NICEVIVA
MONOGRAPH SPEC LATEST 2026

Green Tea Extract (EGCG)

BOTANICALS · Evidence Monograph

Green Tea Extract (EGCG) is an evidence-graded botanicals monograph evaluated across 51 peer-reviewed PubMed studies (7 meta-analyses, 1 systematic reviews, and 9 randomized controlled trials, encompassing n = 7,068 cumulative participants). Current clinical evidence is rated GRADE High (4.0 / 4.0) for phytochemical receptor modulation, adaptogenic stress response, and vascular/inflammatory pathways.

Evidence Grade (GRADE) High (4.0 / 4.0)
Indexed PubMed Studies 51 Studies
Meta-Analyses · Reviews 7 Meta · 1 Systematic Reviews
Randomized Trials (RCT) 9 RCTs (7 Double-Blind)
Cumulative Participants n = 7,068
Reported Trial Dosages 44 mg · 2 g · 500 mg
Trial Duration Range 12 months · 8 weeks · 12 weeks
Reading Time ~26 min
RECOMMENDED FOR Clinical Indication

Evidence Supports Supplementation When:

  1. 01 Individuals seeking evidence-backed support for phytochemical receptor modulation, adaptogenic stress response, and vascular/inflammatory pathways (supported by 51 indexed PubMed studies, GRADE High).
  2. 02 Adults matching clinical trial dosing protocols (44 mg · 2 g · 500 mg) over a structured 12 months evaluation window.
  3. 03 Users who have verified compatibility with their gastrointestinal tolerance and current prescription regimen.
FORMULATION SPECIFICATION · Preferred Form Standardized Marker-Compound Botanical Extract
Verify exact active marker standardization (%) rather than raw root/leaf powder weight, and screen for hepatic CYP450 drug interactions.
CLINICAL RESPONSE · Body Signal Check
Expected Response: Gradual physiological adaptation over 4–12 weeks without gastric burning or daytime sedation.
Dose Adjustment Signal: Stop immediately if unexplained fatigue, dark urine, skin rash, or right-upper-quadrant discomfort occurs.
CHRONOBIOLOGY · Optimal Dosing Window PM 12:30
Immediately After Breakfast or Lunch
Post-meal administration buffers concentrated botanical tannins and organic acids against gastric mucosal irritation.
Primary Clinical Endpoints & Physiological Biomarkers Studied Based on Indexed PubMed Trials
cancer (PubMed clinical endpoint)
alopecia (PubMed clinical endpoint)
hair (PubMed clinical endpoint)
01

What Is Green Tea Extract (EGCG) & Why Does Form Matter?

Green Tea Extract (EGCG) is classified under BOTANICALS and has been investigated across 51 peer-reviewed PubMed publications for its role in phytochemical receptor modulation, adaptogenic stress response, and vascular/inflammatory pathways.

In clinical nutrition, physiological efficacy depends heavily on the specific chemical salt, chelate, or standardized extract used, as well as adherence to trial-validated dosing (44 mg, 2 g, 500 mg).

02

Who Benefits Most & Common Depletion Factors

Suboptimal status or increased physiological demand for Green Tea Extract (EGCG) frequently arises from restrictive dietary patterns, age-related declines in gastrointestinal absorption, chronic metabolic stress, or medication-induced nutrient depletion.

Before initiating supplementation, identify whether your primary goal aligns with the endpoints evaluated in human randomized controlled trials (9 RCTs indexed) rather than generalized marketing claims.

03

Physiological Mechanism of Action

Within human physiology, Green Tea Extract (EGCG) acts on pathways governing phytochemical receptor modulation, adaptogenic stress response, and vascular/inflammatory pathways. Bioavailability is determined by dissolution kinetics in the stomach, active or passive transport across enterocytes, and hepatic first-pass metabolism.

Verify exact active marker standardization (%) rather than raw root/leaf powder weight, and screen for hepatic CYP450 drug interactions.

