However, reporting that soft drinks containing green tea may cause small changes in blood flow in the brain as was actually measured in the study , but do not seem to help in performing memory tasks, was perhaps seen as less headline-worthy. The study was carried out by researchers from Swiss and German Universities and was funded by the University of Basel and grants from Rivella Ltd, Rothrist, Switzerland.

The study was published in the peer-reviewed European Journal of Clinical Nutrition. Due to the funding coming from a drinks company whose products contain green tea extracts, there is the potential for a conflict of interest that would favour positive findings toward green tea to increase sales.

Much of the reporting into studies involving functional magnetic resonance imaging has fallen into a similar trap. While changes in blood flow may be indicative of certain types of neural activity, they cannot provide definitive proof that this is the case.

Similarly, it is often not clear if, or how, these small changes in blood flow are related to actual behaviour or cognitive performance at various tasks. This was a double blind, placebo controlled laboratory study that scanned the brains of men to examine the neural effects of drinking green tea extract or placebo on their brain activation and while performing a memory task.

The researchers state that green tea is being recognised as a beverage with potential benefits for human health and cognitive functions. They cite a number of previous human studies, which they say, provide preliminary evidence that green tea intake may have a positive role in improving effects on cognitive functions.

The men were first given test drinks, then asked to perform tasks known to use working memory. Their whole brains were scanned, but the researchers also focused in on a specific area of the brain they were interested in, called the dorsolateral prefrontal cortex DLPFC , a key area that mediates working memory processing.

The study used two types of commercially available drink provided by Rivella. Each man received all the drinks Variety C at ml and ml and Variety G at ml and ml sequentially across four separate sessions, but the sequence in which they were given the different drinks was different.

Shortly after being given the drink, the brain activity of the volunteers was scanned using functional magnetic resonance imaging fMRI , while the volunteers performed a working memory task. fMRI measures tiny blood flow changes in the brain that are related to its activity. The analysis compared the effects of the different drinks variety C vs.

G and amounts ml vs. egg whites and what you need to know. Can apple cider vinegar help with weight loss? The health benefits explained. Home Wellness Food Humankind Problem Solved Holidays Comics.

Green tea has many benefits: improved brain function, gastrointestinal health and this. Daryl Austin USA TODAY. Facebook Twitter Email. Share your feedback to help improve our site! Together with her husband, Kansas City Chiefs MVP quarterback Patrick Mahomes, Brittany Mohomes shares how she parents two children with severe food….

While there are many FDA-approved emulsifiers, European associations have marked them as being of possible concern. Let's look deeper:. Researchers have found that a daily multivitamin supplement was linked with slowed cognitive aging and improved memory.

A Quiz for Teens Are You a Workaholic? How Well Do You Sleep? Health Conditions Discover Plan Connect. Nutrition Evidence Based 10 Evidence-Based Benefits of Green Tea. Medically reviewed by Kathy W. Warwick, R. Contains plant-based antioxidant compounds.

May improve cognitive function. Could help with fat burning. Might lower the risk of some cancers. May protect the brain from aging. Could help with oral health.

May help with the managing blood sugar. Explore our top resources. Might help prevent heart disease. May help you lose weight. Might help you live longer. Frequently asked questions. The bottom line. How we reviewed this article: Sources. Healthline has strict sourcing guidelines and relies on peer-reviewed studies, academic research institutions, and medical associations.

We avoid using tertiary references. You can learn more about how we ensure our content is accurate and current by reading our editorial policy. Dec 6, Written By Kris Gunnars, Dylan Bailey, MS, RD, FAND. Sep 14, Medically Reviewed By Kathy Warwick, RD, LD. Share this article.

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By Adda Bjarnadottir, MS, RDN Ice. How Nutritionists Can Help You Manage Your Health.

Postmenopausal people have the highest risk of osteoporosis. Some evidence suggests that the high concentration of antioxidants in green tea may enhance bone formation and protection against bone mass loss.

