Today I felt very good in the morning, not that I usually don’t, but it may have something to do with this plant, Camellia sinensis. All the most consumed teas — white, green, oolong, and black — come from the leaves of the same plant, Camilla sinensis. We will focus on green tea because it is the least processed tea made with camilla sinensis.
As Dr. Greger points out in one of his older videos, the world is obsessed with the tea plant. It is the most consumed beverage on earth. But there are hundreds of thousands of plants on earth, why are we drinking this particular one? It’s probably not the taste, it turns out it might be how this plant influences our brain.
We have evidence from EEG’s (brain imaging) that our brain starts to resemble a high state of alpha, a state like that of experienced meditators. The alpha state is when we are fully alert and focused, but calm. It is the state we want to be in, or I do at least. In the image below we see a little yellow-reddish color on the control side after 90 minutes of relaxation from a non-meditator person. Now try to spot the difference to the person on the right after two cups of tea.
A lot of alpha activity going on there. But what about the side effects? It turns out there are several. A 30 percent reduction in breast cancer risk as well as protection against gynecological malignancies, such as ovarian cancer and endometrial cancer. Lowering of cholesterol, blood pressure, blood sugar, and body fat. Protection of the brain from cognitive decline and stroke. Decreased risk of diabetes, tooth loss, and it even has benefits when applied topically to the skin. There are many more health benefits which I’m not going to focus on in this post but you can find them by watching this playlist from Nutritionfacts.org.
I’m really interested in the effects of tea on the brain since I’m also a meditator and know the benefits an improved alpha brain function first-hand. L-theanine is the amino acid which does the magic in our brain. It is found only in two places, in Camellia sinensis (the tea plant) and a mushroom called Bay Bolete.
L-theanine increases dopamine and the production of alpha waves in the brain. It also increases the activity of the inhibitory neurotransmitter GABA, which has anti-anxiety effects. [2,8] L-theanine also has a synergistic effect with caffeine. [3,4,5]
The other beneficial component in green tea is EGCG. EGCG has Antioxidant, Anti-Inflammatory, and Anti-Aging Properties but also enhances memory, attention, and learning.  Researchers have also detected measurable increases in alpha, beta and theta brainwave activity after subjects have ingested EGCG. 
Don’t bother with the single components, it has been shown that green tea is best-consumed whole, instead of individual components as supplements. 
So how do I drink my tea? I like to prepare ice tea since I live in a hot climate. Sometimes I also open the tea bag and mix that stuff with yerba for my terere.
A great article that goes into details of how green tea influences our health:
Also published on Medium.