🍵 Tea Time! for the Brain

The chemistry behind tea's benefits for neurodegenerative disease.

It is recognised that green tea is healthy. Many have even described it as a ‘superfood’ due to its antioxidant properties. This is particularly true of matcha, which originates from Japan. Interestingly, Japan is home to one of the world’s blue zones, and has a famously high life expectancy. So maybe there is a link? But, the quizzical mind will ask if there is any evidence for this. What exactly about tea is beneficial? Before this is answered, a tiny bit of chemistry is required, but this will be kept as light as possible.

---

A Brief Introduction to Tea

Tea is one of the most widely consumed beverages. In fact, it’s second only to water in many societies.

It comes in many different varieties and can be consumed in powder, loose, or tea bag form. Matcha is a powdered tea, characterised by an intense green colour and distinctive earthy taste. Studies have shown that Matcha has the highest concentration health promoting molecules of any tea. Interestingly, this is because the tea is grown underneath the shade of bamboo matts, which protects these molecules from damage. A consequence of this is that Matcha tea leaves have a higher number of chlorophyll (a green pigment that plants use to absorb light), which gives the tea its vivid colour. So, next time you sip a Matcha latte on you way to work, don’t forget to thank the chlorophyll.

The Chemistry of Tea

Green tea is host to a plethora of beneficial and biologically active molecules. This includes caffeine, chlorophyll, and polyphenols like catechins. It is these catechins that have been the most widely researched and contribute to many of the health benefits of tea. By the way, don’t be frightened of ‘polyphenols’. Poly is a Greek word for many and phenol means a ring of carbon atoms.

A diagram of the chemical structure of molecules found in tea.

In fact, polyphenols account for 30% of green tea’s dry weight. This means there are roughly 169-273 mg of phenolic compounds per gram of matcha. These are very powerful antioxidant molecules with properties that are similar to Vitamin C and E. These a proteins that remove oxide radicals from the body, which are toxic compounds. In fact, this is what antioxidant means.

The health benefits of catechins are broad and have been implicated in diseases such as cancer, cardiovascular conditions and even COVID-19. But in this article, we are going to look at green tea’s impact on neurodegenerative diseases.

What is a Neurodegenerative Disease?

Neurodegenerative disease can be characterised as the loss of brain function or activity. The WHO has stated that around 50 million people suffer from dementia. 60-70% of these cases correspond to Alzheimer’s disease.

Unfortunately there are no known cures for many of these conditions and this article is not trying to imply that tea is. However, the catechins found in green tea have demonstrated the ability to reverse some of the underlying problems of these diseases. In particular, the following sections outline recent research on Alzheimer’s, Huntington’s and Parkinson’s diseases.

Alzheimer’s Alzheimer’s disease is associated with plaques that form in the brain. They are referred to as amyloid plaques and are essentially a jumble of proteins that precipitate, which means they form a solid mass as opposed to being dissolved. These plaques are toxic and can cause cell death and damage. When this occurs in the brain it can affect neurons, which leads to symptoms of dementia. It’s important to understand that Alzheimer’s is just a special case of dementia. Patients with the disease suffer from memory loss, confusion and disorientation as well as other symptoms.

The polyphenols were investigated as a way to combat the toxicity of these plaques. It was found that one of these phenol molecules called epigallocatechin-3-gallate (EGCG) helped prevent the formation of these plaques. It was also shown to reduce the death of neurons. In fact, one study even demonstrated that EGCG allowed for the recovery of learning and memory in mice.

Huntington’s Currently, it is only possible to treat the symptoms of Huntington’s disease, which include tremors, difficulty with speech and involuntary muscle movements. Similarly, to Alzheimer’s, this disease is caused by protein aggregation. However, in Huntington’s, the protein responsible is called Htt.

After researchers screened 5000 ‘naturally occurring’ molecules they found that EGCG showed the potential to stop protein aggregation happening in early stages of the disease. It was shown that a 40% reduction in protein aggregates occurred. However, this experiment was carried out with yeast. Finally, our marvellous molecule has been shown to reduce the toxicity of the proteins even if they do form.

Parkinson’s Much like the other brain diseases, Parkinson’s is caused by aggregation of a protein, which has the slightly complex name alpha-synuclein. Perhaps you’re noticing a pattern? The main symptoms of Parkinson’s are trembling of hands, slowness of movement and poor balance.

Similarly to the previous diseases we’ve looked at, EGCG has been shown to prevent this protein from forming. This has been shown to protect rat cells from damage.

Maybe Trust Your Mum’s Herbal Remedies?

As we’ve seen, the polyphenols in green tea, particularly EGCG, have many useful properties. We’ve just looked at three different brain diseases where this molecule has helped to treat the underlying cause of the problem. So what’s the delay, why haven’t we become immortal from drinking Matcha lattes? Well unfortunately, a lot of this research has been conducted in animals and not humans. In addition, these studies use isolated EGCG at concentrations that you are unlikely to find in your cup of tea. But that doesn’t mean that drinking tea is pointless. As well as the psychological benefits of taking time to look after yourself, it has a whole host of other molecules that we discussed, which really do help bring down inflammation. It just might not be the cure for Alzheimer’s.

Nonetheless, I hope that the next time you make yourself that delicious green beverage you’ll remember all of the amazing molecules it contains and the fantastic science that it has allowed us to discover.

On a final note, this is the first in a series of articles looking at the health benefits of tea. So, watch this space and stay tuned to ‘The Pink Zone’.

---

Hi, I’m Yegor 👋. I recently joined the HEA team as a healer. I’m fascinated by biology and chemistry. My goal at The Pink Zone is to introduce cutting-edge research on health in an accessible way. I can’t wait to learn and communicate the wonders of science to you, my dear reader.

Other HEA Channels:

• Check out our website

• Follow our twitter

• Follow our instagram