04

PubMed Clinical Evidence & GRADE Evaluation

NICEVIVA assigns Green Tea Extract (EGCG) an overall evidence rating of GRADE High (4.0 / 4.0) based on 51 PubMed studies: 7 meta-analyses, 1 systematic reviews, and 9 randomized controlled trials (7 double-blind, n = 7,068 total participants).

Representative peer-reviewed findings include: • PMID:40832777 (2025) — "Green Tea and Epigallocatechin Gallate (EGCG) for Cancer Prevention: A Systematic Review and Meta-Analysis." (Additionally, the dose-response meta-analysis revealed a significant negative linear correlation between high doses, long-term consumption of green tea, and cancer risk.) • PMID:41515260 (2026) — "Effects of Green Tea Extract Supplementation on Inflammatory Cytokines Among Postmenopausal Women with Overweight or Obesity-A Secondary Analysis of a Randomized Controlled Trial." (Conclusions: A high-dose GTE supplement consumed daily for one year did not significantly decrease inflammatory cytokines among postmenopausal women with overweight or obesity.) • PMID:41163054 (2025) — "The effects of a newly developed beverage powder supplement on anthropometric measures, body composition, metabolic syndrome components, and appetite in obese or overweight adults: a protocol for a randomized clinical trial study." (This research investigates a unique supplement that integrates these elements, proposing that it will outperform lifestyle changes alone in improving anthropometric measures, body composition, metabolic metrics, blood pressure, and appetite among overweight or obese adults.)

Quantitative Clinical Effect-Size Distribution (Forest Plot)

Displays point effect estimates (squares) and 95% confidence intervals (horizontal lines) across individual clinical studies. Intervals that do not cross the central null line indicate statistically significant clinical outcomes.

Study (PMID · Year)MD Effect Size & 95% CI DistributionEstimate (95% CI)PMID 407329330.02PMID 40326418-0.74 (-0.97–-0.51)PMID 39437887-4.03 (-2.87–-0.02)-4.6Null (0)0.63Metric: MD
05

Formulation Selection, Dosing & Chronobiology

Recommended Formulation: Standardized Marker-Compound Botanical Extract. Verify exact active marker standardization (%) rather than raw root/leaf powder weight, and screen for hepatic CYP450 drug interactions.

Clinical Trial Dosing & Timing: Published studies most commonly utilize 44 mg · 2 g · 500 mg · 1000 mg over 12 months · 8 weeks · 12 weeks · 10 days. Optimal timing window: PM 12:30 · Immediately After Breakfast or Lunch (Post-meal administration buffers concentrated botanical tannins and organic acids against gastric mucosal irritation.).

06

Body Response Monitoring & Dose Adjustment

Expected Positive Response: Gradual physiological adaptation over 4–12 weeks without gastric burning or daytime sedation.

Adjustment & Discontinuation Signals: Stop immediately if unexplained fatigue, dark urine, skin rash, or right-upper-quadrant discomfort occurs.

07

Prescription Drug Interactions & Contraindications

No major high-risk prescription contraindications are flagged in the primary index for Green Tea Extract (EGCG), but divalent minerals, fat-soluble compounds, and botanical extracts can still alter absorption or CYP450 metabolism of concurrent medications.

Always maintain a minimum 2-to-4 hour separation from narrow-therapeutic-index prescriptions and consult your healthcare provider before combining with anticoagulants, thyroid hormones, or chronic disease medications.

08

4 Essential Safety Rules Before & After Dosing

01 · Stop Immediately If:
  • Discontinue use immediately if acute hives, facial/airway swelling, severe abdominal pain, unexplained jaundice, or abnormal bruising/bleeding occurs.
  • Stop 7–14 days prior to scheduled surgery, dental extraction, or invasive endoscopic procedures.
02 · Best Practices for Bioavailability:
  • Follow the optimal chronobiology window (PM 12:30 · Immediately After Breakfast or Lunch) with a full glass of water.
  • Stay within clinically studied daily dosages (44 mg · 2 g · 500 mg) and re-evaluate efficacy after 12 months.
03 · Habits to Avoid:
  • Avoid stacking multiple multi-ingredient supplements that contain overlapping active compounds.
  • Do not wash capsules down with high-tannin coffee, strong tea, or alcohol, which can chelate minerals and irritate gastric mucosa.
04 · Consult Physician / Pharmacist Before Use If:
  • Consult your physician or pharmacist if you take daily prescription medications for thyroid, cardiovascular, metabolic, or neuropsychiatric conditions.
  • Seek professional medical guidance if you are pregnant, breastfeeding, or managing chronic kidney or liver disease.
09 · PUBMED CLINICAL STUDIES

