What are Catechins?

Emma Lloyd

Catechins are a type of antioxidant found in the greatest abundance in the leaves of the tea plant Camellia sinensis. In smaller amounts, they are found in other foods such as red wine, chocolate, berries, and apples. Their health benefits of have been under close examination since the 1990s, due to the strong association of tea with long life and health in many ancient cultures.

Green tea, which has more catechins than black tea, is a dietary staple in China where the risk of stomach cancer appears to be lower.
Green tea, which has more catechins than black tea, is a dietary staple in China where the risk of stomach cancer appears to be lower.

The varieties found in the leaves of the tea plant are also known as catechin polyphenols. They are part of a molecular family called flavonoids, which are plant secondary metabolites. This means they are not essential for the growth of the plant, but are important for its good health.

A cup of tea, which contains catechins.
A cup of tea, which contains catechins.

Medical research has uncovered evidence that catechins are beneficial for the good health of humans as well as plants. In laboratory tests, those present in tea leaves have been shown to inhibit the growth of cancer cells. In addition to this, they are able to prevent the activity of free radicals, the molecules that cause cellular damage that can lead to cancer.

Apples contain catechins.
Apples contain catechins.

Unfortunately, results of catechin-related studies in humans have not been conclusive. Some studies show that tea drinkers have a reduced risk of certain types of cancer, but other studies have shown no evidence that drinking tea has beneficial health effects. This means it is difficult to say for sure how helpful the antioxidants in tea really are.

Loose-leaf black tea.
Loose-leaf black tea.

For example, a study of 18,000 Chinese men found that men who drank tea frequently had a 50% lower risk of developing stomach cancer as compared to men who did not drink tea frequently. On the other hand, a study conducted with approximately 120,000 men and women in the Netherlands investigated the link between tea drinking and the frequency of stomach cancer and found no evidence that tea provided any protection.

One important fact that has been uncovered about catechins is that there are more in green tea than in black tea. All types of tea leaves, whether green or black, undergo the same initial preparation processes, but black tea leaves are also allowed to ferment and oxidize. It is thought that these extra preparation steps reduce the amount of antioxidants, making green tea leaves a better source.

This may be one explanation for the differences in the studies in China and the Netherlands; green tea is a dietary mainstay in China, but is perhaps less so in most other parts of the world. This means it is possible the people in the Netherlands study drank mostly black tea, which contains fewer catechins and may therefore provide less protection.

Loose leaf green tea has high levels of catechins, a potent antioxidant.
Loose leaf green tea has high levels of catechins, a potent antioxidant.

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Discussion Comments


White tea has the most catechins.


I work with tea processing and I would like to amend on the last two paragraphs.

Fermentation is the term used within the tea industry for oxidation, so this has nothing to do with microbial growth (as fermentation is known for). During the oxidation the catechins form long chains (theaflavins and thearubigins), so that explains the reduced amount of catechins in black tea. But there are studies indicating that the TF and TR have health benefits like catechins.


One person's results certainly cannot be taken as proof of anything, but how about 124 million people? Just check two figures: obesity and cancer. You can't possibly blame McDonald's for everything!


It does seem that there are not conclusive results from green tea, based on the above article, where reports variously say absolutely no benefit, or there may be a benefit, based on males only, in one very specific part of the world, who are also likely to have very different diets to the rest of the world.

As ever, one person's results, such as people posting above, cannot be taken as proof of anything. It is merely anecdotal, and may even be posted by representatives of companies that are trying to flog their stuff to us. Take everything with a grain of salt, trust experts not charlatans, and look for good clinical evidence, before spending your money.


As a North American Native some of us drink tea made with cedar and with labrador leaves. How would I find out if there is catechin in these leaves also? -- Mookii


i don't know whether green tea contains catechins that fight diseases because i am not a scientist. what i experience is that since i have been drinking green tea, it relieves my chronic depression and it stablized my mood. now i feel relaxed and in a good mood.


In my experience, I had a problem with forgetting things easily, diabetes, poor memory, general body weakness and depression. i took so many herbal and orthodox medicine with no availability until i discovered the green tea in a store. It was Ahmad Green Tea. The first day i took it i felt highly relieved. All the symptoms vanished. i still take it as a regular meal. sunny, nigeria.


It does seem wise to add to ones diet green tea. The indications are that green tea reduces the risk of some cancers, such as lung cancers.

So even if in time and many more precious studies find that green tea is not as powerful as we think today, there is no harm done by drinking tea on a daily basis.

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