Obesity, Diet, Exercise, Estrogen, Testosterone and Breast Cancer Risk






 

New research confirms suspected links between obesity, estrogen and testosterone levels, and exercise on breast cancer risk.


 

 

OBESITY, DIET, EXERCISE, ESTROGEN, TESTOSTERONE AND BREAST CANCER RISK

Last week, I discussed new research linking even relatively modest levels of regular physical activity with a reduced risk of developing breast cancer (Even Modest Levels of Physical Activity Decrease Breast Cancer Risk).  This week, I will present a newly published clinical research study that may help to explain the well known links between obesity, weight loss, and breast cancer risk.  This new research study appears in the current issue of the Journal of Clinical Oncology.

There is ample evidence that obesity is, by itself, a risk factor for breast cancer, and that the loss of excess weight can reduce obesity-associated breast cancer risk.  Similarly, a woman’s lifetime level of exposure to the female sex hormone estrogen (as well as to testosterone) has also been linked to breast cancer risk.

After menopause, the ovaries no longer produce estrogen.  However, fat cells continue to produce estrogen (and to metabolize testosterone into estrogen), and the link between obesity and breast cancer has, therefore, been presumed to be due to increased estrogen production from fat cells in the bodies of overweight and obese women.  Based upon the findings of this new clinical study, the presumed biological mechanism whereby loss of excess weight reduces breast cancer risk appears to have been confirmed.

In this prospective, randomized, controlled clinical study, obese, sedentary postmenopausal women (ages 50 to 75 years) were randomized into one of four different groups.  The first group was placed on a reduced calorie diet.  The second group engaged in a supervised moderate-to-vigorous aerobic exercise program.  The third group underwent both dieting and a supervised exercise program.  Finally, the fourth group of women served as a “control” group, and these women did not engage in either dieting or exercise.  Blood levels of estrogen and testosterone were measured in all of these women at the beginning and end of this 12-month study.

Compared with the women in the “control” group, estrogen levels decreased by 16 percent with dieting alone, by 5 percent with exercise alone, and by more than 20 percent when dieting was combined with moderate-to-vigorous exercise.  Similarly, testosterone levels declined by 10 percent with dieting alone, and by almost 16 percent when dieting was combined with exercise.  Moreover, greater levels of weight loss were associated with greater decreases in estrogen and testosterone levels.

The findings of this innovative clinical research study lend considerable weight to the longstanding theory that obesity increases breast cancer risk by raising estrogen and testosterone levels in postmenopausal women, while the loss of excess weight decreases breast cancer risk due to reductions in obesity-related elevated levels of estrogen and testosterone.  While there are, doubtless, other biological mechanisms involved, this clinical study adds considerable weight to the data that I discuss in my bestselling book, A Cancer Prevention Guide for the Human Race, linking diet, obesity and exercise (along with other modifiable lifestyle factors) to breast cancer risk.

As our society becomes progressively more obese and sedentary, the incidence of cancer and other serious obesity-related diseases is expected to continue to climb.  If you are significantly overweight, or if you lead a “couch potato” lifestyle, then please meet with your doctor and a personal trainer, and get started on a sensible diet program (as I describe in my book) and exercise program.




At this time, more than 8 percent of Americans are unemployed.  According to the Bureau of Labor Statistics, however, the unemployment rate for veterans who served on active duty between September 2001 and December 2011 is now more than 12 percent.  A new website, Veterans in Healthcare, seeks to connect veterans with potential employers.  If you are a veteran who works in the healthcare field, or if you are an employer who is looking for physicians, advanced practice professionals, nurses, corpsmen/medics, or other healthcare professionals, then please take a look at Veterans in Healthcare. As a retired veteran of the U.S. Army, I urge you to hire a veteran whenever possible.


For a groundbreaking overview of cancer risks, and evidence-based strategies to reduce your risk of developing cancer, order your copy of my bestselling book, “A Cancer Prevention Guide for the Human Race,” from AmazonBarnes & NobleBooks-A-MillionVroman’s Bookstore, and other fine bookstores!

Within one week of publication, A Cancer Prevention Guide for the Human Race was ranked #6 among all cancer-related books on the Amazon.com “Top 100 Bestseller’s List” for Kindle e-books. Within three months of publication, A Cancer Prevention Guide for the Human Race was the #1 book on the Amazon.comTop 100 New Book Releases in Cancer” list.




Disclaimer:  As always, my advice to readers is to seek the advice of your physician before making any significant changes in medications, diet, or level of physical activity



 

Dr. Wascher is an oncologic surgeon, professor of surgery, cancer researcher, oncology consultant, and a widely published author



 

I and the staff of Weekly Health Update would again like to take this opportunity to thank the more than 100,000 health-conscious people from around the world who visit this premier global health information website every month.  (More than 1.3 million pages of high-quality medical research findings were served to the worldwide audience of health-conscious people who visited Weekly Health Update in 2011!)  As always, we enjoy receiving your stimulating feedback and questions, and I will continue to try and personally answer as many of your inquiries as I possibly can.