Drinking green tea may help support living a healthy, long life. Green tea is a source of polyphenols, or plant compounds that act as antioxidants. Research has found that polyphenols have anti-aging effects, such as:.

A review published in found that consuming green tea helps lower LDL "bad" and total cholesterol. Nearly two in five adults in the United States have high cholesterol levels, which raises the risk of heart attack and stroke.

Research has found that the L-theanine content in green tea may improve memory. A study published in found that green tea extract improved working memory among 12 healthy volunteers.

Working memory is a type of short-term memory necessary for cognitive functions like:. In the study, researchers gave the volunteers a milk-based drink that contained either The volunteers then completed certain tasks while an MRI tracked their brain activity. Those who consumed the green tea extract had improved working memory, brain connectivity—how well different areas of the brain work together—and task performance.

The study used a small sample of patients, so the results are not definitive. More research is needed to understand how green tea impacts memory. Green tea may manage and prevent type 2 diabetes.

Some evidence suggests that the antioxidants in green tea may reduce insulin resistance. Insulin resistance causes your cells to be less receptive to insulin than usual. Insulin is a hormone that helps your cells convert sugar into energy.

Insulin resistance is a major risk factor for type 2 diabetes. Stroke is one of the leading causes of death and disability among adults in the United States.

Research has found that drinking green tea may be one way to help prevent your risk of stroke. It's unclear why green tea lowers stroke risk.

Some experts suspect that the lifestyle habits of green tea drinkers, such as eating a balanced diet, may influence stroke risk. Some evidence suggests that green tea may help you lose weight. Green tea is a source of catechins, an antioxidant that helps break down fat. Catechins may increase your metabolic rate, which helps you burn more calories, such as while exercising.

Most available research has only looked at green tea extract rather than steeped tea. Even so, green tea extract may have minimal effects on weight loss. Experts advise eating a balanced diet and regularly exercising to help you lose weight. Excess weight may increase your risk of chronic illnesses like heart disease and type 2 diabetes.

Green tea may protect heart health by lowering blood pressure. Research has found that drinking green tea reduces blood pressure significantly, particularly in people with a high risk of heart disease. High blood pressure is one of the leading causes of heart disease and stroke because it damages the lining of the arteries, which increases the risk of plaque buildup.

As a result, the arteries narrow, restricting blood flow to the heart and brain. Research has found that green tea may lower blood pressure due to its high antioxidant content.

Those antioxidants help decrease inflammation and dilate your blood vessels, which supports healthy blood flow. Eight brewed ounces of green tea contains the following nutrients:.

Green tea is not a significant source of calories or nutrients per cup. Still, green tea contains various antioxidants and small amounts of 27 minerals. Some of the trace amounts of minerals in green tea include:. Small amounts of those minerals can add up, depending on your daily green tea intake.

Consuming up to eight cups of green tea daily is safe. One eight-ounce cup of green tea contains 30—50 milligrams of caffeine. The Food and Drug Administration warns against consuming over milligrams of caffeine daily. Some people may be more sensitive to caffeine than others. Consuming too much caffeine may cause side effects like:.

Talk to a healthcare provider if you are pregnant or breastfeeding. They may advise drinking less than milligrams of caffeine. Too much green tea may raise the risk of birth defects, and caffeine may pass through breast milk.

High doses of green tea may interact with certain medications, including those that treat heart problems and high blood pressure. Although rare, research has linked liver problems to tea products, especially green tea extract.

Whether you sip your green tea iced or hot, here are a few tips to keep in mind:. The caffeine in green tea is a stimulant, increasing alertness and keeping you awake. You may drink a cup of green tea in the morning as a substitute for coffee for an energy boost.

In contrast, caffeine generally stays in your body for up to six hours, so avoid green tea too close to bedtime. Consider pairing a cup of green tea with food. Caffeine increases the amount of acid in your stomach, which may cause an upset stomach and heartburn.

There are several types of green tea, including:. One of the most common types of green tea is Sencha, typically made in Japan. Sencha includes Bancha and Matcha. Bencha has less caffeine and L-theanine, while Matcha has the highest amounts.

