Why Is Green Tea Good For Your Immune System?

While the green tea craze is starting to catch on worldwide, it has been in existence in Japan, China, and India for centuries. As more people begin to realize why green tea is good for your immune system, it’s only becoming more popular!

Traditionally, the Japanese, Chinese, and Indians utilized green tea in their medicine to boost the immune system and prevent various ailments. It wasn't until recently that the western world discovered green tea and started reaping its health benefits. Aside from just warding off illnesses, green tea has also been proven to help with weight loss, skincare, increasing life expectancy, and even boosting brain function.

(For more on the health benefits of green tea, read this next: 10 Top Health Benefits of Drinking Green Tea.)

Why Is Green Tea Good For Your Immune System?

So, how exactly does green tea help improve your immune system? Let's dig in!

Antioxidant Properties

The secret to green tea’s ability to ward off diseases lies in its antioxidant properties.

While the body produces its own antioxidants (endogenous), on their own, they are not very effective when dealing with free radicals (waste substances resulting from oxidative stress). Oxidative stress has been linked to various ailments—think cancer, arthritis, stroke, heart disease, Parkinson’s disease, and respiratory diseases. When the body is unable to deal with free radicals, it is more susceptible to these conditions. That's why we need external sources of antioxidants (exogenous), which green tea is a good source of!

(For more about cancer and green tea, read this post next.)

Compared to other types of tea, green tea has the highest concentration of polyphenols (antioxidants). This can be attributed to the fact that it is a less processed type of tea. Fresh leaves of Camellia sinensis are rapidly steamed to inactivate enzymes and prevent fermentation and oxidation of essential compounds.

As a result, green tea is rich in polyphenol compounds, known as flavanols or catechins. They include:

• epicatechin
• epigallocatechin
• epicatechin-3-gallate
• epigallocatechin-3-gallate (EGCG).

These flavanols facilitate the immune-boosting properties of green tea.

Cancer Prevention

Another reason green tea is good for your immune system has to do with inflammation.

Many cancer studies have shown a strong link between oxidative stress, chronic inflammation, and cancer. Oxidative stress facilitates the transformation of normal cells into inflammatory or tumor cells. When tumor cells grow uncontrollably, they can lead to cancer. Ultimately, many medical professionals deem inflammation a ‘secret killer’ because, in most cases, it is a precursor to various forms of cancer.

Polyphenol antioxidants in green tea reduce cancer risks by inhibiting or slowing down the oxidative damage process in our bodies. EGCG, in particular, stops cancer cells from growing and even directly kills them.

There are many studies to support the anticancer effects of green tea.

Here are two interesting examples to look at:

• A meta-analysis of studies carried out from 1998 to 2009 showed women who drank green tea had a 30% lower risk of developing breast cancer.
• Another study carried out by the Japan Public Health Center involving more than 49,000 male subjects also showed that green tea reduced the risk of men developing prostate cancer by 48%.

Prevention Of Coronary Heart Diseases

Causes of coronary heart disease include low physical activity and a diet high in saturated fats, which lead to clogging of the arteries (atherosclerosis). Green tea helps prevent coronary heart disease in two ways.

First, it facilitates the proper function of endothelial cells, which prevents atherosclerosis. Inflammation of endothelial cells leads to atherosclerosis.

Secondly, it promotes fat oxidation and prevents obesity.

Also, consumption of green tea reduces the risks of:

• High blood pressure
• Stroke
• Osteoporosis
• Type 2 diabetes
• Liver disease
• Viral diseases
• Bacterial infections

Some studies even find that drinking green tea helps accelerate fitness recovery faster than usual.

UV Protection

Ultraviolet radiation from the sun is linked to various health complications. These include DNA damage, immunosuppression, and skin cancers like melanoma and non-melanoma.

While green tea doesn't block UV rays, it reduces the effects of free radicals and prevents inflammation caused by extensive exposure to sun rays. When green tea metabolizes, the metabolites find their way to the skin tissue fluids. Then, they form a kind of protective shield against the effects of UV rays.

A study showed that people who took small oral doses of green tea (two cups for 12 weeks) experienced less reddening of the skin (erythema) when exposed to sun rays than those who did not.

In another study, mice that were administered green tea through water showed fewer tumor incidences in terms of size and multiplicity compared to mice that were not. Since tumors are directly linked to cancer, reducing tumor incidence also reduces the cancer risk in many cases. And finally, the anti-inflammatory effects of green tea also slow down the process of aging.

Antimicrobial Properties

Several studies have also shown that green tea has antimicrobial properties that inhibit the growth of bacteria and viruses. Two particular polyphenol catechins, epigallocatechingallate (EGCG) and epicatechingallate (ECG), can suppress the activities of bacterial and viral factors. They can even reverse the resistance of formidable pathogens, such as methicillin-resistant Staphylococcus aureus (MRSA). ECG and EGCG have the ability to penetrate through phospholipid layers.

As a result, these two catechins alter bacteria and viruses’ functions by disrupting their cytoplasmic membrane, making them vulnerable to antibiotics. Evidence suggests that the two catechin molecules can help effectively control various oral infections, such as dental caries, periodontal disease, tooth decay, and bad breath.

The benefits of green tea are numerous. Some studies even indicate that green tea improves brain function. It may even lower your risk of Alzheimer’s and Parkinson’s diseases in old age.

Another quality that makes this beverage stand out? It can be consumed or ingested in various ways—not just through sipping! You can use it to dress salads, dunk rice (ochazuke), include it in your smoothie, or even use it to prepare a marinade. The choices are innumerable, and you can use it in virtually any type of food.

And don't forget: there are so many types of green tea brands, each with different flavors and health benefits you can take advantage of. So, don't limit yourself to just a single brand and deny yourself the benefits of others! Enjoy as many brands as possible to boost your immune system and keep your body in good shape.

This post was first published in 2019. It was updated in 2021 just for you!