0
selected
-
1.
A combination of green tea, rhodiola, magnesium and B vitamins modulates brain activity and protects against the effects of induced social stress in healthy volunteers.
Boyle, NB, Billington, J, Lawton, C, Quadt, F, Dye, L
Nutritional neuroscience. 2022;25(9):1845-1859
-
-
-
Free full text
-
Plain language summary
Stress is a leading cause of work-related time off. Low magnesium intake has been shown to be associated with anxiety and supplementation has been shown to relieve anxiety-related-symptoms, especially when combined with B vitamins. Green tea and rhodiola have also been used to alleviate stress, anxiety, and fatigue, the latter after just 3 days of intake. This randomised control trial of 100 moderately stressed adults aimed to determine the effects of combining magnesium, B vitamins, green tea, and rhodiola after induced social stress. The results showed that supplementation with a combination of magnesium, B vitamins, green tea, and rhodiola induced a relaxed, alert state and lowered stress, anxiety, and mood disturbances. However, it did not affect stress hormones, heart rate or blood pressure in response to stress. It was concluded that combination treatment is a promising therapy for stress. This study could be used by healthcare professionals to recommend the combination of magnesium, B vitamins, green tea, and rhodiola to individuals with social anxiety before they enter a socially stressful situation.
Abstract
BACKGROUND Magnesium (Mg), green tea and rhodiola extracts have, in isolation, been shown to possess stress and anxiety relieving effects. Green tea and rhodiola have been shown to modulate EEG oscillatory brain activity associated with relaxation and stress perception. The combined capacity of these ingredients to confer protective effects under conditions of acute stress has yet to be examined. We tested the hypothesis that a combination of Mg (with B vitamins) + green tea + rhodiola would acutely moderate the effects of stress exposure. METHODS A double blind, randomised, placebo controlled, parallel group design was employed (Clinicaltrials.gov:NCT03262376; 25/0817). One hundred moderately stressed adults received oral supplementation of either (i) Mg + B vitamins + green tea + rhodiola; (ii) Mg + B vitamins + rhodiola; (iii) Mg + B vitamins + green tea; or (iv) placebo. After supplementation participants were exposed to the Trier Social Stress Test. The effects of the study treatments on electroencephalogram (EEG) resting state alpha and theta, subjective state/mood, blood pressure, heart rate variability and salivary cortisol responses after acute stress exposure were assessed. RESULTS The combined treatment significantly increased EEG resting state theta (p < .02) - considered indicative of a relaxed, alert state, attenuated subjective stress, anxiety and mood disturbance, and heightened subjective and autonomic arousal (p < .05). CONCLUSIONS Mg, B vitamins, rhodiola and green tea extracts are a promising combination of ingredients that may enhance coping capacity and offer protection from the negative effects of stress exposure.Trial registration: ClinicalTrials.gov identifier: NCT03262376.
-
2.
Green Tea Intake and Risks for Dementia, Alzheimer's Disease, Mild Cognitive Impairment, and Cognitive Impairment: A Systematic Review.
Kakutani, S, Watanabe, H, Murayama, N
Nutrients. 2019;11(5)
-
-
-
Free full text
Plain language summary
Around 50 million people worldwide suffer from dementia, with 10 million new cases being diagnosed every year. Diet may play a role in the prevention of dementia. In this systematic review, the authors reviewed eight previous studies examining the effects of green tea on dementia. Six of the eight studies supported a preventative effect of green tea intake. The authors suggested that green tea might positively influence biological mechanisms such as oxidative stress, inflammation, accumulation of plaques in the brain and the maintenance of healthy blood vessels. The authors concluded that green tea intake might reduce the risk for dementia, Alzheimer's disease, mild cognitive impairment, or cognitive impairment, but further studies are needed.
Abstract
Dementia has become a major issue that requires urgent measures. The prevention of dementia may be influenced by dietary factors. We focused on green tea and performed a systematic review of observational studies that examined the association between green tea intake and dementia, Alzheimer's disease, mild cognitive impairment, or cognitive impairment. We searched for articles registered up to 23 August 2018, in the PubMed database and then for references of original articles or reviews that examined tea and cognition. Subsequently, the extracted articles were examined regarding whether they included original data assessing an association of green tea intake and dementia, Alzheimer's disease, mild cognitive impairment, or cognitive impairment. Finally, we included three cohort studies and five cross-sectional studies. One cohort study and three cross-sectional studies supported the positive effects of green tea intake. One cohort study and one cross-sectional study reported partial positive effects. The remaining one cohort study and one cross-sectional study showed no significant association of green tea intake. These results seem to support the hypothesis that green tea intake might reduce the risk for dementia, Alzheimer's disease, mild cognitive impairment, or cognitive impairment. Further results from well-designed and well-conducted cohort studies are required to derive robust evidence.