Indexed PubMed Clinical Studies & Abstracts (51 Studies) · 14 Quantitative Analyses

01
META-ANALYSIS The American journal of Chinese medicine (2025) PMID: 40832777 ↗
Green Tea and Epigallocatechin Gallate (EGCG) for Cancer Prevention: A Systematic Review and Meta-Analysis.
Clinical Trial Synthesis 2025 Meta-Analysis published in The American journal of Chinese medicine (RR 0.72). Key conclusion: Additionally, the dose-response meta-analysis revealed a significant negative linear correlation between high doses, long-term consumption of green tea, and cancer risk.
View Original PubMed Abstract ↓

Previous studies have reported inconsistent effects of green tea and its extract, epigallocatechin gallate (EGCG), on cancer prevention. We aimed to uncover the protective effects of green tea or EGCG against cancer, and to assess the dose-response relationship between cancer risk and green tea consumption by performing a comprehensive meta-analysis of cohort studies. A systematic search of the PubMed, Embase, CENTRAL, AMED, CancerLit, AACR, and CBM databases was conducted from the date of database creation to October 26, 2023, to collect randomized controlled trials (RCTs) and cohort studies on the association between green tea or green tea extract EGCG intake and the risk of cancer occurrence. Meta-analysis was performed using the RevMan 5.4 software and Stata 16 after an independent screening of the literature, extraction of information, and evaluation by two investigators of the risk of bias in included studies. Funnel plots were used to evaluate the publication bias. Dose-response relationships were evaluated using a two-stage restricted cubic spline regression model. The study protocol was registered in PROSPERO (CRD42023484787). The search yielded 2334 papers, and 43, including 7 RCTs and 36 cohort studies, were finally included. The results of the meta-analysis showed that green tea (relative risk [RR]: 0.91, 95% confidence interval [CI]: 0.86-0.96) and EGCG (RR: 0.72, 95% CI: 0.54-0.97) could reduce the risk of cancer to a certain extent compared to controls. It had an especially notable effect in reducing the risk of prostate cancer (RR: 0.43, 95% CI: 0.22-0.83), oral cancer (RR: 0.44, 95% CI: 0.01-0.87), gallbladder cancer (RR: 0.72, 95% CI: 0.51-0.94), and hematological cancers (RR: 0.72, 95% CI: 0.49-0.95), with statistically significant differences. Additionally, the dose-response meta-analysis revealed a significant negative linear correlation between high doses, long-term consumption of green tea, and cancer risk. Green tea or EGCG intake can prevent some cancers. High doses and long-term consumption of green tea could achieve better benefits, providing a basis for the dietary guidelines for green tea in preventing cancer. However, given the hete

02
RANDOMIZED TRIAL (RCT) Nutrients (2026) PMID: 41515260 ↗
Effects of Green Tea Extract Supplementation on Inflammatory Cytokines Among Postmenopausal Women with Overweight or Obesity-A Secondary Analysis of a Randomized Controlled Trial.
Clinical Trial Synthesis 2026 Randomized Controlled Trial (RCT) published in Nutrients involving n = 97 participants; statistical significance reported at p = 0.24. Key conclusion: Conclusions: A high-dose GTE supplement consumed daily for one year did not significantly decrease inflammatory cytokines among postmenopausal women with overweight or obesity.
View Original PubMed Abstract ↓

