Enjoyed for centuries, tea is one of the most widely consumed drinks in the world, and the good news is the humble cuppa may provide more than just a hydrating pick-me-up. Registered nutritionist Kerry Torrens showcases the many health benefits of this popular drink.


What is tea?

Tea is the drink produced by steeping the young leaves and leaf buds of the Camellia sinensis plant in freshly boiled water. The main types of tea include black, green, white and oolong. Each has its own unique flavour and characteristics dependent on the leaves’ origins and processing methods including whether they were fermented (black), unfermented (green and white tea) or semi-fermented (oolong tea). Although often referred to as ‘teas’, herbal and rooibos infusions are made from different plants, so won’t offer the same health benefits as a traditional cuppa.

How is tea made?

Tea leaves go through some or all of the stages of withering, rolling, fermenting and drying, with the objective being to dry the leaf and allow the unique properties of the tea to come through. What sets the different types of tea apart is the degree of fermentation they undergo – white tea receives the least, then green, oolong and, finally, black tea. The process of fermentation alters the polyphenols in the tea, making them more concentrated and complex; the greater the fermentation, the darker the colour and the deeper the flavour of the tea.

Does tea contain caffeine?

All teas from the Camellia sinensis plant naturally contain caffeine. The amount of caffeine varies depending on the degree of processing and the final brew time – white tea being lightly processed has the most caffeine in its dry state, however, because it is brewed for the shortest time it tends to contain the least in its brewed form. Other factors to consider include how hot the water used for brewing is and the length of steeping time.

Read more about the caffeine content of tea.

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Is tea good for you?

  • Rich in protective plant compounds
  • May improve blood pressure
  • May improve cardiovascular health
  • May modulate glycaemic response
  • May reduce diabetes risk
  • May improve gut health
  • May reduce the risk of cancer
  • May alleviate stress and anxiety
  • May improve attention and focus
  • May support bone health

Discover our full range of health benefit guides including the health benefits of matcha tea and get inspired by our delicious tea recipes.

Nutritional profile of tea

One serving (225ml) of black tea with milk contains approximately:

  • 8 Kcal/32KJ
  • 0.4g protein
  • 0.4g fat
  • 0.5g carbohydrate
  • 0.5g sugars
  • 40mg potassium
  • 13mg calcium

Much of tea’s goodness lie in the plant compounds (polyphenols) it contains – the type of tea, the temperature of the water and the steeping time all influence the amount of these protective compounds in your cup.

Hands holding a white and spotty mug of tea

What are the top 10 health benefits of tea?

1. Rich in protective plant compounds

All varieties of tea (black, white, green and oolong) are a rich source of protective plant compounds, called polyphenols. Regularly consuming these polyphenols may help protect the cells of the body from damage and as a result reduce the risk of chronic diseases like heart disease, diabetes and cancer. Catechins in green tea and theaflavins in black tea are the compounds responsible for most of these health benefits.

2. May improve blood pressure

Tea consumption may improve how our blood vessels work and help lower blood pressure. it does this by increasing the availability of a compound called nitric oxide, which helps relax the inner muscles of our blood vessels, allowing the blood to flow more freely.

3. May improve cardiovascular health

Evidence suggests that regular tea consumption may reduce the risk of heart disease, thought to be largely due again to the polyphenol content. Of particular note are the catechins, found to a particularly high level in green tea, which show a positive effect on all cardiovascular outcomes.

4. May modulate glycaemic response

Tea polyphenols help manage our body’s response to carbohydrates by inhibiting digestion and absorption, and stimulating insulin release. Green tea appears to be the most effective in this regard.

5. May reduce diabetes risk

The ability of tea polyphenols to inhibit digestive enzymes like lactase and delay the uptake of glucose (sugar) in the gut has led some studies to conclude that a consistent intake (over a lifetime) of dietary polyphenols may be as effective as some medication in reducing the risk of diabetes; however, more studies are needed.

6. May improve gut health

Many of the polyphenols in the diet, including those from tea, pass unabsorbed to the large intestine where they are broken down by gut bacteria. In this way they provide a source of fuel for our beneficial gut bacteria, allowing them to thrive and diversify and helping to improve gut function and modify the immune system.

