Welcome to Weekly Health Update

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

SATURATED FAT, TRANS-FATS, AND

PREMATURE DEATH IN BREAST CANCER SURVIVORS

As I discuss in detail in my new book, “A Cancer Prevention Guide for the Human Race,” obesity and increased dietary fat intake have both been linked to an increased risk of developing breast cancer and other types of cancer.  Moreover, obesity and lack of exercise have also been clearly associated with an increased risk of recurrent breast cancer, and death due to breast cancer, among women who have previously been diagnosed with this common form of cancer.  However, the impact of diet, alone, on the risk of premature death among women previously diagnosed with breast cancer, has not been well studied.

However, a newly published clinical research study, which appears in the current issue of the journal Breast Cancer Research & Treatment, strongly suggests that unhealthy dietary habits may significantly increase the risk of death in women who have previously been diagnosed with breast cancer.

In this prospectively conducted study, 4,441 women who were diagnosed with breast cancer between 1987 and 1999 were followed for an average of 7 years, and were evaluated using a previously validated 126-item food frequency questionnaire that was administered immediately following the diagnosis of breast cancer.  The clinical outcomes of these 4,441 women were then adjusted for other known risk factors for breast cancer recurrence, including age at breast cancer diagnosis, menopausal status, smoking history, stage of breast cancer at diagnosis, alcohol intake history, prior use of hormone replacement therapy, obesity, and exercise history.  After these other known breast cancer recurrence factors were adjusted for, the impact of diet on death due to breast cancer recurrence, as well as death due to any cause, was then calculated.

When compared to women with the lowest average dietary intake of saturated fat, breast cancer survivors with the highest levels of intake of these unhealthy fats were 41 percent more likely to die from any cause during the course of this study.  Similarly, a high level of trans-fat intake was associated with a whopping 78 percent increase in the risk of death from any cause.  (While it failed to reach statistical significance in this relatively small prospective clinical study, an increased risk of death due to breast cancer recurrence was also associated with increasing levels of saturated fat and trans-fat intake, as well.)

In summary, this study of more than 4,000 breast cancer survivors revealed a striking increase in the risk of premature death among women who consumed large amounts of saturated fat and trans-fats in their diet.  Importantly, this increased risk of premature death was not limited to death caused by breast cancer recurrence, alone, but from multiple different causes of death.  Regarding the link between the intake of unhealthy fats and death due specifically to breast cancer recurrence, the same disturbing trend was observed, although this particular association did not quite reach accepted standards of statistical significance.  (A larger version of this study will, therefore, be necessary to tease out the relationship between unhealthy dietary fats and death due to breast cancer recurrence, specifically; although the findings of this relatively small prospective clinical study are suggestive that such a link likely exists.)

For a complete discussion of the impact of diet, including dietary fats, on cancer risk, and the role of diet and healthy fats in cancer prevention, as well as other important evidence-based approaches to cancer prevention, 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.com “Top 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

Welcome to Weekly Health Update

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

ALPHA-LIPOIC ACID, OBESITY AND WEIGHT LOSS

Alpha-lipoic acid plays a very important role in the energy production centers of our cells (mitochondria).  In recent years, clinical research has suggested that alpha-lipoic acid supplements may have a variety of potential health benefits, including a possible reduction in the risk of cardiovascular disease.  Recent laboratory research has also shown that alpha-lipoic acid supplements markedly reduce the incidence of obesity in obesity-prone rats.  However, it has not been clear whether or not alpha-lipoic acid has any clinically significant anti-obesity effects in humans.  Now, a newly published prospective, randomized, blinded, placebo-controlled clinical research study suggests that alpha-lipoic acid supplementation may indeed improve weight loss in obese humans.

In this study, which appears in the current issue of The American Journal of Medicine, 360 obese patient volunteers were randomized to receive either alpha-lipoic acid supplements or identical-appearing placebo pills.  Patients who were assigned to receive alpha-lipoic acid supplements received either 1,200 milligrams of alpha-lipoic acid per day or 1,800 milligrams per day.  After 20 weeks, all patient volunteers were weighed once again.