Background: Excess adiposity induces low-grade inflammation, including increased C-reactive protein (CRP), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α). Green tea contains epigallocatechin gallate (EGCG), with anti-inflammatory potential. EGCG metabolism is influenced by individual variations in catechol-O-methyltransferase (COMT) genotypes. Objectives: To evaluate the effect of green tea extract (GTE) supplementation on circulating inflammatory cytokines among postmenopausal women with overweight or obesity and differing COMT genotypes. Methods: This study is a secondary analysis of a random subset (N = 97) from the Minnesota Green Tea Trial (MGTT), a randomized double-blinded placebo-controlled trial. The intervention was a high-dose GTE supplement (843 ± 44 mg EGCG/day) or placebo for 1 year. Serum CRP, TNF-α, and IL-6 were measured at 0, 6, and 12 months. Absolute changes in inflammatory cytokines from baseline to month 12 were evaluated using linear mixed-effects models adjusted for age, body mass index (BMI), smoking history, physical activity, and vitamin supplement use. Results: The changes from month 0 to month 12 were not statistically different between the groups for any of the inflammatory cytokines measured. The overall treatment effect was not statistically significant for CRP (p = 0.24), IL-6 (p = 0.59), TNF-α (p = 0.36), nor for the interaction between treatment group and time (all Ps > 0.40). There was no significant interaction between treatment group and COMT genotype for the stated markers. Conclusions: A high-dose GTE supplement consumed daily for one year did not significantly decrease inflammatory cytokines among postmenopausal women with overweight or obesity. The COMT genotype did not modify the effects of GTE supplementation on inflammatory cytokines. Future studies with a larger sample size among those at high risk of systemic inflammation are warranted.

03
RANDOMIZED TRIAL (RCT) Trials (2025) PMID: 41163054 ↗
The effects of a newly developed beverage powder supplement on anthropometric measures, body composition, metabolic syndrome components, and appetite in obese or overweight adults: a protocol for a randomized clinical trial study.
Clinical Trial Synthesis 2025 Randomized Controlled Trial (RCT) published in Trials. Key conclusion: This research investigates a unique supplement that integrates these elements, proposing that it will outperform lifestyle changes alone in improving anthropometric measures, body composition, metabolic metrics, blood pressure, and appetite among overweight or obese adults.
View Original PubMed Abstract ↓

BACKGROUND: Overweight and obesity result from excessive fat accumulation and pose significant global health challenges linked to various diseases. Recent research suggests that gut microbiota, particularly dysbiosis, is vital in obesity development. Next-generation probiotics, especially Akkermansia muciniphila, alongside compounds found in green tea extract and konjac glucomannan, offer promise in obesity management by enhancing gut microbiota balance and metabolic function. This research investigates a unique supplement that integrates these elements, proposing that it will outperform lifestyle changes alone in improving anthropometric measures, body composition, metabolic metrics, blood pressure, and appetite among overweight or obese adults. METHODS: This study will include 72 overweight or obese patients, who will be randomly assigned to either the intervention or control group within a randomized, triple-blind controlled clinical trial. The intervention group will consume 2 g of beverage sachets containing pasteurized Akkermansia muciniphila, green tea extract, and konjac glucomannan three times daily. In comparison, the control group will take 2 g of microcrystalline cellulose three times daily for 8 weeks. Evaluations of anthropometry (body mass index, waist and hip circumference), body composition (fat mass, fat-free mass, total body water, etc.), appetite using a visual analogue scale, blood pressure, and biochemical parameters including fasting blood glucose (FBS), total cholesterol (TC), triglycerides (TG), low- and high-density lipoprotein (LDL and HDL) will be conducted. DISCUSSION: The results of this study will provide evidence for the synergistic effects of Akkermansia muciniphila combined with prebiotics in the management of obesity and its associated metabolic states. TRIAL REGISTRATION: Iranian Registry of Clinical Trials (IRCT20250222064807N2) (2025/03/26). © 2025. The Author(s).

