#3 - Tea Time – Where there is tea, there is hope!

We all love tea, some more than others. 

In fact, I’m drinking tea as I write this post. But did you know that until the mid-16^th century, there was absolutely no tea in Britain? 

I know - how did we survive?

In 2019, a Nature article by Natasha Gilbert dictated the so-called ‘science’ behind the mood-altering properties of tea and how it was able to lower stress levels. Evidently, drinking roughly 100ml of green tea per day reduced the chance of developing depression and dementia. 

Drinking tea has demonstrated to have preventative effects on obesity, cardiovascular disease and immune dysfunction (Sutherland et al., 2005).  The reason why tea may be able to prevent serious diseases, such as the above, is mostly due to the antioxidants present. An example of such anti-oxidant is epigallocatechin gallate (EGCG), which can improve both memory and attention, as well as increase the feeling of calmness in individuals. EGCG is found in green tea, at roughly 42%, so you can imagine just how positive long-term effects may be for reducing the risk of developing depression and dementia, as previously indicated.

Common products, containing antioxidants you may already be familiar with, include wine, dark chocolate, many berries and nuts. We need antioxidants in our body to prevent free radical damage. Free radicals are molecules that can cause extreme cellular and genomic damage, as they can take electrons from these cells. They are usually formed following oxidative stress and inflammatory processes within the body. However, studies have shown that EGCG can prevent the cytotoxicity responsible for necrosis and apoptosis (Sutherland et al., 2005).

Additionally, EGCG has shown to suppress carcinogenesis - the process through which cells become cancerous. Research showed that EGCG inhibited an enzyme called telomerase which normally prevents telomere degradation. So what are telomeres? They are ‘caps’ on the ends of chromosomes in our cells that give chromosomes structural integrity to allow proper replication of DNA when our cells naturally divide. As cells divide, these telomeres become shorter and shorter, so that when they reach a short length, the cell dies in what we call apoptosis.  Evidence has suggested that telomerase activity positively correlates with the degree of malignancy, as they elongate these telomeres. (Naasani et al., 2002). As such, the telomerase enzymes have generally been studied as part of a ‘reverse ageing’ process, as they prevent telomere shortening, which occurs naturally as we get older. This prevention can lead to cancer, as there is a lack of this progressive telomere shortening, hence longer a longer cell ‘life.’

Let’s move onto some organic molecules then. Theanine, a primary amino acid, is an important biologically active component of tea, which contributes to the sweetness and ‘umami’ (delicious) taste of green tea. It also has anti-stress properties in green tea. Research has found that caffeine inhibited this anti-stress effect of theanine. It was concluded that a lowered caffeine content of green tea leaves enabled increases in the anti-stress effects of theanine (Unno et al., 2016). 

So I’ll leave you with some ideal tea brewing times below (see Table 1). Share them around with friends and family, now that you know just how beneficial certain tea types can be!

Just to finish off with a quote by the psychopharmacologist Andrew Scholey:

‘Tea is calming, but alerting at the same time.’

Now think about that mind-bender when you’re sipping your next cuppa…

Table 1: Recommended brewing conditions including temperature and time for 8 tea types

 

Tea	Temperature (°C)	Time (min)
Black	100	3-5
Green	80	2-3
White	70-80	2-3
Yellow	70	2
Oolong	80	2-3
Pu-erh	100	3-5
Herbal	100	5+
Mate	100	3-4

  

Sources:

Gilbert, N., 2019. The science of tea’s mood-altering magic. Nature, 566(7742), pp.S8-S9.

Naasani, I., Oh-hashi, F., Oh-hara, T., Feng, W., Johnston, J., Chan, K. and Tsuruo, T. Blocking telomerase by dietary polyphenols is a major mechanism for limiting growth of human cancer cells in vitro and in vivo. Cancer Research. 63. 824-830. 

Sutherland, B, A., Rahman, R. and Appleton, I. (2005). Mechanisms of action of green tea catechins, with a focus on ischemia-induced neurodegeneration. Journal of Nutritional Biochemistry, 17(1), 291-306.

Unno, K., Hara. A., Nakagawa, A., Iguchi, K., Ohshio, M., Morita, A. and Nakamura, Y. (2016). Anti-stress effects of drinking tea with lowered caffeine and enriched theanine, epigallocatechin and arginine on psychosocial stress induced adrenal hypertrophy in mice. Phytomedicine. 23. 1365-1374.