After 20 weeks, the group of patients that had received 1,800 milligrams of alpha-lipoic acid per day experienced a modest but significant reduction in weight (2.1 percent of body weight) when compared the patient volunteers who had received the placebo pills.

While a 2 percent weight loss may sound trivial, it must be emphasized that obesity is an illness that has been shown to be refractory to almost every medical treatment (other than surgery), including the handful of very expensive prescription medications that have been approved by the FDA to treat obesity.  Certainly, alpha-lipoic acid, by itself, is not likely to reverse the epidemic of obesity that has spread throughout the world.  However, if the findings of this small prospective, randomized, controlled clinical study can be confirmed by larger studies, then alpha-lipoic acid may find use as an adjunct to other weight-loss strategies (including, of course, dieting and exercise).

Finally, as always, I remind readers not to begin new diets, exercise programs, or nutritional supplements (including alpha-lipoic acid) without first discussing such lifestyle changes with their doctors.

For a complete discussion of the impact of obesity on cancer risk, and the role of diet and nutritional supplements in cancer prevention, as well as other important evidence-based approaches to cancer prevention, 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.com “Top 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

Welcome to Weekly Health Update

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

DIETARY SALT (SODIUM) INCREASES STOMACH CANCER RISK

Cancer of the stomach occurs only about half as commonly today in the United States as it did 30 years ago, but it remains one of the “bad actor” cancers that are associated with a high likelihood of death.  On a global scale, stomach cancer remains the #2 cause of cancer-associated death, while in the United States, gastric cancer is currently the #7 cause of cancer-associated death.

Known risk factors for stomach cancer include chronic infection with the Helicobacter pylori bacterium (and other causes of chronic gastric inflammation), smoking, obesity, decreased acid secretion within the stomach, stomach ulcers, pernicious anemia, a family history of stomach cancer, certain inherited cancer syndromes, and other less common risk factors.  As with other GI tract cancers, diet also appears to play an important role in gastric cancer risk.  For example, gastric cancer is more common among people who eat a lot of processed meat and red meat, smoked foods, and salt-cured or pickled foods.  On the other hand, stomach cancer is less common among people who consume a large amount of fresh fruits and vegetables.

The role of salt in gastric cancer risk has been a subject of some debate, as clinical research studies have come to varying and contradictory conclusions regarding this issue.  However, a newly published public health study, which appears in the current issue of the British Journal of Cancer, appears to strongly link excess salt consumption with an increased risk of developing stomach cancer.  In this case-control study, 442 patients with stomach cancer, and 649 healthy patients without any clinical evidence of cancer, were evaluated.  Multiple previously validated dietary questionnaires were administered to all of the study volunteers, with particular attention to dietary salt intake. 

The results of this public health study indicated that the risk of stomach cancer was twice as common among patients who regularly consumed the highest amounts of salt, when compared to patients with the smallest amount of regular salt intake.  After adjusting for other risk factors known to be associated with gastric cancer risk (including Helicobacter pylori status, smoking history, and other known gastric cancer risk factors), increased salt intake was still associated with a doubling of gastric cancer risk. 

While case-control studies, such as this one, do not offer high-level clinical research evidence (unlike the “gold standard” prospective, randomized, blinded clinical research trials that provide “Level 1” clinical research data), the findings of this observational study nonetheless add to an increasing volume of data linking increased salt intake with gastric cancer risk.

Excessive salt intake has also been clearly linked to a significant increase in the risk of high blood pressure, stroke, and cardiovascular disease.  Most hypertension experts are currently recommending that we lower our average daily intake of sodium, from the current 3,500 to 4,000 milligram (mg) per day level in the United States, to somewhere around 1,500 mg per day.  At this level of sodium intake reduction, significant improvements in high blood pressure, and in the risk of stroke and cardiovascular disease, have been demonstrated by multiple high-quality clinical research studies.  (An excellent pamphlet on the topic of dietary sodium reduction, as part of a heart-healthy diet, has been published online by the National Institutes of Health.)    

As with many other dietary and lifestyle factors that have been shown to reduce cancer risk, reducing sodium intake, by reducing your dietary salt consumption, can pay big health dividends not only in terms of cancer risk reduction, but also in terms of reducing those other great global killers of mankind, cardiovascular disease and stroke!

