Effect of Polyphenol Supplementation on Memory Functioning in Overweight and Obese Adults: A Systematic Review and Meta-Analysis
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SUBMITTER: Farag S
PROVIDER: S-EPMC10893550 | biostudies-literature | 2024 Feb
REPOSITORIES: biostudies-literature
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Project description:Background and objectivesIncreasing 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.MethodsA 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 conclusionA 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.
| S-EPMC10212191 | biostudies-literature
Project description:Emerging randomised controlled trials (RCTs) exploring the effect of green tea (GT) supplementation or GT extract (GTE) on blood pressure (BP) among overweight and obese adults yielded inconclusive results. We aim to conduct a systematic review to summarise the evidence of RCTs until now, to clarify the efficacy of GT supplementation or GTE in BP in overweight and obese populations.The Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE and ClinicalTrials.gov will be searched to retrieve potential RCTs. Unpublished studies will be identified by searching the abstract books or websites of the three major conference proceedings: the International Society of Hypertension, the Nutrition & Health Conference and the World Congress of Nutrition and Health. A random-effects meta-analysis will be performed to pool the mean difference for the change in BP from baseline (ie, postintervention BP minus baseline BP) between intervention groups and placebo groups of the included studies, presenting the pooled results with 95% CIs. Subgroups analyses will be conducted according to different doses of GT or GTE, trial duration, geographic regions, overweight versus obese participants, and participants with versus without change in body weight after intervention. Sensitivity analysis will be performed by excluding studies classified as having a high risk of bias, applying a fixed-effects model, using the postintervention BP for analyses and excluding trials with non-study cointerventions.This systematic review will be published in a peer-reviewed journal. It will be disseminated electronically and in print. Summarising the RCT evidence to clarify the efficacy in BP among overweight and obese adults will aid in making the dietary recommendation of GT and improving the clinical management of hypertension.PROSPERO CRD42014007273.
| S-EPMC3996813 | biostudies-literature
Project description:The aim of this systematic review was to assess the effect of vitamin D supplementation on glucose and insulin metabolism in overweight and obese subjects. The search process was based on the selection of publications listed in the databases: PubMed, Scopus, Web of Knowledge, Embase and the Cochrane library that met the inclusion criteria. Twelve randomized controlled trials were included. The analysed population consisted of 1181 individuals with BMIs > 23 kg/m2. Changes in the concentration of 25(OH)D, fasting glucose, insulin and the HOMA-IR index were assessed. In the meta-regression analysis, a restricted maximum likelihood method was applied. To combine individual study results, a meta-analysis was performed. Vitamin D supplementation did not have an effect on glucose concentrations, insulin level and HOMA-IR values when the supplemented dose, time of supplementation and baseline of 25(OH)D concentration were taken under consideration in subgroup-analysis. This meta-analysis provides evidence that vitamin D supplementation has no significant effect on glucose and insulin metabolism in overweight and obese individuals.
| S-EPMC4635423 | biostudies-literature
Project description:Dietary polyphenols have beneficial effects on adipose tissue mass and function in rodents, but human studies are scarce. In a randomized, placebo-controlled study, 25 (10 women) overweight and obese humans received a combination of the polyphenols epigallocatechin-gallate and resveratrol (282 mg/d, 80 mg/d, respectively, EGCG+RES, n = 11) or placebo (PLA, n = 14) supplementation for 12 weeks. Abdominal subcutaneous adipose tissue (SAT) biopsies were collected for assessment of adipocyte morphology and micro-array analysis. EGCG+RES had no effects on adipocyte size and distribution compared with PLA. However, we identified pathways contributing to adipogenesis, cell cycle and apoptosis were significantly downregulated by EGCG+RES versus PLA. Furthermore, EGCG+RES significantly decreased expression of pathways related to energy metabolism, oxidative stress, inflammation, and immune defense as compared with PLA. In conclusion, the SAT gene expression profile indicates a reduced cell turnover after 12-week EGCG+RES in overweight-obese subjects. It remains to be elucidated whether these alterations translate into long-term metabolic effects.
