Green tea consumption and the risk of incident functional disability in elderly Japanese: the Ohsaki Cohort 2006 Study

Interplay among Oxidative Stress, Autophagy, and the Endocannabinoid System in Neurodegenerative Diseases: Role of the Nrf2- p62/SQSTM1 Pathway and Nutraceutical Activation

The onset of neurodegenerative diseases involves a complex interplay of pathological mechanisms, including protein aggregation, oxidative stress, and impaired autophagy. This review focuses on the intricate connection between oxidative stress and autophagy in neurodegenerative disorders, highlighting autophagy as pivotal in disease pathogenesis. Reactive oxygen species (ROS) play dual roles in cellular homeostasis and autophagy regulation, with disruptions of redox signaling contributing to neurodegeneration. The activation of the Nrf2 pathway represents a critical antioxidant mechanism, while autophagy maintains cellular homeostasis by degrading altered cell components. The interaction among p62/SQSTM1, Nrf2, and Keap1 forms a regulatory pathway essential for cellular stress response, whose dysregulation leads to impaired autophagy and aggregate accumulation. Targeting the Nrf2-p62/SQSTM1 pathway holds promise for therapeutic intervention, mitigating oxidative stress and preserving cellular functions. Additionally, this review explores the potential synergy between the endocannabinoid system and Nrf2 signaling for neuroprotection. Further research is needed to elucidate the involved molecular mechanisms and develop effective therapeutic strategies against neurodegeneration.

Tea consumption and risk of bone health: an updated systematic review and meta-analysis

INTRODUCTION

Current research evaluating the association between tea consumption and bone health still has inconsistent findings.

MATERIALS AND METHODS

The electronic databases of Embase, PubMed, Scopus, and Web of Science were systematically searched from inception until December 2022 to identify eligible studies. The calculation of summary relative risks (RRs) and 95% confidence intervals (CIs) was carried out using random-effects models. I2 statistics and Forest plots were used to assess the heterogeneity of RR values across studies.

RESULTS

The pooled relative risks for bone health-related outcomes of interest among tea drinkers, compared to non-drinkers, were 0.910 (95% confidence interval 0.845 to 0.980) for fractures, based on 20 studies, 0.332 (0.207-0.457) for BMD (13 studies), 0.800 (0.674-0.950) for osteoporosis (10 studies), and 1.006 (0.876-1.156) for osteopenia (5 studies). Subgroup analysis of locations showed that the pooled relative risks were 0.903 (0.844-0.966) for the hip, 0.735 (0.586-0.922) for the femur, 0.776 (0.610-0.988) for the lumbar, 0.980 (0.942-1.021) for the forearm and wrist, 0.804 (0.567-1.139) for the phalanges, and 0.612 (0.468-0.800) for Ward's triangle. One-stage dose-response analysis revealed that individuals who consumed less than 4.5 cups of tea per day had a lower risk of bone health-related outcomes than those who did not consume tea, with statistically significant results.

CONCLUSION

There is an association between tea consumption and a reduced risk of fractures, osteoporosis, hip, femur, and lumbar, as well as increased BMD.

An Optimal Dietary Pattern for Healthy Longevity: Scoping Differencing Review between the Mediterranean and the Japanese Diet

BACKGROUND

From the late 1980s to the early 1990s, micronutrients were associated with the concept of healthy aging and it was deemed as important to recognize eating lifestyles that better involved these healthy macronutrients.

METHODS

The present integrative differencing literature review aimed to identify correlations between healthy longevity and both the Mediterranean (MD) and the Japanese diet (JD).

RESULTS

A review of the primary and secondary literature was performed by consulting Embase and Medline (PubMed) databases. The bibliographic research focused on the critical reading of the studies in the last ten years. A total of 10 studies, 3 belonging to Embase and 7 to PubMed, were finally included, which exhaustively agreed with the inclusion criteria considered.

CONCLUSION

In all manuscripts selected, "over" elderly participants reported good adherence to both Mediterranean and Japanese eating behaviours, acceptable anthropometric characteristics, active social life, and regular physical activity.

Mechanisms underlying large-leaf yellow tea mediated inhibition of cognitive impairment in the 5xFAD model of Alzheimer's disease

BACKGROUND

Alzheimer's disease (AD) is the most common cause of dementia and is characterized by amyloid-β (Aβ) peptides and hyperphosphorylated Tau proteins. Evidence indicates that AD and type 2 diabetes mellitus (T2DM) share pathophysiological characteristics, including impaired insulin sensitivity. Large-leaf yellow tea (LYT) has been widely recognized for its health benefits, and we previously found that LYT can improve peripheral insulin resistance.

PURPOSE

This study aimed to investigate the protective effects and underlying mechanisms of LYT in the 5xFAD mouse model of AD.

METHODS

HPLC and spectrophotometric methods determined the chemical composition of the LYT extract. 5xFAD mice were treated with LYT supplementation (2 and 4 mg/ml) in drinking water for six months. Barnes and Y mazes were used to evaluate cognitive function, and the open field test assessed anxiety-like behavior. Immunofluorescence, silver, and Nissl staining were used to evaluate the pathological effects of LYT extract. A FRET-based assay assessed β-site APP cleavage enzyme 1 (BACE1) activity, ELISA measured Aβ levels in the brain, and Western blot analyses explored protein expression levels.

RESULTS

Our results revealed that LYT significantly attenuated memory impairment and anxiety levels and alleviated cerebral neural damage. A reduction of senile plaques was also observed in both the cortex and hippocampus. LYT significantly inhibited the activity of BACE1, which resulted in a lower Aβ protein level. In addition, LYT enhanced insulin receptor substrate 1 (IRS-1)-mediated phosphorylation of phosphoinositide 3-kinase (PI3K) and protein kinase B (AKT), further suppressed glycogen synthase kinase-3β (GSK3β), and ultimately inhibited hyperphosphorylation of the protein Tau. The inhibitory effect of the LYT extract on the phosphorylation of Tau and BACE1 activity was dose-dependent.

CONCLUSION

LYT improves cognitive ability and reduces Aβ production by inhibiting BACE1 activity. Decreases of Tau protein hyperphosphorylation upon LYT treatment appear to be associated with the regulation of the IRS-1/PI3K/AKT/GSK3β axis. Thus, the findings of this study also provide new evidence that LYT regulates insulin signaling pathways within the central nervous system.

Nutrition and Healthy Ageing in Asia: A Systematic Review

BACKGROUND

Nutrition plays a key role in modulating the likelihood of healthy ageing. In the present study, we aimed to conduct a systematic review to assess the impact of nutrition on healthy ageing in Asia.

METHODS

The systematic review was registered in the International Prospective Register of Systematic Reviews database (CRD42023408936) and conducted based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The PubMed, Web of Science, and Embase databases were searched up to February 2023 without language restrictions. We included prospective cohort studies that evaluated the associations of intake of a single food or consumption of a single nutrient at midlife; adherence to various dietary patterns at midlife; and improved adherence to dietary patterns from mid- to late life with the likelihood of healthy ageing and its components.

RESULTS

Out of 16,373 records, we included 71 papers comprising 24 cohorts from Singapore, China, Japan, and Thailand. The healthy ageing components included cognitive function, physical function, and depression. The majority of studies supported the observation that the likelihood of healthy ageing and its components in late life was positively increased by a higher consumption of healthy foods, such as vegetables, fruits, fish, nuts, legumes, tea, milk, and dairy, at midlife, and also by greater adherence to dietary patterns with high diversity scores or high total antioxidant capacities. Furthermore, improved adherence to healthy dietary patterns from mid- to late life also increased the likelihood of healthy ageing in late life.

CONCLUSION

Consuming healthy foods and adhering to healthy dietary patterns at midlife can promote the likelihood of healthy ageing. Moreover, improving diet quality from mid- to late life can still be beneficial.