Green tea is a staple in many cultures and may offer essential benefits, like protecting your bone, brain, and heart health.

Even so, green tea may be risky for people with caffeine sensitivity or who take certain medications. Ask a healthcare provider or dietitian for guidance about how green tea may impact your health goals if you do not currently drink it and are unsure if it's right for you.

You may be able to reap the possible benefits of green tea by consuming it daily. Other factors like eating a balanced diet, getting enough sleep , managing stress, and regularly exercising are essential to good health.

Ensure that you are practicing healthy lifestyle changes in addition to drinking green tea daily. It's safe to drink eight cups of green tea daily.

Each eight-ounce cup of green tea has about 30—50 milligrams of caffeine. The Food and Drug Administration advises not drinking more than milligrams of caffeine daily. Green tea products may add caffeine during manufacturing and only list the amount added.

There's not enough evidence about the optimal amount of green tea to reap the most benefits. Manufacturing typically destroys antioxidants. As a result, bottled green tea drinks, decaf green tea, and green tea powders may lack antioxidants. Instead, try limiting the amount of added sugars, like honey and stevia, and steeping your green tea at home to get the most benefits.

Boros K, Jedlinszki N, Csupor D. Theanine and caffeine content of infusions prepared from commercial tea samples. Pharmacogn Mag. Schmidt A, Hammann F, Wölnerhanssen B, et al.

Green tea extract enhances parieto-frontal connectivity during working memory processing. Psychopharmacology Berl.

Xu R, Yang K, Li S, et al. Effect of green tea consumption on blood lipids: A systematic review and meta-analysis of randomized controlled trials. Nutr J. National Center for Complementary and Integrative Health. Green tea. Unno K, Nakamura Y. Green tea suppresses brain aging.

Williams JL, Everett JM, D'Cunha NM, et al. The effects of green tea amino acid L-theanine consumption on the ability to manage stress and anxiety levels: A systematic review. Plant Foods Hum Nutr. Hidese S, Ogawa S, Ota M, et al.

Effects of L-theanine administration on stress-related symptoms and cognitive functions in healthy adults: A randomized controlled trial. Bartoszek M, Polak J, Chorążewski M. Comparison of antioxidant capacities of different types of tea using the spectroscopy methods and semi-empirical mathematical model.

Eur Food Res Technol. Centers for Disease Control and Prevention. Subjective cognitive decline — a public health issue. Sun K, Wang L, Ma Q, et al. Association between tea consumption and osteoporosis: A meta-analysis. Medicine Baltimore.

restaurants, stores and homes. Today, tea is the most widely consumed beverage in the world after water and can be found in about 8 of 10 U.

households according to New York City's Tea Association of the USA. Green tea is one of more than 1, varieties of tea and is a beverage or dietary supplement promoted for improving mental alertness, relieving digestive symptoms and headaches, and promoting weight loss, per the National Institutes of Health Center for Complementary and Integrative Health.

To produce green tea, leaves from the plant are steamed, pan-fried and dried. Such benefits include improved brain function, fewer gastrointestinal GI symptoms, a boosted metabolism , and even reduced bad breath.

Polyphenols are natural compounds great for reducing inflammation and chronic disease. And research shows that L-theanine is helpful in relieving stress disorders, improving mood, and getting better sleep. The National Institutes of Health Center for Complementary and Integrative Health, notes that when green tea is consumed as a beverage, it's "believed to be safe when used in amounts up to 8 cups per day.

Still, green tea does have caffeine in it, a compound known for stimulating the central nervous system. Drinking too much caffeine can cause insomnia, headaches, dehydration, dizziness and dependency. Green tea has about 28 milligrams of caffeine in 8 ounces of brewed liquid or 19 milligrams in the same amount of a ready-to-drink bottled form, per the Mayo Clinic.