| S-EPMC6224187 | biostudies-literature
Project description:BackgroundObesity induced low-grade chronic inflammation disrupts proper immune and metabolic function. Vitamin D deficiency increases inflammation, which is associated with cardiometabolic risk. This systematic review examines the association between oral vitamin D (VD) supplementation and circulating inflammatory biomarkers and glycemic outcomes from randomized controlled trials (RCTs) of overweight and/or obese adults.MethodsMEDLINE OVID, EMBASE and the Cochrane Central Register of Controlled Trials were searched according to a predefined protocol. Eligible RCTs included adults randomized to receive either oral VD or placebo. Two reviewers independently assessed RCTs for inclusion. Bias was assessed using the Cochrane Collaboration risk of bias tool. Mean differences were calculated comparing end-of-study sample means between the independent VD and placebo groups.ResultsEleven unique RCTs met inclusion criteria from a total of 3,383 identified citations, including 79 screened articles and 14 full text data extractions. Inflammatory and glycemic measures were reported in 7 and 10 RCTs, respectively. Most trial findings were non-significant with considerable heterogeneity in design, participants and outcomes. All but one trial was rated as either high or unclear risk of bias. Two RCTs reported significant changes in inflammatory biomarkers; however, the mean difference between groups was not statistically significant: C-reactive protein 0.19 mg/L (p = 0.88); Tumor Necrosis Factor -0.54 pg/ml (p = 0.20). Two other trials found significant mean differences in fasting plasma glucose -0.32 mmol/L (p = 0.03), Hemoglobin A1c -0.13% (p = 0.04), and Homeostatic Model Assessment -0.86 (p = 0.02) following VD supplementation.ConclusionsOverall, there is no clear established benefit of VD supplementation on inflammatory biomarkers among overweight/obese adults. Baseline serum VD possibly influences the effect of VD repletion on inflammatory markers. Risk of bias was present in most studies, thus supporting the need for higher quality studies in this area to more conclusively understand the role VD supplementation has on inflammatory pathways.
| S-EPMC4846157 | biostudies-literature
Project description:BackgroundPhosphorus status is inversely correlated with body weight; however, the effect of phosphorus supplementation on body weight in a controlled design has not been studied.MethodsThis is a double-blind, randomized, placebo-controlled trial of 63 adults aged 18-45 years with a body mass index (BMI) of ⩾25 kg m(-2) and normal kidney function at the American University of Beirut. Participants were randomly assigned to the placebo or phosphorus group where daily placebo or phosphorus supplements were ingested with three main meals (breakfast, lunch and dinner) for a period of 12 weeks. Primary outcomes were changes in anthropometric measures, blood metabolites (including lipid profile, glucose and insulin) and subjective appetite scores. The trial is registered with Clinical Trial.gov, NCT02329990.ResultsBody weight was significantly lower in the phosphorus group when compared with the placebo group (-0.65 kg (95% confidence interval (CI) -1.69 to 0.40) vs 1.13 kg (95% CI 0.19 to 2.06), P=0.01). Similarly, BMI and waist circumference were significantly lower in the phosphorus group when compared with the placebo group (-0.24 kg m(-2) (95% CI -0.59 to 0.12) vs 0.42 kg m(-2) (95% CI 0.05 to 0.78), P=0.01; -3.62 cm (95% CI-4.90 to -2.33) vs 0.38 cm ( 95% CI-0.44 to 1.20), P<0.001; respectively). Several parameters of subjective appetite scores were decreased in the phosphorus-supplemented group.ConclusionsPhosphorus supplementation for 12 weeks significantly decreases body weight, BMI, waist circumference and subjective appetite scores. These findings support a promising role of the mineral phosphorus in the prevention and management of obesity, especially abdominal adiposity. The exact mechanisms of action and longer-term effects still need to be elucidated.
| S-EPMC4735052 | biostudies-literature
Project description:Background: Polyphenol is considered to exert a favorable impact on cardiovascular health. Methods: To summarize the role of polyphenol antioxidant supplements in cardiovascular disease, we searched for randomized controlled trials up to 10th November 2024 that reported estimates of the effects of polyphenol antioxidant supplements on cardiometabolic risk factors. Results: Of the 17,126 participants in the 281 studies, weighted mean differences [95% confidence intervals] were derived for the intervention condition utilizing random effects modeling. Our results suggest that multiple polyphenol supplements improved cardiovascular risk markers in the overall population. For example, catechin supplementation decreased systolic (-1.56 [-2.75, -0.37] mmHg) and diastolic blood pressure (-0.95 [-1.69, -0.20] mmHg), anthocyanin supplementation improved multiple blood lipid profiles, and curcumin supplementation benefited indicators of glucose metabolism. Conclusions: Our meta-analysis provides comprehensive evidence that antioxidant polyphenol supplementation can have beneficial effects on various cardiometabolic risk factors in the general population. The observed improvements in blood pressure, lipid profile, and glycemic status support the potential role of these supplements in cardiovascular health promotion. However, the heterogeneity among studies indicates that more research is needed to fully understand the optimal use of different polyphenols. Future research should concentrate on conducting a greater number of well-designed randomized controlled trials over extended periods of time to evaluate the long-term impact on cardiovascular endpoints and to ascertain the optimal doses and durations of antioxidant polyphenol supplementation. Furthermore, additional research is required to gain a deeper understanding of the underlying mechanisms responsible for these cardioprotective effects.
