Diet and Nutrition
Green Tea Benefits: 3 Science-Backed Reasons to Add This Drink to Your Diet
Green tea may have health benefits, but research on humans is somewhat inconclusive.
Green tea may improve alertness and is associated with improved heart health.
There’s no evidence that green tea can prevent cancer or improve health in people with diabetes.
Green tea is an unfermented tea that comes from the buds and leaves of the Camellia sinesis plant. It’s the least processed type of tea. Because of this, most of its antioxidants and other helpful compounds are retained. It’s also lower in caffeine than other types of teas — one cup has 30 mg, while the same amount of black tea has 47 mg.
This is why green tea is often thought of as the healthiest tea you can drink. Many of green tea’s possible health benefits have origins in ancient Eastern cultures. But not all of them are rooted in sound evidence.
Green tea contains compounds, called polyphenols, that have many positive effects on your health. Specifically, green tea is rich in a class of polyphenols called catechins. The most abundant catechin in green tea is epigallocatechin-3-gallate (EGCG). Most of green tea’s alleged health benefits are credited to EGCG.
The catechins in green tea may help lower blood pressure in the short term. Some studies show this effect in those with normal blood pressure. But, it seems to be more significant in those with a systolic blood pressure over 130 mm Hg.
Research suggests that drinking green tea may help improve blood sugar control and insulin sensitivity. One meta-analysis showed that green tea may lower fasting glucose, insulin levels, and hemoglobin A1c.
Another study that looked at adults in China found that those who drank green tea every day were less likely to develop diabetes compared to those who did not drink green tea or drank other types of tea.
Green tea also contains L-theanine, an amino acid that promotes relaxation and may improve cognitive function.
In one review, researchers found that drinking green tea could help limit anxiety, while improving memory and attention span. Another study found that some teens who drank 6 cups of decaffeinated green tea a day for 6 weeks had less stress hormones and improved depression, anxiety, and stress symptoms.
While the benefits of green tea are promising, the quantity makes a difference. Many of the benefits of green tea are seen in those who are drinking 6 cups per day, or taking a green tea extract supplement.
Green tea might have added benefits, like improving focus, lowering inflammation, and promoting heart health. But scientists are still studying these claims. Let’s take a closer look.
Consuming moderate amounts of caffeine (less than 400 mg) has been shown to improve alertness. Green tea contains around 30 mg to 50 mg per 8 oz cup (roughly half the amount of caffeine in coffee).
Green tea also includes the amino acid L-theanine, which is thought to create a relaxing effect. What’s more, L-theanine may help counteract some of the negative effects of caffeine, such as a rise in blood pressure.
A small study also suggests that the combination of caffeine and L-theanine might improve performance on mentally demanding tasks, more than caffeine alone. But there isn’t strong enough evidence to confirm this.
Studies show that the EGCG in green tea may have anti-inflammatory effects owing to its antioxidant activity.
But, it’s important to note that many of the studies looking at inflammation used high-dose green tea extract, not brewed tea. This means that you might not have the same results by simply sipping on a cup of tea each night.
One review suggested that drinking green tea daily may lower the risk of heart disease. cardiovascular disease (CVD). A study in Japan showed that drinking at least 5 cups of green tea a day reduced the risk of death from heart problems by 16% to 26%.
Despite this promising research, more studies are needed to make any direct conclusions about green tea and CVD. This is because the people consuming green tea are also thought to be living an overall heart-healthy lifestyle.
While there are some benefits grounded in evidence, other claims linked to green tea may not actually live up to their hype.
According to the National Cancer Institute, studies done on green tea and cancer prevention have been inconclusive. For example, a systematic review of green tea that included over 142 research studies couldn’t find a consistent link between green tea and a lower risk of cancer.
Green tea is often thought to be a miracle drink when it comes to weight loss. But, an extensive review found that drinking green tea had a very small effect on weight loss for people who have extra weight. It also wasn’t shown to help people maintain weight loss.
In general, green tea is good for you. But like most things, there are pros and cons to drinking it. On one hand, the nutrients found in the drink can be a healthy addition to a well-balanced diet. But, you would have to drink a large amount of it to get its benefits.
While brewed green tea is generally safe, green tea extract supplements have much higher doses of EGCG and other catechins, which can have harmful side effects. These include:
Stomach upset
Insomnia
Skin rashes
Spikes in blood pressure
To be safe, drink less than 8 cups of green tea daily. This is because drinking green tea in excess could lead to consuming too much caffeine.
Because green tea contains caffeine, if you are pregnant, limit your consumption to 6 cups a day, so you stay within the 200 mg recommended limit.
Finally, it’s possible that high doses of green tea may get in the way of the effects of some prescription medications, including some statins, antibiotics, and beta blockers. So, it’s always a good idea to talk to your healthcare provider first before taking green tea extract with prescription medications.
Green tea can be enjoyed in many delicious ways. Try adding:
Ice cubes for a refreshing drink
A splash of milk or your favorite creamer
A little bit of honey and lemon to cut through some of the natural bitterness
Ginger for warmth and spice
Matcha powder to smoothies or baked goods
Although some of the claims surrounding green tea’s benefits are overblown, that doesn’t mean the tea isn’t a healthy drink choice — especially compared to sodas and other sugary drinks.
And remember, green tea on its own is unlikely to have a huge benefit. Be sure to also eat various fruits and vegetables, along with healthy fat, protein, and whole grains for an all-around well-being boost.
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