, I2 = 85.4%). Between-study heterogeneity could be explained by polyphenol subclass differences.

CONCLUSION

The findings of this umbrella review support the beneficial effects of polyphenols on anthropometric and metabolic markers, but discretion is warranted to determine the clinical significance of the magnitude of the biomarker improvements.

SYSTEMATIC REVIEW REGISTRATION

International Prospective Register of Systematic Reviews no. CRD42023420206.

Resveratrol for the Management of Human Health: How Far Have We Come? A Systematic Review of Resveratrol Clinical Trials to Highlight Gaps and Opportunities

Resveratrol has long been proposed as being beneficial to human health across multiple morbidities, yet there is currently no conclusive clinical evidence to advocate its recommendation in any healthcare setting. A large cohort with high-quality clinical data and clearly defined biomarkers or endpoints are required to draw meaningful conclusions. This systematic review compiles every clinical trial conducted using a defined dose of resveratrol in a purified form across multiple morbidities to highlight the current 'state-of-play' and knowledge gaps, informing future trial designs to facilitate the realisation of resveratrol's potential benefits to human health. Over the last 20 years, there have been almost 200 studies evaluating resveratrol across at least 24 indications, including cancer, menopause symptoms, diabetes, metabolic syndrome, and cardiovascular disease. There are currently no consensus treatment regimens for any given condition or endpoint, beyond the fact that resveratrol is generally well-tolerated at a dose of up to 1 g/day. Additionally, resveratrol consistently reduces inflammatory markers and improves aspects of a dysregulated metabolism. In conclusion, over the last 20 years, the increasing weight of clinical evidence suggests resveratrol can benefit human health, but more large, high-quality clinical trials are required to transition this intriguing compound from health food shops to the clinic.

Antiobesity pathways of pterostilbene and resveratrol: a comprehensive insight

It may not always be possible for obese individuals to limit energy intake or to provide and/or maintain greater energy expenditure through exercise and physical activity. Therefore, the search for effective methods for obesity continues. Recently, the anti-obesity effect of stilbenes has attracted attention. In this review, aim was evaluating the effect of pterostilbene and resveratrol against obesity and the possible mechanisms in this effect. Dietary phytochemicals can induce body weight loss by increasing basal metabolic rate and thermogenesis and/or altering lipid metabolism. Stilbenes are products of the plant phenylpropanoid pathway. Very important mechanisms for the anti-obesity impact belonging to resveratrol as well as pterostilbene include thermogenic activation in brown adipose tissue alongside the browning of white adipose tissue. Considering nutrition and dietary habits, which have an important place in lifestyle changes for both the prevention and the treatment of obesity, pterostilbene and resveratrol, which are polyphenols and stilbenes, are seen as promising. However, optimal dose, duration, mechanism, long-term safety, side effects, combination, elucidation of genomic interactions, and lifestyle modifications should be considered.

Influence of Polyphenols on Adipose Tissue: Sirtuins as Pivotal Players in the Browning Process

Adipose tissue (AT) can be classified into two different types: (i) white adipose tissue (WAT), which represents the largest amount of total AT, and has the main function of storing fatty acids for energy needs and (ii) brown adipose tissue (BAT), rich in mitochondria and specialized in thermogenesis. Many exogenous stimuli, e.g., cold, exercise or pharmacological/nutraceutical tools, promote the phenotypic change of WAT to a beige phenotype (BeAT), with intermediate characteristics between BAT and WAT; this process is called "browning". The modulation of AT differentiation towards WAT or BAT, and the phenotypic switch to BeAT, seem to be crucial steps to limit weight gain. Polyphenols are emerging as compounds able to induce browning and thermogenesis processes, potentially via activation of sirtuins. SIRT1 (the most investigated sirtuin) activates a factor involved in mitochondrial biogenesis, peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α), which, through peroxisome proliferator-activated receptor γ (PPAR-γ) modulation, induces typical genes of BAT and inhibits genes of WAT during the transdifferentiation process in white adipocytes. This review article aims to summarize the current evidence, from pre-clinical studies to clinical trials, on the ability of polyphenols to promote the browning process, with a specific focus on the potential role of sirtuins in the pharmacological/nutraceutical effects of natural compounds.