For a complete discussion of the role of diet in cancer prevention, and other important evidence-based approaches to cancer prevention, order your copy of my new book, A Cancer Prevention Guide for the Human Race, now!  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.com “Top 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, a professor of surgery, a cancer researcher, an oncology consultant, and a widely published author

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

Texas Blues Jam

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.

Click the following link to join Dr. Wascher on Facebook

Welcome to Weekly Health Update

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

DIET AND LIFESTYLE HABITS THAT

DECREASE COLORECTAL CANCER RISK

In the United States, approximately 106,000 people will be newly diagnosed with colorectal cancer in 2010, and nearly 50,000 people will die of this disease.  Colorectal cancer remains the third most common cancer (excluding skin cancer) in both men and women, and the third most common cause of cancer death in men and women.  Unlike many other types of cancer, an effective method of screening for colorectal cancer is available, in the form of colonoscopy.  Fortunately, the incidence of this cancer has been gradually declining over the past 20 years, due in great part to the early detection, and removal, of precancerous polyps from the colon and rectum at the time of colonoscopy.

The links between specific lifestyle choices and the risk of developing certain types of cancer forms much of the basis of my new book, “A Cancer Prevention Guide for the Human Race.”  The risk of developing colorectal cancer, in particular, has been strongly linked to multiple dietary and other lifestyle factors.  Now, a newly published public health research study from Denmark puts a number on the effectiveness of commonly recommended cancer prevention lifestyle strategies in preventing colorectal cancer.

In this study, which appears in the current issue of the British Medical Journal, 55,487 men and women between the ages of 50 and 64 were prospectively followed for an average of 10 years.  Each of these Diet, Cancer and Health Cohort Study volunteers completed validated surveys regarding their social status, health status, reproductive history, and daily lifestyle habits.  They also completed a food frequency questionnaire that included, among its 193 items, foods known to be associated with colorectal cancer risk (including alcohol).  All study participants also underwent physical examinations that included measurements of their height, weight, and waist circumference.  During the course of this large prospective public health study, 678 participants were newly diagnosed with colorectal cancer.

All study volunteers were assessed in terms of 5 modifiable lifestyle and dietary factors that have repeatedly been linked to a reduction in colorectal cancer risk:  Increased levels of regular physical activity, avoidance of obesity, abstention from tobacco use, minimal intake of alcohol, and the observance of healthy diet habits (including increased fiber intake, decreased dietary fat content, decreased red meat and processed meat consumption, and increased fresh fruit and vegetable intake).  Based upon only these 5 simple colorectal cancer risk factors, the adoption of any one of these 5 colorectal cancer prevention factors was associated with a 13 percent decrease in the risk of developing colorectal cancer.  Among participants who generally observed all 5 lifestyle and dietary prevention factors, the risk of developing colorectal cancer was reduced by 23 percent.  (Of note, while this observed reduction in the risk of colorectal cancer was noted for both colon cancer and rectal cancer, this finding was only statistically significant for cancer of the colon, specifically.)

The results of this large prospectively conducted public health study reaffirm the findings of previous studies, in that the risk of colorectal cancer can be significantly reduced by: Engaging in regular moderate exercise, maintaining a healthy body weight, avoiding tobacco use, minimizing alcohol consumption, and by reducing the intake of red meat and processed meats and fat, while simultaneously increasing the consumption of fresh fruits, fresh vegetables, and whole grain foods.  For a more detailed evidence-based guide to colorectal cancer prevention, order or download your copy of “A Cancer Prevention Guide for the Human Race” now.  

Click the following link to join Dr. Wascher on Facebook

For a groundbreaking overview of cancer risks, and evidence-based strategies to reduce your risk of developing colorectal cancer, and other types of 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!

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, a professor of surgery, a cancer researcher, an oncology consultant, and a widely published author

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

Texas Blues Jam

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.  (As of 9/16/2010, more than 1,000,000 health-conscious people have logged onto Weekly Health Update so far this year!)  As always, I 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.

Welcome to Weekly Health Update

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

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, a professor of surgery, a cancer researcher, an oncology consultant, and a widely published author

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

Texas Blues Jam

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 our premier global health information website every month.  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.

