Green tea, considered a healthy tea worldwide, comes from the Camellia sinensis plant which also yields black and oolong tea. While a small amount of caffeine makes it a gentle pick-me-up, EGCG and L-theanine are the main weapons in its arsenal. The “jitters” characteristic of caffeine can be countered by L-theanine, which increases GABA levels in the brain and makes you feel relaxed. EGCG, a potent antioxidant, helps you balance your blood glucose levels by boosting the production and efficient use of insulin and protects the liver.
Green tea also comes from the same plant that gives you your regular tea, Camellia sinensis. The only difference is that it is made from unoxidized leaves and hence are the least processed.
About 30% of green tea is made of polyphenols called catechins, chief among which is epigallocatechin gallate (EGCG). But EGCG functions best together with the other antioxidants green tea has.
Green tea contains catechins, flavonoids like myricetin, quercetin, and kaempferol, other polyphenols like ellagic acid, gallic acid, methylxanthines like caffeine and theophylline, and an amino acid called L-theanine.
Why It’s So Great
1. Helps Increase Energy
If you’ve tried coffee for an instant energy boost, try green tea now. Both have one common energy-boosting factor: caffeine. Though a cup of green tea has much less caffeine (35–80 mg) than a cup of coffee (100–400 mg), it still functions as a stimulant without making you jittery, like coffee. Here’s how caffeine works.
- Blocks the effect of adenosine: Adenosine is a chemical that accumulates in your brain through the course of the day. When it reaches a threshold amount, it turns on switches called adenosine receptors located on the nerve membrane. As a result, nerve activity slows down and you feel tired and sleepy. Caffeine is an adenosine receptor antagonist. In simple words, it means caffeine mimics adenosine and jams the switches (adenosine receptors) without slowing down nerve activity. With very few adenosine molecules able to make you sleepy, you feel awake and energetic.
- Activates the sympathetic nervous system: As nerve activity carries on unhindered, the pituitary gland also secretes hormones that nudge the adrenal glands to produce adrenaline. Adrenaline then activates your sympathetic nervous system – the part of the nervous system that preps your body for action, increasing your heart rate, pumping more blood into your muscles, and helping release sugar for energy. This is the reason you feel energetic and alive after a cup of coffee.
- Facilitates muscle contraction: Another related benefit is its effect on muscle contraction. It also helps stimulate the release of calcium ions inside muscle cells. Following this, muscles contract. What this translates into is easier movement without too much exertion, helping you carry on exercising longer.
2. Helps Balance Blood Glucose Levels
Optimum blood glucose levels are important for all your body functions to run properly. Your blood glucose levels increase when you eat. But the extra glucose is harmful. So your body tries to remove the excess from the blood by making cells take it up. Green tea complements this glucose-lowering system.
- It has a compound called 7WA which increases the release of insulin when glucose levels are high.
- Green tea catechins increase insulin sensitivity by helping fat cells mature by activating an intracellular molecule called PPARγ (fat cells need to mature to store insulin, and PPARγ decides when the maturation genes should be expressed).
- They also help increase the movement of special transporter proteins called GLUT4 to the cell surface so that they can carry glucose inside the cell. The result is that more glucose is removed from the blood and stored.
One of the benefits of a steady blood glucose level is steady energy throughout the day.
3. Helps with Sleep
This might seem contradictory to you. How is it possible for the same item to have both a stimulating and a soporific effect? It is possible when two different components are at play. While caffeine is a stimulant, L-theanine (N-ethyl-L-glutamine), the chief amino acid in green tea, is a pacifier.
- Increases GABA: GABA is a chemical that blocks the passage of nerve signals and slows down nerve activity. While it may seem like a bad thing (because you need nerve signals for every little function), it actually helps you wind down. High levels of GABA are essential when you are trying to fall asleep or control your anxiety. Thenine favors the conversion of glutamine into GABA rather than into glutamate, a chemical that helps increase nerve activity.
That said, if you want green tea to specifically help you with sleep, make sure to choose the low-caffeine variety. Otherwise, caffeine can fight off the sleep-inducing effects of theanine. Also make sure the water for the tea is not hot but at room temperature.
4. Relaxes You and Uplifts Your Mood
Have you ever made yourself a cup of green tea when you are anxious and fidgety? It could have helped.
- Caffeine gives a free hand to chemicals like serotonin, dopamine, and acetylcholine after blocking adenosine, which dampens their effect. Dopamine helps you concentrate better and being a happiness hormone, also lifts your mood.
- Green tea catechins can block the effect of an enzyme called acetylcholinesterase, which breaks down acetylcholine. Acetylcholine helps make new memories.
- Theanine has been seen to increase alpha brain waves. These are the type of brain waves you have when you are relaxed but focused, like when you are meditating. Which means it makes you feel relaxed but not sleepy.
- Theanine also helps increase GABA levels in the brain, toning down your anxiety.
5. Helps with Detoxification
The liver, the chief detox organ of the body, bears the brunt of the damage by reactive molecules called free radicals released during the detoxification process itself. Any detox diet or drink must focus on helping the liver get rid of its toxin load.
Green tea polyphenols could lend the body’s internal antioxidants a hand in tackling the free radicals and keeping the liver healthy. Being anti-inflammatory, they could also prevent the process of inflammation (which is how your immune system deals with damage caused by free radicals) from carrying on for too long.
However, do note that green tea extract is not as friendly to your liver as a cup of regular green tea. In fact, long-term consumption of green tea extract has been seen to cause liver damage.
You can make green tea by steeping a teabag in a cup of hot water. But don’t consume it the first thing in the morning since it can increase stomach acid or the last thing in the day since the caffeine in it can disrupt your sleep. Drink it between meals, keeping a gap of a couple of hours since some compounds in green tea may bind to nutrients and hinder their absorption. Limit your consumption to two cups a day since too much green tea may not be good for your liver in the long term.