Tags Posts tagged with "Prostate Cancer"

Prostate Cancer

Stock photo
Key lifestyle choices may reduce your risk significantly

By David Dunaief, M.D.

Dr. David Dunaief

Happy “Movember!” The Movember Foundation is in its 11th year of raising awareness and research money for men’s health issues (1). What better time to discuss prostate cancer prevention?

The best way to avoid prostate cancer is through lifestyle modifications, which means learning about both detrimental and beneficial approaches. There are a host of things that may increase your risk and others that may decrease your likelihood of prostate cancer. Your family history does not mean you can’t alter gene expression with the choices you make.

What may increase the risk of prostate cancer? Contributing factors include obesity, animal fat and supplements, such as vitamin E and selenium. Equally as important, factors that may reduce risk include vegetables, especially cruciferous, and tomato sauce or cooked tomatoes.

Vitamin E and selenium

In the SELECT trial, a randomized clinical trial (RCT), a dose of 400 mg of vitamin E actually increased the risk of prostate cancer by 17 percent (2). Though significant, this is not a tremendous clinical effect. It does show that vitamin E should not be used for prevention of prostate cancer. Interestingly, in this study, selenium may have helped to reduce the mortality risk in the selenium plus vitamin E arm, but selenium trended toward a slight increased risk when taken alone. Therefore, I would not recommend that men take selenium or vitamin E for prevention.

Obesity

Obesity showed conflicting results, prompting the study authors to analyze the results further. According to a review of the literature, obesity may slightly decrease the risk of nonaggressive prostate cancer, however increase risk of aggressive disease (3). Don’t think this means that obesity has protective effects. It’s quite the contrary. The authors attribute the lower incidence of nonaggressive prostate cancer to the possibility that it is more difficult to detect the disease in obese men, since larger prostates make biopsies less effective. What the results tell us is that those who are obese have a greater risk of dying from prostate cancer when it is diagnosed.

Animal fat, red and processed meats

The risk of developing prostate cancer increases with age. Stock photo

It seems there is a direct effect between the amount of animal fat we consume and incidence of prostate cancer. In the Health Professionals Follow-up Study, a large observational study, those who consumed the highest amount of animal fat had a 63 percent increased risk, compared to those who consumed the least (4).

Here is the kicker: It was not just the percent increase that was important, but the fact that it was an increase in advanced or metastatic prostate cancer. Also, in this study, red meat had an even greater, approximately 2.5-fold, increased risk of advanced disease. If you are going to eat red meat, I recommend decreased frequency, like lean meat once every two weeks or once a month.

In another large, prospective (forward-looking) observational study, the authors concluded that red and processed meats increase the risk of advanced prostate cancer through heme iron, barbecuing/grilling and nitrate/nitrite content (5).

Omega-3s paradox

When we think of omega-3 fatty acids or fish oil, we think “protective” or “beneficial.” However, these may increase the risk of prostate cancer, according to one epidemiological study (6). This study, called the Prostate Cancer Prevention Trial, involving a seven-year follow-up period, showed that docosahexaenoic acid (DHA), a form of omega-3 fatty acid, increased the risk of high-grade disease 2.5-fold. This finding was unexpected. If you choose to eat fish, salmon or sardines in water with no salt are among the best choices.

Lycopene – found in tomato sauce

Tomato sauce has been shown to potentially reduce the risk of prostate cancer. However, uncooked tomatoes have not shown beneficial effects. This may be because, in order to release lycopene, the tomatoes need to be cooked (7). It is believed that lycopene, which is a type of carotenoid found in tomatoes, is central to this benefit.

In a prospective (forward-looking) study involving 47,365 men who were followed for 12 years, the risk of prostate cancer was reduced by 16 percent (8). The primary source of lycopene in this study was tomato sauce. When the authors looked at tomato sauce alone, they saw a reduction in risk of 23 percent when comparing those who consumed at least two servings a week to those who consumed less than one serving a month. The reduction in severe, or metastatic, prostate cancer risk was even greater, at 35 percent. There was a statistically significant reduction in risk with a very modest amount of tomato sauce.

