Benefits and disadvantages of green tea

Green tea advantages


Green tea benefits are categorized by their effectiveness.


Possibly Beneficial

Benefits and disadvantages of green tea


There are many Benefits and disadvantages of green tea, green tea can help lower cholesterol levels, diastolic blood pressure, and the risk of developing hyperlipidemia in men with coronary heart disease, according to a study published in the International Journal of Cardiology in 2016. Furthermore, in males without heart disease, there is an inverse relationship between regular green tea consumption and the risk of coronary artery disease, and drinking three cups of green tea per day can considerably reduce female risk of coronary artery disease. [1]


Reducing the risk of endometrial cancer: A systematic review and meta-analysis of several studies published in Gynecologic Oncology in 2016 suggested that there may be a link between drinking green tea and a lower risk of endometrial cancer, though the analysis concluded that more research is needed. It’s obvious, and the reasons for the connection are well-defined. [2]

Assisting in the reduction of blood cholesterol levels: A meta-analysis of 14 studies published in The American Journal of Clinical Nutrition in 2011 found that drinking green tea or its extract reduced blood cholesterol and LDL (bad) cholesterol levels while having no effect on good cholesterol levels (HDL). [3]

Lower blood pressure: A systematic review published in the Journal of Hypertension in 2015 included 14 studies that found that drinking green tea or its extract reduced blood pressure significantly in overweight and obese adults, indicating the need for more high-quality studies with larger sample sizes to confirm the effectiveness of green tea in lowering blood pressure. [4]

Caffeine in green tea is likely to raise blood pressure in persons who already have hypertension, although this effect may be reduced in people who consume caffeine consistently from green tea and other sources. [5]

Reducing the risk of ovarian cancer: In 2012, a systematic review of 22 studies published in the journal Gynecologic Oncology found that green tea and its components had a positive effect in improving ovarian cancer in laboratory studies, and that drinking green tea could lower the risk of developing ovarian cancer. Cancer of the ovaries. [6]
Parkinson’s disease is the second most common neurodegenerative disorder worldwide, and phenolic compounds in green tea, which have antioxidant properties and are beneficial to nerves, may help reduce the risk of developing Parkinson’s disease, according to a review published in the journal CNS & Neurological Disorders – Drug Targets in 2016. [7]


Insufficient Proof
lowering the chance of amyloidosis, an uncommon condition in which an aberrant protein called amyloid builds up in the body’s organs and disrupts their normal activities [8]

According to research published in the Journal of Clinical Research in Cardiology. Green tea and its extract had an inhibitory effect on the development of cardiac amyloidosis in 2012, but more research is needed to validate this efficacy. [9]

Improved athletic performance: Scientific evidence on the effect of green tea on athletic performance is mixed, with some preliminary research suggesting that drinking green tea extract does not improve breathing or athletic performance in people doing endurance exercise, while other preliminary research suggests that taking green tea supplementation tablets three times daily with meals improved some exercise breathing tes. [5]

Benefits and disadvantages of green tea

Lowering the risk of bladder cancer: According to a review published in the journal Medicines in 2018, there is inconsistent information regarding the effect of green tea on bladder cancer. Some laboratory and animal studies have shown that phenolic compounds in green tea can inhibit the proliferation and spread of cancer cells in the bladder, as well as migration. However, some human studies have found no significant link between green tea consumption and the risk of bladder cancer, so more research is needed to confirm the effect of green tea against cancer. [10]
Possible reduction in the risk of breast cancer: According to the findings of a study published in the journal Molecular nutrition & food research in 2011, while there is evidence of green tea’s protective properties in animal studies, the effect in humans is unclear due to the small number of studies. The results of these research in humans are conflicting, and the mechanisms through which green tea consumption impacts breast cancer risk in humans are not fully understood. [11]

Cervical cancer prevention: An in vitro study published in the International Journal of Gynecological Cancer in 2010 found that the polyphenol chemicals in green tea limit the growth of cancer cells in the cervix by reducing the proliferation of virus-related cervical cells. The human papillomavirus (HPV), which is linked to more than 95% of cervical cancer cases. [12]