Can habitual tea drinking be an effective approach against age-related neurodegenerative cognitive disorders: A systematic review and meta-analysis of epidemiological evidence

Our present knowledge about the efficacy of tea consumption in improving age-related cognitive disorders is incomplete since previous epidemiological studies provide inconsistent evidence. This unified systematic review and meta-analysis based on updated epidemiological cohort studies and randomized controlled trials (RCTs) evidence aimed to overcome the limitations of previous reviews by examining the efficacy of distinct types of tea consumption. PubMed, Embase, and MEDLINE were searched up to May 20, 2022, and 23 cohorts and 12 cross-sectional studies were included. Random-effects meta-analyses were conducted to obtain pooled RRs or mean differences with 95% CIs. The pooled RRs of the highest versus lowest tea consumption categories were 0.81 (95% CIs: 0.75-0.88) and 0.69 (95% CIs: 0.61-0.77), respectively. The pooled mean difference of four included RCTs revealed a beneficial effect of tea on cognitive dysfunction (MMSE ES: 1.03; 95% CI, 0.14-1.92). Subgroup analyses further demonstrated that green and black tea intake was associated with a lower risk of cognitive disorders in eastern countries, especially in women. The evidence quality was generally low to moderate. The present review provides insight into whether habitual tea consumption can be an effective approach against age-related neurodegenerative cognitive disorders and summarizes potential mechanisms based on currently published literature.

A comprehensive review on the prevention and regulation of Alzheimer's disease by tea and its active ingredients

Alzheimer's disease (AD) has brought a heavy burden to society as a representative neurodegenerative disease. The etiology of AD combines multiple factors, concluding family, gender, head trauma, diseases and social psychology. There are multiple hypotheses explaining the pathogenesis of AD such as β-amyloid (Aβ) deposition and tau hyperphosphorylation, which lead to extracellular amyloid plaques and neurofibrillary tangles in neurons. The existing therapeutic drugs have several disadvantages including single target, poor curative effect, and obvious side effects. Tea contains many bioactive components, such as tea polyphenols (TPP), L-theanine (L-TH), tea pigment, tea polysaccharides and caffeine. The epidemiological investigations have shown that drinking tea can reduce the risk of AD. The mechanisms of tea active ingredients in the prevention and regulation of AD includes reducing the generation and aggregation of Aβ; inhibiting tau aggregation and hyperphosphorylation; inhibiting neuronal apoptosis and regulate neurotransmitters; relieving oxidative stress and neuroinflammation as well as the regulation of intestinal flora. This review summarizes the different signaling pathways that tea active ingredients regulate AD. Furthermore, we propose the main limitations of current research and future research directions, hoping to contribute to the development of natural functional foods based on tea active ingredients in the prevention and treatment of AD.

Japanese Diet and Mortality, Disability, and Dementia: Evidence from the Ohsaki Cohort Study

The Japanese dietary pattern has long been discussed as one of the factors behind the longevity of Japanese people. However, the health benefits of the Japanese dietary pattern have not been fully elucidated. We published the first report in the world regarding the relation between the Japanese dietary pattern and cardiovascular disease mortality in 2007 using cohort studies including Japanese residents of Ohsaki City, Miyagi Prefecture, Japan. Since then, we have developed the Japanese Diet Index (JDI) that was based on previous findings to assess the degree of the Japanese dietary pattern and to advance the evidence on the health effects of the Japanese dietary pattern. So far, we have explored the associations between the JDI score (in quartiles) and various outcomes. For all-cause mortality, in comparison to Q1 (the lowest), the multivariable hazard ratios (HRs) and 95% confidence intervals (95%CIs) were 0.92 (0.85–1.00) for Q2, 0.91 (0.83–0.99) for Q3, and 0.91 (0.83–0.99) for Q4 (the highest). For functional disability, the multivariable HRs (95%CIs) were 0.94 (0.81–1.09) for Q2, 0.90 (0.77–1.05) for Q3, and 0.79 (0.68–0.92) for Q4. For dementia, the multivariable HRs (95%CIs) were 0.88 (0.74–1.05) for Q2, 0.87 (0.73–1.04) for Q3, 0.79 (0.66–0.95) for Q4. In addition, people with higher adherence to the Japanese dietary pattern also showed decreases in disability and dementia risks. The purpose of this article was to review all six papers, summarize the health effects of the Japanese dietary pattern, and discuss implications for future research.

The chemistry, processing, and preclinical anti-hyperuricemia potential of tea: a comprehensive review

Hyperuricemia is an abnormal purine metabolic disease that occurs when there is an excess of uric acid in the blood, associated with cardiovascular diseases, hypertension, gout, and renal disease. Dietary intervention is one of the most promising strategies for preventing hyperuricemia and controlling uric acid concentrations. Tea (Camellia sinensis) is known as one of the most common beverages and the source of dietary polyphenols. However, the effect of tea on hyperuricemia is unclear. Recent evidence shows that a lower risk of hyperuricemia is associated with tea intake. To better understand the anti-hyperuricemia effect of tea, this review first briefly describes the pathogenesis of hyperuricemia and the processing techniques of different types of tea. Next, the epidemiological and experimental studies of tea and its bioactive compounds on hyperuricemia in recent years were reviewed. Particular attention was paid to the anti-hyperuricemia mechanisms targeting the hepatic uric acid synthase, renal uric acid transporters, and intestinal microbiota. Additionally, the desirable intake of tea for preventing hyperuricemia is provided. Understanding the anti-hyperuricemia effect and mechanisms of tea can better utilize it as a preventive dietary strategy.HighlightsHigh purine diet, excessive alcohol/fructose consumption, and less exercise/sleep are the induction factors of hyperuricemia.Tea and tea compounds showed alleviated effects for hyperuricemia, especially polyphenols.Tea (containing caffeine or not) is not associated with a higher risk of hyperuricemia.Xanthine oxidase inhibition (reduce uric acid production), Nrf2 activation, and urate transporters regulation (increase uric acid excretion) are the potential molecular targets of anti-hyperuricemic effect of tea.About 5 g tea intake per day may be beneficial for hyperuricemia prevention.

Trends and biopsychosocial correlates of physical disabilities among older men and women in Taiwan: examination based on ADL, IADL, mobility, and frailty

Background

This study examines correlates of disabilities related to ADL, IADL, mobility, and frailty in men and women with a nationally representative sample of older adults living in the community.

Methods

A total of 10,898 noninstitutionalized Taiwanese nationals aged 65 years and older enrolled in the 2001 (N = 2,064), 2005 (N = 2,727), 2009 (N = 2,904), and 2013 (N = 3,203) National Health Interview Survey (NHIS) were analyzed.

Results

The prevalence of mobility disabilities and frailty in older adults in Taiwan decreased during the past decade (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\chi }_{Mobility}^{2}= -5.4$$\end{document}χMobility2=-5.4, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\chi }_{Frailty}^{2}= -6.2$$\end{document}χFrailty2=-6.2). Exercise, social engagement, and tea and coffee intake were found to be associated with lower levels of all types of disabilities in both men and women. In addition, a diet based on carbohydrates, falls, depressive symptomatology, lung and metabolic diseases were risks for most of the disabilities under consideration. Gender-specific independent correlates included: being married (OR = 0.63, 95%CI: 0.40–0.98), eggs/beans/fish/meat consumption (OR = 0.35, 95% CI = 0.16–0.80); depressive symptoms, obesity and cataracts, which were associated with higher IADL (OR = 3.61, 1.63, and 1.18, respectively) and frailty limitations (OR = 10.89, 1.27, and 1.20, respectively) in women. Cognitive impairment was found to be an important correlate for ADL limitations in men (OR = 3.64, 95%CI: 2.38–5.57).

Conclusions

Exercise, social participation and diet (more tea and coffee intake and lower carbohydrates) were correlates for lower levels of disability. Some gender-specific correlates were also identified, including associations of disability with depressive symptoms, obesity, and cataracts that were more distinct in women, and lower levels of disability which were especially significant in men who were married, eat more eggs, beans, fish, and meat, and those free from cognitive impairment.

Risk Factors of Long-Term Care Insurance Certification in Japan: A Scoping Review

This study aimed to review evidence on future long-term care associated with pre-existing factors among community-dwelling Japanese older adults. We systematically searched cohort and nested case–control studies published between 2000 and 2019 that assessed long-term care certification using the PubMed, CINAHL, and EMBASE databases. The relationship between long-term care insurance information and risk factors was investigated. The protocol was registered with the Open Science Framework. We extracted 91 studies for synthesis, including 84 prospective cohort studies, 1 retrospective cohort study, and 6 nested case–control studies. Certification for long-term care was classified into two endpoints: onset of functional disability and dementia. There were 72 studies that used long-term care certification as a proxy for functional disability, and 22 used long-term care information to indicate the onset of dementia. Common risk factors related to functional disability were physical function, frailty, and oral condition. Motor function and nutritional status were common risk factors for dementia. We found consistent associations between premorbid risk factors and functional disability and dementia. The accumulation of evidence on the incidence of long-term care and associated factors can aid the development of preventive measures. Future studies should aim to integrate this evidence.