Welcome to Weekly Health Update

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

Diacylglycerols (also known as diglycerides) are dietary fatty acids that are found, in small concentrations, in many vegetable-based cooking oils, including canola and soybean oils.  However, triacylglycerols, known more commonly as triglycerides, make up the vast majority of the fat content in vegetable-based cooking oils.  Triglycerides, which are the most common sources of dietary fat, are rapidly absorbed by the body and are easily converted into body fat.  (High levels of triglycerides in the blood have also been linked to obesity and cardiovascular disease.) 

Compared with triglyceride fats, diglycerides are more rapidly metabolized in the human body, and are less prone to being deposited as body fat.  In laboratory studies, dietary supplementation with diglyceride oil has been shown to reduce the accumulation of body fat in rats, and to improve overall fat energy metabolism.

A newly published clinical research study, which appears in the current issue of the Journal of Nutrition, further suggests a potential role for diglyceride oils in the prevention and treatment of obesity in humans.

In this study, 26 overweight women with elevated blood triglyceride levels participated in a “crossover” study of diglyceride oil dietary supplementation.  In the first phase of this study, these women volunteers were secretly randomized to receive either diglyceride-enriched vegetable oil (Enova oil, 40 grams per day) or an oil blend containing standard sunflower, safflower and rapeseed oils (40 grams per day, in a 1:1:1 ratio) for 28 days.  After a 4-week break, these patient volunteers were then switched (or “crossed over”) to the opposite dietary oil group for an additional 28 days.

In this study, diglyceride oil supplementation did not appear to alter overall energy metabolism, nor did it reduce blood levels of triglycerides.  However, the daily intake of diglyceride-enriched cooking oil did, indeed, significantly decrease the accumulation of body fat in these overweight women during the course of this small, brief clinical research study.

While switching to diglyceride-enriched cooking oil, alone, is unlikely to prevent or completely eliminate obesity, this vegetable-based fat source may have an important role to play as part of a lifestyle- and diet-based approach to maintaining a healthy weight. 

Now for some bad news related to diglyceride-enriched cooking oils.  Kao Corporation, the manufacturer of Enova oil (also sold as Econa oil), has recently suspended the sales of this product due to concerns about high levels of potentially carcinogenic glycidol fatty acid esters in this and other diglyceride-enriched products.  (These same fatty acid esters are also present in other vegetable-based cooking oils, but at much lower concentrations.)  Hopefully, though, Kao Corporation, or another manufacturer, will find a way to reduce the concentration of glycidol fatty acid esters in diglyceride-enriched food products, and these products will then return to the marketplace.   

To learn more about the critical roles of diet and weight control in the prevention of cancer, look for the publication of my new landmark book, “A Cancer Prevention Guide for the Human Race,” in the summer of this year.

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

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

http://www.youtube.com/watch?v=7-Tdv7XW0qg

Welcome to Weekly Health Update

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

NUTS, DIET & OBESITY

In last week’s column, I reviewed recent research suggesting a role for walnuts in reducing elevated cholesterol levels.  Based upon some of the comments that I received from readers regarding this “walnut column,” I will present some additional favorable new health research findings on nuts in this week’s column.

Hard-shelled nuts tend to be rich in inflammation-fighting omega-3 fatty acids (luckily, the majority of the fat content in hard-shelled nuts is in the form of heart-healthy unsaturated fats), and in plant sterols.  As I discussed last week, these compounds help to lower the level of LDL (the “bad cholesterol”) in the blood.

The Mediterranean Diet, which is rich in fish, whole grains, nuts, fresh fruits, and fresh vegetables (and low in red meat and highly processed foods), has repeatedly been shown to decrease the risk of the top two causes of premature death throughout the world (cardiovascular disease and cancer).  However, some health experts have expressed concerned about the relatively high fat content of nuts, and the possibility that daily nut consumption might lead to an increased risk of obesity.  Fortunately, a newly published prospective public health study suggests that the moderate intake of nuts, in combination with the Mediterranean Diet, is actually associated with a decreased risk of obesity.