Cold Relief: According to a 2007 study published in the Journal of the American College of Nutrition, green tea pills with a specific formula are safe to use and effective in reducing cold symptoms, as well as improving the functioning of gamma delta T cells. T cell) in people who are healthy. [13]

Depressive symptom reduction: In 2009, a study published in The American Journal of Clinical Nutrition found a link between frequent green tea consumption and a lower prevalence of depressive symptoms in the elderly. [14]

Possible reduced risk of esophageal cancer: A meta-analysis of ten studies published in BMC Gastroenterology in 2012 found no significant link between green tea consumption and the risk of esophageal cancer in people who did not drink alcohol, but green tea did have a protective effect against the disease. More research is needed to confirm the benefit of regular green tea consumption on lowering the incidence of esophageal cancer in women. [15]
Green tea and its bioactive components have the potential to reduce the incidence of bone fractures by enhancing bone mineral density and boosting osteoblast activity, according to a review published in Nutrition Research in 2009. as well as osteoclast inhibition [16]

Lowering the risk of type 2 diabetes: A preliminary study published in the Annals of Internal Medicine in 2006 found that drinking green tea and caffeine was linked to a lower risk of type 2 diabetes, with the effects being stronger among women and men who were overweight. Caffeine use was linked to a 33% decreased chance of developing diabetes. [17]

Possible Influenza Infection Reduction: According to a study published in The Journal of Nutrition in 2011, daily green tea consumption can reduce the risk of influenza infection in children, but more clinical studies are needed to confirm this effect and assess the safety of tea consumption by children. [18]


Seasonal allergic rhinitis relief: According to a 2014 study published in Allergology International, several chemicals in green tea can help relieve seasonal allergic rhinitis symptoms, but additional research is needed to verify its usefulness. [19]
Green tea, which contains large concentrations of catechins, has been shown to reduce the incidence of leukemia among adults aged 16 to 29, according to a study published in the journal Cancer Causes & Control in 2009. However, no significant benefit was detected in the younger age groups. [20]


Drinking green tea can reduce the risk of acquiring liver illnesses, such as hepatocellular carcinoma and hepatitis, according to a meta-analysis published in the International Journal of Clinical and Experimental Medicine in 2015. Green tea has been shown to help with steatosis, cirrhosis, and chronic liver disease, but additional research is needed to fully assess the long-term advantages of green tea. [21]

Lower risk of lung cancer: According to a meta-analysis of 22 research published in Lung Cancer in 2009, greater green tea drinking is linked to an 18% lower risk of lung cancer. [22]

Increases alertness and focus: According to a review of 49 research published in Current Pharmaceutical Design in 2017, L-theanine and caffeine, which are contained in green tea, have a positive effect on sustained attention, memory, and distraction. The chemical also aids relaxing by reducing caffeine-induced alertness. [23]

Help maintain a healthy liver: According to a 2013 study published in the International Journal of Molecular Medicine, daily ingestion of 700 milliliters of green tea with more than 1 gram of catechins for 12 weeks decreased liver fat levels and reduced inflammation. By lowering oxidative stress in non-alcoholic fatty liver disease patients. [24]

Lowering the risk of non-Hodgkin lymphoma, often known as lymphoma, a cancer that starts in white blood cells called lymphocytes, which are a vital part of the immune system. [25]

According to a review of several research published in the journal Nutrition and Cancer in 2019, increasing green tea consumption may be linked to a lower incidence of non-lymphoma. Hodgkin’s [26]
Regular use of green tea can help reduce the incidence of mouth cancer, according to a preliminary study published in the journal General Dentistry in 2002. This could be due to the polyphenol chemicals in green tea, which can promote Programmed cell death (Apoptosis) in oral cancer cells. [27]

Lowering the risk of pancreatic cancer: According to a 2012 study published in the journal Cancer Epidemiology, regular consumption of green tea was linked to a 32 percent lower risk of pancreatic cancer in women, and lowering the temperature of tea was linked to a lower risk of pancreatic cancer in both men and women, depending on the amount of tea consumed and the time spent drinking the tea. [28]
Increased green tea consumption is associated with a lower risk of death from pneumonia in Japanese women, according to a preliminary study published in The American journal of clinical nutrition in 2009. Pneumonia is defined as swelling and inflammation of the tissues of one or both lungs, usually caused by a bacterial infection, [29],

and a preliminary study published in The American journal of clinical nutrition in 2009 indicated that increased green tea consumption is associated with a lower risk of death from pneumonia in Japanese women. [30]
Reduced risk of prostate cancer: According to a systematic review and meta-analysis published in Medicine in 2017, higher green tea drinking reduced the risk of prostate cancer, and the catechins in green tea had a good effect in reducing the risk of this disease. More research is needed to back up this claim. [31]