The Association between Habitual Green Tea Consumption and Comprehensive Frailty as Assessed by Kihon Checklist Indexes among an Older Japanese Population

Background: It is unclear whether habitual green tea consumption is related to comprehensive frailty. Objectives: We conducted this study to investigate this relationship among an elderly Japanese population. Methods: This was a cross-sectional study of baseline data from 2012. The study included 5668 Japanese participants (2766 men and 2902 women aged 65 years or older). The subjects completed a validated self-administered food frequency questionnaire that included questions on their green tea consumption. We evaluated comprehensive frailty using a 25-item Kihon Checklist (KCL), which comprised seven domains (instrumental activities of daily living (IADL), physical function, malnutrition, oral or eating function, socialization and housebound, cognitive function, and depression). Frailty was defined as a KCL score greater than or equal to seven. Results: We found that a higher consumption of green tea was associated with a lower prevalence of comprehensive frailty in both sexes. Further age-stratified analysis showed that a higher consumption of green tea among women was associated with a lower prevalence of comprehensive frailty, regardless of age. In men, however, this association was found only in the older age groups. An analysis of the association between green tea consumption and the frailty subdomains showed that green tea consumption was associated with a lower prevalence of oral dysfunction and cognitive problems in both sexes. In addition, only in women was higher green tea consumption found to be associated with a lower prevalence of IADL and mobility-related disability problems. Conclusions: Green tea consumption is inversely associated with the prevalence of comprehensive frailty in Japanese men and women. Longitudinal studies are required to confirm this association.

Green Tea Suppresses Amyloid β Levels and Alleviates Cognitive Impairment by Inhibiting APP Cleavage and Preventing Neurotoxicity in 5XFAD Mice

SCOPE

The consumption of green tea is considered to be associated with a lower incidence of neurodegenerative diseases. In the present study, it is investigated the role of amyloid precursor protein cleavage, glial cell activation, neuroinflammation, and synaptic alterations in the protective effects of green tea against the amyloid β (Aβ) accumulation and cognitive impairment.

METHODS AND RESULTS

5XFAD mice are treated with green tea extract (GTE) for 8 or 16 weeks. Barnes maze and Y maze testing demonstrated that spatial learning and memory ability are markedly improved by GTE treatment. Immunofluorescence staining, ELISA, and western blot showed GTE significantly alleviate the formation of Aβ and reduce the levels of sAPPβ and C99, as well as sAPPα and C83. Meanwhile, GTE suppressed GFAP and Iba1 levels in the glial cells, increased PSD95 and synaptophysin levels in synaptic cells. Further, the IL-1β level is decreased, RNA sequencing reveals the genes annotated in response to stimulus and immune response are regulated.

CONCLUSION

Our findings indicate GTE suppresses Aβ levels and alleviate cognitive impairment in 5XFAD mice. These beneficial effects are accompanied by inhibition of APP cleavage pathways, suppression of glial cell activation and pro-inflammatory responses, and a reduction of synapse loss.

The Association between Tea Consumption and the Risk of Fracture: A Dose-Response Meta-Analysis of Prospective Cohort Studies

OBJECTIVES

Inconsistent results exist on the role of tea consumption on subsequent risk of fracture. A dose-response meta-analysis was therefore conducted to assess the association of tea consumption with the risk of fracture based on prospective cohort studies.

METHODS

The electronic databases of PubMed, Embase, and the Cochrane library were systematically searched to identify prospective cohort studies from inception until September 2020. The categories of high versus low and dose-response meta-analyses for tea consumption on the risk of fracture were calculated using the random-effects model. Eight prospective cohort studies recruited 774,134 individuals selected for the final meta-analysis.

RESULTS

An increment of 1 cup in tea consumption was not associated with the risk of fracture [relative risk (RR), 0.98; 95% confidence interval (CI), 0.96-1.00; P = 0.102]. Moreover, the highest tea consumption category was associated with a reduced risk of fracture (RR, 0.93; 95% CI, 0.88-0.98; P = 0.005). Furthermore, heavy (RR, 0.91; 95% CI, 0.85-0.98; P = 0.008) and mild (RR, 0.97; 95% CI, 0.94-1.00; P = 0.046) tea consumption were associated with lower risk of fracture. However, moderate tea consumption was not associated with the risk of fracture (RR, 0.98; 95% CI, 0.94-1.02; P = 0.281).

CONCLUSION

This study found that increased tea consumption may provide a protective role in the risk of fracture. The benefits of tea consumption should be further explored according to the characteristics of the individuals.

Changes in a specific dietary pattern and incident dementia: A prospective cohort study

BACKGROUND & AIMS

Previous studies have reported that the Japanese diet is associated with a lower risk of dementia; however, whether changes in adherence to the Japanese diet affects incident dementia remains unknown. We aimed to evaluate the association between long-term changes in adherence to the Japanese diet and risk of incident dementia among older Japanese individuals.

METHODS

We collected dietary information from community-dwelling older individuals living in Ohsaki city, Japan using a validated 39-item food frequency questionnaire in 1994 and 2006. Adherence to the Japanese diet was assessed using the 8-item Japanese Diet Index (JDI8) score (range: 0 to 8 points). Changes in adherence to the Japanese diet were defined as changes in the JDI8 score from 1994 to 2006. Next, the participants were classified into five groups: great decrease, moderate decrease, no changes [ref.], moderate increase, or great increase. Then, 3146 Japanese adults aged ≥65 years in 2006 were followed-up for 5.7 years. Incident dementia was retrieved from the long-term care insurance database. The Cox proportional hazards model was used to estimate multivariable-adjusted hazard ratios (HRs) and 95% confidence intervals (95% CIs) for incident dementia.

RESULTS

During 14,336 person-years of follow up, 231 cases of dementia were ascertained. Compared with no changes in the JDI8 score, the multivariable-adjusted HRs (95%CIs) were 1.72 (1.13, 2.62) for great decrease, 1.10 (0.73, 1.66) for moderate decrease, 0.82 (0.54, 1.25) for moderate increase, and 0.62 (0.38, 1.02) for great increase (p-trend <0.0001).

CONCLUSIONS

An increase in adherence to the Japanese diet was associated with a reduced risk of incident dementia, whereas a decrease in adherence was associated with an elevated risk among older Japanese individuals.

The role of nutraceuticals as a complementary therapy against various neurodegenerative diseases: A mini-review

In recent times, many scientists have given great attention to nutraceuticals (complementary medicine) as it widely used for promoting health status. In particular for the prevention and treatment of various neurological diseases or disorders without or less adverse effects. The current mini-review was intended to compile all popular (major) nutraceuticals against various neurodegenerative diseases (NDDs) including Parkinson's disease (PD), Alzheimer's disease (AD), Huntington's disease (HD) with special reference to clinical trials. Preliminary reviews indicated that nutraceuticals like curcumin, resveratrol, Epigallocatechin-3-gallate (EGCG), Coenzyme Q10, ω-3 FA (DHA/EPA/ALA), showed better neuroprotective activity against various NDDs in human setting (clinical trial). Hence this contribution will focus only on those popular nutraceuticals with proposed brief mechanisms (antioxidant, anti-inflammatory, mitochondrial homeostasis, autophagy regulation, promote neurogenesis) and its recommendation. This mini-review would aid common people to choose better nutraceuticals to combat various NDDs along with standard neuroprotective agents and modified lifestyle pattern.

Green tea extract containing enhanced levels of epimerized catechins attenuates scopolamine-induced memory impairment in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Green tea has been used as a traditional medicine to control brain function and digestion. Recent works suggest that drinking green tea could prevent cognitive function impairment. During tea manufacturing processes, such as brewing and sterilization, green tea catechins are epimerized. However, the effects of heat-epimerized catechins on cognitive function are still unknown. To take this advantage, we developed a new green tea extract, high temperature processed-green tea extract (HTP-GTE), which has a similar catechin composition to green tea beverages.