That brewed amount is significantly less than the 96 milligrams of caffeine per 8 ounces of brewed coffee, but more than the 22 milligrams of caffeine found in 8 ounces of Cola.

Much of the reporting into studies involving functional magnetic resonance imaging has fallen into a similar trap. While changes in blood flow may be indicative of certain types of neural activity, they cannot provide definitive proof that this is the case.

Similarly, it is often not clear if, or how, these small changes in blood flow are related to actual behaviour or cognitive performance at various tasks.

This was a double blind, placebo controlled laboratory study that scanned the brains of men to examine the neural effects of drinking green tea extract or placebo on their brain activation and while performing a memory task.

The researchers state that green tea is being recognised as a beverage with potential benefits for human health and cognitive functions. They cite a number of previous human studies, which they say, provide preliminary evidence that green tea intake may have a positive role in improving effects on cognitive functions.

The men were first given test drinks, then asked to perform tasks known to use working memory. Their whole brains were scanned, but the researchers also focused in on a specific area of the brain they were interested in, called the dorsolateral prefrontal cortex DLPFC , a key area that mediates working memory processing.

The study used two types of commercially available drink provided by Rivella. Each man received all the drinks Variety C at ml and ml and Variety G at ml and ml sequentially across four separate sessions, but the sequence in which they were given the different drinks was different.

Shortly after being given the drink, the brain activity of the volunteers was scanned using functional magnetic resonance imaging fMRI , while the volunteers performed a working memory task.

fMRI measures tiny blood flow changes in the brain that are related to its activity. The analysis compared the effects of the different drinks variety C vs.

G and amounts ml vs. Participants were told to abstain from any substance use for the duration of the study, and from the intake of alcohol, caffeine, green tea products and citrus juices for up to 24 hours before each study day. Volunteers, who regularly use green tea or green tea products, or took any regular medication including over-the counter drugs, had ever used any illicit psychotropic substances, who consumed four to five units of alcohol daily or 20 units per week, or had any psychiatric, neurological or severe medical illness history were excluded.

The whole brain analysis showed no significant differences in brain activity measured by fMRI or task performance between the men consuming the two different drinks, or different amounts of the drinks. In fact, there was no difference in task performance even when they focused on the DLPFC area of the brain only.

However, there were some statistically significant findings reported for brain activity differences. Compared to giving ml of the control drink, ml of the green tea increased brain activation in the specific areas of the brain called the middle frontal gyrus and inferior parietal lobule.

This small study involving functional brain scans on 12 healthy males showed that drinking a soft drink laced with green tea extract might affect activation in the specific area of the brain involved in working memory dorsolateral prefrontal cortex.

However, it failed to show this influenced performance in a working memory task, this might have been because the study was too small to detect a difference in task performance. This study is useful for researchers interested in understanding the potential influence of green tea extract on activity in the brain.

Until further research explores this link, the immediate implications of this research to the average morning coffee or green tea drinker are minimal. A further limitation of this study was that green tea extract was consumed via a soft drink rather than a pure extract.

While a pragmatic effort was made to choose two very similar drinks, one with and one without green tea extract, using a pure extract would have better isolated its potential effect. Changes to blood flow inside the brain does not automatically correspond to you suddenly becoming smarter or having a better memory.

Hamilton Anxiety Rating Scale and Hamilton Depression Rating Scale were used to exclude subjects with moderate to severe anxiety or depression. Thus, subjects who have developed dementia are excluded. AD markers were all measured with enzyme-linked immunosorbent assay ELISA.

Serum Aβ 40 and Aβ 42 levels were detected by human Aβ 40 and Aβ 42 ELISA kits Reddot, British Columbia, Canada , and serum pTau levels were determined by human phosphorylated Tau Protein ELISA kit Jianglai Biological, Shanghai, China.

Oxidative stress markers were all measured with biochemical kits Nanjing Jiancheng, Nanjing, China. The whole detection was used in a blinded manner with respect to subject information.

