Green Tea and Breast Cancer

March 31st, 2010 by admin 1 comment »

Green Tea and Breast Cancer

Breast cancer is the most prevalent form of cancer in women the world over. Green tea made from tea plant leaves (Camellia sinensis) has been found to contain flavonoids, which are antioxidants in the polyphenol group.

The results of surveys comparing medical histories between green tea drinkers and non-drinkers show that green tea can inhibit breast cancer cell growth. The most effective flavonoid in cancer prevention is thought to be epigallocatechin-gallate (EGCG).

A Review of Published Studies

A lot of research has been conducted since 1998 about the effects of green tea on breast cancer. This is because many studies, whether epidemiological, molecular or clinical have generated results proving that green tea has some anti-inflammatory and anti-cancerous properties. AA Ogunleye and his colleagues conducted a systematic search of studies of breast cancer risk and recurrence that were published between 1998 and 2009.1

The researchers used 5 databases of published studies and found 5617 cases of breast cancer. Of those cases, they pinpointed 7 studies of breast cancer incidence and 2 studies of breast cancer recurrence that included green tea consumption as a variable. There was a great deal of variation in the results. They concluded there is probably a beneficial effect of green tea on breast cancer even though the studies were so variable. There is a clear need for more studies under controlled conditions to make any definitive conclusions.

A literature review of the effects green tea, green tea extract or its purified polyphenol (-)-epigallocatechin-3-gallate (EGCG), an antioxidant, on health benefits was conducted by Y. Clement, from the University of the West Indies.2 Data was gleaned from 2 electronic databases: PubMed (1966 to 2009) and the Cochrane Library (Issue 4, 2008). Although observations were made from observational studies Clement concluded there are trends toward green tea assisting in the prevention of breast cancer incidence.

Green tea has proved to have anti-tumor ability. In a laboratory experiment, cells infected with human breast cancer cells grew cancerous tumors. Following cell treatment with green tea polyphenols or EGCG tumor growth was inhibited and tumor cells were killed.3

A current experimental study looked at the effect of green tea on the efficacy of a common chemotherapy drug, paclitaxel, with taxol as the active ingredient.4 Taxol is extracted from the bark of the Pacific yew tree (Taxus brevifolia). Over time, cancer cells can develop resistance paclitaxel. The identification of “chemosensitizers”, substances that make cancer cells more susceptible to chemotherapy treatment, is vital for cancer treatment as the second decade of the 21st century begins.

One such chemosensitizer has proven to be EGCG extracted from green tea. Researchers compared cancer cell death when treated with the chemotherapy drug paclitaxel alone, with EGCG alone or paclitaxel and EGCG in combination. The combination of the two substances showed the most significant effect on tumor destruction than either one alone (a synergistic effect).

Common stumbling blocks when using natural chemicals, such as polyphenolic compounds, in the human body are bioavailability and instability in the living system. The chemicals may be stable and bioavailable until the compound is introduced to the body. There are many reactions the natural chemicals are subject to and the environment within the body may not be hospitable for them.

So along with the development of chemosensitizers for use in disease treatment, “prodrugs” are sometimes required to maintain the viability of the treatment under physiologic conditions. Researchers have developed a prodrug of EGCG called Pro-EGCG (1) to increase the stability, bioavailability and anticancer activities of EGCG.5

EGCG is unstable in the body and is poorly bioavailable. The researchers, when trying to create a prodrug for EGCG, added chemical groups to the areas on the molecule that are available to react with other molecules. The researchers named the new molecule Pro-EGCG (1). Now the EGCG can be protected by preventing other molecules from attaching to it and forming completely different molecules that would likely not have anti-cancerous effects. EGCG and Pro-EGCG (1) given in combination enhances tumor cell death and growth suppression and has potential use in preventing and treating cancer.

1Green tea consumption and breast cancer risk or recurrence: a meta-analysis.

Ogunleye, AA, Xue F, Michels KB. Breast Cancer Res Treat. 2010 Jan;119(2):477-84. Epub 2009 May 13.

2Can green tea do that? A literature review of the clinical evidence. Clement Y. Prev Med. 2009. 49(2-3):83-7. Epub 2009 May 22.

3Green tea polyphenols and its constituent epigallocatechin gallate inhibits proliferation of human breast cancer cells in vitro and in vivo. Thangapazham RL, Singh AK, Sharma A, Warren J, Gaddipati JP, Maheshwari RK. Cancer. Lett. 2007. 245(1-2):232-41. Epub 2006 Mar 6.

4(-)-Epigallocatechin gallate sensitizes breast cancer cells to paclitaxel in a murine model of breast carcinoma. Ting Luo, Jiao Wang, Yancun Yin , Hui Hua, Jing Jing, Xiangming Sun, Minjing Li, You Zhang and Yangfu Jiang. Breast Cancer Research. 2010. 12(1):R8.

5 A novel prodrug of the green tea polyphenol (-)-epigallocatechin-3-gallate as a potential anticancer agent. Landis-Piwowar KR, Huo C, Chen D, Milacic V, Shi G, Chan TH, Dou QP. Cancer Res. 2007. 67(9):4303-10.