AIM OF THE STUDY

This study aimed to investigate the effect of HTP-GTE on scopolamine-induced cognitive dysfunction and neuronal differentiation, and to elucidate its underlying mechanisms of action.

MATERIALS AND METHODS

The neuronal differentiation promoting effects of HTP-GTE in SH-SY5Y cells was assessed by evaluating neurite length and the expression level of synaptophysin. The DNA methylation status at the synaptophysin promoter was determined in differentiated SH-SY5Y cells and in the hippocampi of mice. HTP-GTE was administered for 10 days at doses of 30, 100 and 300 mg/kg (p.o.) to mice, and its effects on cognitive functions were measured by Y-maze and passive avoidance tests under scopolamine-induced cholinergic blockade state.

RESULTS

HTP-GTE induced neuronal differentiation and neurite outgrowth via the upregulation of synaptophysin gene expression. These beneficial effects of HTP-GTE resulted from reducing DNA methylation levels at the synaptophysin promoter via the suppression of DNMT1 activity. The administration of HTP-GTE ameliorated cognitive impairments in a scopolamine-treated mouse model.

CONCLUSIONS

These results suggest that HTP-GTE could alleviate cognitive impairment by regulating synaptophysin expression and DNA methylation levels. Taken together, HTP-GTE would be a promising treatment for the cognitive impairment observed in dysfunction of the cholinergic neurotransmitter system.

Chronic Polyphenon-60 or Catechin Treatments Increase Brain Monoamines Syntheses and Hippocampal SIRT1 Levels Improving Cognition in Aged Rats

Polyphenolic compounds from green tea have great interest due to its large CONSUMPTION and therapeutic potential on the age-associated brain decline. The current work compares a similar dose regimen of a whole-green-tea extract and catechin in old rats over the course of 36 days. Results showed a significant improvement in visuo-spatial working memory and episodic memory of old rats after polyphenolic compounds administration assessed by behavioral tests. No effects were observed on the age-associated motor coordination decline. Statistically, results were correlated with significant improvements, mainly in hippocampal and striatal noradrenergic and serotonergic systems, but also with the striatal dopaminergic system. Both polyphenolic treatments also reverted the age-associated reduction of the neuroinflammation by modulating protein sirtuin 1 (SIRT1) expression in hippocampus, but no effects were observed in the usual reduction of the histone-binding protein RBAP46/48 protein linked to aging. These results are in line with previous ones obtained with other polyphenolic compounds, suggesting a general protective effect of all these compounds on the age-associated brain decline, pointing to a reduction of the oxidative stress and neuroinflammatory status reduction as the leading mechanisms. Results also reinforce the relevance of SIRT1-mediated mechanism on the neuroprotective effect and rule out the participation of RBAP46/48 protein.

Association between improved adherence to the Japanese diet and incident functional disability in older people: The Ohsaki Cohort 2006 Study

BACKGROUND & AIMS

Although it has been reported that the Japanese dietary pattern is associated with a lower risk of incident functional disability among older people, the potential benefits of improving adherence to the Japanese diet remain unclear. The aim of the present study was to evaluate the association between 12-year change in adherence to the Japanese diet and the subsequent risk of incident functional disability in older people in Japan.

METHODS

We analyzed 10-year follow-up data from a cohort study of 2923 Japanese older adults (age ≥65 years) in 2006. We collected dietary information using a validated 39-item food frequency questionnaire at two time points (1994 and 2006). Adherence to the Japanese diet (high intake of rice, miso soup, seaweeds, pickles, green and yellow vegetables, fish, green tea; low intake of beef and pork, and coffee) was assessed using the Japanese Diet Index (JDI), which ranges from 0 to 9. Participants were categorized into five groups according to changes in the JDI score at these two time points. Data on incident functional disability from December 2006 to November 2016 were retrieved from the public long-term care insurance database. The Cox proportional hazards model was used to estimate the hazard ratios (HRs) and 95% confidence intervals (CIs) for incident functional disability.

RESULTS

During 22,466 person-years of follow-up, 1093 cases of incident functional disability were documented. Compared with participants in the group with the largest decrease in the JDI score (≤-2), the multivariate-adjusted HR (95% CI) of incident functional disability was 0.77 (0.61-0.98) for those in the largest increase group (≥+2).

CONCLUSIONS

Improved adherence to the Japanese diet was associated with a significantly lower risk of incident functional disability in older people in Japan.

Tea consumption and risk of fractures: an updated meta-analysis

This meta-analysis included 16 studies, involving seven cohort studies and nine case-control studies, and the results indicated that tea consumption may be associated with a reduced the risk of fractures.

INTRODUCTION

Regarding relationship of tea consumption with the risk of fractures remains controversial. We performed a meta-analysis to elucidate the association between tea consumption and the risk of fractures.

METHODS

Relevant articles were identified up to March 2019 by searching PubMed, Web of Science, and Embase databases. The pooled relative risks (RRs) with 95% confidence intervals (CIs) were computed utilizing fixed or random effects model based on heterogeneity.

RESULTS

Altogether 16 studies (seven cohort and nine case-control studies) were included in this meta-analysis, involving 772,707 participants with 37,166 fracture cases. The RRs (95% CIs) of fracture for the highest versus lowest category of tea consumption were 0.86 (0.78-0.94). Subgroup analysis indicated significant associations in cohort studies (0.90 (0.86-0.94)) and case-control studies (0.77 (0.69-0.85)).

CONCLUSIONS

The current meta-analysis indicates that tea consumption may be associated with a reduced the risk of fractures.

Dietary supplementation of a high-temperature-processed green tea extract attenuates cognitive impairment in PS2 and Tg2576 mice

Green tea intake is generally recognized as an effective supplement that promotes mental clarity and cognitive function. These health benefits of green tea have been attributed mainly to its effective component, epigallocatechin gallate (EGCG). Because various catechin derivatives potently enhance these health benefits, we manipulated the extraction process with a high-temperature intervention. High-temperature-processed green tea extract (HTP-GTE) showed an elevated proportion of gallocatechin gallate (GCG) content. To investigate the preventive effects of HTP-GTE on cognitive decline, we found its neuroprotective effects against amyloid β (Aβ)-induced neurotoxicity in neurons and clarified that GCG significantly inhibited Aβ aggregation in vitro. Moreover, we showed that HTP-GTE intake attenuated several cognitive-decline phenotypes in a model mouse of Alzheimer's disease. These beneficial effects of HTP-GTE against cognitive decline were due to the distinctive composition of the extract and suggest the possibility that HTP-GTE supplementation could attenuate cognitive decline of Alzheimer's disease.

The Japanese Dietary Pattern Is Associated with Longer Disability-Free Survival Time in the General Elderly Population in the Ohsaki Cohort 2006 Study

BACKGROUND

Epidemiologic observations have raised expectations that the Japanese dietary pattern could promote longer disability-free survival (DFS) times among the Japanese population; however, no previous study has examined this issue.

OBJECTIVE

The aim of this study was to investigate the association between the Japanese dietary pattern and DFS time in the elderly Japanese population.

METHODS

We analyzed follow-up data covering a 10-y period for 9456 elderly Japanese individuals (aged ≥65 y) participating in a community-based prospective cohort study. Dietary habits were assessed using a food-frequency questionnaire. Based on previous studies, we used 9 food items to calculate the Japanese Diet Index (JDI) score: rice, miso soup, fish and shellfish, green and yellow vegetables, seaweed, pickled vegetables, green tea (1 point for each item if the consumption value was more than or equal to the median, and 0 points otherwise), beef and pork, and coffee (0 points for each item if the consumption value was more than or equal to the median, and 1 point otherwise). Differences in median age at incident disability or death [50th percentile differences (PDs)] according to quartiles (Q1-Q4) of the JDI score were estimated using Laplace regression.

RESULTS

During the follow-up period, 4233 (44.8%) incident disability or death events occurred. In addition, a higher JDI score was significantly associated with longer DFS time: compared with the lowest quartile of JDI scores (Q1), the multivariate-adjusted 50th PD (95% CI) was 7.1 (1.8, 12.4) mo longer for Q4. Each 1-SD increase of the JDI score was associated with 3.7 (1.7, 5.7) additional months of life without disability (P-trend < 0.01). No differences were seen in sex or chronic condition (no or ≥1 chronic condition) at baseline. A post hoc analysis showed a larger effect on DFS time when using a modified JDI score without coffee.

