According to a 2019 Molecules study, although green tea is made from the same leaves as black tea, green tea leaves are not fermented. This not only preserves the green color of the tea, but also enhances its antioxidant content, which may explain why it is so good for your health.
Here are some of the health benefits and risks of green tea, as well as tips for incorporating it into your diet.
Benefits.
Drinking green tea regularly can help prevent some chronic diseases and manage other ailments. Previous research has shown that green tea has several benefits
Potential to improve mental health.
Drinking hot green tea relaxes you for chemical reasons: according to a study published in the journal Molecules in 2021, an amino acid called theanine is found in tea as well as in mushrooms.
Relieves stress.
Causes relaxation
Relieves anxiety caused by caffeine
According to a 2016 study published in the journal Pharmacognosy, green tea in particular has the highest concentration of theanine compared to other teas such as oolong, black and white teas.
A 2020 review published in Plant Foods for Human Nutrition found that taking 200 to 400 milligrams of theanine supplements daily reduces stress and anxiety in stressed people.
A 2019 study published in the journal Nutrients also found that 30 people without serious mental illness who took 200 milligrams of theanine daily for four weeks had greater improvements in depression, anxiety and sleep compared to those who took a placebo.
Both studies highlight the potential mental health benefits of theanine, but the amount of theanine used is much higher than that found in a cup or two of green tea (about 8 milligrams per cup, according to Food Chemistry).
Potential to improve memory
Studies have also shown that green tea can improve memory, in part because of its theanine content. For example, a study of 12 healthy volunteers published in the journal Psychopharmacology in 2014 found that green tea extract improved subjects' working memory (a type of short-term memory important for planning, understanding, reasoning and problem solving).
Patients were given a milk-based drink containing 27.5 milligrams of green tea extract, or a placebo. They then completed the task while their brain activity was monitored with MRI scans. Those who took the green tea extract had improved brain connectivity (different areas of the brain working well together), working memory and task performance.
The results are not so clear-cut because the sample of patients in this study was very small. Further research is needed to determine how green tea affects memory.
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Protection against neurodegenerative diseases.
Several studies have shown that drinking green tea protects against some neurodegenerative diseases, such as Alzheimer's and Parkinson's. This is likely due to green tea's high content of powerful compounds called antioxidants: according to a 2018 study published in the journal European Food Research and Technology, green tea was found to be the best free radical killer among green, black and Earl Grey teas. It was. Antioxidants protect cells from damage that can eventually lead to neurodegenerative diseases.
According to a 2022 study published in Frontiers in Nutrition, 1,545 elderly people in China with healthy brain function were followed for a year, and those who usually drank tea, including green tea, had lower rates of cognitive decline than those who did not. This was true even after adjusting for factors such as education, smoking and physical activity.
According to the U.S. Centers for Disease Control and Prevention (CDC), cognitive decline is one of the first noticeable symptoms of Alzheimer's disease and related dementias. Cognitive decline is defined as worsening or increasing symptoms of confusion and memory loss.
Decreased cholesterol levels.
According to the CDC, about 38% of U.S. adults have high cholesterol, which increases the risk of heart attack and stroke. The good news. Green tea can help.A 2020 meta-analysis of 31 studies published in the Nutrition Journal found that consumption of green tea was associated with lower levels of both total and LDL (bad) cholesterol.
Reduced blood pressure.
In addition to lowering cholesterol, green tea can protect heart health by lowering blood pressure: a 2020 meta-analysis of 1,697 people in the journal Medicine found that drinking green tea significantly reduces blood pressure, especially in people with high blood pressure and a high risk of cardiovascular disease. The study found that. High blood pressure is one of the leading causes of heart disease and stroke because it damages the lining of the arteries. This leads to plaque buildup in arteries and narrowing of arteries leading to the heart and brain, the Centers for Disease Control and Prevention reports. If left untreated, high blood pressure can lead to kidney failure.
Green tea's ability to lower blood pressure may be due to its high antioxidant content, according to the same 2020 analysis mentioned above. These antioxidants reduce inflammation and dilate blood vessels, allowing blood to flow more easily.
However, most of the studies reviewed in that analysis lasted three to 16 weeks, so it's unclear whether drinking green tea for longer periods of time may or may not improve blood pressure.
Stroke prevention potential
According to the CDC, stroke is the leading cause of death and disability among adults in the United States. Drinking green tea may be one way to prevent stroke risk.