In the Health Professionals Follow-up Study, the results were similar, with a 21 percent reduction in the risk of prostate cancer (9). Again, tomato sauce was the predominant food responsible for this effect. This was another large observational study with 47,894 participants. Although tomato sauce may be beneficial, many brands are loaded with salt. I recommend to patients that they either make their own sauce or purchase a sauce with no salt, such as one made by Eden Organics.

Vegetable effects

Vegetables, especially cruciferous vegetables, reduce the risk of prostate cancer significantly. In a case-control study (comparing those with and without disease), participants who consumed at least three servings of cruciferous vegetables per week, versus those who consumed less than one per week, saw a 41 percent reduction in prostate cancer risk (10). What’s even more impressive is the effect was twice that of tomato sauce, yet the intake was similarly modest. Cruciferous vegetables include broccoli, cauliflower, bok choy, kale and arugula, to name a few.

When it comes to preventing prostate cancer, lifestyle modification, including making dietary changes, can reduce your risk significantly.

References:

(1) www.movember.com. (2) JAMA. 2011; 306: 1549-1556. (3) Epidemiol Rev. 2007;29:88. (4) J Natl Cancer Inst. 1993;85(19):1571. (5) Am J Epidemiol. 2009;170(9):1165. (6) Am J Epidemiol. 2011 Jun 15;173(12):1429-1439. (7) Exp Biol Med (Maywood). 2002; 227:914-919. (8) J Natl Cancer Inst. 2002;94(5):391. (9) Exp Biol Med (Maywood). 2002; 227:852-859; Int. J. Cancer. 2007;121: 1571–1578. (10) J Natl Cancer Inst. 2000;92(1):61.

Dr. Dunaief is a speaker, author and local lifestyle medicine physician focusing on the integration of medicine, nutrition, fitness and stress management. For further information, visit www.medicalcompassmd.com or consult your personal physician.

Adding cruciferous vegetables to your diet significantly decreases the risk of developing multiple cancers. Stock photo
Small studies show diet may affect gene expression

By David Dunaief, M.D.

Dr. David Dunaief

Cancer, a word that for decades was whispered as taboo, has become front and center in the medical community. Cancer is the number one killer of Americans, at least those less than 85 years old, even ahead of cardiovascular disease (1). We have thought that diet may be an important component in preventing cancer. Is diet a plausible approach?

An April 24, 2014, article published in the New York Times, entitled “An Apple a Day and Other Myths,” questioned the validity of diet in the prevention of cancer. This article covered cancer in general, which is a huge and daunting topic.

The article’s author referenced a comment by Walter Willet, M.D., a professor at the Harvard School of Public Health’s Epidemiology and Nutrition Department, as indicating that the research is inconsistent when it comes to fruits and vegetables. The article went on to state that even fiber and fats may not play significant roles in cancer.

I don’t necessarily disagree with this assessment. However, I would like to emphasize that Willet also commented that there are no large, well-controlled diet studies. This leaves the door open for the possibility that diet does have an impact on cancer prevention. I would like to respond.

As Willet hinted, the problem with answering this question may lie with the studies themselves. The problem with diet studies in cancer, in particular, is that they rely mainly on either retrospective (backward-looking) or prospective (forward-looking) observational studies.

Observational studies have many weaknesses. Among them is recall bias, or the ability of subjects to remember what they did. Durability is also a problem; the studies are not long enough, especially with cancer, which may take decades to develop. Confounding factors and patient adherence are other challenges, as are the designs and end points of the studies (2). Plus, randomized controlled trials are very difficult and expensive to do since it’s difficult and much less effective to reduce the thousands of compounds in food into a focus on one nutrient. Let’s look at the evidence.