CONCLUSION

These results suggest that the Japanese dietary pattern is associated with improved DFS time in the general elderly population.

The association between emotional and instrumental social support and risk of suicide death: A population-based cohort study

Suicide is an important public health issue and previous studies have suggested that social support can one preventive factor. However, the association between emotional and instrumental social support and suicide death has not been investigated in detail. The purpose of this study was to investigate the association between each type of social support and suicide death based on a population-based cohort study. We analyzed follow-up data for 47,223 subjects (aged ≥40 y) participating in a community-based, prospective cohort study. At the baseline, the subjects were asked five questions about social support. The end point of the study was suicide mortality, based on data from the National Vital Statistics. The Cox model was used to estimate the multivariate-adjusted hazard ratios of suicide death. In addition, stratified analysis was conducted to test the interaction of each type of social support with gender (male/female) and age (<65/≥65 y) separately. Among 320,880 person-years of follow-up, 90 cases of suicide death were documented. There were significant association between instrumental social support and lower risk of suicide death, and the hazard ratio was 0.60 (95% CI: 0.38-0.94). Emotional social support was also associated with a lower risk of suicide death, but not to a significant degree, and the hazard ratio was 0.70 (95% CI: 0.42-1.17). It is suggested that instrumental social support was significantly associated with a lower risk of suicide death, and emotional social support tended to be associated with a lower risk of suicide death.

Education level and incident functional disability in elderly Japanese: The Ohsaki Cohort 2006 study

As the factors that link education level with incident functional disability in elderly Japanese have never been investigated, the present study investigated this issue in an elderly Japanese population. A 9-year prospective cohort study (2006–2015) was conducted among 8,680 Japanese individuals (≥65 years), Ohsaki city, Japan. In a baseline survey, we collected data on education level and potential mediators. Data on incident functional disability were retrieved from the Long-term Care Insurance database. The Cox proportional hazards model was used to estimate the hazard ratios (HRs) and 95% confidence intervals (CIs) for incident functional disability by education level (below upper-secondary education (reference), and upper secondary education and above). Mediating effects were estimated using accelerated failure time model and a logistic regression model. During 9-year follow-up period, 2,742 cases (31.6%) of incident functional disability were observed, and education level showed an inverse association with functional disability (P for trend <0.01). Participation in community activities had the largest mediating effect (34.7%) on the relationship between education level and incident functional disability. This effect remained among those aged 65–74 years (19.9%) but became negligible among those aged ≥75 years. Other potential mediators (such as smoking and drinking status) were also tested, but these showed only small mediating effects. The inverse association between education level and the incident risk of functional disability appears to be largely mediated by participation in community activities among elderly Japanese, especially those aged 65–74 years.

The Impact of Psychological Distress on Incident Functional Disability in Elderly Japanese: The Ohsaki Cohort 2006 Study

Background: Although psychological distress is known to be a risk factor for death, there are relatively few data on the impact of psychological distress on incident functional disability in older adults. The aim of this study was to examine the impact of psychological distress on incident functional disability in older adults. Methods: We conducted a cohort study of 12,365 disability-free individuals aged ≥65 years who live in Ohsaki City, Japan. In 2006, the level of psychological distress was assessed using the K6 (range: 0⁻24 points). Data on 10-year functional disability were retrieved from the public Long-term Care Insurance database. The multivariate-adjusted hazard ratios (HRs) and population attributable fractions (PAFs) according to the K6 groups (<5, 5⁻9, 10⁻12, and ≥13 points) were estimated. Results: Among 94,636 person-years, incident functional disability occurred in 4533 persons (36.7%). Significantly higher risk was observed in higher K6 score groups. The multiple-adjusted HRs (95% CIs) of incident functional disability were 1.14 (1.06⁻1.22) for 5⁻9 points, 1.28 (1.15⁻1.43) for 10⁻12 points, and 1.62 (1.44⁻1.84) for ≥13 points, in comparison with <5 points (p-trend < 0.001). The PAFs in each of the K6 score groups were 3.0% for 5⁻9 points, 1.7% for 10⁻12 points, and 2.6% for ≥13 points. Conclusions: Even when mild to moderate, psychological distress had a considerable impact on incident functional disability in this cohort.

Role of green tea catechins in prevention of age-related cognitive decline: Pharmacological targets and clinical perspective

Over the past decade, a wide range of scientific investigations have been performed to reveal neuropathological aspects of cognitive disorders; however, only limited therapeutic approaches currently exist. The failures of conventional therapeutic options as well as the predicted dramatic rise in the prevalence of cognitive decline in the coming future show the necessity for novel therapeutic agents. Recently, a wide range of research has focused on pharmacological activities of green tea catechins worldwide. Current investigations have clarified mechanistic effects of the catechins in inflammatory cascades, oxidative damages, different cellular transcription as well as transduction pathway in various body systems. It has been demonstrated that green tea polyphenols prevent age-related neurodegeneration through improvement of endogenous antioxidant defense mechanisms, modulation of neural growth factors, attenuation of neuroinflammatory pathway, and regulation of apoptosis. The catechins exhibited beneficial effects in cellular and animal models of neurodegenerative diseases including Alzheimer's disease, MS, and Parkinson's disease. The present review discusses the current pharmacological targets, which can be involved in the treatment of cognitive decline and addresses the action of catechin derivatives elicited from green tea on the multiple neural targets.

Association between social participation and incident risk of functional disability in elderly Japanese: The Ohsaki Cohort 2006

BACKGROUND

Although several longitudinal studies have examined the relationship between social participation and incident functional disability, the related mechanisms have remained unclear. The aim of this study was to examine the mechanisms linking social participation to incident functional disability.

METHODS

We analyzed follow-up data for 11,992 older adults (≥65 years) participating in a community-based, prospective cohort study covering a 9-year period. At the baseline, the subjects were asked about three types of participation in community activities (volunteering, hobbies, and neighborhood associations) and the frequency of their participation. Data on incident functional disability were retrieved from the public Long-term Care Insurance database. The Cox model was used to estimate the multivariate-adjusted hazard ratios of incident functional disability. We then conducted mediation analysis to assess the magnitude of the mediating effect.

RESULTS

Among 84,760 person-years of follow-up, there were 3,984 cases of incident functional disability. The hazard ratio was 0.79 (95% CI: 0.73-0.86) for participating in one type of activity, 0.82 (95% CI: 0.74-0.90) for two types of activity and 0.70 (95% CI: 0.64-0.77) for three types of activity in comparison with no participation in any activity. Among the estimated mediating effects, cognitive activity accounted for 9.3%, time spent walking for 8.3%, psychological state for 4.6%, and social support for 2.8% of the reduced risk of incident functional disability.

CONCLUSION

The results of this population-based cohort study indicate that cognitive activity and time spent walking are important mechanisms linking social participation to incident functional disability.

Consumption of green tea but not coffee is associated with the oral health-related quality of life among an older Japanese population: Kyoto-Kameoka cross-sectional study

BACKGROUND/OBJECTIVES

The consumption of both green tea and coffee is known to induce positive health effects; however, it remains unclear whether there is an association between the consumption of these beverages and oral health-related quality of life (OHRQoL). Thus, the present study investigated the relationship between the consumption of green tea and coffee and OHRQoL.

SUBJECTS/METHODS

We analyzed cross-sectional baseline data in 2012. The subjects were 7514 Japanese participants (3563 men, 3951 women; ≥65 years of age). Each subject completed a validated self-administered questionnaire that included items on the frequency of the consumption of green tea and coffee. OHRQoL was evaluated using the self-reported General Oral Health Assessment Index (GOHAI), which assesses oral health problems in older adults. A GOHAI score <50 points was defined as a poor OHRQoL.

