If avocado is a superfood, is there potentially a “superdrink”? Green tea may just be one. Though it’s mostly water, the base ingredient – the leaves of the Camellia sinensis plant – is highly beneficial to your health, and humans have known that since the ancient Chinese dynasties.
There’s plenty to discuss when it comes to the benefits of drinking green tea (it may even cut your mortality risk) [1]. But does that mean you should start drinking green tea every day? Will you really benefit from incorporating a cup or three of green tea into your daily diet?
Everything to know about tea
There are many common tea types, with green and black tea as the most popular. Green tea, unlike black tea, is unoxidised – meaning it is immediately steamed to preserve the green colour [2]. This means the tea has a higher concentration of chlorophyll and antioxidants since the tea did not undergo oxidation.
The first written records of green tea date back to China’s Han dynasty, where the Chinese used it for medicinal purposes. Green tea would treat inflammation and wounds, and aid digestion. It was beginning in the Tang dynasty that people began consuming green tea purely for pleasure.
Many countries – including China and Japan – have historically developed ritualistic preparations for green tea (such as matcha), called tea ceremonies. These ceremonies are often considered status symbols and activities of nobility.
Green tea reached European shores sometime in the late 19th century, after the innovation of clipper ships. These ships shortened the time it took to transport goods from Asia to Europe, which then allowed traders to carry fresh green tea instead of only cooked black tea.
Nowadays, green tea is widely available in most countries, in various forms – loose leaf, powder, extracts. It’s even become a popular flavouring for pastries and milk tea. [1]
Nutritional value of tea
There are 0 kCal in a single 16oz (473ml) serving of green tea, since the beverage contains 0g of fat, 0mg of cholesterol, and 0g of carbohydrates. This is because the drink consists mostly of water infused with the tea leaves. Green tea does, however, contain small amounts of sodium, calcium, phosphorus, potassium and zinc.
Green tea’s true nutritional value lies in its concentration of polyphenols, called flavonoids. Polyphenols are bioactive components that naturally occur in plants. In green tea, these polyphenols encourage antioxidants in our bodies, which hinder oxidative DNA damage.
As we go through life, our cells undergo something called “oxidative stress”. This is caused by excessive amounts of free radicals in our bodies, which damage our cells and alter DNA. Regular cellular metabolism produces free radicals in small amounts, but external sources such as pollution can induce higher concentrations than is healthy. [2]
Polyphenols trigger the expression of different antioxidant enzymes in our bodies, which combat oxidative stress. Emerging research shows that green tea can mitigate the symptoms of neurodegenerative diseases such as Alzheimer’s and other forms of dementia.
Green tea also induces autophagy, which is the process of your body cleaning out damaged cells and regenerating healthier ones. This can revitalise the overall health of a person. [3]
Green tea may lower mortality risk
Meanwhile, a study of almost 500,000 people analysed a link between consuming tea and lowered “all-cause” or “specific-cause” mortality [3]. After an 11-year follow-up, the researchers found a modest association between consuming over 2 cups of tea per day and a lower risk of all-cause mortality.
They also found inverse associations between tea consumption and mortality due to cardiovascular and ischemic heart conditions and stroke.
The results of this study suggest a link between consuming 2+ cups of tea per day and a lowered risk of mortality. It shows that tea can positively affect a person’s longevity. [4]
Side effects of drinking green tea
There are potential risks and side effects from consuming tea, though [4]. For caffeine-sensitive people, large quantities of green tea can cause adverse reactions such as
- Symptoms of anxiety
- Irritability
- Stomach aches and nausea
- Insomnia
Concurrent consumption with certain medications such as nadolol could also pose a risk of potential negative interactions. Catechins in green tea could inhibit the uptake of certain chemicals and components, which could adversely increase or decrease their effects.
A person may also suffer stomach irritation if they consume green tea without eating first.
Should I drink green tea every day?
This does not, however, mean that you should start drinking large quantities of tea to your diet. You risk triggering the side effects if you consume excessive amounts, especially if you’re caffeine-sensitive. Much research remains largely observational or associative, so it needs controlled, randomised studies to replicate results and strengthen the link between green tea and longevity.
There’s no denying the health benefits of green tea and caffeine, however. They do have proven positive effects on a person’s physiological and cognitive well-being – from boosting cognitive function to reducing inflammation and oxidative stress.
So should you include green tea in your diet? If you enjoy the taste, then it can be beneficial in moderation and you’re not overly sensitive to caffeine. 2–3 cups a day is more than enough to enjoy the positive effects. Just make sure you’re not using it as a substitute for water!
(And also – this means plain green tea. Consuming large amounts of matcha bubble tea, for example, could cause your blood sugar to spike or give you indigestion.)
Drinking green tea for longevity
So is plain green tea a “superdrink” that you should drink every day? In moderation, yes. Adding a cup or 3 of green tea or matcha to your every day beverages can benefit your health – and that’s besides it being tasty, as well!
Green tea is possibly one of the healthiest drinks you can consume, especially with its high concentration of polyphenols and low caloric content. It’ll make you more alert and improve your metabolism, and overall, just make you feel good. So go ahead and brew yourself some green tea while you read your favourite book or watch your favourite TV series – it’ll be worth it.
[1] https://www.artoftea.com/blogs/tea-101/what-is-green-tea
[2] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3614697/
[3] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6412948/
[4] https://www.acpjournals.org/doi/pdf/10.7326/M22-0041