Reducing stress: According to a preliminary study published in Biological and Pharmaceutical Bulletin in 2017, drinking low-caffeine green tea can help students’ bodies cope with excessive stress and strain. [32]

Reducing the risk of stroke: According to a study published in the Tohoku journal of experimental medicine, the incidence of stroke and cerebral hemorrhage was two or more times higher in people who consumed small amounts of green tea daily compared to people who consumed green tea daily over a four-year period. Who consume more green tea on a daily basis. [33]

Other benefits: Tea is said to be beneficial in a variety of other situations, but there isn’t enough data to back this up, so we’ll just list a few examples: [5] Improving infertility, which is defined as the failure to conceive within a year of trying.
Improving the condition of oral leukoplakia, which manifests as white spots inside the mouth and is most commonly caused by smoking.
You may learn more about the benefits of drinking green tea before bed by reading this article.

Green tea’s weight-loss benefits


A systematic review of a number of studies on the effect of green tea on weight loss published in the Cochrane database of systematic reviews in 2012 found that the results of these studies on the effect of green tea on weight loss varied, but that green tea can contribute to unremarkable weight loss in people suffering from overweight or obesity, and that it has no effect on maintaining the lost weight. [34]

The article Benefits of green tea for weight reduction contains further information on the benefits of green tea for weight loss.

The nutritional value of green tea
The nutrients in 100 milliliters of unsweetened green tea are listed in the table below: [35]

aspect of nutrition

  • phosphorus 26 milligrams nutritional amount water 99.88 ml calories 0 calories
  • 19 milligrams potassium
  • Calcium
  • a single milligram
  • 7 milligrams sodium
  • 0.005 milligrams copper
  • 0.01 milligrams zinc
  • 12 mg of caffeine


Effects of green tea


Grade of green tea safety
Green tea is generally regarded safe for most healthy individuals when consumed in moderate doses, and green tea extract can be used for up to two years by most people, but it might cause stomach distress and constipation in some people, as well as liver and kidney problems in rare cases. [5]

Green tea in excessive amounts or for lengthy periods of time is possibly dangerous. Green tea contains caffeine, which can cause mild to severe adverse effects such as headaches, nervousness, sleep problems, vomiting, diarrhea, irritability, irregular heartbeat, tremor, heartburn, dizziness, ringing in the ears, convulsions, and confusion when consumed in excessive amounts. Green tea also includes a chemical component that, in large concentrations, has been related to liver harm. [5]

Drinking green tea in the amounts found in foods and drinks is probably safe for children, but there isn’t enough information about the safety of taking green tea extract for children, and cases of liver damage have been reported in adults who have used green tea extract, so some experts advise against it. Green tea is not recommended for children under the age of 18. [5]

Green tea is probably safe to drink during pregnancy in amounts up to 6 cups per day, which contains approximately 300 milligrams of caffeine, but it is likely to be unsafe to consume more than 300 milligrams of caffeine during pregnancy, as this has been linked to an increased risk of miscarriage and many other negative effects. Green tea may also increase the risk of developing fetuses with birth defects associated with folic acid deficiency. [5]

Caffeine passes through the body and can affect the infant, so the nursing mother should monitor her caffeine consumption to ensure that the daily limit of two to three cups does not exceed the caffeine sources, as excessive caffeine consumption by the nursing mother can lead to adverse effects in the infant. It causes insomnia, irritation, and increased bowel movements. [5]

Green tea has some drawbacks.