RESULTS

Following adjustment for age, body mass index, total energy intake, alcohol, smoking, medication use, coffee, and fruit and vegetable consumption, increased consumption of green tea showed a strong positive association with the GOHAI score in both men and women (P_trend < 0.001 in both). In contrast, after adjusting for all factors, no statistically significant association was observed between coffee consumption and the GOHAI score in men (P_trend = 0.538) or women (P_trend = 0.607). The respective multivariate-odds ratios (95% confidence intervals) for a poor OHRQoL associated with green tea consumption frequencies of none, <1 cup/day, 1-2 cups/day, and ≥3 cups/day were 1.00, 1.01 (0.80-1.27), 0.95 (0.74-1.21), and 0.78 (0.61-0.99) (P_trend = 0.024) in men, and 1.00, 1.19 (0.90-1.57), 0.98 (0.74-1.29), and 0.86 (0.67-1.12) (P_trend = 0.014) in women.

CONCLUSIONS

Regardless of sex, green tea consumption was positively associated with the GOHAI score. Therefore, ≥3 cups/day of green tea may reduce the risk of a poor OHRQoL, especially in men.

Association of Tea Consumption with Risk of Alzheimer's Disease and Anti-Beta-Amyloid Effects of Tea

Neurodegenerative disease Alzheimer’s disease (AD) is attracting growing concern because of an increasing patient population among the elderly. Tea consumption is considered a natural complementary therapy for neurodegenerative diseases. In this paper, epidemiological studies on the association between tea consumption and the reduced risk of AD are reviewed and the anti-amyloid effects of related bioactivities in tea are summarized. Future challenges regarding the role of tea in preventing AD are also discussed.

Association between tea consumption and risk of cognitive disorders: A dose-response meta-analysis of observational studies

Background

The epidemiological evidence for a dose-response relationship between tea consumption and risk of cognitive disorders is sparse. The aim of the study was to summarize the evidence for the association of tea consumption with risk of cognitive disorders and assess the dose-response relationship.

Methods

We searched electronic databases of Pubmed, Embase, and Cochrane Library (from 1965 to Jan 19, 2017) for eligible studies that published in the international journals. A random-effects model was used to pool the most adjusted odds ratios (ORs) and the corresponding 95% confidence intervals (CIs).

Results

Seventeen studies involving 48,435 participants were included in our study. The meta-analysis showed that a higher tea consumption was associated with a significant reduction in the risk of cognitive disorders (OR=0.73, 95% CI: 0.65-0.82). When considering the specific types of tea consumption, the significantly inverse association is only found in green tea consumption (OR=0.64, 95% CI: 0.53-0.77) but not in black/oolong tea consumption (OR=0.75, 95% CI: 0.55-1.01). Dose-response meta-analysis indicated that tea consumption is linearly associated with a reduced risk of cognitive disorders. An increment of 100 ml/day, 300 ml/day, and 500 ml/day of tea consumption was associated with a 6% (OR=0.94, 95% CI: 0.92-0.96), 19% (OR=0.81, 95% CI: 0.74-0.88), and 29% (OR=0.71, 95% CI: 0.62-0.82) lower risk of cognitive disorders.

Conclusions

Tea consumption is inversely and linearly related to the risk of cognitive disorders. More studies are needed to further confirm our findings.

Diabetes and Alzheimer's Disease: Can Tea Phytochemicals Play a Role in Prevention?

Dementia and diabetes mellitus are prevalent disorders in the elderly population. While recognized as two distinct diseases, diabetes has more recently recognized as a significant contributor to risk for developing dementia, and some studies make reference to type 3 diabetes, a condition resulting from insulin resistance in the brain. Alzheimer's disease, the most common form of dementia, and diabetes, interestingly, share underlying pathological processes, commonality in risk factors, and, importantly, pathways for intervention. Tea has been suggested to possess potent antioxidant properties. It is rich in phytochemicals including, flavonoids, tannins, caffeine, polyphenols, boheic acid, theophylline, theobromine, anthocyanins, gallic acid, and finally epigallocatechin-3-gallate, which is considered to be the most potent active ingredient. Flavonoid phytochemicals, known as catechins, within tea offer potential benefits for reducing the risk of diabetes and Alzheimer's disease by targeting common risk factors, including obesity, hyperlipidemia, hypertension, cardiovascular disease, and stroke. Studies also show that catechins may prevent the formation of amyloid-β plaques and enhance cognitive functions, and thus may be useful in treating patients who have Alzheimer's disease or dementia. Furthermore, other phytochemicals found within tea offer important antioxidant properties along with innate properties capable of modulating intracellular neuronal signal transduction pathways and mitochondrial function.

Scientific opinion on the safety of green tea catechins

The EFSA ANS Panel was asked to provide a scientific opinion on the safety of green tea catechins from dietary sources including preparations such as food supplements and infusions. Green tea is produced from the leaves of Camellia sinensis (L.) Kuntze, without fermentation, which prevents the oxidation of polyphenolic components. Most of the polyphenols in green tea are catechins. The Panel considered the possible association between the consumption of (-)-epigallocatechin-3-gallate (EGCG), the most relevant catechin in green tea, and hepatotoxicity. This scientific opinion is based on published scientific literature, including interventional studies, monographs and reports by national and international authorities and data received following a public 'Call for data'. The mean daily intake of EGCG resulting from the consumption of green tea infusions ranges from 90 to 300 mg/day while exposure by high-level consumers is estimated to be up to 866 mg EGCG/day, in the adult population in the EU. Food supplements containing green tea catechins provide a daily dose of EGCG in the range of 5-1,000 mg/day, for adult population. The Panel concluded that catechins from green tea infusion, prepared in a traditional way, and reconstituted drinks with an equivalent composition to traditional green tea infusions, are in general considered to be safe according to the presumption of safety approach provided the intake corresponds to reported intakes in European Member States. However, rare cases of liver injury have been reported after consumption of green tea infusions, most probably due to an idiosyncratic reaction. Based on the available data on the potential adverse effects of green tea catechins on the liver, the Panel concluded that there is evidence from interventional clinical trials that intake of doses equal or above 800 mg EGCG/day taken as a food supplement has been shown to induce a statistically significant increase of serum transaminases in treated subjects compared to control.

Neuroprotective Effects and Mechanisms of Tea Bioactive Components in Neurodegenerative Diseases

As the population ages, neurodegenerative diseases such as Parkinson's disease (PD) and Alzheimer's disease (AD) impose a heavy burden on society and families. The pathogeneses of PD and AD are complex. There are no radical cures for the diseases, and existing therapeutic agents for PD and AD have diverse side effects. Tea contains many bioactive components such as polyphenols, theanine, caffeine, and theaflavins. Some investigations of epidemiology have demonstrated that drinking tea can decrease the risk of PD and AD. Tea polyphenols can lower the morbidity of PD and AD by reducing oxidative stress and regulating signaling pathways and metal chelation. Theanine can inhibit the glutamate receptors and regulate the extracellular concentration of glutamine, presenting neuroprotective effects. Additionally, the neuroprotective mechanisms of caffeine and theaflavins may contribute to the ability to antagonize the adenosine receptor A2AR and the antioxidant properties, respectively. Thus, tea bioactive components might be useful for neuronal degeneration treatment in the future. In the present paper, the neuro protection and the mechanisms of tea and its bioactive components are reviewed. Moreover, the potential challenges and future work are also discussed.

Mediterranean Diet and Musculoskeletal-Functional Outcomes in Community-Dwelling Older People: A Systematic Review and Meta-Analysis

BACKGROUND

Population aging is increasing and this process together with its characteristics influence the prevalence and incidence of chronic conditions and musculoskeletal-functional outcomes such as frailty, functional disability and sarcopenia. Nutritional strategies focused on dietary patterns, such as a Mediterranean diet, can be protective from these outcomes.

PURPOSE

To investigate the association between adherence to a Mediterranean diet and frailty, functional disability and sarcopenia in community-dwelling older people.

METHODS

We systematically reviewed electronic databases (MEDLINE, EMBASE, and others) and grey literature for articles investigating the relationship between adherence to a Mediterranean diet and frailty, functional disability and sarcopenia in community-dwelling people aged 60 and over. Study selection, quality of study assessment and data extraction were conducted independently by two authors. Random effects meta-analyses were performed, and pooled Odds Ratios (OR) were obtained.