-
3.
Long-Term Green Tea Supplementation Does Not Change the Human Gut Microbiota.
Janssens, PL, Penders, J, Hursel, R, Budding, AE, Savelkoul, PH, Westerterp-Plantenga, MS
PloS one. 2016;11(4):e0153134
-
-
-
Free full text
Plain language summary
Green tea catechins have been shown to play a role in body weight regulation though the mechanism is poorly understood. Few studies have investigated the effect of catechins on the gut microbiota. The aim of this study was to evaluate whether green tea supplementation induces changes in the composition of the human gut microbiota. 58 participants were randomised to consume either green tea or placebo capsules for 12 weeks. Faecal samples were collected and total bacterial profiles were analysed at the baseline and end of the trial. According to this study, there were no significant changes in the composition of the gut microbiota, nor in body weight and body fat, among those receiving the green tea capsules compared with the control group. The authors conclude that this may be due to the gut microbiota differences among overweight and normal weight individuals.
Abstract
BACKGROUND Green tea catechins may play a role in body weight regulation through interactions with the gut microbiota. AIM: We examined whether green tea supplementation for 12 weeks induces changes in composition of the human gut microbiota. METHODS 58 Caucasian men and women were included in a randomized, placebo-controlled design. For 12 weeks, subjects consumed either green tea (>0.56 g/d epigallocatechin-gallate + 0.28 ∼ 0.45 g/d caffeine) or placebo capsules. Fecal samples were collected twice (baseline, vs. week 12) for analyses of total bacterial profiles by means of IS-profiling, a 16S-23S interspacer region-based profiling method. RESULTS No significant changes between baseline and week 12 in subjects receiving green tea or placebo capsules, and no significant interactions between treatment (green tea or placebo) and time (baseline and week 12) were observed for body composition. Analysis of the fecal samples in subjects receiving green tea and placebo showed similar bacterial diversity and community structures, indicating there were no significant changes in bacterial diversity between baseline and week 12 in subjects receiving green tea capsules or in subjects receiving placebo capsules. No significant interactions were observed between treatment (green tea or placebo) and time (baseline and week 12) for the gut microbial diversity. Although, there were no significant differences between normal weight and overweight subjects in response to green tea, we did observe a reduced bacterial alpha diversity in overweight as compared to normal weight subjects (p = 0.002). CONCLUSION Green tea supplementation for 12 weeks did not have a significant effect on composition of the gut microbiota. TRIAL REGISTRATION ClinicalTrials.gov NCT01556321.
-
4.
A double-blind, placebo-controlled randomised trial evaluating the effect of a polyphenol-rich whole food supplement on PSA progression in men with prostate cancer--the U.K. NCRN Pomi-T study.
Thomas, R, Williams, M, Sharma, H, Chaudry, A, Bellamy, P
Prostate cancer and prostatic diseases. 2014;17(2):180-6
-
-
-
Free full text
-
Plain language summary
Green tea, pomegranate, curcumin and broccoli have been shown to have anti-cancer effects in pre-clinical studies. The aim of this double-blind placebo controlled trial was to evaluate the effectiveness of a combination of wholefood extracts from these foods in men with prostate cancer as evaluated by progression of PSA (prostate specific antigen), a prostate cancer marker, over a six months intervention period. There was a statistically and clinically significant reduction in PSA progression in the supplement group compared to the placebo group, and significantly more men in the supplement group had no PSA progression compared to placebo group. The number of adverse effects was not statistically significantly different between the two groups. No interactions were seen between the supplement and warfarin and blood pressure lowering medication. The authors conclude that this wholefood supplement offers significant short-term benefits, and encourage larger studies into longer term benefits.
