Green tea and health - 5 effects scientifically proven
Matcha & Sencha green tea are literally on everyone's lips. Claims about the positive effects of green tea on health, psyche, aging and weight can be found in countless blog articles, lifestyle magazines and books. What is mostly missing, however, is the scientific evidence to back up these claims. In this article we want to give you as objective as possible an overview of the current state of knowledge about 5 health effects of green tea. You will find the corresponding sources in link form at the end of the article. So you can read each claim in detail and make your own picture of the scientific studies.
We will update this article regularly. If you come across any promising articles or studies, or if you have any questions/comments, don't hesitate to comment or contact us. We will be happy to check it out for you.
Overview
1. green tea helps with anxiety, depression and stress
2. lower high blood pressure with green tea
3. how green tea works against fatty liver
4. prevent osteoporosis with green tea
Preface to scientific studies
In order to scientifically prove the health effect of green tea, we pay particular attention in this article to randomized controlled trials (RCT), as these have the best causal association from the influencing variable (green tea) to the target variable (health effect). Participants are divided into a control group ("placebo group") and an intervention group ("real agent") and compared. This type of study forms the so-called gold standard of study types and is the most expensive & complex.
In order to save costs and reduce effort, observational studies are often used without the observed effects being subsequently proven with a controlled study. For example, one takes the group of green tea drinkers and compares them with non-green tea drinkers. However, there is no control group here and the presumed effects of green tea can also have completely different reasons. For example, people who drink green tea regularly often live more active & conscious lives and may be healthier as a result. A large part of the claims about the health effects of green tea come only from observational studies. The findings from these are more conjecture and not proven.
Another type of study we consider in this article is meta-studies. In this case, the results of several studies are processed together and reinterpreted. Depending on which studies are reprocessed here, a meta-study can certainly fulfill a high evidential function.
1. green tea helps with anxiety, depression and stress
The immediately noticeable positive effect of green tea is the calming and relaxing effect of tea time with your favorite Sencha or Matcha. Green tea allows you to pause for a moment & calm down from everyday stress. This effect has already been scientifically proven in many studies and the substance responsible has even been identified: the amino acid L-theanine.[1] This is also responsible for the full-bodied taste of Japanese green tea & is perceived as an umami flavor. Gyokuro, Kabusecha & Matcha green tea in particular contain a lot of L-theanine. This is achieved by shading the tea plants for a long time before harvesting.
Japanese green tea generally has a particularly relaxing effect due to its high theanine content.
Two of the most recent studies were able to specifically demonstrate that:
green tea helps with long-term psychological effects of Corona, such as fatigue, anxiety and depression [2].
green tea reduces stuttering and associated symptoms, such as anxiety, stress & depression [3].
The peace & relaxation that one feels with a daily cup of green tea is therefore not only subjectively perceived imagination, but is actually based on phsyiological processes: the concentration of several stress hormones such as cortisol is reduced & the release of the happiness hormone serotonin, for example, is promoted.
2. lower high blood pressure with green tea
Breathe deeply: green tea helps in stressful moments & can lower blood pressure
Nearly one in three Germans suffers from high blood pressure and its consequences.[4] A 2014 meta-study that re-evaluated the results of 20 controlled studies, among others, clearly demonstrated a reduction in blood pressure and cholesterol levels through daily consumption of green tea.[5]
A Chinese meta-study from the same year, which re-evaluated the results of 13 controlled studies, came to similar conclusions.[6] Combined with the stress-lowering effects already discussed, green tea is an excellent way to prevent cardiovascular disease.
3. how green tea works against fatty liver
Although green tea can have a positive effect on a diseased liver, scientists are ambivalent: the active ingredients of green tea in tablet form in particular can also have negative consequences for a healthy liver. Scientists therefore recommend that green tea should only be consumed as a drink. If, for example, matcha green tea is brewed in hot water and not consumed in tablet form, it is not only safe but also has a positive effect. We have already reported on the possible risks of green tea extracts in our article on the frequently claimed health risks of green tea.
Physically & mentally fit: Hasegawa san is still passionate about tea farming at over 80 & makes our Matcha N°1
Fatty liver is a condition that, like hypertension, affects almost one in three people and can have serious health consequences if left undiagnosed.[7] A meta-study from 2020 found that if fatty liver is already present, daily consumption of green tea can reduce levels of harmful enzymes.[Another meta-study demonstrated not only a reduction in enzymes, but also the inhibition of other inflammatory processes in the liver.[9] Along with an active lifestyle and healthy diet, green tea can make a significant contribution to curing fatty liver - especially considering that no effective drug or medical therapy for fatty liver currently exists.
4. prevent osteoporosis with green tea
Fit into old age - that's what most of us want. Green tea can make a contribution here: a Chinese observational study of over 1,000 women was able to demonstrate a much higher bone density in those who drink green tea daily than in the non-green tea drinkers.[10] This would mean that regular green tea consumption can strengthen the bones and, if the worst comes to the worst, reduce the risk of fracture. A 2011 Chinese study even demonstrated this effect in women over 50 whose bone density was relatively low. Through the administration of green tea polyphenols, an increase in the activities in the body for the repair & reformation of bones could be achieved after only 4 weeks.[11] The evidence is therefore becoming more and more solid that green tea is a proven means for the prevention & treatment of osteoporosis.
5. green tea reduces the risk of Alzheimer's & dementia
Although research on the effect of green tea on Alzheimer's disease and dementia is still young, there are already promising results. In 2019, a systematic review of previous studies was published, which demonstrated a preventive effect of the active ingredients from green tea in most of the studies. In particular, effects such as prevention of heart attacks and reduction of inflammation in the brain were also demonstrated.[12]
Not only good for memory: green tea could even prevent Alzheimer's & diabetes.
Another study conducted in Japan over a 5-7 year period was able to link green tea consumption to a reduction in dementia risk.[13] Further clinical studies are still needed to clearly demonstrate the beneficial effects of green tea on the brain.
CONCLUSION: Green tea helps
The positive effect of the daily cup of green tea on our health could not only be proven in the mentioned points but is also already suspected & researched in other numerous application areas. Many more studies, especially controlled clinical studies, are needed to capture, understand and prove the holistic effect of green tea. Until then, however, you are on the safe side if you enjoy delicious and above all tested pesticide-free Sencha & Matcha green tea every day.
But how can you be sure that it really is green tea without pesticides? Here is quite clear: Whether it is conventional green tea or organic tea - pesticide-free must be proven by testing. This is also the reason why we have each of our teas externally tested for pesticides. We provide you with the corresponding test report in our green tea store on the product page of each of our Senchas & Matchas and show you where exactly the tea comes from. Only in this way can you be sure that only what is in it, should be in it: 100% pesticide-free & unblended green tea.
If you want to learn more about the effects of green tea, be sure to read our article on the commonly claimed health risks of green tea.