For example, a 2020 study published in the American Journal of Clinical Nutrition examined the tea drinking habits of about 500,000 Chinese adults. The results showed that tea consumption, especially green tea, was associated with a lower risk of stroke. In fact, the more green tea people drank, the lower their risk of stroke was.
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Potential for protecting bone health
Green tea may also prevent bone mass loss. For example, a study published in the journal Nutrients in 2022 found that among some 6,500 postmenopausal Korean women, those who did not drink green tea at all or drank less than one cup daily for the past year had less bone mass in their spine or hips than those who drank green tea three times a day. This was found in people who drank less than one cup of green tea daily.
Loss of bone mass increases the risk of developing osteoporosis, a disease that leads to brittle bones and fractures in the hip, spine and wrist, the National Library of Medicine reports. Postmenopausal women are particularly at risk of developing osteoporosis.
This may explain why a 2017 analysis published in the journal Medicine concluded that tea consumption is associated with a reduced risk of osteoporosis, possibly due to a high concentration of antioxidants that prevent bone loss and promote bone formation.
Helps prevent and manage type 2 diabetes
Drinking tea, including green tea, may be an effective way to prevent and manage type 2 diabetes, according to a 2019 review published in the journal Antioxidants. The review found that antioxidants found in green tea, in particular, may reduce insulin resistance.
Insulin resistance occurs when cells become less sensitive to insulin, a hormone that helps cells turn blood sugar into energy; according to the CDC, it is a major risk factor for type 2 diabetes.
Improved longevity.
Drinking tea, including green tea, is associated with a longer and healthier life, according to a 2020 study published in the European Journal of Preventive Cardiology.
The study included 100,902 people from China with no history of heart attack, stroke, or cancer for more than seven years. Participants were assigned to one of the following categories.
Habitual tea drinkers (those who drink tea at least three times a week)
Unaccustomed tea drinkers (those who drank tea less than three times a week)
Those who drank tea three or more times a week had a lower risk of death from all causes compared with those who did not drink tea. There was also a reduced risk of developing atherosclerotic cardiovascular disease, in which plaques build up in blood vessels and increase the risk of heart attack and stroke, according to the American Heart Association (AHA).
Specifically, green tea has been linked to a reduced risk of death from all causes except coronary heart disease.Researchers believe this may be because the antioxidants in green tea protect cells from damage that can lead to disease.
Nutrition.
Green tea is not a significant source of calories, vitamins and minerals per cup. According to the U.S. Department of Agriculture, 8 ounces of tea contains the following nutrients
Calories: 2.45
Fat: 0 grams
Sodium: 2.45 milligrams
Carbohydrates: 0 grams
Protein: 0.5 grams
According to a 2022 review published in the journal Chinese Medicine, tea also contains various antioxidants and a small amount of 27 minerals. These include the following.
Potassium, which promotes hydration
Magnesium, which helps control blood sugar levels
Selenium, which supports the immune system
These amounts are very small, but can make up the total daily intake of green tea.
Risks.
The National Center for Complementary and Integrative Health (NCCIH), a division of the National Institutes of Health (NIH), says that drinking up to 8 cups of green tea a day is safe. However, the organization warns that higher doses may interact with certain medications, such as those used to treat high blood pressure and heart disease. Although rare, liver damage has also been linked to consumption of tea products, mainly green tea extract taken in pill form.
Precautions When Drinking Green Tea
Green tea can be drunk hot or with ice, but there are a few things to be aware of.
Consider buying natural, decaffeinated green tea. One cup of green tea contains 20-50 milligrams of caffeine. According to the Food and Drug Administration (FDA), it can cause anxiety, heart palpitations and nervousness in people who are sensitive to caffeine. Note that according to a 2016 article in the journal Food Chem, removing caffeine may reduce antioxidants, but the results are mixed.
Watch out for sweeteners If you add sugar, honey or other sweeteners to your tea, remember that the AHA advises that women consume no more than 6 teaspoons of added sugar per day and men no more than 9 teaspoons. Excessive sugar consumption can lead to weight gain, type 2 diabetes and heart disease.
Make changes Green tea is delicious on its own, but it can also be used in smoothies, oatmeal, rice or steamed vegetables.
A brief overview
Green tea is popular in many cultures and can provide several important health benefits, including brain, heart and bone protection. However, there are health risks for people taking certain medications and those with caffeine sensitivities. If you don't currently drink green tea and aren't sure if it's right for you, check with your therapist or nutritionist to see how green tea can affect your personal health goals.