By Emily Laurence
Long before it made its way to the West, green tea was sipped in East Asia, with its earliest roots traced to China in the twelfth century. Its many health benefits were recognized from the start and green tea has always played a strong role in Traditional Chinese Medicine. To this day, China is still the number one producer of green tea.
Because green tea is one of the most popular teas in the world, it’s also one of the most studied by scientific researchers. There are thousands of studies on the health benefits of green tea and how drinking it on a regular basis affects cardiovascular health, brain health, as well as the body as a whole. Here, registered dietitian Neva Cochran, RD, explains what exactly those benefits are. She also details exactly how much green tea you need to drink a day to experience the benefits as well as tips for buying it. Keep reading for everything you need to know.
What are the health benefits of green tea?
1. It’s good for your heart
If you’re looking for something to sip on throughout the day for heart-protective benefits, Cochran says green tea is a great option. “Green tea is high in flavanols, which is a type of antioxidant, and these flavanols have been linked to reducing LDL cholesterol, also known as ‘bad’ cholesterol,” Cochran says. This, she adds, means it can lower the risk of heart disease.
A scientific article published in the journal Nutrition Review says that observations in southeastern Asian countries show a connection between green tea consumption and a decreased number of cardiovascular health problems. It also says there has been a connection between regular green tea drinking and reduced body fat, which is also connected to cardiovascular health.
2. Green tea is good for your brain
Drinking green tea does more than just support a healthy heart; Cochran says it benefits the brain, too. This, she says, is credited to its caffeine content as well as catechins, which are a type of polyphenol and antioxidant. “Catechins help protect the body from free radicals. This benefits the whole body and of course the brain as well,” Cochran says.
An article published in the journal Phytomedicine that took into account 21 separate studies on green tea found that its consumption was linked to better attention and memory. The researchers say they believe this to be connected to the caffeine and l-theanine (an amino acid associated with calm and focus) in the tea. Between the catechins, caffeine, and l-theanine, clearly there are several components in green tea that make it such a brain health-boosting beverage.
3. Drinking green tea could improve your mood
The same paper published in Phytomedicine found that green tea was linked to feeling less anxious. “This is likely because of the l-theanine in green tea,” Cochran says. “Many scientific studies have found a connection between l-theanine and mood as well as with cognitive function,” she says. The combination of l-theanine and caffeine leads to a feeling of cognitive alertness without the jitters that some can experience with coffee.
4. It can help you feel more alert
Another benefit of the caffeine in green tea: it can help you feel more alert. While some teas, like chamomile or lavender, are more associated with feelings of relaxation or sleepiness, the caffeine content in green tea makes it more of a good one to sip throughout the day, not in the evening. Another benefit: it doesn’t have the crash that drinking coffee causes many to experience.
5. Green tea could protect against certain cancers
Cochran says green tea’s antioxidant content also means that sipping it on a regular basis could protect against certain cancers, but she also adds a major caveat to this benefit. “Green tea is by no means a silver bullet and The National Cancer Institute does not recommend for or against the use of tea to reduce the risk of any type of cancer.” Disclaimer in place, there are some components in green tea that may lessen the risk. A paper published in the journal Cancer and Metastasis Reviews says that green tea’s EGCGs (a type of beneficial catechin) have been shown to inhibit tumor growth.
While this finding is noteworthy, Cochran says some of the other claims of green tea and cancer prevention may be overblown. “[For example], a meta-analysis with eight studies on green tea and breast cancer found reduced risk in three studies but no reduction in five studies,” she says. “There is also a lack of evidence for green tea and lower risk of prostate cancer and no significant association between endometrial cancer risk and green tea consumption.”
6. It could help lower blood sugar levels
“In a meta-analysis of 22 studies with 1,584 subjects, green tea catechins significantly lowered fasting blood sugar levels,” Cochran says, adding that it may also help prevent type 2 diabetes. “[This is because] green tea can inhibit digestive enzymes that help break down sugars in the gut to slow down the absorption of sugars so blood sugar levels rise more slowly,” she says.
7. Drinking green tea is good for your bones
One benefit of drinking green tea that Cochran says is often overlooked is that it’s good for your bones. “Tea polyphenols enhance bone formation and inhibit bone breakdown resulting in greater bone strength,” she says. As one scientific paper published in Nutrition Review says, “epidemiological evidence has shown an association between tea consumption and the prevention of age-related bone loss in elderly women and men. Ingestion of green tea and green tea bioactive compounds may be beneficial in mitigating bone loss of this population and decreasing their risk of osteoporotic fractures.” In non-science speak that means milk isn’t the only bone-benefitting beverage.
8. It’s hydrating
Cochran says that because green tea has caffeine, many don’t think it’s truly a hydrating drink, but that’s not the case. “Especially for people who don’t like the taste of plain water, green tea can be extremely helpful in helping someone meet their hydration goals,” she says.
Additional nutrient content, dosage, and side effects
Clearly drinking green tea comes with many benefits. But in terms of hitting your nutrient goals for macronutrients like protein, fiber, and healthy fats, you’ll have to get them elsewhere. There are none of these nutrients in green tea. So while green tea is connected to many health benefits, it shouldn’t be mistaken as something to be consumed in the place of nutrient-rich foods.
In terms of how much green tea you have to drink to actually experience the benefits highlighted above, Cochran says the majority of scientific studies of green tea range between four to six cups a day. In terms of side effects, drinking too much could cause a headache, primarily because of the tea’s caffeine content. But other than that, it’s a low-risk beverage in terms of unwanted side effects.