Drinking a cup of green tea can help you feel refreshed and calm, especially when you’re feeling stressed or anxious. But there’s more to this drink than its soothing taste. This drink may hold the key to fighting cancer.
Tea (Camellia sinensis) is one of the oldest and most consumed beverages today. Today, several types of tea are sold, including oolong tea, black tea, white tea, and yellow tea. But among these varieties, green tea stands out because of its high content of flavonoids called catechins. This is because when tea is processed or fermented, beneficial catechins are converted into theaflavins.1
The main catechin found in green tea is called epigallocatechin gallate (EGCG), according to a recent study.2,3 This powerful antioxidant offers significant benefits, especially by helping to fight or inhibit cancer.
Understanding the therapeutic potential of EGCG
The American Cancer Society estimates that there will be approximately 2 million new cases of cancer and more than 600,000 deaths in the United States by 2023.4 Fortunately, there are natural dietary compounds that can help prevent or manage this disease.
EGCG is one such example. This is a natural compound in green tea known for its health benefits. These catechins are not just antioxidants. It plays an important role in regulating cell signaling pathways important for cancer development and progression. The ability of EGCG to affect these pathways makes it a promising candidate for cancer prevention and treatment strategies.
Two studies,5,6 Both were published in the journal Molecules, but separated by a year to highlight how EGCG can help prevent cancer. In the most recent review published in March 2024, researchers highlighted the effects of EGCG on cancer cell lines in animal models, particularly highlighting EGCG’s anti-proliferative, anti-angiogenic and pro-apoptotic properties. Basically, it helps fight cancer by targeting several key aspects that cancer cells rely on to grow and spread.
EGCG targets cancer hallmarks
The impact of EGCG on cancer is enormous. A 2024 study found that EGCG interferes with the signals that cancer cells use to multiply rapidly. By blocking these growth signals, EGCG effectively slows the division of cancer cells, making it more difficult for tumors to expand.
In addition to preventing cancer cell growth, EGCG also inhibits angiogenesis, the process by which tumors develop their own blood supply. Without this blood supply, cancer cells receive less oxygen and nutrients, hindering their growth and reducing the size of the tumor. According to researchers:
“Cancers require a regular blood supply to develop, and if this supply is interrupted, the cancer can become dormant. The ability to inhibit the angiogenic process is considered a strength in cancer treatment efforts. Angiogenesis plays an important role in the development of many health problems.”
Moreover, EGCG promotes apoptosis, the programmed death of cells. This means that EGCG helps reduce the overall number of cancer cells in the body by triggering a natural process that eliminates damaged cells, including cancerous cells.
“EGCG has shown promising effects in inducing apoptosis in cancer cells in laboratory studies and animal models. It has been found to activate several pathways associated with apoptosis, including activation of caspases and enzymes involved in initiating and executing the apoptotic process.” Researchers noted:
This study also highlighted how EGCG affects essential signaling essential for cancer cell survival and metabolism. By targeting these pathways, EGCG not only hinders the growth of cancer cells, but also makes them more vulnerable to existing cancer treatments.
This multifaceted approach is what sets EGCG apart as a potential therapeutic agent. The ability to target multiple cancer hallmarks at once makes it a promising agent for cancer treatment, providing a comprehensive approach to managing and potentially reducing cancer growth.7
“Anticancer drugs are successful in treating cancer, but they can have negative side effects, including changes in physiological and biochemical processes, exhaustion, hair loss, infection, nausea, and vomiting. The evaluation of numerous biological compounds and natural products has proven effective in preventing and suppressing cancer. It plays an important role.
Many experimental and clinical studies have shown that EGCG has anticancer properties. “EGCG is a key physiological anticancer agent because it plays a role in triggering multiple anticancer processes in many cancer hallmarks.” The researchers concluded:
EGCG may prevent many types of cancer
An initial molecular study published in 2023 found that8 It provides the same conclusions as the latest research. It also highlights some of the mechanisms of action of EGCG and how it can positively impact your health. According to researchers, this powerful compound has the following properties:9
- Powerful antioxidant capacity — The antioxidant activity of EGCG is 25 to 100 times more powerful than that of vitamins C and E. It is the most active of all catechins.
- Anti-inflammatory effects — According to the authors, “Several studies have shown that EGCG modulates the expression of inflammation-related genes and proteins such as TNF-α, IL-1β, and MMPs.”
- Welfare effects — EGCG affects cancer development by altering the way genes are controlled in cells. It prevents cancer growth, suppresses oncogenes, and even reactivates genes that cause apoptosis.
The study authors also noted that multiple in vitro and in vivo studies have demonstrated the multidirectional, antitumor properties of this catechin. They looked at different types of cancer cells, including bladder, breast, cervical, liver, colon, stomach, lung, and head and neck cancers.10
EGCG affects key cell signaling pathways in cancer treatment
A 2023 study also discussed how EGCG targets multiple signaling pathways essential for cancer cell growth and survival.11 EGCG interferes with the epidermal growth factor receptor (EGFR) pathway, thereby disrupting signaling that normally promotes tumor growth and division. This inhibition helps slow or even stop the progression of certain cancers.
