Hello again

Here we are, looking into another category: green tea. Most of you are familiar with it.

There has been a lot of research done about it. The ones I consider relevant were done over extended periods of time on large group of people. Somehow this kind of studies come from Japan and other Asian countries but in Europe and US the bulk of studies are still done on animals or in vitro. I am not a doctor but if you take a look at the global cancer data by countries from 2020 for example you will find one country missing: Japan. In all disclosure it’s name does get mentioned in colorectal cancer statistics of cases recorded but it disappears from the top 10 in deaths for same type of cancer, meaning that even with an incident rate of 38.5 (ASR/100.000) most of the patients survive.

Of course, if you look closely you will see (as I think you already assume) that the tendencies of drinking tea is not the only factor but combining it with a healthy lifestyle surely does have an impact on our bodies.

Now let’s see, I think I have some input that might surprise you still.

First of all: What is Green Tea?

Well, this part, who is following this blog has already read a little about the subject and for who is new, welcome and if you are curious about some basic information about green tea you can find it here.

Today we are concentrating more on the benefits of this well known drink, but not only.

One of the benefits that is believed to be associated with green tea is cardiovascular disease. Now, some scientists from US and Europe say that there are more studies needed but, for example: one large study in Japan followed 40.000 adult participants over 11 years and found that daily green tea consumption was linked to lower risk of death from cardiovascular disease.

Studies show that green tea may improve the main risk factors for cardiovascular diseases, which includes improving total cholesterol and LDL (bad) cholesterol levels.

Green tea also increases the antioxidant capacity of the blood, which protects the LDL particles from oxidation,  which is one part of the pathway toward heart disease.

The study in Japan shows that people who drink green tea have up to 31% lower risk of dying from a cardiovascular disease.

Green tea contains a catechin called epigallocatechin-3-gallate (EGCG). Catechins are natural antioxidants that help prevent cell damage and provide other benefits.

I could write an entire article about this EGCG (and maybe I will in the future) but for now it is important to know that it is one of the most powerful compounds in green tea. Research has tested its ability to help treat various diseases. It appears to be one of the main compounds that gives green tea its medicinal properties like reduce inflammation, aid weight loss, and help prevent heart and brain disease.

There is one thing to say here: even if EGCG is predominantly found in green tea, it also exists even if in smaller amounts in other foods, like:

• Other Teas: white, oolong, and black teas
• Fruits: cranberries, strawberries, blackberries, kiwis, cherries, pears, peaches, apples, and avocados
• Nuts: pecans, pistachios, and hazelnuts

It is important to note that the loose leaf tea is made from the buds and in certain cases the addition of next 2 leaves of Camellia Sinensis plant. This allows for only the smallest amount of fluoride to reside in the loose leaf tea. To further reduce your fluoride intake I always advise brewing your favorite cup with filtered water and keep in mind that tea bags have been associated with high levels of fluoride due to what part of the plant is used and the processing of the tea bags.

For more information you can take a look here.

Do keep in mind the form you buy the tea in. You might be interested in reading “Tea Bags: good or bad?“

Effects on brain function:

With green tea it is not just that it keeps you alert but it actually boosts brain function.

Even if green tea is not containing as much caffeine as coffee (on more on this subject you could read Coffee vs. tea. The caffeine), it still can boost the brain activity as caffeine isn’t the only brain-boosting compound in green tea. It also contains amino acid L-theanine, which can cross the blood-brain barrier.

The L-theanine increases the activity of the inhibitory neurotransmitter GABA, which has anti-anxiety effects. It also increases dopamine and the production of alpha waves in the brain. Furthermore L-theanine and caffeine have a synergetic effect.

Effects on fat burning:

Nowadays most of the fat burning supplements include green tea and there’s a reason for it.

On this matter though you don’t find a lot of research but it appears that consuming green tea extract increases calories burned by 4% during workout and increases fat oxidation by 17%.

Returning for a bit to what I was saying previously, the big C word: Cancer

As I said, In my opinion the numbers say already a lot by looking at the statistics, but there are ongoing studies in US and Europe that link green tea compounds with a reduced risk of cancer, including the following studies:

• breast cancer: observational studies found that women who drank the most green tea had an approximately 20-30% lower risk of developing breast cancers
• prostate cancer: Seeing that the prostate cancer is much lower in Asian countries than Western populations, there was a study in Japan that involved 49,920 men aged 40-69 that associated green tea consumption with a decreased risk of advanced prostate cancer.
• Colorectal cancer: data from 29 studies showed that drinking green tea on a regular basis lowers the risk of developing colorectal cancer by 42%.

To get the most health benefits it is recommended not to add milk in your green tea. Some studies suggest that milk can reduce the antioxidant value in some teas.

Long term effect on brain

Studies show that green tea not only improves the brain function on short term but it also protects it from aging.

Alzheimer’s disease is a common neurodegenerative disease and the most common cause of dementia in older adults and Parkinson’s disease is another common neurodegenerative disease that involves the death of dopamine-producing neurons in the brain.

In test tubes studies show that the catechin compounds in green tea have protective effects on neurons lowering the risk of dementia.

Also, test tube studies suggest that catechins can suppress the growth of bacteria, potentially lowering the risk of infections. Studies indicate that the catechins in green tea can inhibit the growth of oral bacteria in the lab, still waiting for estended research on this matter in western countries but the results are promissing.

Type 2 diabetes

In recent decades the cases of type 2 diabetes increased and are still rising.

Type 2 diabetes involve having elevated blood sugar levels, which can be caused by insulin resistance or an inability to produce insulin.

Studies show that green tea may improve insulin sensitivity and reduce blood sugar levels.

Again from Japan an extended study on individuals found that those who drank the most green tea had an approximately 42% lower risk of type 2 diabetes.

Live Longer

The Ohsaki study was conducted on 40,530 Japanese adults aged between 40 and 79 years without history of stroke, coronary heart disease, or cancer at baseline. Participants were followed up for up to 11 years (from 1995 to 2005) for all-cause mortality and for up to 7 years (1995 to 2001) for cause-specific mortality.

This study showed that those who drank the most green tea (5 cups per day or more) were significantly less likely to die during the study period.:

• death of all causes: 23% lower in women , 12% lower in men
• death from heart disease: 31% lower in women, 22% lower in men
• death from stroke: 42% lower in women, 35% lower in men

Another study: The prospective Shizuoka Elderly Cohort, conducted on 14,001 older Japanese individuals found that those who drank the most green tea were 76% less likely to die during the 6 year study period.

However there are some things to consider when drinking green tea.

Side effects

Like everything in life moderation is the key. But let’s take a look at the risks if you exceed the safe amount that is considered to be 8 cups a day. I for one advise to keep it under 5 cups a day and you will see in a moment why.

Green tea may cause stomach irritation when brewed too strongly or consumed on an empty stomach. Green tea contains tannins that can increase the amount of acid in your stomach. Excess acid can lead to digestive issues including constipation, acid reflux, and nausea. Brewing green tea with water that is too hot can exacerbate these side effects. Brew your green tea with water around 70 C. The optimal temperature for specific tea is always shown on high quality loose leaf tea so you just need to follow the instructions.

Green tea can also cause diarrhea when consumed in large amounts (more than 8 cups a day). Caffeine produces a laxative effect as it stimulates the colon muscles to contract and release more frequently. This results in more frequent trips to the bathroom and can cause upset stomach. If you suffer from irritable bowel syndrome, avoid green tea.

To avoid these side effects, do not drink green tea on an empty stomach. Instead, consume green tea after each meal. If you suffer from acid reflux disease, stomach ulcers, avoid green tea since it can increase acidity.