10 Science-Backed Reasons To Drink More Tea

Tea is more than just a popular cold-weather beverage. For thousands of years, tea has been, and still is today, a tradition and ritual, rooted deep in cultures around the world. Originating in China, possibly as early as 2737 B.C., tea drinking spread to Japan, then Holland, and eventually throughout the rest of Europe. Dutch settlers to America first introduced tea in 1650. Britain was one of the last European countries to adopt tea, though it was heavily taxed in the beginning. Most of the tea imports were illegally smuggled until the British government slashed the tax rate in 1784, enabling tea to become an affordable drink for all and not just a beverage for the wealthy.

In the U.K. alone, roughly 75 million cups of tea are consumed daily, while it is estimated that over 3 billion cups are consumed worldwide every day. Tea's popularity isn't just due to its pleasant taste either. For centuries it has been drunk for its therapeutic benefits, which have now been heavily studied. So, let's break down all the science-backed reasons you should be drinking more tea.

Tea seems to solve just about any problem. Stressful day at work? Curl up with a warm mug. Feeling sluggish? Perk up with a matcha latte. Under the weather? Soothe a sore throat with some tea and honey.

The medicinal benefits of tea, no matter the variety, have been known for thousands of years. And now, modern science is backing up a lot of those benefits. Here are 10 science-backed reasons to drink more tea:

Black, oolong, and green tea's polyphenols all have been shown to increase calorie expenditure1 and reduce body fat. Interestingly, tea actually promotes one type of fat: brown fat2. This type of fat is more metabolically active and contains more mitochondria than white fat, which means brown fat can actually burn calories and improve metabolism.

In a review of 15 studies3, it was found that those who consumed two to six cups of green tea a day for longer than 12 weeks had lower body fat and body weight than those who did not. Not a fan of brewed tea yet? Green tea extract, a concentrated form of green tea available in powders and pills, has also shown metabolism-boosting weight loss benefits.

Inflammation has been linked to everything from diabetes to cognitive decline. In fact, it has been implicated as the root of almost all chronic diseases. The antioxidant polyphenols in tea are powerful inflammation fighters. In fact, the EGCG in green tea is as much as 100 times more potent than the antioxidant power of vitamin C4.

Research has shown that tea can be beneficial for those with inflammatory bowel disease as well as other inflammation-driven diseases5.

In a study of more than 40,000 adults, it was found that regular tea consumption reduced the risk of dying6 from heart disease, stroke, and some cancers. In fact, participants who drank five or more cups of green tea per day had a 16% lower risk of cardiovascular death compared to those who drank less than one cup per day. Researchers credit green tea's effect on hypertension and obesity along with potent polyphenols for its protective effect.

Chronic diseases are among the leading causes of death in the U.S., making tea all the more important to drink daily. More benefit was seen in those who drank three to four cups a day versus one cup or no cups, so drink up!

Green tea may help reduce complications from diabetes7. Diabetes is a worldwide health concern, with significant risks of complications, early death, and poorer quality of life. Research shows tea can improve insulin sensitivity, protect pancreatic cells from further damage, and decrease inflammation, all benefiting those at risk for or already diagnosed with diabetes.

Regular tea consumption may lower the risk of getting Alzheimer's disease and other neurodegenerative diseases8. While the exact causes of Alzheimer's are still unclear and there is no cure, research confirms that green and black tea drinking improves cognitive scores among those with dementia and Alzheimer's disease.

Additionally, it can boost memory and increase attention span to prevent cognitive decline. The combination of caffeine and L-theanine in tea has been shown to improve reaction time, visual processing, memory, and concentration9. It even changes the way your brain is organized for more efficient information processing.

Green tea's catechin EGCG is a potent antioxidant that has major cancer-fighting potential. Lab and animal studies have found that EGCG can reduce metastasis10 and improve outcomes for cancers of the breasts, lungs, colon, skin, and others.

While more clinical studies in humans are needed, some long-term observational studies have found similar cancer-fighting benefits. For example, Japanese women who drank 10 or more cups of green tea a day (120 ml or 4 ounces each) had a seven-year delay in cancer11 onset. This amount of tea was reported to be equivalent to 2.5 grams of green tea extract.