RESULTS

After the literature search, screening and eligibility investigation, we included 12studies, with a total of 20,518 subjects. A higher adherence to a Mediterranean diet was found to be inversely associated with frailty (OR 0.42, 95% CI: 0.28-0.65, I2=24.9%, p=0.262) and functional disability (OR 0.75, 95% CI: 0.61-0.93, I2=0.0%, p=0.78). Highly different study characteristics prevented us from performing a meta-analysis for sarcopenia. Cohort data indicated no association between adherence to a Mediterranean diet and sarcopenia; however, cross-sectional results showed a positive relationship.

CONCLUSION

A Mediterranean diet is protective of frailty and functional disability, but not of sarcopenia. More longitudinal studies are needed to understand the relationship between a Mediterranean diet and sarcopenia.

Green tea (Camellia sinensis) and l-theanine: Medicinal values and beneficial applications in humans-A comprehensive review

Green tea (Camellia sinensis) is a famous herb, and its extract has been extensively used in traditional Chinese medicinal system. In this context, several studies have revealed its health benefits and medicinal potentialities for several ailments. With ever increasing scientific knowledge, search for safer, potential and novel type of health-related supplements quest, scientists are re-directing their research interests to explore natural resources i.e. medicinal herbs/plant derived compounds. Green tea consumption has gained a special attention and popularity in the modern era of changing lifestyle. The present review is aimed to extend the current knowledge by highlighting the importance and beneficial applications of green tea in humans for safeguarding various health issues. Herein, we have extensively reviewed, analyzed, and compiled salient information on green tea from the authentic published literature available in PubMed and other scientific databases. Scientific literature evidenced that owing to the bioactive constituents including caffeine, l-theanine, polyphenols/flavonoids and other potent molecules, green tea has many pharmacological and physiological functions. It possesses multi-beneficial applications in treating various disorders of humans. This review also provides in-depth insights on the medicinal values of green tea which will be useful for researchers, medical professionals, veterinarians, nutritionists, pharmacists and pharmaceutical industry. Future research emphasis and promotional avenues are needed to explore its potential therapeutic applications for designing appropriate pharmaceuticals, complementary medicines, and effective drugs as well as popularize and propagate its multidimensional health benefits.

Green tea effects on cognition, mood and human brain function: A systematic review

BACKGROUND

Green tea (Camellia sinensis) is a beverage consumed for thousands of years. Numerous claims about the benefits of its consumption were stated and investigated. As green tea is experiencing a surge in popularity in Western culture and as millions of people all over the world drink it every day, it is relevant to understand its effects on the human brain.

PURPOSE

To assess the current state of knowledge in the literature regarding the effects of green tea or green tea extracts, l-theanine and epigallocatechin gallate both components of green tea-on general neuropsychology, on the sub-category cognition and on brain functions in humans.

METHODS

We systematically searched on PubMed database and selected studies by predefined eligibility criteria. We then assessed their quality and extracted data. We structured our effort according to the PRISMA statement.

OUTCOME

We reviewed and assessed 21 studies, 4 of which were randomised controlled trials, 12 cross-over studies (both assessed with an adapted version of the DELPHI-list), 4 were cross-sectional studies and one was a cohort study (both assessed with an adapted version of the Newcastle-Ottawa assessment scale). The average study quality as appraised by means of the DELPHI-list was good (8.06/9); the studies evaluated with the Newcastle-Ottawa-scale were also good (6.7/9).

CONCLUSIONS

The reviewed studies presented evidence that green tea influences psychopathological symptoms (e.g. reduction of anxiety), cognition (e.g. benefits in memory and attention) and brain function (e.g. activation of working memory seen in functional MRI). The effects of green tea cannot be attributed to a single constituent of the beverage. This is exemplified in the finding that beneficial green tea effects on cognition are observed under the combined influence of both caffeine and l-theanine, whereas separate administration of either substance was found to have a lesser impact.

Chlorogenic Acid Extends the Lifespan of Caenorhabditis elegans via Insulin/IGF-1 Signaling Pathway

Coffee and tea, two of the most popular drinks around the world, share many in common from chemical components to beneficial effects on human health. One of their shared components, the polyphenols, most notably chlorogenic acid (CGA), was supposed to account for many of the beneficial effects on ameliorating diseases occurred accompanying people aging, such as the antioxidant effect and against diabetes and cardiovascular disease. CGA is also present in many traditional Chinese medicines. However, the mechanism of these effects was vague. The aging signaling pathways were conservative from yeast and worms to mammals. So, we tested if CGA had an effect on aging in Caenorhabditis elegans. We found that CGA could extend the lifespan of C. elegans by up to 20.1%, delay the age-related decline of body movement, and improve stress resistance. We conducted genetic analysis with a series of worm mutants and found that CGA could extend the lifespan of the mutants of eat-2, glp-1, and isp-1, but not of daf-2, pdk-1, akt-1, akt-2, sgk-1, and clk-1. CGA could activate the FOXO transcription factors DAF-16, HSF-1, SKN-1, and HIF-1, but not SIR-2.1. Taken together, CGA might extend the lifespan of C. elegans mainly via DAF-16 in insulin/IGF-1 signaling pathway.

Effects of a Community-Based Program for Oral Health and Nutrition on Cost-Effectiveness by Preventing Disability in Japanese Frail Elderly: A Quasi-Experimental Study Using Propensity Score Matching

OBJECTIVE

In the Japanese Long-Term Care Insurance (LTCI) system, a community-based program for oral health and nutrition (OHN program) has been implemented with the aim of reducing incident disability and care costs. However, the effectiveness of this program has not been confirmed epidemiologically. The purpose of the present study was to test the hypothesis that the OHN program does reduce incident disability and care costs.

DESIGN

A prospective study with a 28-month follow-up period was conducted using data from administrative databases at Tagajo City, Japan. Among frail elderly persons (aged 65 years or more) who were enrolled in the LTCI program in Tagajo, 64 participants in the OHN program and 128 controls (nonparticipants) were selected by propensity score matching.

MEASUREMENTS

We used 2 types of outcome measure: composite outcome (incident disability and death) and care cost. Data on incident disability were retrieved from the public LTCI database. Care cost was defined as the total amount of LTCI service cost added to medical care cost.

RESULTS

The hazard ratio of composite outcome was significantly lower for the intervention group than for the control group (hazard ratio = 0.32, 95% confidence interval 0.12-0.82). Even when we set incident disability as an outcome, the hazard ratio for the intervention group did not change (hazard ratio = 0.33, 95% confidence interval 0.11-0.97). The mean cumulative care cost during the 28 months tended to be lower for the intervention group ($4893) than that for the control group ($5770), but this was not statistically significant by the gamma regression model (cost ratio = 0.85, P = .513). The mean care cost per unit follow-up period (1 month) for the intervention group was significantly lower (cost ratio = 0.54, P = .027).

CONCLUSIONS

The results of this study suggest that the OHN program is effective for preventing incident disability and, consequently, for saving care costs per unit survival period.

Impact of Pain on Incident Risk of Disability in Elderly Japanese: Cause-specific Analysis

BACKGROUND

Although several cross-sectional studies have reported that pain is associated with functional disability in the elderly, data regarding a longitudinal association between pain and disability are inconsistent. This study aimed to investigate the association of pain severity with subsequent functional disability due to all causes as well as stroke, dementia, and joint disease/fracture.

METHODS

The authors conducted a prospective cohort study of 13,702 Japanese individuals aged 65 yr or older. Information regarding pain severity during the previous 4 weeks and other lifestyle factors was collected via questionnaire in 2006. Data on the incidence of functional disability were retrieved from the Long-term Care Insurance database. Cox proportional hazards regression analysis was used to estimate the multivariate-adjusted hazard ratios for incident functional disability.

RESULTS

The authors documented 2,686 (19.6%) cases of incident functional disability. The multivariate hazard ratio of functional disability was 1.15 (95% CI, 1.02 to 1.31) among respondents with moderate pain and 1.31 (95% CI, 1.12 to 1.54) among respondents with severe pain in comparison with those without pain (P trend < 0.001). These positive associations were particularly remarkable for disability due to joint disease/fracture: the multivariate hazard ratio was 1.88 (95% CI, 1.37 to 2.58) for moderate pain and 2.76 (95% CI, 1.93 to 3.95) for severe pain (P trend < 0.001). There was a negative association between pain severity and disability due to dementia (P trend = 0.041) and no significant association between pain severity and disability due to stroke.

CONCLUSIONS

Among elderly Japanese individuals, the authors found a significant positive association between pain severity and future incident functional disability.