Prevention and Treatment of Obesity-Related Inflammatory Diseases by Edible and Medicinal Plants and Their Active Compounds

Obesity, defined by excessive fat mass and its associated low-grade chronic inflammation, leads to insulin resistance, diabetes, and metabolic dysfunctions. The immunomodulatory properties of natural agents have gained much interest in recent decades. Some of the plant-derived agents are known to be immunomodulators that can affect both innate and adaptive immunity, e.g., thymoquinone, curcumin, punicalagin, resveratrol, quercetin, and genistein. Natural immunomodulators may contribute to the treatment of a number of inflammatory diseases, as they have significant efficacy and safety profiles. The immunomodulatory effects of traditional Greco-Arab and Islamic diets and medicinal plants are well acknowledged in abundant in vitro studies as well as in animal studies and clinical trials. This review highlights the role of Greco-Arab and Islamic diets and medicinal plants in the management of inflammation associated with obesity. Although previously published review articles address the effects of medicinal plants and phytochemicals on obesity-related inflammation, there is no systematic review that emphasizes clinical trials of the clinical significance of these plants and phytochemicals. Given this limitation, the objective of this comprehensive review is to critically evaluate the potential of the most used herbs in the management of obesity-related inflammation based on clinical trials.

Resveratrol Supplementation in Obese Pregnant Rats Improves Maternal Metabolism and Prevents Increased Placental Oxidative Stress

Maternal obesity (MO) causes maternal and fetal oxidative stress (OS) and metabolic dysfunction. We investigated whether supplementing obese mothers with resveratrol improves maternal metabolic alterations and reduces OS in the placenta and maternal and fetal liver. From weaning through pregnancy female Wistar rats ate chow (C) or a high-fat diet (MO). One month before mating until 19 days’ gestation (dG), half the rats received 20 mg resveratrol/kg/d orally (Cres and MOres). At 19dG, maternal body weight, retroperitoneal fat adipocyte size, metabolic parameters, and OS biomarkers in the placenta and liver were determined. MO mothers showed higher body weight, triglycerides and leptin serum concentrations, insulin resistance (IR), decreased small and increased large adipocytes, liver fat accumulation, and hepatic upregulation of genes related to IR and inflammatory processes. Placenta, maternal and fetal liver OS biomarkers were augmented in MO. MOres mothers showed more small and fewer large adipocytes, lower triglycerides serum concentrations, IR and liver fat accumulation, downregulation of genes related to IR and inflammatory processes, and lowered OS in mothers, placentas, and female fetal liver. Maternal resveratrol supplementation in obese rats improves maternal metabolism and reduces placental and liver OS of mothers and fetuses in a sex-dependent manner.

The therapeutic effects and mechanisms of action of resveratrol on polycystic ovary syndrome: A comprehensive systematic review of clinical, animal, and in vitro studies

BACKGROUND

Polycystic ovary syndrome (PCOS) is one of the most important and common polygenic endocrine disorders among women of reproductive age. Resveratrol, a natural phenol, is involved in various biological activities, including antioxidant, antiseptic, anti-inflammatory, anti-aging, and anti-cancer effects.

METHODS

This systematic review aimed to investigate the therapeutic effects and mechanisms of actions of resveratrol in PCOS. The present study was conducted according to the guidelines of the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) statements. We searched PubMed, Science Direct, Google Scholar, Scopus, ISI Web of Science, ProQuest, and Embase databases up to August 2021 by using the relative keywords. Original studies published in the English language that assessed the effects of resveratrol on PCOS and its associated complications were considered. Out of 417 records screened, only 24 articles met the inclusion criteria: 10 in vitro, 10 animal, and 4 human studies.