| S-EPMC11644654 | biostudies-literature
Project description:ObjectiveTo investigate the effect of auricular acupoint stimulation on overweight and obese adults.MethodsWe searched databases including PubMed, EMBASE, Allied and Complementary Medicine Database, National Knowledge Infrastructure, and the PerioPath Index to Taiwan Periodical Literature. The modified Jadad scale was used to assess study quality. We investigated the effect of auricular acupoint stimulation on anthropometric measurements.ResultsEighteen randomized controlled trials (RCTs) were included in our systematic review. Thirteen RCTs were pooled in a meta-analysis that revealed a significant reduction in body weight (BW) with a mean difference (MD) of -1.21 kg and a 95% confidence interval (CI) from -1.94 to -0.47 with a heterogeneity of I2 = 88%. Significant decreases in body mass index (BMI; MD: -0.57 kg/m2; 95% CI -0.82 to -0.33; I2 = 78%), body fat (BF; MD: -0.83%; 95% CI -1.43 to -0.24; I2 = 0%), and waist circumference (WC; MD: -1.75 cm; 95% CI -2.95 to -0.55; I2 = 87%) were also revealed.ConclusionsThis meta-analysis shows that auricular acupoint stimulation improves physical anthropometric parameters including BW, BMI, BF, and WC in overweight and obese adults. These methods are less effective on hip circumference and waist-to-hip ratio.
| S-EPMC5735786 | biostudies-literature
Project description:BackgroundThe placentas of obese women accumulate lipids that may alter fetal lipid exposure. The long-chain omega-3 fatty acids (n–3 FAs) docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) alter FA metabolism in hepatocytes, although their effect on the placenta is poorly understood.ObjectiveWe aimed to investigate whether n–3 supplementation during pregnancy affects lipid metabolism in the placentas of overweight and obese women at term.DesignA secondary analysis of a double-blind randomized controlled trial was conducted in healthy overweight and obese pregnant women who were randomly assigned to DHA plus EPA (2 g/d) or placebo twice a day from early pregnancy to term. Placental FA uptake, esterification, and oxidation pathways were studied by measuring the expression of key genes in the placental tissue of women supplemented with placebo and n–3 and in vitro in isolated trophoblast cells in response to DHA and EPA treatment.ResultsTotal lipid content was significantly lower in the placentas of overweight and obese women supplemented with n–3 FAs than in those supplemented with placebo (14.14 ± 1.03 compared with 19.63 ± 1.45 mg lipid/g tissue; P < 0.05). The messenger RNA expression of placental FA synthase (FAS) and diacylglycerol O-acyltransferase 1 (DGAT1) was negatively correlated with maternal plasma enrichment in DHA and EPA (P < 0.05). The expression of placental peroxisome proliferator–activated receptor γ (r = −0.39, P = 0.04) and its target genes DGAT1 (r = −0.37, P = 0.02) and PLIN2 (r = −0.38, P = 0.04) significantly decreased, with an increasing maternal n–3:n–6 ratio (representing the n–3 status) near the end of pregnancy. The expression of genes that regulate FA oxidation or uptake was not changed. Birth weight and length were significantly higher in the offspring of n–3-supplemented women than in those in the placebo group (P < 0.05), but no differences in the ponderal index were observed. Supplementation of n–3 significantly decreased FA esterification in isolated trophoblasts without affecting FA oxidation.ConclusionSupplementing overweight and obese women with n–3 FAs during pregnancy inhibited the ability of the placenta to esterify and store lipids. This trial was registered at clinicaltrials.gov as NCT00957476.
| S-EPMC4807706 | biostudies-literature
Project description:The prevalence of overweight and obesity is rising rapidly, currently affecting 1.9 billion adults worldwide. Prebiotic dietary fibre supplementation is a promising approach to improve weight loss and reduce metabolic complications in overweight and obese subjects due to modifications of the microbiota composition and function. Previous systematic reviews and meta-analyses addressing similar questions revealed discordant evidence and/or are outdated. We searched MEDLINE, Embase, Google Scholar, and forward and backward citations for randomised controlled trials (RCTs) with isolated soluble dietary fibre supplementation for at least 12 weeks in overweight and obese patients measuring body weight, published through April 2022. We expressed the results as mean differences (MDs) using the random-effects model of the metafor package in R and assessed risk of bias using the Cochrane RoB2 tool. We conducted the study according to the PRISMA guidelines and registered the protocol on PROSPERO (CRD42022295246). The participants with dietary fibre supplementation showed a significantly higher reduction in body weight (MD -1.25 kg, 95% CI -2.24, -0.25; 27 RCTs; 1428 participants) accompanied by a significant decrease in BMI, waist circumference, fasting blood insulin, and HOMA-IR compared to the control group. Certainty of evidence was high, paving the way for the implementation of isolated soluble dietary fibre supplementation into clinical practice.
| S-EPMC9268533 | biostudies-literature