Not all drinks are good for you mouth (looking at you, sugary sodas and juices!). But teas can actually improve oral health12. Tea contains fluoride and can improve bacterial populations in the mouth. This reduces the risk of periodontal disease, cavities, and possibly even oral cancer. So even if you skimp on flossing here and there, you can still feel good about your oral health if you are sipping tea.

Is there anything tea can't do? A 2018 review13 reports struggles with fertility are heavily influenced by the degree of oxidative stress in reproductive tissues. Enter: tea. The polyphenols in tea have confirmed anti-inflammatory and potent antioxidant effects. Therefore, the authors suggest, tea can improve fertility in both men and women. More research is needed, but it certainly looks promising.

This one might surprise you. While it was previously thought that tea (and coffee) promoted dehydration by acting like a diuretic and causing the body to lose more fluid, recent research14 finds that up to six to eight cups of tea a day is just as hydrating as the same amount of water. 

Gut health isn't all just fiber and probiotics. Research shows that tea's polyphenols can beneficially modify gut bacteria15. This can lead to positive health effects like reduced carbohydrate absorption, improved blood sugar levels, and weight loss.

OK, now that you are craving a warm mug of tea, which type should you have? There are four main kinds of teas (not including herbal teas, which can be made from a wide variety of plants): black, green, oolong, and white. These four types are all made from the leaves of the evergreen shrub, Camellia sinensis but are processed differently.

White tea is the least processed form of tea from the Camellia sinensis plant, providing a more delicate flavor and contains less caffeine than black tea (though caffeine levels vary among brands). For white tea, the leaves are harvested when they still are covered in silvery white hairs.

Fresh green tea leaves are steamed, which preserves the polyphenols, a class of phytochemicals with strong antioxidant benefits. The majority of polyphenols in green tea are flavonoids. The type of flavonoids that confer the most heart health benefits are catechins16, and green tea is full of them! Epigallocatechin gallate, or EGCG, is the most prominent and most studied catechin. Green tea contains a small amount of caffeine, similar to that of white tea, ranging from 25 to 35 mg per cup.

Matcha is essentially green tea powder but differs from brewed green tea in that the tea leaves are covered prior to harvest, yielding a more concentrated flavor and higher caffeine and antioxidant levels.

Oolong tea is derived from partially fermented tea leaves and contains similar amounts of caffeine as white and green tea. Oolong tea, though less popular, provides many of the same benefits as the more well-researched green tea.

Black tea is the most processed of the tea leaves, but this allows the polyphenols to offer unique benefits. Black tea contains more caffeine than any other teas made from the Camellia sinensis plant. The caffeine content combined with black tea's processing has shown more pronounced benefits17 in regard to obesity prevention and treatment than other teas. 

RELATED READ: Take A Sip: Here The 6 Healthiest Teas You Can Drink For Longevity

While tea is considered safe in amounts up to six cups a day for most people, some herbal teas are made from plants that may be allergens to some. For example, those allergic to the daisy family or ragweed may need to avoid dandelion tea.

Other concerns include:

Caffeine. Caffeine content varies in teas and among brands but is highest in black tea. White, green, and oolong tea are lowest, providing only around 25 to 35 mg per 8-oz. cup. Those who are allergic or sensitive to caffeine should choose herbal, white, green, or oolong teas and avoid drinking any caffeinated teas in the afternoon or evening.

Iron-deficiency anemia. Tannins and caffeine in tea (and coffee) can reduce iron absorption, especially from plant sources. Vegetarians, vegans, and those with anemia should be cautious about their tea consumption.

Children. While the FDA provides no guidelines for safe caffeine intake for children, The European Food Information Council reports that children may consume one to two cups of tea a day, depending on age, without going above safe caffeine limits.

Heat damage. Heard the media reports about hot beverages and cancer risk? A recent study from 201618 reported an increase in esophageal cancer risk in those who consumed tea less than four minutes after pouring, or at temperatures above 65 degrees Celsius (150 degrees Fahrenheit). Despite this and other research, it still appears that sips of beverages below 150 degrees Fahrenheit (65 degrees Celsius), easily obtained by waiting five or more minutes after steeping time before ingestion, is most likely safe.

Despite your tea of choice, the research is clear. Drink three to six cups every day of white, green, oolong, black, or herbal tea as a way to stay warm in the cold months, cool off during the hot months, and to enjoy a healthier heart, brain, and body.