04
RANDOMIZED TRIAL (RCT) Nutrients (2025) PMID: 41010475 ↗
Synergistic Effects of Green Tea Extract and Ginger Supplementation on Endurance Performance and Thermal Perception in Normothermic and Cold Environments: A Randomized, Placebo-Controlled, Double-Blind Crossover Trial.
Clinical Trial Synthesis 2025 Randomized Controlled Trial (RCT) published in Nutrients; statistical significance reported at p = 0.05. Key conclusion: Conclusions: Green tea enhances endurance and fat oxidation in normothermic conditions, while its combination with ginger can optimize performance, thermal comfort, and recovery in cold environments.
View Original PubMed Abstract ↓

Background/Objectives: This study assessed the individual and combined effects of green tea extract and ginger supplementation on endurance performance, metabolic responses, perceived exertion, thermal sensation, and muscle soreness in normothermic and cold environmental conditions. Methods: In a randomized, double-blind crossover trial, sixteen recreationally active males (age: 23.4 ± 0.4 years; VO2 max: 46.8 ± 2.8 mL/kg/min) were tested in eight conditions (placebo [maltodextrin], green tea [500 mg], ginger [1000 mg], combined), all in normothermic (21-24 °C) and cold (5-7 °C) environments. All supplements and the placebo were encapsulated in identical capsules to ensure blinding. Participants completed a submaximal time-to-exhaustion (TTE) test at 70% VO2 max on a cycle ergometer. TTE, respiratory exchange ratio (RER), perceived exertion (RPE), thermal sensation (TSS), and muscle soreness via a visual analog scale (VAS), assessed 24 h post-exercise, were measured. Results: In normothermic condition, green tea and combined supplementation significantly increased TTE and reduced RER compared to the placebo (p < 0.05), and that combined supplementation lowered RPE relative to the placebo and ginger (all p < 0.05). In cold conditions, combined supplementation significantly enhanced TTE, reduced RER, and improved TSS compared to the placebo and ginger (p < 0.05), while all supplements decreased VAS relative to the placebo (p < 0.05). Ginger alone showed no significant effect on TTE or RER but improved TSS and VAS in cold compared to the placebo (p < 0.05). Cold placebo conditions exhibited significantly higher RPE and VAS than all normothermic conditions (p < 0.05). Conclusions: Green tea enhances endurance and fat oxidation in normothermic conditions, while its combination with ginger can optimize performance, thermal comfort, and recovery in cold environments. These findings suggest a practical nutritional strategy for mitigating environmental stress during exercise, specific to the acute supplementation in males. Trial Registration: This trial was registered at ClinicalTrials.gov (Identifier: NCT07150533).

05
RANDOMIZED TRIAL (RCT) BMJ open (2025) PMID: 40962336 ↗
Effect of plant-based foods and (poly)phenol supplementation on gut-microbiota metabolism in participants with overweight or obesity and cardiometabolic risk: a study protocol for a single-blind, parallel and randomised controlled trial.
Clinical Trial Synthesis 2025 Randomized Controlled Trial (RCT) published in BMJ open involving n = 99 participants. Key conclusion: Blood samples will be collected at both baseline and after 12 weeks.
View Original PubMed Abstract ↓

INTRODUCTION: Dietary (poly)phenols have beneficial properties that may play a relevant role in the management of overweight/obesity and cardiometabolic risk factors, modulating physiological and molecular pathways involved in energy metabolism, adiposity and gut microbiota-derived metabolites. METHODS AND ANALYSIS: The Prevention/Precision Diet in Araucanía (PREDIET-ARAC) trial is a randomised, single-blind, parallel arm, placebo-controlled, clinical trial designed to assess the potential health benefits of (poly)phenol intake through either diet or supplementation. The study will evaluate the effectiveness of a healthy plant-based diet (PBD) rich in (poly)phenols compared with (poly)phenol supplementation during a caloric restriction intervention.A total of 99 adults (aged 25-45 years) with overweight or obesity (body mass index: 25-35 kg/m²) and cardiovascular risk factors will be recruited from primary health centres in Temuco, Araucanía Region, Chile. Participants will be randomised (stratified by age: <35 vs ≥35 years, and sex) in a 1:1:1 ratio into one of three 12-week intervention groups, all undergoing a caloric deficit: (i) the PBD group follows a healthy hypocaloric PBD rich in (poly)phenols, (ii) supplementation group follows a healthy hypocaloric diet and receives polyphenol supplementation (≈26 g/day from maqui, green tea, olive oil leaf, cranberry and grape extracts, corresponding to ~800 mg/day of (poly)phenols) and (iii) control group that will receive a healthy hypocaloric diet with placebo supplementation. The primary outcome is body weight, while cardiometabolic risk factors serve as secondary outcomes.Dietary data will be collected using dedicated software through three 24-hour dietary recalls at baseline and post-intervention. (Poly)phenol intake will be estimated using the Phenol-Explorer database. The main data collection will include general and lifestyle questionnaires, anthropometric and bioimpedance measurements, blood pressure assessments using sphygmomanometers, physical activity monitoring through accelerometers and strength evaluations via dynamometry. Blood samples will be collected at both baseline and after 12 weeks. For the an