RESULTS

The results obtained in the present study showed that resveratrol supplementation might be effective in improving PCOS-related symptoms by reducing insulin resistance, alleviating dyslipidemia, improving ovarian morphology and anthropometric indices, regulating the reproductive hormones, and reducing inflammation and oxidative stress by affecting biological pathways.

CONCLUSION

According to the available evidence, resveratrol may reduce the complications of PCOS. However, further studies are recommended for a comprehensive conclusion on the exact mechanism of resveratrol in PCOS patients. This article is protected by copyright. All rights reserved.

Resveratrol for Weight Loss in Obesity: An Assessment of Randomized Control Trial Designs in ClinicalTrials.gov

Resveratrol is a polyphenol that may improve weight loss outcomes in obese individuals. However, assessing the effectiveness of resveratrol supplementations as an appropriate intervention for weight loss in obesity across randomized control trials (RCTs) has been complicated by variability in their design. This study aims to evaluate design elements across RCTs of resveratrol interventions in obesity with weight loss as an end-point outcome, as recorded in ClinicalTrials.gov. We found discrepancies in participant inclusion criteria (sample size, age ranges, sex, BMI, medical conditions), interventional design (delivery modalities, dosages, duration) and primary outcomes measured (anthropomorphic, blood biomarkers). We identified a near three-fold variation in study sample size, two-fold variation in minimum inclusion age, five modalities of therapeutic resveratrol delivery with interventional durations ranging from two weeks to six months. Weight loss was only identified as a primary outcome in three of the seven studies evaluated. In conclusion, heterogeneity in trial design using resveratrol suggests that weight-loss-related outcomes are difficult to interpret and cross-validate. Indeed, conclusions drawn from human studies have been inconsistent, which may be attributed to study design heterogeneity including major differences in sample population, age, sex, BMI, underlying health conditions and end-point measures.

Melatonin supplementation and anthropometric indicators of obesity: A systematic review and meta-analysis

OBJECTIVE

According to in vivo and in vitro studies, melatonin appears to be a potential supplement for obesity reduction. The aim of this study was to review the literature on randomized clinical trials that evaluated the effects of melatonin supplementation on anthropometric indicators of obesity in humans.

METHODS

We conducted a systematic review with meta-analysis in the following databases: Pubmed, LILACS, Scielo, Scopus, Web of Science, Cochrane, and Embase. We included studies that evaluated melatonin supplementation's effects, compared with placebo, on anthropometric measures, including body weight, body mass index (BMI), and waist circumference, in people ≥18 y of age. This systematic review and meta-analysis were registered on PROSPERO: CRD42021241079.

RESULTS

Of the 23 studies included, 11 showed significant results from melatonin supplementation on weight loss, BMI, or waist circumference, compared with placebo. In the meta-analysis, melatonin supplementation significantly reduced body weight (standardized mean difference, -0.48; 95% confidence interval, -0.94 to -0.02; P = <0.01; I² = 92%). Results for BMI and waist circumference were null. The I² tests were significant for the analyses with significant results.

CONCLUSION

The results demonstrated that melatonin supplementation was responsible for significantly reducing body weight. More studies are needed before melatonin can be recommended for weight loss.

The Role of Resveratrol Administration in Human Obesity

Obesity is a widespread disease that is associated with numerous and serious comorbidities. These include metabolic syndrome, diabetes mellitus, cardiovascular-cerebrovascular disease, hypertension, obstructive sleep apnea syndrome, cancer, and sexual and hormonal disorders. The treatment of obesity has therefore become a goal of great clinical and social relevance. Among the therapeutic strategies against obesity, resveratrol has aroused great interest. This polyphenol has anticancer and antioxidant properties and cytoprotective and anti-inflammatory effects. Other favorable effects attributed to resveratrol are anti-lipid, anti-aging, anti-bacterial, anti-viral, and neuroprotective actions. Administration of resveratrol appears to improve the metabolic profile in obese and/or insulin-resistant patients. This article aims to review the main results of clinical studies evaluating the effects of administering resveratrol alone in overweight/obese patients.