Besides water, tea is the most popular beverage around the world. In fact, it’s estimated that around 3 billion people worldwide consume tea in general. Green tea, one of the most prevalent types of tea, offers a wide array of antioxidants and is linked to many health benefits.
Read on for more about the potential benefits of green tea, along with a few of the possible side effects to consider.
What Is Green Tea?
Green tea is a beverage made from the leaves of Camellia sinensis, which is the same plant used to make other types of tea including black or oolong teas. However, unlike other types of tea, green tea doesn’t undergo the same oxidation and withering processes, giving it a unique flavor and antioxidant profile. Instead, green tea is made by steaming or pan frying, then drying the leaves of the Camellia sinensis plant.
For thousands of years, green tea has been used for its medicinal properties in China and Japan. Today, it’s widely used for its purported ability to help increase alertness, promote weight loss and alleviate headaches and digestive issues–and, of course, for its pleasing taste. Green tea and its components have also been recently studied for their ability to protect against conditions like heart disease and cancer.
4 Health Benefits of Green Tea
Thanks to its content of beneficial compounds and antioxidants, green tea may offer several health benefits.
Helps Protect the Heart
“Green tea contains catechins, a type of flavonoid with potent antioxidant properties,” says Sam Schleiger, a functional medicine dietitian based in Elkhorn, Wisconsin and founder of the nutrition practice Simply Nourished. “These catechins help reduce the formation of plaques in the arteries, lower LDL (“bad”) cholesterol levels and improve blood lipid profiles, ultimately decreasing the risk of heart disease.”
These heart health benefits appear in research as well. According to one 2016 review of nine studies, people who drank one to three cups of green tea per day had a lower risk of stroke and heart attack. Additionally, people who consumed at least 10 cups per day had lower levels of LDL cholesterol compared to those who drank less than three cups daily. Similarly, a 2023 analysis of seven studies shows that drinking green tea may be linked to a lower risk of coronary heart disease.
May Support Weight Loss
Green tea contains compounds like caffeine and epigallocatechin gallate (EGCG), both of which may speed up metabolism and help break down fat cells, explains Amy Shapiro, a registered dietitian and founder of Real Nutrition NYC, a nutrition counseling practice. “Caffeine is a stimulant that has been shown to aid in fat burning and to improve exercise outcomes,” continues Shapiro. “It boosts the effects of some fat burning hormones like norepinephrine, which tells fat cells to release fat into the bloodstream to be used as energy instead of storing it.”
One 2020 study shows an association between green tea consumption and reductions in body weight, body mass index (BMI) and belly fat in individuals living with obesity. What’s more, another review concluded that green tea consumption has the potential to promote weight loss in women with polycystic ovary syndrome (PCOS), although researchers note the exact dosage of green tea that can cause this kind of weight loss has not been determined.
May Boost Brain Health
“Green tea contains caffeine, which can improve alertness, concentration and memory,” says Schleiger. “Additionally, it contains an amino acid called L-theanine that promotes relaxation and increases the production of neurotransmitters like dopamine and serotonin, leading to improved brain function,” she adds.
According to one review in Phytomedicine, green tea may offer several benefits for brain function, including helping decrease anxiety, improving memory and increasing attention. Although more research is needed, another review reports that certain compounds in green tea may even help treat or play a role in preventing neurodegenerative disorders like Alzheimer’s disease, thanks to its ability to neutralize free radicals, ease inflammation and block the build-up of specific types of protein in the brain.
May Help Stabilize Blood Sugar Levels
Some research suggests that green tea may help keep blood sugar levels steady. This could be due to its content of EGCG, which Shapiro explains, “seems to prevent the breakdown of starches, which leads to increased blood sugar.”
In short-term studies, drinking green tea helped decrease fasting blood sugar levels. Still, more studies are needed, as other research has found that green tea has no effect on long-term blood sugar control or insulin levels.
Green Tea Precautions
Schleiger recommends enjoying green tea in moderation to maximize the potential health benefits. Around two to three cups per day is a reasonable amount for most people, according to Schleiger.
However, there are several instances where you might need to cut back on your consumption. For starters, green tea contains caffeine, which some people might need to limit or avoid. Each cup contains around 30 to 40 milligrams, though the exact caffeine content varies depending on the specific type and brewing method. According to the Food and Drug Administration (FDA), consuming up to 400 milligrams per day of caffeine is safe for most adults, but high amounts can cause side effects like dizziness, anxiety, fast heart rate and dehydration.
It’s also possible that green tea may cause stomach irritation in some, which Schleiger says is due to its content of tannins (polyphenols that are present in many plant foods). If you have a history of digestive issues, she recommends monitoring your tolerance, moderating your intake and drinking green tea after meals rather than on an empty stomach.
Green tea could also interact with certain medications, according to Schleiger. “For example, it can inhibit the absorption of certain medications, such as beta-blockers or blood thinners, potentially reducing their effectiveness,” she says. For this reason, it’s important to talk to a doctor before making green tea part of your daily beverage routine, especially if you’re taking medications or have any underlying health issues.
Due to its many potential benefits, as well as the fact that simply drinking it can help you stay refreshed and hydrated, green tea can be a helpful addition to almost any diet. If you’re thinking of adding it to your routine, have a quick chat with your doctor to make sure it works for your personal health history.