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Components of Cardiovascular Disease and Green Tea

March 25th, 2010 by admin 4 comments »

An estimated 785,000 Americans had their first heart attack in 2009 and 470,000 of them are likely to have a recurrent heart attack. High cholesterol, high blood pressure, obesity, diabetes, tobacco use, and secondhand smoke are all risk factors for heart disease.

We are fortunate because enjoying between 1 and 4 cups of green tea each day is heart-healthy and has no harmful side effects for most people. Researchers estimate 3 cups of green tea each day leads to an 11% decrease in the rate of heart attack. Another study found drinking 4 cups of tea per day significantly reduced the risk of death following a heart attack.

Kenneth J. Mukamal, of the Division of General Medicine and Primary Care at Beth Israel Deaconess Medical Center and his colleagues conducted a study on the effects of tea consumption on heart attacks.2 The “Onset Study” was conducted in 45 community hospitals and tertiary care medical centers in the United States. From August 1989 to September 1994, there were 1935 patients (601 women and 1334 men) interviewed approximately 4 days after having a heart attack. It is important to note that the tea drinking level was self-reported by patients and based on their tea drinking during the past year.

Researchers found that when heart attack survivors were heavy-tea drinkers they had a 44% reduced risk of dying during the 3.5 years after their heart attacks. The reduction was based on comparison of the death rates of non-tea drinkers in the study. Moderate tea drinkers realized a 28% reduction in the risk of dying as compared to those who do not drink tea. Dr. Mukamal found the highest response to tea-drinking came from patients already living with heart disease.

Cholesterol

Green tea will help lower low density lipoprotein (LDL) cholesterol and blood pressure and control obesity and diabetes. These are all risk factors for developing heart disease. Green tea, in combination with a low fat and low cholesterol diet may reduce LDL levels by 10%. Drinking green tea will also raise high density lipoproteins (HDLs), the “good” cholesterol, in the blood and lower total cholesterol.3

Quercetin is an antioxidant in the flavonol class of molecules present in green tea. Its properties contribute to its ability to oxidize LDLs. This is significant because oxidized LDLs are critical molecules in the process that makes plaque.4 Plaque is the build-up of calcium, fats and atheromas in the arteries. This condition is commonly called “hardening of the arteries” which narrows or completely blocks the flow of blood through hardened arteries. Drinking 4 cups of tea per day improves cell quality in the lining of the heart and blood vessels and strengthens the cardiovascular system.

Inflammation

Catechins, a class of flavonols found in green tea, have been studied for their beneficial effects in the prevention of autoimmune disorders and cancer, among other maladies. Recently, catechins were found to prevent inflammation as well. Inflammation in the cardiovascular system has been identified as a contributor to heart disease. Catechins help prevent or limit cardiovascular disease by stopping processes which make molecules that act as green lights for the inflammatory process to begin.

Some scientists have concluded “catechins are potent agents for the treatment and prevention of inflammation-related cardiovascular diseases because they are critically involved in the suppression of pro-inflammatory signaling pathways.”5

1Heart Disease and Stroke Statistics—2009 Update. A Report from the American Heart Association Statistics Committee and Stroke Statistics Subcommittee. Lloyd-Jones D, Adams R, Carnethon M, et al. Circulation. 2009.119:e21-e181.

2Tea Consumption and Mortality After Acute Myocardial Infarction. Kenneth J. Mukamal, MD, MPH, MA; Malcolm Maclure, ScD; James E. Muller, MD; Jane B. Sherwood, RN; Murray A. Mittleman, MD, Dr PH. Circulation. 2002.105:2476.

3 Heat-epimerized tea catechins rich in gallocatechin gallate and catechin gallate are more effective to inhibit cholesterol absorption than tea catechins rich in epigallocatechin gallate and epicatechin gallate. Ikeda I, Kobayashi M, Hamada T, Tsuda K, Goto H, Imaizumi K, Nozawa A, Sugimoto A, Kakuda T. 2003. J Agric Food Chem 51(25):7303–7.

4Bioavailability and health effects of dietary flavonols in man. PC Hollman and Katan, MB. Arch Toxicol Suppl. 1998. 20:237-48.

5Tea polyphenols regulate key mediators on inflammatory cardiovascular diseases.
Suzuki J, Isobe M, Morishita R, Nagai R. Mediators Inflamm. 2009:494928. Epub 2009 Jul 19.

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Who Doesn’t Like Benefits?

February 24th, 2010 by admin No comments »

With the current craze of being healthy that has infected the United States, new products and health plans have been popping up all around the country.  With so many unreliable products being released, people are looking for a product that they can trust.  Those individuals do not have to look any further.  In fact, there is a product that has been trusted to preserve the health of nations for centuries.  That product is green tea.

Green tea has been found to have several health benefits.  Some, such as weight loss and preventing cancer are well known, while others might be surprising.  For example, green tea is used in candy to prevent gum disease and in ointments to treat genital warts.  People also use green tea bags to reduce puffiness under the eyes and on the skin to soothe sunburn.  Drinking green tea has been accredited with helping individuals with losing weight and preventing cancer, as previously stated, as well as reducing the risk of heart disease, lowering cholesterol, controlling blood sugar, reducing inflammation due to Crohn’s disease and ulcerative colitis, and protecting the liver against toxic substances.