Gender, education level, smoking history, alcohol consumption, history of hypertension, hypercholesterolemia, diabetes, and atrial fibrillation were considered to be categorical variables. These were shown as the number of cases percentage and analyzed by the chi-square test. The remaining items were continuous variables and presented as mean ± standard deviation Mean ± SD.

Two independent-sample t-tests werea used for comparisons between two groups of normal distribution and one-way analysis of variance was used among multiple groups.

Finally, we adopted logistic regression analysis to evaluate the correlation between green tea consumption and MCI, following adjustments for individual characteristics. Statistical analyses were conducted using SPSS The characteristics of the participants are shown in Table 2 , Figure 2A with cases Differences were observed in gender There were more males, more smokers, and lower physical activity scores in the tea-consuming group, which is consistent with the social phenomenon that middle-aged and elderly men prefer tea consumption.

And the trend of smoking may be related to gender. Figure 2. A First, the subjects were divided into two groups for preliminary analysis, including cases There were 42 cases Table 2.

Demographic and clinical characteristics of tea-consuming and non-consuming group. In subgroup analysis, there were cases Compared with the non-consumption group, the medium and high groups had more males and smokers, but no more for physical activity scores.

There were significant differences for MoCA The MoCA, HVLT immediate recall, delayed recall, and delayed recognition scores were higher while the TMT-B time and VST interference time were shorter in the tea-consuming group, as shown in Table 4 ; Figure 3.

It is suggested that green tea consumption has a protective effect on cognitive function in a way, which is mainly reflected in the memory and executive function domain.

Figure 3. The difference for MoCA score between non-consuming group and tea-consuming group. The MoCA score was higher in the tea-consuming group significantly. MoCA, Montreal Cognitive Assessment scale.

Table 4. The cognition differences between the non-consuming group and tea-consuming group. The results of subgroup analysis were similar to the above difference that was mainly reflected in memory and executive function.

Compared with the non-consumption group, the low group generally had no significant difference. The MoCA scores Probably, higher tea consumption frequency and volume have a stronger protective effect on cognitive function.

Figure 4. The results of subgroup analysis for MoCA scores. Compared with the non-consuming group, the MoCA score gradually increased in the low, medium, and high group, of which there was a significant difference only in the medium and high group, but not in the low group. In terms of anti-oxidative stress, there were significant differences for serum SOD The tea-consuming group had lower serum MDA levels and higher serum SOD and GPx levels, as presented in Table 6 , Figure 5.

Figure 5. The differences in serum AD markers between the non-consuming group and the tea-consuming group. There were significant differences in serum pTau A , Aβ42 C , and total Aβ D levels between the two groups but no difference in serum Aβ40 B levels.

The serum pTau, Aβ42, and total Aβ levels were lower in the tea-consuming group. Aβ, Amyloid-β; pTau, phosphorylated tau Table 6. The biomarker differences between non-consuming group and tea-consuming group.

In terms of anti-AD pathology, there were significant differences for serum pTau 3. The serum pTau , Aβ 42 , and total Aβ levels in the tea-consuming group were lower, as presented in Table 6 and Figure 6.

It can be seen that green tea consumption may protect cognitive function by reducing AD pathology and improving anti-oxidative stress capacity. Figure 6.

The differences in serum oxidative stress markers between the non-consuming group and tea-consuming group. There were significant differences in serum SOD A , MDA B , and GPx D levels between the two groups, but no difference in serum GR C levels.

The tea-consuming group had lower serum MDA levels and higher serum SOD and GPx levels. SOD, superoxide dismutase; MDA, Malondialdehyde; GPx, Glutathione peroxidase; GR, Glutathione reductase.

The trend of blood marker levels in subgroup analysis was similar to the above but slightly different. However, in the pairwise comparison for serum GR with the non-consumption group, the high group showed a significant difference The difference in the pairwise comparison was mainly reflected in the medium and high groups, where the serum MDA levels were lower while the SOD, GPx, and GR levels were higher, but no difference in the low group generally.