The EPIC trial

Considered the largest of the nutrition studies is the European Prospective Investigation into Cancer and Nutrition (EPIC). It is part of what the author was using to demonstrate his point that fruits and vegetables may not be effective, at least in breast cancer. This portion of the study involved almost 300,000 women from eight different European nations (3). Results showed that there was no significant difference in breast cancer occurrence between the highest quintile of fruit and vegetable consumption group compared to the lowest. The median duration was 5.4 years.

Does this study place doubt in the dietary approach to cancer? Possibly, but read on. The most significant strength was its size. However, there were also many weaknesses. The researchers were trying to minimize confounding factors, but there were eight countries involved, with many different cultures, making it almost impossible to control. It is not clear if participants were asked what they were eating more often than at the study’s start. Risk stratification was also not clear; which women, for example, might have had a family history of the disease?

Beneficial studies with fruits and vegetables

Also, using the same EPIC study, results showed that fruit may have a statistically significant impact on lung cancer (4). Results showed that there was a 40 percent decrease in the risk of developing lung cancer in those that were in the highest quintile of fruit consumption, compared to those in the lowest quintile. However, vegetables did not have an impact. The results were most pronounced in the northern European region. I did say the answer was complex.

Ironically, it seems that some other studies, mostly smaller studies, show potentially beneficial effects from fruits and vegetables. This may be because it is very difficult to run an intensive, well-controlled, large study.

Prostate cancer

Dean Ornish, M.D., a professor of medicine at UC San Francisco Medical School, has done several well-designed pilot studies with prostate cancer. His research has a focus on how lifestyle affects genes. In one of the studies, results of lifestyle modifications showed a significant increase in telomere length over a five-year period (5).

Telomeres are found on the end of our chromosomes; they help prevent the cell from aging, becoming unstable and dying. Shorter telomeres may have an association with diseases, such as cancer and aging and morbidity (sickness). Interestingly, the better patients adhered to the lifestyle modifications, the more telomere growth they experienced. However, in the control group, telomeres decreased in size over time. There were 10 patients in the lifestyle (treatment) group and 25 patients in the control group — those who followed an active surveillance-only approach.

In an earlier study with 30 patients, there were over 500 changes in gene expression in the treatment group. Of these, 453 genes were down-regulated, or turned off, and 48 genes were up-regulated, or turned on (6). The most interesting part is that these changes occurred over just a three-month period with lifestyle modifications.

In both studies, the patients had prostate cancer that was deemed at low risk of progressing into advanced or malignant prostate cancer. These patients had refused immediate conventional therapy including hormones, radiation and surgery. In both studies, the results were determined by prostate biopsy. These studies involved intensive lifestyle modifications that included a low-fat, plant-based, vegetable-rich diet. But as the researchers pointed out, there is a need for larger randomized controlled trials to confirm these results.

Cruciferous vegetables

A meta-analysis involving a group of 24 case-control studies and 11 observational studies, both types of observational trials, showed a significant reduction in colorectal cancer (7). This meta-analysis looked at the effects of cruciferous vegetables, also sometimes referred to as dark-green, leafy vegetables.

In another study that involved a case-control observational design, cruciferous vegetables were shown to significantly decrease the risk of developing multiple cancers, including esophageal, oral cavity/pharynx, breast, kidney and colorectal cancers (8). There was also a trend that did not reach statistical significance for preventing endometrial, prostate, liver, ovarian and pancreatic cancers. The most interesting part is that the comparison was modest, contrasting consumption of at least one cruciferous vegetable a week with none or less than one a month. However, we need large, randomized trials using cruciferous vegetables to confirm these results.

In conclusion, it would appear that the data are mixed in terms of the effectiveness of fruits and vegetables in preventing cancer or its progression. The large studies have flaws, and pilot studies require larger studies to validate them. However, imperfect as they are, there are results that indicate that diet modification may be effective in preventing cancer. I don’t think we should throw out the baby with the bath water. There is no reason not to consume significant amounts of fruits and vegetables in the hopes that it will have positive effects on preventing cancer and its progression. There is no downside, especially if the small studies are correct.