The current issue of the journal Nutrition, Metabolism & Cardiovascular Diseases includes the findings of the Mediterranean “PREDIMED” prospective public health study, which enrolled 847 older men and women, with an average age of 67 years.  The diets and activity levels of these patient volunteers were carefully evaluated in this study, and all of these elderly volunteers underwent clinical examinations to determine their waist circumference, and their body mass index, or BMI (a measure of body fat content that is adjusted for both height and weight).

After correcting for other dietary and lifestyle factors associated with obesity in these patient volunteers, the data from this study revealed that increased nut intake was associated with both a decreased BMI and decreased waist circumference.  For every serving of 30 grams of nuts consumed, waist circumference decreased by 2.1 centimeters (approximately 1 inch), and BMI was reduced by 0.78 (kilograms per meter-squared) in these patient volunteers.  Increased vegetable intake was also associated with a decreased waist circumference, as well.  (Not surprisingly, meat intake was significantly associated with an increase in both BMI and waist circumference.)  Moreover, these findings were observed in both male and female study participants.

Walnuts, almonds, hazelnuts, pecans, pistachios, pecans, macadamia nuts, and peanuts (which are, technically, not nuts, but which have a nutritional profile similar to hard-shelled nuts) are all rich in omega-3 fatty acids and other heart-healthy nutrients.  Because these nuts do contain a significant number of “healthy fat” calories, however, nuts should be consumed in moderation, as with all fat-containing foods.  Currently, most experts recommend that 30 to 45 grams (1 to 1.6 ounces) of nuts be added to our daily diet to maximize the health benefits of these delicious nutritional treats!

To learn more about nuts and the Mediterranean Diet as part of a comprehensive, evidence-based cancer prevention lifestyle, look for the publication of my new book, in the spring of this year:

“A Cancer Prevention Guide for the Human Race”

http://www.redcross.org/

http://www.imcworldwide.org/haiti

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

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

http://www.youtube.com/watch?v=7-Tdv7XW0qg

I and the staff of Weekly Health Update would like to take this opportunity to thank the nearly 120,000 new and returning readers who visited our premier global health information website last month.  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. 

Welcome to Weekly Health Update

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

SOY ISOFLAVONES REDUCE BREAST CANCER

RECURRENCE RISK

Regular readers of this column are already aware of the controversy surrounding soy isoflavone intake and breast cancer risk.  As happens frequently in clinical research (unfortunately), contradictory research findings have made it difficult to understand the true relationship between dietary soy intake and breast cancer risk (if one exists).  There is, for example, both laboratory and clinical data suggesting that a diet rich in soybean-derived products may be associated with a lower risk of developing breast cancer.  At the same time, because genistein and other dietary isoflavones are known to weakly mimic the effects of estrogen, there has been some concern that a diet rich in isoflavone “phytoestrogens” may increase both the risk of developing a new breast cancer and the risk of developing a recurrence of a previous breast cancer.  (In fact, there is data from laboratory research studies showing that genistein can indeed fuel the growth of human breast cancer cells growing in culture dishes, when exposed to high concentrations of this soy-derived isoflavone.)

A growing body of public health research, primarily from Asian countries where tofu and other soy-based foods are frequently consumed, appears to link increased soy consumption with a decreased lifetime breast cancer risk, particularly when soy-based foods are consumed during adolescence, during the time when development of the female breast is most active (Soy & Breast Cancer Risk).  (Interestingly, there is also recent research suggesting that soy products might also reduce the risk of prostate cancer, which is another hormonally driven cancer:   Genistein & Prostate Cancer Cells, Dietary Soy & Prostate Cancer Risk.)

Although epidemiological research is, increasingly, suggesting that a diet rich in soybean-derived foods might lower a woman’s lifetime risk of developing breast cancer, many breast cancer experts have remained apprehensive regarding dietary isoflavone intake in women with a prior history of breast cancer, in view of the estrogen-like effects of these “phytoestrogens.”  As I have already noted, there is considerable research data available to suggest that soy-derived isoflavones can, at least under certain laboratory conditions, stimulate estrogen-sensitive breast cancer cells to grow and divide.  These research findings have left many oncologists feeling uncomfortable in recommending soy-based foods to their breast cancer patients.  Now, a newly publish public health study in the Journal of the American Medical Association suggests that soy-based foods may actually reduce the risk of breast cancer recurrence, and death due to any cause, in women who have previously been diagnosed with this very common form of cancer.