Abstract
BACKGROUND Polyphenol-rich foods such as pomegranate, green tea, broccoli and turmeric have demonstrated anti-neoplastic effects in laboratory models involving angiogenesis, apoptosis and proliferation. Although some have been investigated in small, phase II studies, this combination has never been evaluated within an adequately powered randomised controlled trial. METHODS In total, 199 men, average age 74 years, with localised prostate cancer, 60% managed with primary active surveillance (AS) or 40% with watchful waiting (WW) following previous interventions, were randomised (2:1) to receive an oral capsule containing a blend of pomegranate, green tea, broccoli and turmeric, or an identical placebo for 6 months. RESULTS The median rise in PSA in the food supplement group (FSG) was 14.7% (95% confidence intervals (CIs) 3.4-36.7%), as opposed to 78.5% in the placebo group (PG) (95% CI 48.1-115.5%), difference 63.8% (P=0.0008). In all, 8.2% of men in the FSG and 27.7% in the PG opted to leave surveillance at the end of the intervention (χ2 P=0.014). There were no significant differences within the predetermined subgroups of age, Gleason grade, treatment category or body mass index. There were no differences in cholesterol, blood pressure, blood sugar, C-reactive protein or adverse events. CONCLUSIONS This study found a significant short-term, favourable effect on the percentage rise in PSA in men managed with AS and WW following ingestion of this well-tolerated, specific blend of concentrated foods. Its influence on decision-making suggests that this intervention is clinically meaningful, but further trials will evaluate longer term clinical effects, and other makers of disease progression.
-
5.
Effects of green tea catechins and theanine on preventing influenza infection among healthcare workers: a randomized controlled trial.
Matsumoto, K, Yamada, H, Takuma, N, Niino, H, Sagesaka, YM
BMC complementary and alternative medicine. 2011;11:15
-
-
-
Free full text
Plain language summary
Influenza infection is the main cause of acute respiratory illnesses worldwide with limited prevention and treatment options. Pre-clinical experiments have shown that green tea catechins can prevent influenza infection in vitro, but clinical evidence has not been conclusive. The aim of this randomised, double-blind study was to evaluate the clinical efficacy of two compounds from green tea, catechins and theanine, in preventing influenza infection. 196 participants completed the 5 months study. The incidence of clinically defined influenza infections was significantly lower in the catechin/theanine group than in the placebo group. The incidence of laboratory-confirmed influenza infection was also lower in the catechin/theanine group than in the placebo group, but this difference was not statistically significant. No serious adverse events were observed in either group. The occurrence of mild symptoms, such as bloating and constipation, did not significantly differ between the two groups. The authors concluded that the effectiveness of catechin/theanine in this trial might be underestimated due to methodological limitations and that larger scale randomised trials are needed to confirm the effectiveness of catechin/theanine to prevent laboratory-confirmed influenza infection.
Abstract
BACKGROUND Experimental studies have revealed that green tea catechins and theanine prevent influenza infection, while the clinical evidence has been inconclusive. This study was conducted to determine whether taking green tea catechins and theanine can clinically prevent influenza infection. METHODS DESIGN, SETTING, AND PARTICIPANTS A randomized, double-blind, placebo-controlled trial of 200 healthcare workers conducted for 5 months from November 9, 2009 to April 8, 2010 in three healthcare facilities for the elderly in Higashimurayama, Japan. INTERVENTIONS The catechin/theanine group received capsules including green tea catechins (378 mg/day) and theanine (210 mg/day). The control group received placebo. MAIN OUTCOME MEASURES The primary outcome was the incidence of clinically defined influenza infection. Secondary outcomes were (1) laboratory-confirmed influenza with viral antigen measured by immunochromatographic assay and (2) the time for which the patient was free from clinically defined influenza infection, i.e., the period between the start of intervention and the first diagnosis of influenza infection, based on clinically defined influenza infection. RESULTS Eligible healthcare workers (n = 197) were enrolled and randomly assigned to an intervention; 98 were allocated to receive catechin/theanine capsules and 99 to placebo. The incidence of clinically defined influenza infection was significantly lower in the catechin/theanine group (4 participants; 4.1%) compared with the placebo group (13 participants; 13.1%) (adjusted OR, 0.25; 95% CI, 0.07 to 0.76, P = 0.022). The incidence of laboratory-confirmed influenza infection was also lower in the catechin/theanine group (1 participant; 1.0%) than in the placebo group (5 participants; 5.1%), but this difference was not significant (adjusted OR, 0.17; 95% CI, 0.01 to 1.10; P = 0.112). The time for which the patient was free from clinically defined influenza infection was significantly different between the two groups (adjusted HR, 0.27; 95% CI, 0.09 to 0.84; P = 0.023). CONCLUSIONS Among healthcare workers for the elderly, taking green tea catechins and theanine may be effective prophylaxis for influenza infection. TRIAL REGISTRATION ClinicalTrials (NCT): NCT01008020.