• Ross Thomson

Evidence-based health benefits of tea


If there is one thing that there is plenty of around the internet, it is unsubstantiated claims about the health benefits of tea. It is difficult to determine what is true and what is not. It is time to bring some clarity to the issue and, with links to real data sources,  highlight the proven scientific properties of tea.



Green or Black

Firstly most health claims are aimed around green tea, however green, white, black and oolong teas are from the same plant, Camelia sinensis, they are just processed differently once they are picked. They are all very similar in composition and contain similar amounts of antioxidants and caffeine. So black teas can provide just as much health benefits as green tea, albeit in slightly different ways.


Mineral Content 

Tea is a source of the mineral manganese, essential for bone growth and body development. It also contains potassium which is vital for maintaining body fluid levels, as well as fluoride which helps to prevent tooth decay by remineralising the enamel.


Antioxidant Effects

Polyphenols, Flavonoids, Antioxidants and Catechins; all of these chemical terms get floated about when discussing the health benefits of tea.  These terms can sound jargony and difficult to differentiate. But it is simpler that it seems, as in fact they are all kind of the same thing, or be more precise they are subcomponents of the same thing. Each one  contain different types of antioxidant properties so can all be called antioxidants.


Polyphenols are a large parent class of chemical compounds synthesized by fruits, vegetables, teas, cocoa and other plants that possess certain health benefits. Flavonoidsand flavanols are a subclass of polyphenols which when present in food affect characteristics such as astringency, bitterness, sourness, sweetness, salivary viscosity, aroma, and colour formation. One of the subcategories of flavanols are called catechins which are found in high quantities in green and white teas. Although black and oolong teas also contain catechins, they are in much lower concentrations. This is because the compounds are changed during the oxidation process into Flavonoids which contain a subcategory called theaflavins. These theaflavins are in high quantity in black and oolong teas, creating the copper brown colour of the tea and altering the flavour profile.


Both theaflavins and catechins are molecules which inhibit oxidation of other molecules. Oxidation is a useful process for making black tea, but in the human body this process can create a chemical reaction that produces free radicals which damage cells and cause things like cancers. Theaflavins' antioxidant effect has been found to provide a layer of protection from Parkinsons and its ability to reduce the absorption of bad cholesterol means it associated with positive cardiovascular health.  Its antioxidant effect provides it with an potential to combat cancerous cells, with specific links to helping with stomach, liverthyroid, and breast cancers. It also has been found to help stomach ulcers in mice and as well as possessing anti-gingivitis properties.

Catechins found in green tea also contain anti-cancer properties and can influence cancer metabolism in a multitude of ways, specific studies have shown the preventative effects of drinking green tea on breast and prostate cancer. With a study done on mice, there is research suggesting that regular consumption of catechins can help with overall life expectancy. If you are looking for better skin then the catechins have been found to be quite effective in combating acne, also a regular consumption of a compound mixing green tea with milk was found to notably improved skin integrity and texture

These polyphenols clearly have a positive effect on the body, but it should also be stated that their overall effect can be slightly exaggerated as many studies are conducted using high concentrated supplements. This means the dose of catechins or theaflavins are not always equivalent to what you would find in a cup of tea. You might find you have to drink quite a few cups a day to get closer to those positive effects.


Weight Loss


Tea drunk without milk has no calories and even when milk is added it only contains around 13 calories per cup. So if you are looking for low calorie drinks for your healthy diet then tea is a good choice over sugary drinks. However can tea actually help you lose weight?


A 2014 study found that ingestion of black tea over 3 months improved body weight and body fat distribution, however  was inconclusive as to whether it had any effect past 3 months.  Another study found that the catechins found in green tea can help improve fat oxidation during exercise which is essentially the process by which giant lipid molecules are broken back down into smaller parts which can then be used by the body as energy.  The general consensus found in a meta analysis of 11 studies was that catechins has a “small positive effect on weight loss and weight maintenance”.

The effect of tea on weight loss is fairly incremental, so if you think that drinking tea will make you skinny, it won't. However drinking tea as part of healthy lifestyle will give you a small boost in terms of how your body processes fats. What I think is the biggest positive of drinking tea is that it is a delicious enjoyable drink that contains no calories. Switching from sugary drinks to tea could make a huge difference in reducing your daily calorie intake.


Caffine and L-theanine

Caffeine is the well known stimulant that can help you feel more awake and give you a jolt of energy, but research has also been done on its ability to combat the onset of Parkinson's. Caffeine does have a negative side as well, as it can increase anxiety and restlessness, but tea does have a special weapon up it's sleeve to combat some of the negative effects of caffeine; the amino acid L-theanine.


L-theanine has been found to have a relaxing effect on the brain and ability to reduce the effects of plethora of symptoms, in particular it has been studied for its potential ability to relax, improve cognition, and boost mood. It also appears to be complement the stimulant effects of caffeine by reducing headaches and improving performance on cognitively demanding tasks. It's ability to relax also counter the anxiety inducing effects that excessive caffeine intake can produce.

We have a hole blog devoted to Caffine and L-theanine which you can read here


Super-Tea

Tea is good for you, the fact that there are literally thousands of studies researching their various components prove this. How good it is for you could be over stated slightly and should be taken with a pinch of salt as many studies use high concentrate supplements of particular components, such as catechins and theanine, in order to determine their effectiveness. So drinking a one cup of tea isn't going to cure all your ills or make you super skinny. But increasing your tea consumption to 4 cups a day as part of a healthy diet can be beneficial for you in the long term. There is so much choice for different types of tea as well, the flavour profiles are amazingly diverse. Green tea, black tea, white tea and oolong tea is all from the same plant, so dont just think that drinking green tea is the only healthy option. We here at R-tea prefer black teas and have wide range of teas to choose from, browse our black tea collection below.

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