In this study, which was performed in Shanghai, China, 5,042 female breast cancer survivors (ages 20 to 75 years) were followed for an average of almost 4 years.  All of these patient volunteers underwent detailed surveys regarding their lifestyle habits, including their diets.  These patients, who were originally diagnosed with breast cancer between 2002 and 2006, were surveyed at 6, 18, 36 and 60 months following their original diagnosis with breast cancer.  

The results of this study indicate that the breast cancer survivors who consumed the greatest amount of soy-based foods in their daily diets were 32 percent less likely to experience a recurrence of their breast cancer when compared to the women who consumed the least amount of soy-based isoflavones.  Moreover, the women who consumed the greatest amount of soy were also 29 percent less likely to die, from any cause, when compared to the women who consumed the least amount of soy-derived foods.

A particularly interesting and unexpected finding of this study was that both women with estrogen sensitive breast cancers and women with tumors that were not sensitive to estrogen appeared to experience a significantly decreased risk of breast cancer recurrence if they frequently consumed soy products.  Another important finding of this study was that women who were taking the estrogen-blocking cancer treatment drug tamoxifen also appeared to enjoy a reduced risk of breast cancer recurrence with higher levels of dietary soy intake.  Additionally, the researchers noted that high levels of soy intake appeared to be about as effective in reducing the risk of breast cancer recurrence as the breast cancer prevention drug tamoxifen, alone.

The results of this very important study mirror the findings of the only other prospective clinical study that has looked at the impact of soy-based foods on breast cancer recurrence (the “Life After Cancer Epidemiology,” or “LACE,” study).  The LACE study, which was performed in the United States, followed nearly 2,000 breast cancer survivors for, on average, more than 6 years.  In the LACE study, women who were taking tamoxifen, and who also consumed the highest amount of soy-based dietary isoflavones, were 50 percent less likely to develop a recurrence of their breast cancer when compared to women who reported the lowest consumption of soy-derived foods.

As I have pointed out previously, epidemiological research studies based upon dietary surveys are susceptible to several types of bias which, in turn, can cause researchers to draw the wrong conclusions.  In this case, however, there are now two large prospective cohort studies that have reached essentially the same conclusions (albeit with a rather limited duration of patient follow-up).  Both studies strongly suggest that high levels of soy-based isoflavones in the diet may be able to significantly reduce the risk of breast cancer recurrence.  Based upon the findings of this large Chinese study, the apparent cancer risk reduction effect associated with high levels of soy intake also appears to benefit premenopausal and postmenopausal women, as well as women who are taking the estrogen-blocking drug tamoxifen, women with estrogen-sensitive tumors, and women with (counter-intuitively) estrogen-resistant tumors.

In view of the limited duration of patient follow-up in both of these clinical breast cancer studies, as well as the limitations of survey-based epidemiological research in general, I would like to see updated data from both of these studies after at least 10 years of patient observation before I would be willing to tell my breast cancer patients that they should significantly increase their dietary soy intake.  On the other hand, the rather compelling data presented by both of these clinical research studies will also make me less anxious when any of my breast cancer patients decide, of their own accord, to increase their intake of soy-derived isoflavones.

Note:  Weekly Health Update is currently undergoing an extensive upgrade to better serve its tens of thousands of health-conscious readers around the world.  Beginning in January 2010, newly archived columns will be available by selecting the “Archives” tab on the right side of your screen (all archived columns prior to January 2010 will continue to be available by selecting the “Archives 2007-2009” tab at the top of the screen.)

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

Welcome to Weekly Health Update

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

Salt (Sodium) Intake, Stroke & Cardiovascular Disease

Table salt consists of the elements sodium and chloride, both of which are essential for life.  There is a great deal of clinical research suggesting that more than 5 to 6 grams of salt intake per day (which is equal to 2 to 2.4 grams of sodium)  is associated with a significant increase in the risk of developing high blood pressure which, in turn, is associated with a significantly increased risk of stroke and cardiovascular disease.  Unfortunately, in most countries, the average daily salt intake for adults is considerably greater than 6 grams per day.  Moreover, in many countries of the world, the average daily adult intake of salt is a whopping 12 grams per day, or almost 5 grams of sodium per day. 