06
RANDOMIZED TRIAL (RCT) Journal of nutritional science and vitaminology (2025) PMID: 40887285 ↗
Effects of Oligonol(®) Supplementation on Abdominal Fat in Japanese Overweight Volunteers: A Randomized, Double-Blind, Placebo-Controlled, Parallel Group Study.
Clinical Trial Synthesis 2025 Randomized Controlled Trial (RCT) published in Journal of nutritional science and vitaminology involving n = 32 participants. Key conclusion: These results indicate that Oligonol had the abdominal visceral fat reduction effect in overweight participants.
View Original PubMed Abstract ↓

Obesity is known to induce diabetes, hypertension, and dyslipidemia, and reducing obesity is important from the perspective of disease prevention. Oligonol, a standardized oligomerized-polyphenol from Litchi chinensis fruit extract, is expected to have high absorption and body fat reduction. In this study, the effects of Oligonol intake on abdominal fat were examined in overweight Japanese participants. This randomized, double-blind, placebo-controlled trial was performed including 66 overweight adult men and women (body mass index [BMI] of 25 or more and less than 30 kg/m2) who were assigned to receive a daily dose of placebo or 200 mg Oligonol (40 mg as monomers and dimers of flavanols from lychee and tea) for 12 wk. The primary endpoint was a reduction of the visceral fat area (VFA) as quantified by computed tomography scanning after continual intake of test foods for 12 wk. In addition, body weight, BMI, waist circumference, peripheral blood tests, and general urinalysis were performed. Of 66 participants (33 per group), 63 were included in the efficacy analysis (placebo n=32; Oligonol n=31). Intake of 200 mg Oligonol significantly reduced abdominal VFA compared with the placebo group. No clinically relevant adverse events related to the intake of Oligonol were observed. These results indicate that Oligonol had the abdominal visceral fat reduction effect in overweight participants.

07
RANDOMIZED TRIAL (RCT) Nutrients (2025) PMID: 40732933 ↗
Evaluation of the Postprandial-Hyperglycemia-Suppressing Effects and Safety of Short-Term Intake of Mulberry Leaf and Water Chestnut Tea: A Randomized Double-Blind Placebo-Controlled Crossover Trial.
Clinical Trial Synthesis 2025 Randomized Controlled Trial (RCT) published in Nutrients involving n = 31 participants; statistical significance reported at p = 0.0006 (MD 0.02). Key conclusion: Conclusions: Short-term consumption of Kanzaki MW tea effectively suppressed postprandial glucose variability without safety concerns.
View Original PubMed Abstract ↓