EGCG also affects the JAK-STAT pathway, which is important for transmitting information from chemical signals outside the cell to the cell nucleus, resulting in DNA transcription and activity. By regulating this pathway, EGCG reduces the ability of cancer cells to proliferate and resist apoptosis.
Additionally, the PI3K-AKT-mTOR pathway, known for its role in regulating cell growth, metabolism, and survival, is another target of EGCG. By inhibiting this pathway, EGCG not only inhibits tumor growth but also enhances the effectiveness of other cancer treatments, making it a valuable component of combination therapy.
Besides these pathways, the antioxidant properties of EGCG play an important role in its anticancer effects. By neutralizing harmful free radicals, EGCG helps protect cells from DNA damage that leads to cancer development. The combination of these pathway inhibition and antioxidant activity makes EGCG a versatile agent in the fight against cancer.
Preclinical studies using cell culture and animal models have consistently shown that EGCG reduces tumor size and prevents metastasis. Clinical trials further support these findings and indicate that EGCG alone and in combination with other treatments improves outcomes in cancer patients. These studies highlight the potential of EGCG as a complementary therapy in cancer treatment protocols.
By targeting these key signaling mechanisms and strengthening the body’s natural defenses against cancer, EGCG shows promising potential in preventing and treating various types of cancer.
EGCG has low bioavailability.
Despite its promising effects, EGCG faces a major challenge: low bioavailability. This term refers to the extent and rate at which the active ingredient is absorbed and becomes available at the site of action.
Studies have shown that EGCG has limited absorption in the body, making it difficult to achieve effective concentrations in the bloodstream. These limitations represent a significant barrier to its use in clinical settings.
However, current research is focused on overcoming these obstacles. Scientists are exploring advanced delivery systems to improve the bioavailability of EGCG. Technologies such as encapsulation in nanoparticles or liposomes are being developed to improve stability and absorption.12 These innovations will help EGCG reach its targets within the body more efficiently, maximizing its therapeutic potential.
Understanding the mechanisms of EGCG and improving its delivery could revolutionize cancer treatment. Making EGCG more accessible and effective could make it a key component in the fight against cancer, providing a natural and complementary approach to existing treatments. This knowledge not only highlights the importance of EGCG in cancer research, but also opens new avenues for the application of EGCG in health and well-being.
A quick way to increase the bioavailability of EGCG is to:
The easiest way to increase the benefits of green tea is to add vitamin C. In the case of tea, a little lemon juice is effective. Studies have shown that vitamin C significantly increases the amount of catechins the body can absorb.
A 2020 Indonesian study published in Pharmacy and Pharmaceutical Sciences Journal (Jurnal Farmasi Dan Ilmu Kefarmasian Indonesia)13 showed a difference in catechin levels in tea after adding vitamin C. The researchers prepared two sets of green tea samples. One group was given varying amounts of vitamin C, ranging from 1 to 3 mg. No vitamin C was added to the other group.
After recording the catechin content, all green tea samples were left for four days and then retested for catechin content. Researchers found that catechins decreased by only 9.76% in green tea samples fortified with vitamin C. In samples without vitamin C, catechins decreased by 19.83%.
“Epigallocatechin gallate (EGCG) is the most abundant green tea catechin and has a powerful antioxidant effect that prevents cancer cells. EGCG contained in green tea solution is very vulnerable to degradation, so it is urgent to increase the stability of EGCG through the addition of vitamin C. Vitamin C regenerates the radical EGCG into normal EGCG.” The authors concluded:14
Meanwhile, adding milk to green tea has the opposite effect. Milk contains proteins that bind to and neutralize the tea’s antioxidants, reducing the tea’s health benefits. According to one study, “all [beneficial vascular protective] Adding milk to tea completely inhibits its effectiveness.”15
Find high-quality green tea
Find out what to look for in terms of quality when buying green tea. One sign that you’re drinking high-quality green tea is that the tea is actually green. If your green tea appears brown instead of green, it has likely been oxidized, damaging or destroying its most valuable compounds.
Brewing loose tea leaves can also provide more antioxidants. It also helps you avoid potential toxins and microplastics found in tea bags. In a 2019 study, researchers found that placing one tea bag in hot water releases billions of plastic particles.16
One cup of green tea provides about 20 to 35 mg of EGCG, so drinking three cups a day can give you up to 60 to 105 mg. Studies have also used higher doses of more than 1,500 mg per day. However, there is still no clear evidence as to exactly how EGCG is best.
The good news is that most research on green tea is based on drinking around three cups a day, which is easily attainable and enjoyable for most people.
