BLOG #43: A review on the health benefits of matcha: how can catechins in matcha benefit your health?

Matcha & EGCG

Matcha is becoming increasingly popular in the Western market, mainly caused by the health benefits of matcha, but which of these claims are true? And what compounds are related to these so claimed health benefits? Let’s start with a quick introduction about matcha and why matcha is considered to be healthier than other teas.

Difference between Matcha tea and loose green tea?

All tea originates from the same plant species, the Camelia Sinensis. The main difference between most types of tea and matcha is that matcha is a powdered green tea. The grinding process that matcha goes through directly relates to the amount of compounds that can be extracted from the drink (Fujioka et al., 2016). Several studies have confirmed that extraction of biologically active compounds (such as theanine, caffeine, chlorophyll and polyphenols) occur in a higher and faster rate in powdered tea compared to loose leaf tea (Shishikura & Khokar, 2005 ; Komes et al., 2010).

Matcha is a super food

Another reason why matcha is sometimes referred to as a ‘super food’ is because of the high concentration of biologically active compounds. This high concentration is caused by the traditional processing method of matcha. One of the most important steps in the process of making matcha is that the tea bushes, to make the Hug the Tea matcha, are covered to shade the leaves from direct sunlight for approximately 4 to 5 weeks. This results in a stress reaction in the tea bushes, causing the plants to naturally produce more chlorophyll (the plant compound responsible for photosynthesis). In the course of this process, the plants also produce higher amounts of amino acids, resulting in the unique flavour and aromatic characteristics of matcha. As already shortly mentioned above, the main biologically active compounds in matcha are theanine, caffeine, chlorophyll and polyphenols. In this blog post we’ll zoom into a specific type of polyphenols, called catechins.

Matcha contains unique catechins

Catechins are a type of phenolic compounds and are known for their antioxidant activity. They occur naturally in a relatively high concentration in Camelia Sinensis leaves. The catechin content in green teas is relatively high compared to black teas (5.46-7.44mg/g for green teas, compared with 0-3.47mg/g in black teas) (Reygaert, 2018). The four main catechins in matcha are epicatechin (EC), epicatechin-3-gallate (ECG), epigallocatechin (EGC) and epigallocatechin-3-gallate (EGCG), of which the latter is most active and abundant (Kochman et al., 2021). These catechins have high antioxidant activity due to their ability to neutralise free radicals, which can otherwise damage human tissue (Sharangi et al., 2009 ; Lobo et al., 2010).

Antioxidant property of EGCG

A bold claim that is often made about matcha is that it has anticarcinogenic properties, mainly caused by the catechin EGCG. This claim is mainly based on the antioxidant property of EGCG. This property can cause a decrease in oxidative DNA damage, which decreases the risk of developing mutations that can lead, in one of the worst scenarios, to carcinogenic cells (Hakim et al., 2003). A quick reminder: carcinogenic cells grow abnormally and uncontrollable and can spread to other parts of the body. EGCG can also easily bind to specific target proteins (such as enzymes and receptors), which may inhibit signalling in metabolic pathways that are essential for the development of tumours. Moreover, ECGC may even induce apoptosis (programmed cell-death) of malignant cells by binding to these target proteins (Yang et al., 2009). While the mechanisms in which EGCG is involved are quite well understood, there’s still a lot to be investigated before claims can be made in relation to consuming matcha. First of all, most studies that have found that EGCG in tea have anticarcinogenic properties are in vitro studies. This means that these studies were performed in a laboratory with cell lines, but not in living organisms. While this is a useful finding, it doesn’t tell us how EGCG in tea reacts in the living human body. Additionally, the cancer preventive effects of matcha haven’t been consistently observed in human studies, due to many confounding factors within the participants (such as lifestyle, diet, ethnicity) and also within the amount and quality of matcha that was being consumed during these studies. Another disclaimer that should be made is that it’s not clear yet what the threshold of EGCG is before it has anticarcinogenic properties and if this threshold can be met with the consumption of matcha without exceeding the maximum daily intake of other compounds, such as caffeine.

