Green Tea and Cancer Prevention

Tea is breaking tradition lately, particularly green tea. It is finding its way into foods like green-tea braised scallops, sesame green tea noodles, and green tea ice cream. Teas were reputed to be beneficial to the health of humans for centuries, especially in ancient Chinese cultures. Green and black teas together make up the most consumed beverage, second to water (Beltz 389). Yet, as far back as we can go in written medical records, we find mentions of cancer and cancer-like diseases. Could it be that green tea can help fight cancer on top of everything else it is presumed to do? The answer is yes. Drinking green tea is associated with decreased frequency of cancer development (Beltz 389). Green tea is one of the best natural cancer preventative because it is the highest natural source of EGCG, a contributor to the discontinuation of cancer cell survival.

To begin, malignant neoplasm, commonly known as cancer, is a class of diseases in which a group of cells have abnormal and uncontrolled cell growth. The mutated, toxic, or defective cells start multiplying at rapid rates. The excess of cells begin to form a swelling called a tumor. If the reproduction of these cells aren’t suppressed, they can invade and destroy surrounding tissues (Oxford Reference Online). Eventually, metastasis occurs. Metastasis is when the cancerous cells spread from the original tumor to other parts of the body. Cancer cells can spread through the bloodstream, the lymphatic system, and across the body cavities, such as the abdomen or chest (Oxford Reference Online). It is once these secondary tumors, or metastases, spread that the cancer is deadly.

Cancer occurs when there is a defect in apoptosis. Apoptosis is “programmed cell death” (Oxford Reference Online). Some cells that our bodies produce are destined to die because of this genetically controlled cell destruction program we have installed in our bodies. It is the body’s defense mechanism against mutant cells. This process of cell suicide is required in order to maintain healthy cells throughout the body, and get rid of the mutants. Once this process is interrupted, cells begin to grow and reproduce unchecked. When apoptosis is no longer present in mutated cells, the cells are “immortal” and reproduce like wild fire. The result is a cancerous tumor.

The growth and spread of cancer cells rely, to a large extent, on a proinflammatory factor secreted by the cancer cells. Without this, cancer cells become more fragile. The factor is referred to as nuclear factor-kappa B, or NF-kappa B (Servan-Schreiber 40). Nuclear factor-kappa B is a transcription factor involved in rapid cellular responses. If and when the cell needs to reproduce, the NF-kappa B is freed from the cytoplasm and makes it way to the nucleus, where it “switches on” the appropriate genes to produce regeneration. It is when NF-kappa B remains switched on inside the cell that it contributes to formations of tumors (Oxford Reference Online). Eliminating or blocking cancer cell’s production of NF-kappa B makes cancer cells controllable once again because it reintroduces apoptosis. Stopping NF-kappa B early can also prevent cancer from forming metastases. Today, “almost every cancer preventive is an inhibitor of NF-kappa B,” says professor Albert Baldwin, PhD, from University of North Carolina (Servan-Schreiber 40).

Naturally, coming from a plant, Camellia sinensis, green tea is a complex mixer of bioactive components. Polyphenols are chemical substances characteristic to plants that are loaded with antioxidants. Thirty-six percent of a green tea leaf is pure polyphenols, which contain catechins epigallocatechin gallate (EGCG), epigallocatechin (EGC), epicatechin gallate (ECG), and epigcatechin (EC) (Beltz 389). Of the several categories of polyphenols, flavonoids are known to exert antioxidant activities that are generally more potent and effective against a broader range of toxins than the traditional antioxidant nutrients vitamins C, and E (Murray 61). Flavonoids make up the color in the fruits and flowers, and therefore are responsible for many of the nutritional properties of foods and juices (Murray 61). A catechin is just a flavonoid compound characterized according to its own chemical structure. Catechins are the flavonoids that are specific to Camellia sinensis. Flavonoids, especially catechins, are abundant in green tea. They have antioxidant, anti-inflammatory, antiallergic, antiviral, and anticancer properties (Beltz 389). Flavonoids have been proven to be helpful in maintaining healthy small blood vessels and connective tissue, and consumption of flavonoids will help delay plaque buildup in the blood vessels and arteries.

