Green tea (EGCG) and cancer

What is green tea

Green tea is a type of tea made from fresh tea leaves of the Camellia sinensis plant that have not undergone fermentation. It is known for its light flavor and green color and is rich in antioxidants, especially catechins, which are believed to have health benefits. Green tea is often associated with improved cardiovascular health, weight management, and various other health effects. It also contains caffeine, but in smaller amounts than black tea or coffee.

Green tea as a supplementary treatment for cancer. Effect, pros, and cons.

Green tea contains polyphenols, especially epigallocatechin gallate (EGCG), which have shown potential cancer-preventive and cancer-fighting properties [3, 4].

Effect of green tea

Antioxidant effect

EGCG can neutralize free radicals, which can damage cells and lead to cancer.

Inhibition of tumor growth

EGCG can inhibit the growth and spread of cancer cells. Recent research shows that EGCG can inhibit breast cancer progression by suppressing the EGFR/Src signaling pathway [6].

Improve effect of chemotherapy and radiotherapy

EGCG can make cancer cells more susceptible, making chemotherapy and radiation therapy more effective [7].

Advantages of green tea

Improved effect of traditional treatment

Can potentially enhance the efficacy of chemotherapy and radiotherapy.

Anti-inflammatory effect

Can exert an anti-inflammatory effect that may be beneficial during cancer treatment. It can modulate the JAK/STAT pathway, which is central to inflammation and cancer progression [10].

Strengthens the immune system

Can strengthen the immune system.

Few side effects

Relatively few side effects compared to traditional cancer treatments.

Symptom relief

Can provide some degree of relief for cancer symptoms.

Disadvantages

Cannot stand alone as a treatment for cancer

Overdose

Green tea can be overdosed, potentially damaging the liver. Therefore, do not use more than recommended on the package and only provided that your liver is functioning well.

Limited evidence

Limited scientific evidence for its effectiveness in cancer patients.

Interactions

Can interact with certain cancer drugs.

High-dose intake can cause side effects such as nausea, constipation, and insomnia.

Can also delay or prevent effective traditional cancer treatment.

Mechanisms of action

EGCG (Epigallocatechin gallate) functions as a versatile metabolic regulator that attacks cancer cells through several independent signaling pathways. A central mechanism is the inhibition of the enzyme CYP17A1, which blocks the formation of androgens (male sex hormones). This is particularly critical in prostate cancer, as it removes the growth signals that the tumor depends on [8].

At the cellular level, EGCG acts as an antagonist against the GRP78 protein. This protein normally functions as a “survival helper” that enables cancer cells to withstand the stressful environment of a tumor and develop resistance to chemotherapy. By deactivating GRP78, the cell’s defenses are significantly weakened [9].

Furthermore, EGCG directly interferes with the cancer cell’s communication system by inhibiting the JAK/STAT [10] and EGFR/Src signaling pathways [6]. These function as the cell’s internal “command centers” for division and movement; when blocked, the cancer cell loses the ability to multiply uncontrollably and, even more importantly, the ability to invade neighboring tissue and form metastases.

Typical question

How much and how often can you drink green tea?

Answer:

It depends on how concentrated it is in the blend, how strong you prepare it, what other medications and supplements you are taking, how robust you are yourself, etc. Therefore, it is very difficult for others to answer.

However, some drink virtually nothing else. Others take a single cup. Personally, I have 2-3 cups a day and supplement with a single capsule.

However, one should be aware that green tea can be overdosed. And as mentioned above, it can also interact with other preparations.

Note

Green tea should not be used as a substitute for traditional cancer treatment.

If green tea is nonetheless used as an alternative treatment, this measure cannot stand alone.

People undergoing cancer treatment should talk to their doctor before consuming green tea or other dietary supplements.

The optimal dose of green tea for cancer prevention or treatment is unknown.

Conclusion

Green tea, rich in polyphenols like epigallocatechin gallate (EGCG), has been shown to possess potential cancer-preventive and fighting properties. Research indicates that EGCG can have an antioxidant effect, inhibit tumor growth [6], and improve the efficacy of chemotherapy and radiotherapy [7]. Furthermore, green tea can contribute to strengthening the immune system and provide anti-inflammatory benefits [10], while generally having few side effects. However, there is limited scientific evidence for its efficacy in cancer treatment, and it should not be considered a substitute for conventional treatments. Overdosing can lead to negative health effects, making it important to use green tea with caution.

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