Some groups should be cautious when drinking green tea since it may have harmful side effects, and the following are examples of these groups: [36] [37]

Green tea consumption can exacerbate anemia in certain people.
People with blood problems: Green tea contains caffeine, which might raise the risk of bleeding, so people with bleeding disorders should avoid it.
Caffeine in green tea might induce an irregular heartbeat in those with heart problems.
People with diabetes: Because the caffeine in green tea might impact blood sugar control, people with diabetes who drink it should closely check their blood sugar levels.
People with glaucoma: Drinking green tea can increase pressure inside the eye, which begins within 30 minutes of drinking green tea and lasts for at least 90 minutes.
Those with high blood pressure: Caffeine in green tea can raise blood pressure in people with high blood pressure, although this effect does not appear to occur in people who regularly consume green tea or other caffeinated beverages.
Irritable Bowel Syndrome sufferers: Green tea’s caffeine, especially when consumed in high amounts, might aggravate diarrhea and IBS symptoms.
Green tea extract supplements have been linked to a variety of liver damage disorders, therefore green tea extracts may worsen the condition of persons with liver illness.
People with osteoporosis: Caffeine consumption should be limited to fewer than 300 mg per day, comparable to two to three cups of green tea, and part of the calcium lost can be replaced for. Calcium supplements can help you avoid caffeine.
People who suffer from anxiety: Caffeine use can enhance feelings of anxiety, as well as impact sleep, upset stomach, and headaches in certain people. [38]
medication interactions with green tea
Some drugs, such as the ones listed below, can interact with green tea and cause health concerns. [36]

Quinolone antibiotics: Because some antibiotics slow down how quickly the body breaks down caffeine, taking them with green tea can raise the risk of green tea side effects like tremor, headache, and elevated heart rate. These antibiotics include Ciprofloxacin and Enoxacin.
Birth control pills can slow down the breakdown of caffeine in the body, therefore drinking green tea while on birth control can raise the likelihood of green tea adverse effects.
Estrogen: Estrogen slows down the breakdown of caffeine in the body, and taking estrogen tablets with green tea increases the likelihood of negative side effects.
Caffeine can stimulate the heart, and asthma medications or beta-adrenergic agonists can also stimulate the heart, therefore taking caffeine with some of these treatments, such as Albuterol and Metaproterenol, may induce excessive cardiac stimulation and heart issues.
Green tea can excite the body, and some depression medicines can stimulate the body as well, thus consuming green tea with some of these drugs, such as Phenelzine and Tranylcypromine, may increase the chance of side effects from green tea.
Hepatotoxic medicines: These are drugs that can hurt the liver, and taking green tea extracts with them can raise the risk of liver damage. If you use this sort of medication, you should avoid using green tea extracts. Acetaminophen (Acetaminophen) and Amiodarone (In English: Acetaminophen and Amiodarone).
Anticoagulant drugs: Because green tea slows blood coagulation, eating it with anticoagulant medications like aspirin, warfarin, or ibuprofen may increase the risk of bruising and bleeding.
Some cancer medications include: Green tea may affect the efficiency of various cancer treatments, including Bortezomib, thus it’s best to avoid green tea products when taking these drugs.
Nicotine: Stimulant medicines like nicotine excite the neurological system, which can induce tension and increase heart rate, and the caffeine in green tea can have the same effect, so combining green tea with nervous system stimulants could cause difficulties. Green tea has a higher chance of adverse effects, which is bad for your health.
Pentobarbital: The stimulating effects of caffeine in green tea can prevent the medicine from causing sleep.
Diabetes medications: There is conflicting evidence about the effect of caffeine on increasing and decreasing blood sugar, and taking some diabetes medications with caffeine can reduce their effectiveness, so blood sugar levels should be monitored, and it may be necessary to change the dose of diabetes medication under the supervision of a doctor. Insulin and glimepiride are two of these medications.


When should you consume green tea?


Because some components in green tea might interfere with iron and other mineral absorption, it is best to drink it between meals, and taking caffeine sources before bed can induce sleep disruptions, so it is best to avoid it. [39]

Read the article on the best time to drink green tea for more information about the ideal time to drink tea.

An introduction to green tea


The origins of green tea, also known as Chinese green tea [40], may be traced back to China and India, where it has been consumed for centuries and continues to grow in popularity today. The type of tea is defined by the level of oxidation to which the leaves have been subjected, with the exception of herbal tea made from the leaves of the Camellia sinensis plant (scientific name: Camellia sinensis). 41] It also has stronger antioxidant content than black tea. [40]

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