However, it is the anti-inflammatory properties of flavonoids and catechins that is significant to fighting cancer cells. Numerous studies have shown that EGCG (found in green tea catechins) leads to growth inhibition or death of cancer cells (Beltz 389). Flavanoids have anticarcinogenic effects through inducing apoptosis. Also, the cancer cell line is more sensitive to polyphenols than normal cells (Erguder 1). Immunotherapy and chemotherapy are usually effective in treatment of small tumors in animals, but these remedies are generally ineffective in the treatment of large tumors. EGCG as a chemotherapeutic agent is, however, effective in inhibiting the growth of large tumors. It also enhances the effects of radiotherapy on cancer cells in the laboratory (Servan-Schreiber 120). This means, EGCG leads to the end of rapid reproduction of cancer cells by blocking the NF-kappa B factor, and therefore, halting the growth and severity of any cancerous tumor. EGCG also reduces the growth of the new blood vessels that tumors need for metastases. A single glass of brewed green tea has 50 to 100mg of polyphenols, most of which are catechins (Erguder 1). Three to four cups a day is enough to provide an adequate daily dose of antioxidants to preserve healthy cells and stop the breeding of cancer cells (Servan-Schreiber 97).

The principal difference between populations with the highest cancer rates and those with the lowest was in their food intake. When Asians developed breast or prostate cancer, their tumors were usually much less aggressive than a Westerner’s. In fact, wherever green tea is consumed abundantly there is a lower incidence of cancer (Servan-Schreiber 97). All the tea in the world came originally from China, so it isn’t any wonder that the Chinese are large consumers of tea. Of the top fifteen countries with the highest rate of death by cancer, the United States was 9th on the list with 322 deaths per 100,000 (Death from cancer by country 1). China, with the largest country population in the world, didn’t even make it on the list. Neither did Japan. It is believed and wondered if the chemical molecules contained in green tea are powerful anticancer agents.

As a result, there have been many experiments with green tea and cancer cells. One recent study tested whether green tea had anti-cancerous potential in the human stomach and colon cancers. For this experiment, patients were randomly chosen among subjects who had surgery for stomach and colon cancer in the Ankara University Faculty of Medicine, in Turkey. There were samples of six cancerous and six non-cancerous gastric tissues, and seven cancerous and seven non-cancerous colon tissues tested. The experiment tested four different concentrations of green tea extract: zero extract, 0.05%, 0.5%, and 1.25%. After a one hour incubation period, the xanthine oxidase (an important enzyme in the digestive tract that is effected by gastric cancer cells), that was low due to the cancer before the treatment, increased in relationship with the concentration of extract (in both the colon and stomach samples) (Erguder 2). The EGCG in the green tea extract induced apoptosis on the gastric carcinoma tested in these samples.

Similarly, green tea could also be a promising agent against breast cancer. EGCG that was orally given to female rats with breast cancer showed anticarcinogenic activity. Female rats with mammary tumors were given green tea as their drinking fluid for up to 24 hours, and within that time 90-95% of the rats experienced promising signs. The burden of their tumors had significantly decreased. Additionally, the appearance of the tumors were latent (Guo 1). When human breast cancer cells were treated with EGCG, the cells had the same effects as the rats: the cancerous cells stopped growing and the cancer became less aggressive.

In brief, green tea has not been used to treat cancer. We only have witnessed its potential to stop cancer from spreading. Scientists agree that the catechins present in green tea, especially EGCG, are significant to the health of humans and animals because they promote cell wellbeing. It has not been proven that green tea catechins can treat and remove cancer completely. Yet, we do know that a steady daily sum of EGCG wards off the risk of cancer

Works Cited:
A Dictionary of Nursing. Oxford University Press, 2008. Oxford Reference Online. Oxford University Press. Peninsula College Library. 2 Mar. 2008 <>.

Beltz, Lisa Ann. "Mechanisms of Cancer Prevention by Green and Black Tea Polyphenols." Anti-Cancer Agents in Medicinal Chemistry. 2 Mar. 2008 < &AN=24195567&site=ehost-live>.

Ergüder, Imge B. "EFFECTS OF AQUEOUS GREEN TEA EXTRACT ON ACTIVITIES OF DNA TURN-OVER ENZYMES IN CANCEROUS AND NON- CANCEROUS HUMAN GASTRIC AND COLON TISSUES." Alternative Therapies in Health and Medicine 14.3 (2008): 30-3. Health Module. ProQuest. 6 Mar. 2008 <>.

Guo, Shangqin, Yang, Sanghwa, Taylor, Chad, Sonenshein, Gail E. "Green Tea Polyphenol Epigallocatechin-3 Gallate (EGCG) Affects Gene Expression of Breast Cancer Cells Transformed by the Carcinogen 7,12-Dimethylbenz[a]Anthracene1-3." The Journal of Nutrition : International Conference on Diet, Nutrition, and Cancer 135.12S (2005): 2978S-2986S. Research Library Core. ProQuest. 3 Mar. 2008 <>.

Murray, Dr. Michael. How to Prevent and Treat Cancer with Natural Medicine. New York: Riverhead Books, 2002.

Servan-Schreiber, David. Anti Cancer. Great Britain: Penguin Books Ltd, 2008.


More pages