References: (1) CA Cancer J Clin. 2011;61(4):212. (2) Nat Rev Cancer. 2008;8(9):694. (3) JAMA. 2005;293(2):183-193. (4) Int J Cancer. 2004 Jan 10;108(2):269-276. (5) Lancet Oncol. 2013 Oct;14(11):1112-1120. (6) Proc Natl Acad Sci U S A. 2008 Jun 17;105(24):8369-8374. (7) Ann Oncol. 2013 Apr;24(4):1079-1087. (8) Ann Oncol. 2012 Aug;23(8):2198-2203.

Dr. Dunaief is a speaker, author and local lifestyle medicine physician focusing on the integration of medicine, nutrition, fitness and stress management. For further information, visit www.medicalcompassmd.com.

By Dr. David Dunaief

Prostate cancer is the second most common cancer in men, after skin cancer. The American Cancer Society estimates that, in 2016, there will be almost 190,000 new prostate cancer diagnoses in the United States and just over 26,000 deaths (1). What better time to discuss prostate cancer prevention than in “Movember,” a month dedicated to raising awareness of men’s health issues?

The best way to avoid prostate cancer is through lifestyle modifications, which means garnering knowledge about both detrimental and beneficial approaches. There are a host of things that may increase your risk and others that may decrease your likelihood of prostate cancer. Your genetics or family history do not mean you can’t alter gene expression with the choices you make.

What may increase the risk of prostate cancer? Contributing factors include obesity, animal fat and supplements, such as vitamin E and selenium. Equally as important, factors that may reduce risk include vegetables, especially cruciferous, tomato sauce or cooked tomatoes, soy and even coffee.

Vitamin E and selenium

In the SELECT trial, a randomized clinical trial (RCT), a dose of 400 mg of vitamin E actually increased the risk of prostate cancer by 17 percent (2). Though significant, this is not a tremendous clinical effect. It does show that vitamin E should not be used for prevention of prostate cancer. Interestingly, in this study, selenium may have helped to reduce the mortality risk in the selenium plus vitamin E arm, but selenium trended toward a slight increased risk when taken alone. Therefore, I would not recommend that men take selenium or vitamin E for prevention.

Obesity

Obesity showed conflicting results, prompting the study authors to analyze the results further. According to a review of the literature, obesity may slightly decrease the risk of nonaggressive prostate cancer, however increase risk of aggressive disease (3). Don’t think this means that obesity has protective effects. It’s quite the contrary. The authors attribute the lower incidence of nonaggressive prostate cancer to the possibility that it is more difficult to detect the disease in obese men, since larger prostates make biopsies less effective. What the results tell us is that those who are obese have a greater risk of dying from prostate cancer when it is diagnosed.

Animal fat, red meat and processed meats

It seems there is a direct effect between the amount of animal fat we consume and incidence of prostate cancer. In the Health Professionals Follow-up Study, a large observational study, those who consumed the highest amount of animal fat had a 63 percent increased risk, compared to those who consumed the least. Here is the kicker: It was not just the percent increase that was important, but the fact that it was an increase in advanced or metastatic prostate cancer (4). Also, in this study, red meat had an even greater, approximately 2.5-fold, increased risk of advanced disease. If you are going to eat red meat, I recommend decreased frequency, like lean meat once every two weeks or once a month.

In another large, prospective (forward-looking) observational study, the authors concluded that red and processed meats increase the risk of advanced prostate cancer through heme iron, barbecuing/grilling and nitrate/nitrite content (5).

Omega-3s paradox

When we think of omega-3 fatty acids or fish oil, we think “protective” or “beneficial.” However, these may increase the risk of prostate cancer, according to one epidemiological study (6). This study, called the Prostate Cancer Prevention Trial, involving a seven-year follow-up period, showed that docosahexaenoic acid (DHA), a form of omega-3 fatty acid, increased the risk of high-grade disease 2.5-fold. This finding was unexpected.