In the United States, the American Heart Association (AHA) currently recommends no more than 2.3 grams of sodium intake per day (equivalent to 5 grams, or about one teaspoon, of salt per day).  At the same time, the AHA also states that the ideal daily intake of sodium should actually be about 1.5 grams per day but, in an acknowledgment regarding the high intake of salt-rich processed foods in the United States, the AHA considers the 2.3 gram per day dietary sodium target to be more “realistic” for Americans.

There is considerable public health research data suggesting that the reduction of average daily adult salt intake, to 6 grams per day, or less, would result in a significant lowering of blood pressure in both people with and without high blood pressure.  Based upon these research findings, some public health experts have predicted that lowering the average daily salt intake below 6 grams per day could reduce the incidence of stroke by almost 25 percent, and the incidence of cardiovascular disease by almost 20 percent.  Unfortunately, there have not been any large-scale prospective, randomized, placebo-controlled clinical research trials performed to validate these estimates.  On the other hand, there have been multiple short-term prospective public health trials that have followed groups (cohorts) of patients in terms of their dietary intake of salt and the incidence of stroke and cardiovascular disease events.  Now, a newly published research study, in the British Medical Journal, has performed a meta-analysis of 13 of these “prospective cohort” studies, encompassing a total of 177,025 patient volunteers, with average durations of patient follow-up ranging from 4 to 19 years.  (Meta-analysis is a method of combining the data from multiple different clinical studies into a single “super-study,” in an effort to improve the validity of the resulting data, as well as the conclusions that are reached from such data.)

Among these more than 177,000 patient volunteers, there were 11,000 “vascular events” observed, including stroke and heart attacks (myocardial infarctions).  When the incidence of these vascular events was analyzed, along with dietary salt intake, the patients with the highest daily salt intake were observed to experience a 23 percent greater risk of stroke, and a 17 percent greater risk of cardiovascular disease, when compared to the adults who consumed less salt on a daily basis.

The increasing consumption of salt-rich processed foods throughout both the developed and underdeveloped countries of the world has been pushing daily salt intake to ever higher levels, with many Western countries reporting average daily adult salt intake of nearly 10 grams per day.  In other countries, and most notably in Asia and Eastern Europe, dietary practices that include a high concentration of heavily salted foods have pushed daily salt intake into the 10 to 12 gram per day range for the average adult.

The World Heart Federation estimates that there are 5.5 million annual deaths from stroke across the globe, and an additional 17.5 million annual deaths from cardiovascular disease.  Based upon the increased incidence of stroke and cardiovascular disease predicted by this meta-analysis study, even a rather modest decrease in the average adult daily salt intake, to the World Health Organization’s target of 5 grams per day, should result in 1.25 million fewer deaths per year from stroke and nearly 3 million fewer annual deaths from cardiovascular disease around the world.  Needless to say, this is a tremendous potential public health dividend from a rather simple alteration in our dietary habits.  (On the surface, reducing our daily salt intake would appear to be a rather simple goal.  However, the more complicated reality is that to achieve even the World Health Organization’s rather liberal target of 5 grams of salt per day, our entire food chain would have to be comprehensively reexamined and overhauled.) 

The world’s increasing consumption of highly-processed foods, which often contain high levels of salt as a preservative, are largely responsible for the high levels of salt intake in the developed world (in addition to a preference for salt-cured foods in much of Asia and Eastern Europe).  In the United States, the sodium content of most processed foods is readily available on food packages.  Unfortunately, most restaurants in the United States have not been as forthcoming about the sodium content of the food on their menus (as well as other important nutritional information), and so it continues to be very difficult to determine the actual salt content of much of what we eat here in the United States and, indeed, throughout much of the world.

Note:  Weekly Health Update is currently undergoing an extensive upgrade to better serve its tens of thousands of health-conscious readers around the world.  Beginning in January 2010, newly archived columns will be available by selecting the “Archives” tab on the right side of your screen (all archived columns prior to January 2010 will continue to be available by selecting the “Archives 2007-2009” tab at the top of the screen.)

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