The difference in the pairwise comparison was also reflected in the medium and high group, where the serum pTau , Aβ 42 , and total Aβ levels were lower. The results were displayed in Table 7 for details. Thus, high consumption of green tea is more likely to affect AD pathology and anti-oxidative stress capacity.

Statistically, significant inverse associations were observed between green tea consumption and mild cognitive impairment in logistic regression analysis, as shown in Table 8 , Figure 7. With the non-consumption group as reference, the crude odds ratios of MCI for different groups were respectively 1.

We included a variety of potential confounders in our multivariate logistic models. However, the results did not change substantially even after adjustment for these variables.

Figure 7. The logistic regression analysis between green tea consuming and cognitive impairment. Statistically, significant inverse associations were observed between green tea consuming and mild cognitive impairment. Model 1: Crude model. Model 2: Adjusted for age, gender, education, smoking history, alcohol consuming, BMI, and physical activity scores.

OR, odds ratio; CI, confidence interval. Table 8. This study found that higher levels of green tea consumption may exert favorable effects on cognitive function and serum biomarkers of AD and oxidative stress in middle-aged and elderly adults.

As for the assessment of cognitive function, we used a battery of neuropsychological tests containing 11 scales and covering five prime cognitive domains. The results demonstrated that the MoCA scores of the tea-consuming group were significantly higher than that of the non-consumption group and were better as the frequency and volume of tea increased.

In logistic regression analysis, there was a significant negative correlation between green tea consumption and MCI.

The higher the levels of tea consumption, the lower the risk of cognitive impairment, which suggests that the protective effect of green tea on cognition may be related to frequency and volume. Furthermore, green tea consumption mainly affected memory and executive function, which was also consistent with the neuropsychological evaluation of vascular cognitive impairment.

The most common impaired cognitive domains in vascular cognitive impairment patients were processing speed and executive function Van der Flier et al. It follows that green tea is likely to be an intervenable vascular protective factor by acting on cerebral blood vessels and its risk factors to achieve the effect of improving cognition.

There have been many reports in the past on the vascular protective effects of green tea. Antioxidants, such as goji berries, green tea, thymus, and so on, may prevent cellular damage by reducing reactive oxygen species ROS overproduction or interfering in reactions that involve ROS.

Increased production of ROS favors vascular dysfunction, inducing altered vascular permeability and inflammation, accompanied by the loss of vascular modulatory function, the imbalance between vasorelaxation and vasoconstriction, and the aberrant expression of inflammatory adhesion molecules Bielli et al.

The mechanism underlying the association between green tea consumption and cognitive function may be concerned with endogenous antioxidant defense and anti-AD pathology.

As mentioned above, previous evidence has indicated that, on the one hand, the intervention of green tea in animal models of cognitive impairment could change the levels of oxidative stress markers such as SOD, MDA, and glutathione and improve spatial learning and memory. On the other hand, green tea could inhibit the formation of Aβ plaques and Tau, thereby reversing the cognitive impairment of animals.

In this study, we selected the seven classic markers both in the two aspects to be detected, adding new evidence to the mechanism demonstration from a clinical perspective.

In terms of anti-oxidative stress, our results were consistent with the past. The intervention of green tea reduced the cytotoxicity of MDA and increased the levels of SOD, GPx, and GR, which were pretty important enzymes to protect the structure and function of cell membranes from damage, indicating that green tea improves the ability to resist oxidative stress.

Oxidative stress, which occurs when there is an imbalance between oxidant and antioxidant levels in the cell resulting in increased ROS production, is another important metabolic facet of AD pathology.

Specifically, increased levels of ROS cause damage to macromolecules within the cell, and it is this damage of lipids, proteins, and nucleic acids that gives rise to pathological consequences. In the brain, ROS are eliminated by the free radical scavenger glutathione GSH through a chemical reaction that converts GSH to its oxidized state.

As such, higher intracellular GSH levels protect cells from ROS-mediated insults. Therefore, regular green tea consumption may improve cognitive function by increasing antioxidant capacity. And the higher the levels of consumption, the stronger the correlation for this mechanism.