However, this does not mean that men should cut back on fish consumption; the effects of omega-3s on heart disease prevention are significant, and heart disease is far more prevalent. Also, this is only one study finding. If you choose to eat fish, salmon or sardines in water with no salt are among the best choices.

Lycopene — found in tomato sauce

Tomato sauce has been shown to potentially reduce the risk of prostate cancer. However, uncooked tomatoes have not shown beneficial effects. This may be because, in order to release lycopene, the tomatoes need to be cooked (7). It is believed that lycopene, which is a type of carotenoid found in tomatoes, is central to this benefit.

In a prospective (forward-looking) study involving 47,365 men who were followed for 12 years, the risk of prostate cancer was reduced by 16 percent (8). The primary source of lycopene in this study was tomato sauce. When the authors looked at tomato sauce alone, they saw a reduction in risk of 23 percent when comparing those who consumed at least two servings a week to those who consumed less than one serving a month. The reduction in severe, or metastatic, prostate cancer risk was even greater, at 35 percent. There was a statistically significant reduction in risk with a very modest amount of tomato sauce.

In the Health Professionals Follow-Up Study, the results were similar, with a 21 percent reduction in the risk of prostate cancer (9). Again, tomato sauce was the predominant food responsible for this effect. This was another large observational study with 47,894 participants. Although tomato sauce may be beneficial, many brands are loaded with salt. I recommend to patients that they either make their own sauce or purchase a sauce with no salt, such as one made by Eden Organics.

Vegetable effect

Vegetables, especially cruciferous vegetables, reduce the risk of prostate cancer significantly. In a case-control study (comparing those with and without disease), participants who consumed at least three servings of cruciferous vegetables per week, versus those who consumed less than one per week, saw a 41 percent reduction in prostate cancer risk (10). What’s even more impressive is the effect was twice that of tomato sauce, yet the intake was similarly modest. Cruciferous vegetables include broccoli, cauliflower, bok choy, kale and arugula, to name a few.

Where does coffee fit in?

Surprisingly, coffee may reduce the risk of prostate cancer. It was recently shown in the Health Professionals Follow-Up Study, where there was a dose-response curve. In other words, the more coffee consumed, the lower the risk. Even those who consumed one to three cups a day saw a 30 percent reduction in the risk of lethal prostate cancers, whether the coffee was caffeinated or decaffeinated (11). Coffee contains bioactive compounds, such as phenolic acids, which have antioxidant effects.

There is a caveat. Although, in this study, more was better, that is not always true in many other studies. Therefore, I would not recommend drinking more than three cups per day, because of other potentially detrimental effects. I think it is apt to finish with two thoughts. Aaron Katz, M.D., from Columbia University Medical Center, had it right when he mentioned that lifestyle modification was important. He was talking about those with early-stage prostate cancer. However, the same philosophy can be applied to prevention of prostate cancer. My goal in writing this article was to arm you with the knowledge you need to start protecting yourself or your loved ones today.

References: (1) www.cancer.org. (2) JAMA. 2011; 306: 1549-1556. (3) Epidemiol Rev. 2007;29:88. (4) J Natl Cancer Inst. 1993;85(19):1571. (5) Am J Epidemiol. 2009;170(9):1165. (6) Am J Epidemiol. 2011 Jun 15;173(12):1429-1439. (7) Exp Biol Med (Maywood). 2002; 227:914-919. (8) J Natl Cancer Inst. 2002;94(5):391. (9) Exp Biol Med (Maywood). 2002; 227:852-859; Int. J. Cancer. 2007;121: 1571–1578. (10) J Natl Cancer Inst. 2000;92(1):61. (11) J Natl Cancer Inst. 2011;103:876-884.

Dr. Dunaief is a speaker, author and local lifestyle medicine physician focusing on the integration of medicine, nutrition, fitness and stress management. For more information, visit www.medicalcompassmd.com or consult your personal physician.