Background/Objectives: Postprandial hyperglycemia is a risk factor for diabetes and cardiovascular diseases, even in healthy individuals. Kanzaki mulberry leaf and water chestnut tea (MW tea), a blend of mulberry (Morus alba) leaves and water chestnut (Trapa japonica) leaves and husks, is rich in polyphenols and 1-deoxynojirimycin (DNJ) and may suppress postprandial glucose spikes, but evidence regarding its short-term daily intake is limited. This study aimed to evaluate the postprandial glycemic response and safety of two-week MW tea consumption using continuous glucose monitoring (CGM). Methods: We conducted a randomized, double-blind, placebo-controlled, two-period crossover trial involving 31 participants. Each intervention period lasted two weeks, separated by a one-week washout. Participants consumed either MW tea or a placebo before meals. Interstitial glucose levels were measured every 15 min using CGM. Postprandial glucose responses were recorded every 15 min for 180 min after a standardized meal on the first day of each period. The primary outcome was the coefficient of variation (CV) in glucose levels, calculated using data from the central 10 days of each intervention period. Safety was assessed using CGM-derived hypoglycemia metrics and blood test results. Results: The CV of glucose levels during the MW tea period was significantly lower than during the placebo period (mean difference: 0.02, p = 0.0006). A significant reduction in 1 h postprandial glucose area under the curve was also observed. No significant differences were found in hypoglycemia occurrence, liver/renal/inflammatory markers, or self-reported adverse symptoms. Notably, 1,5-anhydroglucitol (1,5-AG) levels significantly increased during MW tea intake, suggesting improved glycemic control. Conclusions: Short-term consumption of Kanzaki MW tea effectively suppressed postprandial glucose variability without safety concerns. These findings support MW tea as a promising natural supplement for glycemic management and the prevention of diabetes.

08
CLINICAL STUDY American journal of physiology. Regulatory, integrative and comparative physiology (2025) PMID: 40701649 ↗
Gut microbiota-targeted dietary supplementation with fermentable fibers and polyphenols prevents hypobaric hypoxia-induced increases in intestinal permeability.
Clinical Trial Synthesis 2025 Randomized Controlled Trial (RCT) published in American journal of physiology. Regulatory, integrative and comparative physiology. Key conclusion: Findings suggest that targeting the gut microbiota with a combination of fermentable fibers and polyphenols can prevent hypobaric hypoxia-induced increases in intestinal permeability but that benefit does translate into a reduction in altitude illness symptoms.NEW & NOTEWORTHY Di
View Original PubMed Abstract ↓

Interactions between the gut microbiota and intestinal barrier may contribute to the pathophysiology of high-altitude illnesses. This study aimed to determine the effects of targeting the gut microbiota using dietary supplementation with a blend of fermentable fibers and polyphenol sources on gut microbiota composition, fecal short-chain fatty acids (SCFAs), and intestinal function and permeability during hypobaric hypoxia exposure. Healthy adults participated in a randomized, placebo-controlled, crossover study. Food products containing oligofructose-enriched inulin, galacto-oligosaccharide, high-amylose corn starch, cocoa, green tea and cranberry extracts, and blueberry powder (FP) or maltodextrin (placebo; PL) were consumed daily during three 2-wk phases separated by a ≥1-wk washout. During the final 36 h of each phase, participants resided in a hypobaric chamber simulating low (LA; 500 m) or high (HA; 4,300 m) altitude creating three experimental conditions: PL + LA, PL + HA, and FP + HA. Twenty-six participants completed ≥1 study phase and 13 [12 male; 21 ± 3 yr; body mass index (BMI) 25.4 ± 2.4 kg/m2] completed all three phases. Results demonstrated that FP mitigated hypoxia-induced increases in intestinal permeability within the small intestine and proximal colon while increasing Bifidobacterium relative abundance and decreasing gut microbiota α-diversity and colonic pH. Higher Bifidobacterium relative abundance and lower colonic pH were associated with greater reductions in intestinal permeability. However, FP did not alter fecal SCFA concentrations and increased gastrointestinal symptoms and altitude sickness during hypobaric hypoxia exposure. Findings suggest that targeting the gut microbiota with a combination of fermentable fibers and polyphenols can prevent hypobaric hypoxia-induced increases in intestinal permeability but that benefit does translate into a reduction in altitude illness symptoms.NEW & NOTEWORTHY Dietary supplementation targeting the gut microbiota may provide novel approaches to improving physiologic responses to environmental stressors such as those experienced during sojourn at high terrestrial altitudes. This study demonstrated t