Tea Consumption and Health-Related Quality of Life in Older Adults

BACKGROUND

Although tea consumption has been reported to have various health benefits in humans, its association with health-related quality of life (HRQOL) has not been investigated directly. We aimed to examine the relationship between tea consumption and HRQOL among older Chinese adults.

METHODS

We analyzed community-based cross-sectional data of 5,557 older Chinese individuals aged 60 years or older who participated in the Weitang Geriatric Diseases study. Information on tea consumption and HRQOL assessed by the European Quality of Life-5 dimensions (EQ-5D) were collected by questionnaires. We estimated the relationship of tea consumption and the EQ-5D index score using linear regression models and the association between tea consumption and self-reported EQ-5D health problems using logistic regression models.

RESULTS

The EQ-5D index score was higher for habitual tea drinkers than their counterparts. In multivariate linear analyses controlling for socio-demographic conditions, health conditions, and lifestyle habits, the differences in ED-5D index score between individuals with and without tea drinking habits was 0.012 (95% confidence interval, 0.006-0.017). In multivariate logistic analyses, habitual tea drinking was inversely associated with reporting of problems in EQ-5D dimensions mobility (odds ration [OR], 0.44; 95% CI: 0.23-0.84); pain/discomfort (OR, 0.74; 95% CI: 0.61-0.90); and anxiety/depression (OR, 0.60; 95% CI: 0.38-0.97). These associations were more evident for black or oolong tea than green tea.

CONCLUSION

Habitual tea consumption was associated with better HRQOL in older adults.

Association between Coffee Consumption and Incident Risk of Disabling Dementia in Elderly Japanese: The Ohsaki Cohort 2006 Study

Epidemiological studies of the association between coffee consumption and dementia have yielded inconsistent results. Therefore, we investigated the association between coffee consumption and incident risk of dementia in an elderly Japanese population. 23,091 subjects aged ≥65 y living in Ohsaki City, northeastern Japan, responded to the baseline survey in 2006. Of these, we analyzed 13,137 subjects who gave informed consent and were not disabled at baseline. The outcome was the incidence of disabling dementia defined by usage of the Long-term Care Insurance database. We used the Cox proportional hazards regression model for multivariate analysis. During 5.7 y of follow-up period, we identified 1,107 cases of incident dementia. Overall, coffee consumption was significantly associated with a lower risk of incident dementia. The multivariate-adjusted HRs for the incidence of dementia according to coffee consumption categories (never, occasionally, 1-2 cups/d, and ≥3 cups/d) were 1.00, 0.73 (95% CI, 0.62-0.86), 0.72 (95% CI, 0.61-0.84), and 0.82 (95% CI, 0.65-1.02; p for trend = 0.009), respectively. In addition, this significant inverse association was more remarkable among women, non-smokers, and non-drinkers. Coffee consumption is significantly associated with a lower risk of incident dementia.

Does tea consumption correlate to risk of fracture? A meta-analysis

Fractures are important causes of healthy damage and economic loss nowadays. The conclusions of observational studies on tea consumption and fracture risk are still inconsistent. The objective of this meta-analysis is to determine the effect of tea drinking on the risk of fractures. In this study, a comprehensive literature search was conducted in Pubmed, Embase and reference lists of the relevant articles. Observational studies that reported an estimate of the association between tea drinking and incidence of fractures were included. A meta-analysis was conducted by the STATA software. The results indicated that a total of 9 studies involving 147,950 individuals that examined the association between tea consumption and risk of fractures were included in this meta-analysis. The odds ratios (ORs) with 95% confidence intervals (CIs) were pooled using a random-effects model. The pooled OR of 9 observational studies for the tea consumption on risk of fracture was 0.89 (95% CI, 0.78-1.04). In the subgroup analyses, no significant association was detected in neither cohort studies (n = 3; OR, 0.97; 95% CI, 0.89-1.06) nor case-control studies (n = 6; OR, 0.91; 95% CI, 0.70-1.19), respectively. Because of the varied and limited data of the included studies, we are not able to conduct the dose-response meta-analysis. In conclusion, tea consumption might be not associated with the risk of fractures. The following large-sample and well-designed studies are required to confirm the existing conclusions.

Estimate of consumption of phenolic compounds by Brazilian population

OBJECTIVE: Estimate the intake of phenolic compounds by the Brazilian population. METHODS: To estimate the average per capita food consumption, micro data from the National Dietary Survey and from the Household Budget Survey from 2008 to 2009 was analyzed. The phenolic content in food was estimated from the base of Phenol-Explorer. It was chosen according to compatibility and variety of food items and usual method of preparation. RESULTS: The Brazilian population consumed, on average, 460.15 mg/day of total phenolic compounds, derived mainly from beverages (48.9%), especially coffee and legumes (19.5%). Since this analysis of classes of phenolics it was possible to observe an intake of 314 mg/day of phenolic acids, 138.92 mg/day of flavonoids and 7.16 mg/ day of other kinds of phenolics. Regarding the variables studied this present study shows that those men who live in the countryside and in the northeastern region of the country had a higher consumption of phenolic compounds. Besides, consumption was higher by adults and the elderly, the medium income classes, the population with incomplete and complete primary education and those with adequate nutrition and also overweight status. CONCLUSION: The intake of phenolic compounds can be considered low, especially where consumption of fruit and vegetables is insufficient. We can conclude that coffee and black beans were the best contributors to phenolic intake.

Association between the disability prevention program "Secondary Preventive Services" and disability incidence among the elderly population: A nationwide longitudinal comparison of Japanese municipalities

AIM

The aim of the present ecological study was to evaluate the relationship between the rate of participation in Secondary Preventive Services (SPS) and the incidence of disability in Japanese municipalities.

METHODS

We used the national statistics data for Long-term Care Insurance (LTCI), because all Japanese people aged ≥65 years are eligible for LTCI services depending on their functional status assessed by a national uniform standard in all municipalities. The disability incidence rate for the 2-year period in 2009-2010 was compared among five different levels of SPS participation in 2006-2008. The primary outcome was the sum total disability incidence rate in LTCI from 2009 to 2010. The outcome was divided according to disability level into three patterns: "all levels (Support Level 1 - Care Level 5)", "mild disability (Care Level ≤1)" and "moderate to severe disability (Care Level ≥2)".

RESULTS

There was a significant inverse association between the SPS participation rate and disability incidence rate. Among 1541 municipalities, those in the highest SPS participation rate quintile (≥9.79 per 1000 elderly population) had a lower disability incidence rate for all levels than those in the lowest quintile (<1.86 per 1000 elderly population; absolute rate difference 0.6%; age-adjusted incident rate ratio 0.94; 95% CI 0.89-0.99). This inverse association was observed for mild disability and not for moderate to severe disability.

CONCLUSIONS

Municipalities with a higher SPS participation rate have a lower incidence rate of mild disability. SPS could be an effective health policy for containing mild disability incidence among the elderly.

Tea consumption didn't modify the risk of fracture: a dose-response meta-analysis of observational studies

Background

Fractures are important causes of healthy damage and economic loss nowadays. The conclusions of observational studies on tea consumption and fracture risk are still inconsistent. The objective of this meta-analysis is to determine the effect of tea drinking on the risk of fractures.

Methods

A comprehensive literature search was conducted in PubMed, Embase and reference lists of the relevant articles. Observational studies that reported an estimate of the association between tea drinking and incidence of fractures were included. A meta-analysis was conducted by the STATA software.

Results

A total of 9 studies involving 147,950 individuals that examined the association between tea consumption and risk of fractures were included in this meta-analysis. The odds risks (ORs) with 95% confidence intervals (CIs) were pooled using a random-effects model. The pooled OR of 9 observational studies for the tea consumption on risk of fracture was 0.89 (95% CI, 0.78-1.04). In the subgroup analyses, no significant association was detected in neither cohort studies (n = 3; OR, 0.97; 95% CI, 0.89-1.06) nor case–control studies (n = 6; OR, 0.91; 95% CI, 0.70-1.19), respectively. No significant association was detected in the dose–response meta-analysis.

Conclusions

Tea consumption might not be associated with the risk of fractures. The following large-sample and well-designed studies are required to confirm the existing conclusions.

Virtual slides

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/5309904231178427.