Returning to the subject of weight loss, green tea is a great product to use in conjunction with eating right and exercising.  In fact, a study on mice showed that those mice who exercised did not burn as much fat as those mice who drank green tea and did not exercise, and those mice that drank green tea and exercised burned more fat than the other mice.  The key to this are the polyphenols found in green tea.  The polyphenols can be considered to be glucose regulators considering the way in which they prevent the glucose from moving into fat cells.  They also activate the enzymes that dissolve triglyceride, or excess food.  All of this ultimately leads to fat burn.  Also, caffeine paired with a certain polyphenol called epigapigallocatechin gallate, which is also referred to as EGCG, work together to create thermogenesis, which is basically the process of fat being used for energy.   This causes an increase in energy, greater stamina to exercise, as well as a reduction in excess water weight.

Another product that green tea contains is theanine, which is considered a natural relaxant.  Theanine is known to promote a feeling of well-being.  This can be very beneficial to individuals in fast-past, high-demand occupations, or for individuals who may just need a pick-me up.  Feeling at peace also reduces stress which can help decrease negative health factors.

Another major benefit of green tea is that it is a lifelong product with lasting results.  Incorporated in a daily routine, green tea has been proven to reduce body fat and maintain healthy bodily functioning.  Since it is a natural, healthy, medicinal product, green tea does not have negative effects, when consumed properly, or in other words, when it is not over-consumed or taken in conjunction with the wrong medication/additional supplements.  To assure the proper use of green tea, it is recommended that you consult with your physician before incorporating green tea into your daily routine.  Pregnant women are especially cautioned to consult their physician before using green tea, as the green tea can get into their breast milk and could lead to some effects to their child(ren).  It is also recommended that green tea users investigate the green tea products that they plan to use and check to make sure that the product contains standard green tea extract, and that the manufacturer holds the proper credentials and strict compliance with the GMP regulations.

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The Truth About Green Tea

February 16th, 2010 by admin No comments »

One of the growing trends in the United States as of late has been that of the health conscious consumer.  With increased attention being brought to the alarming rates of obese people in the States and knowledge of the devastating effects that an obese population can bring (death, disease, etc.),  more and more people have been looking for ways to get in shape, stay in shape, and to live long, healthy, happy lives.  One product that has been found to aid in these endeavors would be green tea.  With all of the hoopla around green tea, many people have gathered that it is healthy, but yet many still do not know how or why it is seen as so special.

Green tea has been deemed as a traditional staple beverage and medicinal ingredient amongst Asian communities, and many know that the concept of brewing tea first developed in Asian communities.  However, not many are aware that many teas have their origin in China.  In fact, the concept of brewing tea in general developed in China.  It is believed that brewing tea developed from Chinese cultural practices and has been accredited to both religious and royal origins.  Both the Chinese and the Japanese communities hold sacred tea ceremonies, but the Japanese developed theirs after Japanese monks traveled to China and learned the Chinese tea ceremony rituals; they saw it as part of their efforts to embrace the Chinese culture.

Though there are several different kinds of teas, black tea has become most popular in the United States, while green and oolong teas are beginning to grow in popularity as well.  Though all of these teas are called by different names, they all come from the same plant, which is called the camellia sinensis plant.  Though they are native to the mountainous region of southwest China, camellia sinensis plants are grown throughout Asia and in parts of the Middle East and Africa.  Camellia sinensis plants are well known for the polyphenols that they possess, which are known to possess potent antioxidants, the most studied being epigapigallocatechin gallate, otherwise known as EGCG.  These teas also possess alkaloids, which give the teas stimulating effects.

What differentiates the three types of teas is the process that they go through to reach their final state.  Oolong tea is partially fermented and black tea is completely fermented, while green tea is not fermented.  The more the tea is fermented, the more polyphenols it losses and the more caffeinated it becomes, making it less healthy.  Green tea is made by sun-drying the leaves, which keeps in most of the nutrients and then crushing them into the powdered form.  Therefore, since green tea is the form that is not fermented, it has the highest count of polyphenols and the least amount of caffeine, making it the healthiest.

Green tea has been found to have several health benefits.  Some, such as weight loss and preventing cancer are well known, while others might be surprising.  For example, green tea is used in candy to prevent gum disease and in ointments to treat genital warts.  People also use green tea bags to reduce puffiness under the eyes and on the skin to soothe sunburn.  Drinking green tea has been accredited with helping individuals with losing weight and preventing cancer, as previously stated, as well as reducing the risk of heart disease, lowering cholesterol, controlling blood sugar, reducing inflammation due to Crohn’s disease and ulcerative colitis, and protecting the liver against toxic substances.

Even with all of its positive effects, clinicians warn that green tea has its negatives, including leading to symptoms such as dizziness, irritability, insomnia, vomiting, and even mania.  But these are traditionally caused by drinking too much green tea or drinking it in conjunction with different medications.  It is always a good idea to consult a physician when considering adding green tea into a health routine.

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