A possible explanation is that though the content of Aβ 40 is higher than Aβ 42 in human cerebrospinal fluid and blood, Aβ 42 has stronger toxicity and is easier to aggregate, thus forming the core of Aβ plaques and triggering neurotoxic effects.

So, the sensitivity to drugs or interventions is higher than Aβ It can also be seen from existing research that the mechanism of green tea was more suited to Aβ For example, a molecular dynamics simulation experiment reported that EGCG could change the shape of Aβ 42 through hydrogen bond interactions, damage its molecular dynamics and thereby disrupt Aβ 42 protofibril Zhan et al.

Animal experiments have also revealed that EGCG significantly improved cognitive impairment in aged rats and reduced the formation of Aβ 42 plaques in the brain Wei et al. In addition, serum pTau demonstrated its potential as an early AD marker once again. It was first discovered that there was an association between serum pTau and green tea consumption, which also provides new ideas for our future research.

In short, regular consumption of green tea may affect the formation of Aβ and Tau and thus protect cognition. In the meanwhile, it has been reported that oxidative stress plays a key role in the pathogenesis of AD.

Antioxidants are compounds that have the ability to counteract the oxidative damage conferred by ROS. Therefore, the antioxidant therapy may provide benefits and halt the progress of AD to advance stages by counteracting neuronal degeneration Walia et al. In conclusion, our study explored the relationship between green tea consumption and cognitive function among middle-aged and elderly people in China, as well as its anti-AD and oxidative stress effects.

First, we comprehensively reflected on the green tea habits by inquiring about the frequency, the volume, and the years of consumption, and the subjects were divided into several groups accordingly. Next, the cognition assessment was more diversified.

MoCA was used for overall screening that is more sensitive to MCI than the Mini-Mental State Examination scale. The battery of scales covered five prime domains including memory, language, attention, executive function, and visual space.

And the influence of anxiety or depression was also excluded. Moreover, we converted the results of basic research into clinical evidence in the analysis of blood markers and the detection indicators were more comprehensive. Finally, maybe in contrast to Eastern and Western culture and diet patterns, most orientals are accustomed to long-term green tea consumption, in comparison to coffee in the West.

Among the subjects of this study, the average consumption duration in the tea-consuming group was Consequently, the results of our study that green tea consumption was associated with better cognitive function may also be related to the years, adding new evidence to the argument for this issue.

The present study has some limitations. It was a cross-sectional study but determining the impact of diet on cognitive function is a long process. Our findings must be validated in a long-term follow-up study.

Our researchers have tried their best to reduce the degree of bias in the process. If cerebrospinal fluid samples can be collected for analysis, stronger evidence will be obtained in the future.

At last, the participants of our study were normal middle-aged and elderly people or those with MCI. Whether green tea consumption has a protective effect on patients with dementia is not yet known. These also provide us with future research directions.

Green tea consumption is associated with better cognitive function, which is mainly reflected in memory and executive function. It might achieve protective effects by reducing AD-related pathology and improving anti-oxidative stress capacity. And higher levels of tea consumption may have a stronger protective effect on cognitive function.

The raw data supporting the conclusions of this article will be made available by the authors, without undue reservation.

The studies involving human participants were reviewed and approved by ClinicalTrials. gov Protocol Registration and Results System PRS ID: NCT RZ: involved in study design, interviewing subjects, and drafting the manuscript.

LZ: involved in study design, data analysis, and revising the manuscript. ZL: involved in collecting blood samples. PZ: involved in assessing cognitive function. HS: involved in detecting biomarkers. D-aY: involved in interviewing subjects.

JC: involved in assessing cognitive function. J-jZ: involved in study design, revising the manuscript, and obtaining funding. This study was supported by National Natural Science Foundation of China grant numbers and , J-jZ. The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers.

Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher. We would like to thank for the support of the fund, thank Wuhan University and thank Dr. Jiangtao Yu for his assistance in generating all the figures.

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