Green Tea Lowers Risk of Breast Cancer . . . and More!
Green Tea Lowers Risk of Breast Cancer . . . and More!
According to new research published in Nutrition Journal, the consumption of green tea may reduce the risk of developing breast cancer. The researchers speculate that it may exert this effect by modifying the metabolism of estrogen, according to new research.
Led by Dr Barbara Fuhrman, at the National Cancer Institute, at NIH, the research team followed nearly 200 pre-and postmenopausal women to assess the effect of green tea on estrogen metabolism, a known causal factors in the development of breast cancer.
Fuhrman and her colleagues found that daily consumption of green tea was associated with lower levels of estrogen metabolites. They suggest this could be explained by the fact that polyphenols found in green tea can influence enzymes that metabolize estrogens.
This supports the observation of lower urinary levels of estrogen metabolites in postmenopausal Japanese American women, who drink higher amounts of green tea than American women.
In their words, “As a rich source of phytochemicals that can interact with and regulate xenobiotic metabolising enzymes, green tea may modify metabolism or conjugation of estrogens and may thereby impact breast cancer risk.”
The results of this recent study should not come as a surprise. In his book, Nutritional Medicine, Dr. Alan Gaby points out the following:
“A group of polyphenols known as catechins that are present in green tea have demonstrated anticancer effects in animals and in vitro. In case reports, administration of epigallocatechin gallate (EGCG), one of the major green tea polyphenols, appeared to induce partial remission in several patients with low-grade B cell malignancies. Administration of green tea catechins also reduced the incidence of prostate cancer in men with high-grade prostate intraepithelial neoplasia (the main premalignant lesion that leads to prostate cancer). In addition, treatment with a green tea extract prevented the development of new colorectal adenomas in patients with a history of colorectal adenomas, suggesting that green tea might help prevent colorectal cancer.”
He provides several examples:
“After a report was published indicating that EGCG induced apoptotic cell death in leukemic B cells from patients with chronic lymphocytic leukemia (CLL), many patients with CLL and other low-grade lymphomas began using products containing tea polyphenols. The authors of this report are aware of 4 patients with low-grade B cell malignancies (3 with chronic lymphocytic leukemia and 1 with B cell lymphoma) seen in their clinical practice who began oral self-treatment with EGCG-containing products and appeared to have an objective clinical response shortly thereafter. Three of these patients met standard criteria for a partial response. Some of the patients had had steady clinical, laboratory, and/or radiographic evidence of disease progression prior to taking green tea products. Spontaneous remission/regression is rare in patients with low-grade B cell malignancies.37
”Sixty men with high-grade prostate intraepithelial neoplasia were randomly assigned to receive, in double-blind fashion, 600 mg/day of green tea catechins or placebo for 1 year. After 1 year, significantly fewer patients in the active-treatment group than in the placebo group had developed prostate cancer (3.3% vs. 30%; p < 0.01).38
“One hundred thirty-six Japanese patients who had had a colorectal adenoma surgically removed and had had no recurrence after 1 year were randomly assigned to receive 1.5 g/day of green tea extract or to serve as a control group for 1 year. Mean baseline consumption of green tea was 6 cups per day, and the addition of green tea extract was equivalent to an additional 4 cups per day. The dosage was based on a previous epidemiological study in which consumption of 10 cups or more per day of green tea was associated with a reduction in colorectal cancer incidence. After 1 year, the incidence of new colorectal adenomas was significantly lower in the active-treatment group than in the control group (15% vs. 31%; p < 0.05).39"
(Gaby, Alan R., MD. Nutritional Medicine. Alan R. Gaby, M.D., 01/2011. Fritz Perlberg Publishing . Concord, NH www.doctorgaby.com. The book is available at Willner Chemists. Product Code: 59437, List price $295.00, Willner price: $266.50 )
There are many other benefits associated with green tea, of course, from weight loss to eczema. We have spoken about it many times on the Willner Window radio show. One of the transcripts is provided below, but you can read the others, and listen to mp3 audio by going to www.willner.com, click on the “reference library” tab, and then select the keyword “green tea” from the pull-down menu.
Green tea is available in supplement form, as a capsule and as a convenient dropper bottle concentrate. Information on these products is provided in the sidebar.
The following is an excerpt from "The Willner Window" Radio Show.
To see other transcripts, and mp3 audio files, go to www.willner.com, and click on the “radio show” tab.
Arnie: Good afternoon everyone, this is .... Welcome to The Willner Window. For those of you who might be first-time listeners, the focus of this show is nutritional supplements–vitamins, herbs, homeopathic remedies–and their proper usage. With me this afternoon is . .
Last week, we brought you up to date on one of the more interesting new supplements, flax lignans. We find certain supplements to be especially interesting for two reasons. For one thing, they are very useful. In other words, they significantly improve our health, or help to prevent very serious health problems. For another, there is scientific evidence that they really work, rather than just a lot of marketing hype.
Don: So we spoke last week about flax lignans. This week, we want to bring you up to date on another supplement that meets our requirements as something we find interesting. Green Tea. The interesting thing about green tea is that not only is it thought to be beneficial to our health, and supported by scientific research, but it also is the subject of a lot of marketing effort as well.
So, while you might not have heard so much about flax lignans, you certainly have been hearing a lot about green tea. Numerous green tea products are being advertised on the radio, and tv. Even mainstream companies like Lipton are now advertising green tea drinks. What we want to do today is fill you in on why green tea continues to be of interest–or, to be more accurate, is becoming more and more interesting, and to perhaps give you some guidelines on what type of green tea supplements you might want to purchase.
Arnie: Why so much interest in green tea? Primarily because of the numerous studies that indicate it protects against certain types of cancer. In addition, it has been shown to be protective against certain types of heart disease, tooth decay, and even effective as a weight loss agent.
Dr. Podell: Is green tea really this good, or are is this just wishful thinking? Is there good science behind it, or is it just a lot of marketing hype by people who want to sell various types of green tea products and supplements?
Well, to answer that question, nothing would beat a series of good, controlled clinical studies on humans. Unfortunately, that is hard to come by, especially for non-drug substances like green tea and green tea concentrates.
But there is another measure of just how seriously green tea is being taken by the scientific community, and that is the amount of research being done in an attempt to identify the "mechanism of action," and the active components, in green tea.
Don: After all, if researchers are devoting time to identify the "mechanism of action," they must believe that it indeed has an action. In other words, they are convinced that green tea does indeed prevent certain cancers, for example.
And sure enough, we have seen a number of studies devoted to just this purpose–attempting to identify the "mechanism of action" of green tea.
Dr. Podell: Now we don't want to bore you with the details, and we are not trying to impress you with a bunch of fancy chemical names. So let's just run through a few quickly so that you get the idea.
There was a study at the University of Rochester Medical Center identifying what the call a chaperone protein known as HSP90. Cancer cells have increased levels of this protein, and green tea may modulate HSP90. They speculate that when EGCG, a component of green tea, binds to HSP90, it prevents HSP90 from activation the AH recepter which, in turn, is responsible for a cascade of events leading to the activation of harmful genes, and cancer cell activity.
Arnie: Another potential mechanism for green tea's action was developed at the University of Wisconsin and Case Western Reserve University in Cleveland. They based their work on the fact that green tea polyphenols reduce levels of insulin-like growth factor-1, also known as IGF-1,
Interestingly enough, this radio transcript if from 2005.
And, for more information on Green Tea and cancer (Colorectaland Stomach-Esophageal) look up the article in the previous catalog/newsletter (Winter 2013)