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Green tea: a flavonoid-rich superfood

In this video, Dr. Janiak discusses why green tea could be beneficial for our health, and how it differs from other kinds of tea such as black and red
Michal Janiak: Hi. I’m Michal Janiak and I’m here to talk about green tea. Do you know what is the most consumed beverage in the world? Water. Tea holds the second position. What is interesting, overall consumption of green tea is estimated for about 25% of total tea consumption. Green tea gains more and more attention. Probably, in your local shop, you can find fermented, semi-fermented, or non-fermented teas or we can say black, red, and green. There are plenty types of teas. Many scientists claim that the most healthy and natural is our today’s superfood, green tea. Actually, why is green tea so healthy when compared to the most popular in Europe, black tea? They are both produced from the same plant Camellia sinensis.
Both green tea and black tea are rich sources of bioactives. They also contain caffeine. Among the spectrum of antioxidants, there are some significant changes due to oxidation of tea. The major difference is in production process. Green tea and black tea are both dried in the final step, but black tea is additionally fermented which affects its chemical composition. This fermentation process is in most cases enzymatic oxidation which, in fact, is not real microbial fermentation as we know it, for example, from yogurt. The most significant process that differentiates properties of different teas is a conversion of some antioxidants into others. Green tea antioxidant profile is very similar to one that we can find in fresh leaves.
Black tea contains compounds that cannot be found in fresh leaves because they were produced during oxidation process. Green tea has super influence on our health, but what is mechanism of action, what are free radicals, and what is the relation between them and antioxidants? Antioxidants help our organisms in fighting with free radicals. Those are very reactive molecules that can be found in our organsims. Free radicals want to gain electron from any source that they can find, vitamins, lipids, DNA, proteins, and other cellular structures. They don’t choose. They are quite specific, so damage can be very random and it can manifest with different symptoms especially when it’s frequent or long-lasting. It’s called oxidative stress.
Antioxidants prevent biological structures or biologically active substances from oxidation. Our bodies produce antioxidants but in certain circumstances, they are not enough. Here comes green tea which is packed with antioxidants that we can enjoy daily. Those compounds in green tea are called catechins. The most active antioxidant in green tea is EGCG. Its full name is epigallocatechin gallate. In fact, its high content in green tea makes it very special among other teas. EGCG is a catechin, and catechins belong to chemical family of polyphenols, which are plant metabolites. All of them possess antioxidant properties. They help plants to protect themselves from different environmental stress factors such as pathogens, insects, or others. We can, also, benefit from catechin’s properties.
What is interesting, green tea infusion contains mostly catechins. Along with caffeine, green tea bioactives are also responsible for its taste. They have not only bitter taste but catechins, additionally, can bind to mouth cavity mucosa. This phenomenon leads to astringent taste. It can be felt also during consumption of other foods like red wine or berries. Catechins and EGCG, in particular, are responsible not only for those properties but what is even more important for many health beneficial ones. Many long-living people claim that they drink green tea every day, and guess what, free radicals might be one of the factors that make us age faster. Many studies suggest that it is recommended to drink up to five cups of green tea per day.
I’m going to enjoy my third one. Cheers.

Can green tea improve our health?

Green tea is consistently ranked among the healthiest beverages and could be considered the most widely consumed superfood.

The mechanism through which green tea could exert its effect on our body and brain depends on the bioactive compounds it contains, such as caffeine and L-theanine, two molecules that directly affect brain function.

Even if black and green tea might look similar, there are differences in their production process and in their antioxidant content. Of particular interest to the topic of this week is the fact that green tea is very rich in a molecule called epigallocatechin gallate, or EGCG.

EGCG belong to the same group of molecules as cocoa flavonoids do and therefore, could exert their effect through similar mechanisms. Just like other flavonoids, EGCG is also a potent antioxidant in vitro, and could help fight free radicals and oxidative damage in our body.

According to scientific data and to the conclusion of the European Food Safety Authority, green tea is considered to be safe when prepared and consumed in the traditional ways, but the majority of studies on EGCG have been conducted in vitro, and there is no conclusive evidence of a health benefit coming from green tea consumption.

Therefore, while green tea can be considered a healthy beverage (apart from the sugar used to sweeten it), it cannot be considered neither a cure nor a preventative measure for some illnesses.

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