 






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Green Tea Reduces Cholesterol, Blood Sugar and Insulin Levels





 

New research finds that green tea may reduce the risk of cardiovascular disease and diabetes.



 

GREEN TEA REDUCES CHOLESTEROL, BLOOD SUGAR AND INSULIN LEVELS

As I discuss in my bestselling book, A Cancer Prevention Guide for the Human Race, the evidence for green tea as a cancer prevention agent is quite mixed, with most (but not all) studies showing little impact on cancer risk or cancer-associated death rates.  Some research studies, however, have suggested that green tea may affect levels of the female sex hormone estrogen in ways that could potentially reduce the risk of developing breast cancer.  However, most of the research in this area has not been in the form of prospective, randomized, placebo-controlled, double-blinded clinical research, which is considered the “gold standard” method of conducting clinical research.

A newly published prospective, randomized, double-blinded, placebo-controlled clinical trial evaluated 103 postmenopausal women, and their response to green tea supplements.  This study appears in the current issue of the journal Cancer Prevention Research.

In this study, the women volunteers were randomly divided into three groups.  One group received 400 milligrams (mg) of epigallocatechin gallate (EGCG) per day, for two months.  (EGCG is considered the most active ingredient in green tea.)  The second group of women received 800 mg of EGCG per day, also for two months.  The third group, which served as this study’s control group, received placebo (sugar) capsules that appeared identical to the EGCG capsules.  Neither the female volunteers nor the study nurses who dispensed the capsules to these study volunteers knew which group each woman had been randomized into.

Repeated measurements of urine levels of EGCG were performed, and blood levels of estrogen, testosterone (the primary male sex hormone), cholesterol, glucose (blood sugar), insulin, and growth factors were tested on all of the 103 study volunteers throughout the course of this study.

The results of this innovative study revealed that green tea supplements had no apparent effect on the levels of estrogen and testosterone in the blood of these postmenopausal research volunteers, which suggests that any potential breast cancer prevention effects associated with EGCG are probably unrelated to sex hormone levels.  However, while EGCG had no apparent impact on sex hormone levels, LDL-cholesterol (the “bad cholesterol”) levels significantly decreased among the women who were secretly randomized to receive EGCG supplements.  Additionally, blood levels of glucose and insulin, which are linked to diabetes risk, also significantly declined in the two groups of women who received EGCG supplements.  (Diabetes, itself, is a powerful risk factor for developing cancer.)

While green tea supplementation had no discernible effect on the levels of male and female sex hormones in the blood of the postmenopausal women participating in this study, EGCG supplementation was observed to significantly reduce LDL-cholesterol, glucose, and insulin levels in these women.  Therefore, while the impact of green tea on breast cancer risk remains unclear at this time, the results of this clinical research study suggest a potential clinical role for green tea in the prevention of cardiovascular disease and diabetes, which are, like cancer, two of the great killers of modern humans.


For a groundbreaking overview of cancer risks, and evidence-based strategies to reduce your risk of developing cancer, order your copy of my bestselling book, “A Cancer Prevention Guide for the Human Race,” from AmazonBarnes & NobleBooks-A-MillionVroman’s Bookstore, and other fine bookstores!

Within one week of publication, A Cancer Prevention Guide for the Human Race was ranked #6 among all cancer-related books on the Amazon.com “Top 100 Bestseller’s List” for Kindle e-books. Within three months of publication, A Cancer Prevention Guide for the Human Race was the #1 book on the Amazon.comTop 100 New Book Releases in Cancer” list.



Disclaimer:  As always, my advice to readers is to seek the advice of your physician before making any significant changes in medications, diet, or level of physical activity


Dr. Wascher is an oncologic surgeon, professor of surgery, cancer researcher, oncology consultant, and a widely published author


I and the staff of Weekly Health Update would again like to take this opportunity to thank the more than 100,000 health-conscious people from around the world who visit this premier global health information website every month.  (More than 1.3 million pages of high-quality medical research findings were served to the worldwide audience of health-conscious people who visited Weekly Health Update in 2011!)  As always, we enjoy receiving your stimulating feedback and questions, and I will continue to try and personally answer as many of your inquiries as I possibly can.