7. May reduce the risk of cancer

Polyphenols found in tea may work with other factors to slow the development of certain types of cancer. However, convincing evidence is to date limited to oral cancer, with suggestive evidence for other forms including liver, breast and colon cancer. More well-designed studies are needed, along with consideration of the additional factors that may influence these findings.

8. May alleviate stress and anxiety

Unlike coffee which is considered energising, tea is generally seen as a relaxing drink. Although both drinks contain caffeine, only tea contains the amino acid l-theanine which has a relaxing effect thanks to its ability to increase alpha brain waves.

9. May improve attention and focus

Drinks containing both caffeine and l-theanine appear to have the greatest impact on our attention and focus. A cup of green tea provides 25mg of l-theanine, and as well as being associated with less cognitive dysfunction, its consumption appears to help us maintain better concentration and focus.

That said, it’s not just green tea that offers these benefits. A study looking at the impact of drinking black tea reported quicker performance, improved memory and fewer errors being committed.

10. May support bone health

There is some evidence to suggest that opting for tea, especially green tea, may help maintain bone density and as a result reduce the risk of fracture. The protective effect is thought to once again be thanks to tea’s polyphenol content.

Tea garden at sunrise, with tea leaves close up in the foreground

What impact does adding milk or sugar have on tea’s health benefits?

There’s conflicting evidence on the impact of adding milk to black tea; it may affect our ability to absorb the beneficial polyphenols and have a knock-on effect on the cardiovascular benefits of the drink. That said, some studies suggest milk makes no difference and that in fact it may instead be the infusion time that holds the key to enjoying these benefits.

Furthermore, it would appear that adding a small amount of milk and sugar to tea appears to make little difference to the levels of l-theanine, but adding high amounts of milk does. Sugar added to hot drinks, like tea, counts as a ‘free sugar’ – the type we are advised to cut back on. It may also influence our absorption of polyphenols, with studies suggesting that if you like to sweeten your tea, stevia may be a better option because it doesn’t affect the availability of these beneficial compounds.

Is bubble tea healthy?

Served hot or cold, bubble tea is a Taiwanese recipe that involves blending tea with milk, sugar, fruit and fruit juices, then adding ‘bubbles’ in the form of tapioca pearls and shaking vigorously. These additions increase the drink’s carbohydrate content, making it high in both calories and sugar.

How much tea should I drink in a day?

While some teas provide more benefits than others, there’s plenty of evidence that regularly drinking tea offers numerous advantages. However, the number of cups that might be considered optimum over a day will vary from person to person and be dependent on the type of tea you choose. For the average person, who is not sensitive to caffeine, up to three to four cups of black tea per day may be acceptable, while those who opt for green tea may be able to enjoy considerably more.

That said, if you’re sensitive to caffeine, it’s advisable to limit the total number of caffeinated drinks you consume, including tea. Consuming too much from any source may disrupt your sleep and, in some people, increase anxiety. If this is relevant to you, look to reduce your intake and aim to have your last caffeinated drink at about noon. Other groups who should limit their caffeine intake include pregnant women.

If you’ve been diagnosed with iron-deficiency anaemia you should be aware that tea contains tannins. These natural compounds interfere with our absorption of iron, so it’s wise to avoid drinking tea with a meal – instead wait at least an hour before you enjoy a brew.

Overall, is tea good for you?

Tea offers numerous health benefits – it’s a relaxing drink that helps increase our attention and focus, is heart-friendly, good for the gut and may help manage blood sugar. Tea makes a useful option if you are looking for a flavourful, low-calorie, unsweetened hot drink with less caffeine than coffee.

Enjoyed this? Now read…

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The health benefits of peppermint tea

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Types of tea: the ultimate guide

Health benefits of rooibos tea


All health content on bbcgoodfood.com is provided for general information only, and should not be treated as a substitute for the medical advice of your own doctor or any other healthcare professional. If you have any concerns about your general health, you should contact your local healthcare provider. See our website terms and conditions for more information.

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