EGCG can neutralize free radicals

Another claim about matcha is that it can improve cognitive functions and that it may even prevent neurodegenerative disorders. Several studies have suggested that working memory processing can be improved by drinking matcha. One of these studies focused on brain activity in a specific region in the frontal lobe, a brain region that plays a key role in working memory processing. This study found that EGCG in green teas, such as matcha, can modulate brain activity in the frontal lobe, showing that EGCG can influence parts of the brain involved in working memory (Borgwardt et al., 2012). Another study, in which the participants consumed green tea-based drinks found short-term plasticity of parieto-frontal brain connections (Schmidt et al., 2014). These connections are also key in working memory processing and this study showed that EGCG can have a clear impact on this neural pathway.  The claim that EGCG can help to prevent neurodegenerative disorders is again mainly based on the property of EGCG to neutralise free radicals. Several studies with animal studies have found that ECGC can cause a reduction in neuroinflammation. Since neuroinflammation is directly related to the development of disorders such as Alzheimer’s Disease and Parkinson’s Disease, it has been suggested that EGCG may help to prevent these disorders. The shortcomings of these studies are very similar to the studies that suggest anticarcinogenic properties of matcha. The studies that have suggested an improvement of working memory processing don’t provide the dosage of matcha or EGCG before its effect is noticeable. Moreover, it’s not clear if matcha should be consumed regularly and how long the effect on working memory lasts. Most studies that have suggested that EGCG can prevent neurodegenerative disorders are again not studies on human beings, but mostly in rodents. What makes it more complicated is that most neurodegenerative disorders are not well understood yet. Therefore, it is still too early to draw any constructive conclusions on the effects of matcha.

Matcha & a healthy lifestyle

While these studies on the health benefits of EGCG in matcha seem very promising, there’s still a lot to be investigated before we know for sure that these claims are true. Something that we can take away from all these studies is that EGCG in matcha is all but unhealthy! Just keep in mind that matcha is not a miracle worker, and that a healthy diet and exercise are key before matcha can benefit your health. But for now, take a moment and just enjoy your warm bowl of matcha.

Resources:

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Ettcheto M., Cano A., Manzine P.R., Busquets O., Verdaguer E., Castro-Torres R.D., García M.L., Beas-Zarate C., Olloquequi J., Auladell C., et al. Epigallocatechin-3-Gallate (EGCG) Improves Cognitive Deficits Aggravated by an Obesogenic Diet Through Modulation of Unfolded Protein Response in APPswe/PS1dE9 Mice. Mol. Neurobiol. 2019 doi: 10.1007/s12035-019-01849-6.

Fujioka K., Iwamoto T., Shima H., Tomaru K., Saito H., Ohtsuka M., Yoshidome A., Kawamura Y., Manome Y. The Powdering Process with a Set of Ceramic Mills for Green Tea Promoted Catechin Extraction and the ROS Inhibition Effect. Molecules. 2016;21:474. doi: 10.3390/molecules21040474

Hakim, I. A. et al. Effect of increased tea consumption on oxidative DNA damage among smokers: a randomized controlled study. J. Nutr. 133, 3303S–3309S (2003).

Komes D., Horžić D., Belščak A., Ganić K.K., Vulić I. Green Tea Preparation and Its Influence on the Content of Bioactive Compounds. Food Res. Int. 2010;43:167–176. doi: 10.1016/j.foodres.2009.09.022.

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Shishikura Y., Khokhar S. Factors Affecting the Levels of Catechins and Caffeine in Tea Beverage: Estimated Daily Intakes and Antioxidant Activity. J. Sci. Food Agric. 2005;85:2125–2133. doi: 10.1002/jsfa.2206. 

Schmidt   A, Hammann   F, Wolnerhanssen   B, et al. Green tea extract enhances parieto-frontal connectivity during working memory processing. Psychopharmacology (Berl). 2014  Oct;231(19): 3879–3888.

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(written by N. Becker – Bachelor in Psychobiology)

Nienke and Hidde in front of HUG THE TEA bar in The Hague