 









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Obesity, Alcohol, Smoking and Breast Cancer Risk

Welcome to Weekly Health Update


“A critical weekly review of important new research findings for health-conscious readers”




OBESITY, ALCOHOL, SMOKING AND BREAST CANCER RISK

As I discuss in detail in my recent book, A Cancer Prevention Guide for the Human Race, there are several important lifestyle and dietary factors that have been linked to cancer risk by numerous high-level research studies. Moreover, breast cancer risk, as well as the risk of several other hormone-responsive cancers in particular, appears to be especially associated with potentially modifiable lifestyle and dietary factors, including obesity, alcohol intake, smoking, lack of physical activity, high-fat diets (and diets rich in animal-based foods, specifically), as well as other modifiable risk factors.

While certain lifestyle and dietary risk factors linked to breast cancer risk have been confirmed by numerous research studies, the underlying mechanisms whereby these risk factors increase breast cancer risk has not been entirely clear. Now, a comprehensive new review of 13 prospective breast cancer public health studies sheds important light on the important topic of breast cancer prevention, and provides much-needed insight into how our own personal habits may directly increase our risk of developing breast cancer. The findings of this new cancer prevention study are scheduled to appear in the next issue of theBritish Journal of Cancer.

Of the 13 prospective clinical research studies that were analyzed in this report, 7 were performed in the United States, 1 was performed as part of a multinational European study, and 1 each was performed in Australia, Italy, Japan, Sweden, and the United Kingdom. Altogether, 6,291 women were evaluated in these 13 prospective public health studies.

As has been shown in many previous studies, this report confirmed that women with high levels of the sex hormones estrogen and testosterone in their blood are 2 to 3 times more likely to develop breast cancer when compared with women who have low circulating levels of these hormones.

Among postmenopausal women, who make up the great majority of all new breast cancer cases, the single most significant risk factor for having elevated levels of estrogen in the blood was obesity, in this study. Although obesity has long been known to be a risk factor both for developing breast cancer and for experiencing a recurrence of a prior breast cancer, it has not been entirely clear how excess body weight actually causes breast cancer risk to increase. (Aromatase, an enzyme that is manufactured by fat cells, is known to increase the production of estrogen in overweight and obese women and men, and has long been suspected to contribute to breast cancer risk in obese women.) Perhaps the most important finding of this new report, therefore, is to confirm the long-suspected linkage between excess weight and elevated levels of estrogen in the blood. Increased estrogen levels, in turn, are known to increase a woman’s risk of developing breast cancer.

The findings of this report also indicate that, second only to obesity, regular alcohol intake and smoking were the next most significant lifestyle-related factors associated with an increased circulating level of estrogen and other sex hormones. (Both alcohol and smoking have previously, and consistently, been linked to breast cancer risk. Indeed, as I discuss in A Cancer Prevention Guide for the Human Race, women who consume 2 or more alcoholic beverages per day have been shown, by multiple studies, to experience a significant increase in breast cancer risk, as well as an increased risk of several other cancers.)

While some breast cancer risk factors (such as gender, age, and family history) cannot be changed, this new report, and the research studies which it analyzes, confirms that women can significantly reduce their risk of developing breast cancer by making evidence-based changes in their lifestyle and diet. When it comes to cancer, an ounce of cancer prevention really is worth a ton of cancer treatment or cancer cure.



For a comprehensive guide to living an evidence-based cancer prevention lifestyle, order your copy of my new book, A Cancer Prevention Guide for the Human Race.  For the price of a cheeseburger, fries, and a shake, you can purchase this landmark new book, in both paperback and e-book formats, and begin living an evidence-based cancer prevention lifestyle today!

For a groundbreaking overview of cancer risks, and evidence-based strategies to reduce your risk of developing cancer, order your copy of my new book, A Cancer Prevention Guide for the Human Race,” from Amazon, Barnes & Noble, Books-A-Million,Vroman’s Bookstore, and other fine bookstores!

On Thanksgiving Day, 2010, A Cancer Prevention Guide for the Human Race was ranked #6 among all cancer-related books on the Amazon.com “Top 100 Bestseller’s List” for Kindle e-books! On Christmas Day, 2010, A Cancer Prevention Guide for the Human Race was the #1 book on the Amazon.comTop 100 New Book Releases in Cancer” list!


Disclaimer:  As always, my advice to readers is to seek the advice of your physician before making any significant changes in medications, diet, or level of physical activity



Dr. Wascher is an oncologic surgeon, professor of surgery, cancer researcher, oncology consultant, and a widely published author



For a different perspective on Dr. Wascher, please click on the following YouTube link:

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I and the staff of Weekly Health Update would again like to take this opportunity to thank the more than 100,000 health-conscious people, from around the world, who visit this premier global health information website every month. (More than 1.2 million health-conscious people visited Weekly Health Update in 2010!) As always, we enjoy receiving your stimulating feedback and questions, and I will continue to try and personally answer as many of your inquiries as I possibly can.





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