09
META-ANALYSIS Advances in nutrition (Bethesda, Md.) (2025) PMID: 40355028 ↗
Associations between Diet and Cognitive Function in Stroke Survivors: A Systematic Review and Meta-analysis.
Clinical Trial Synthesis 2025 Meta-Analysis published in Advances in nutrition (Bethesda, Md.); statistical significance reported at p = 0.009 (SMD -0.4). Key conclusion: The substantial heterogeneity among studies hinders conclusions about other dietary strategies.
View Original PubMed Abstract ↓

Poststroke cognitive decline is a major form of disability in stroke survivors. Although dietary interventions have shown potential in improving cognitive outcomes in stroke-free populations, their effects on stroke survivors remain unclear. This review aimed to evaluate associations between diet and cognitive function in stroke survivors. MEDLINE, Embase, Scopus, and CINHAL were searched for studies from inception to 16 December, 2024. Eligible articles were observational and interventional studies on adult stroke survivors that evaluated the association/effect of any nutritional exposure/intervention on cognitive performance and dementia risk. Studies were excluded when an intervention was combined with nonnutritional treatment. Random-effects meta-analysis was used for similar randomized clinical trials. This review included 20 clinical trials and 14 observational studies assessing the intake of energy and proteins and a variety of single nutrients, as well as dietary patterns, single foods, and phytochemicals. Meta-analyses revealed a positive effect of energy-protein supplementation on global cognition [standardized mean difference (SMD): 0.62; 95% confidence interval (CI): 0.15, 1.08; P = 0.009], and a negative effect of B-vitamins (folic acid, vitamin B6, and vitamin B12) (SMD: -0.40; 95% CI: -0.72, -0.08; P = 0.02). Adherence to the Mediterranean-Dietary Approaches to Stop Hypertension (DASH) Intervention for Neurodegenerative Delay and plant-based diets, as well as higher consumption of fruits, milk, coffee, vitamin E, and selenium, were related to better cognitive outcomes; no significant association was observed for adherence to DASH and Mediterranean diets and consumption of vitamins D and C. Butter and sugar intake and calcium supplementation were associated with negative cognitive outcomes. Mixed results were seen for omega (ω)-3, tea, and plant extracts. The available evidence indicates that energy-protein supplementation may benefit cognition after stroke, whereas B-vitamin supplementation has no effect. The substantial heterogeneity among studies hinders conclusions about other dietary strategies. This review was registered with PROSPERO as CRD4

10
META-ANALYSIS International journal of food sciences and nutrition (2025) PMID: 40326418 ↗
Effects of green tea supplementation on obesity indices and adipokines in adults: a grade-assessed systematic review and dose-response meta-analysis of randomised controlled trials.
Clinical Trial Synthesis 2025 Meta-Analysis published in International journal of food sciences and nutrition (MD -0.74). Key conclusion: CONCLUSION: Supplementation with green tea seems to be effective in reducing excess adiposity.
View Original PubMed Abstract ↓

BACKGROUND: In this systematic review and meta-analysis, the impact of green tea supplementation on measurement/indices of adiposity was investigated. METHODS: Using predefined keywords, online databases (PubMed, Scopus, Web of Science Core Collection, and Google Scholar) were searched for relevant studies, published from inception up to February 2024. Data were extracted and registered. Subgroup analyses and the investigation of linear and non-linear associations were carried out. RESULTS: Green tea supplementation reduced BW (WMD: -0.74 kg; 95% CI: -0.97, -0.51), BMI (WMD: -0.29 kg/m2; 95% CI: -0.38, -0.19), WC (WMD: -1.04 cm; 95% CI: -1.55, -0.53), BFP (WMD: -0.65%; 95% CI: -1.03, -0.27), and leptin (WMD: -0.92 ng/ml; 95% CI: -1.71, -0.14), but did not change adiponectin levels (WMD: 0.20 µg/ml; 95% CI: -0.17, 0.57). CONCLUSION: Supplementation with green tea seems to be effective in reducing excess adiposity.

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