Growing prostate cancer cells need an essential nutrient, the amino acid called leucine, which is pumped into the cell by specialised proteins. And this could be prostate cancer’s weak link.

The team at the Centenary Institute found, in a study to be published this month in Cancer Research, that prostate cancer cells have more pumps than normal. This allows the cancer cells to take in more leucine and outgrow normal cells.

Dr Holst says one of the other spin-offs of the discovery is a better understanding of the links between prostate cancer and eating foods high in leucine which include meat and poultry, seafood and dairy. Read more

It’s been established that abdominal fat and type 2 diabetes are associated with sexual dysfunction, urinary issues, and chronic inflammation. All in all, not a healthy package, and one that is also a recipe for cardiovascular problems.

But according to endocrinologist Dr. Gary Wittert, of the University of Adelaide in Australia, and his team, there is “a lifestyle change that’s quick, cheap, easy, and can improve health substantially beyond anything that medication can do.”

See Weight Loss, Exercise, and Prostate Health

That lifestyle change involves losing about 10 percent of body weight. To show the potential impact of weight loss on erectile function and urinary symptoms, Wittert and his colleagues enrolled 31 obese men who had type 2 diabetes into their study.

All the men were screened for urological and sexual problems and then were assigned to one of two diets: a liquid meal replacement plan that provided about 1,000 calories per day, or a high-protein diet that included fresh fruits and vegetables, lean meat, and fish, and that reduced caloric intake by about 600 calories per day.

The men followed their assigned diet plan for eight weeks: those on the liquid diet lost 8 to 10 percent of their body weight, and those on the high-protein diet lost 5 percent. In addition, men in both groups said their sexual health and urinary symptoms had improved, too.

For the next 44 weeks, all the men were switched to the high-protein diet, and they responded well, losing about 10 percent of their body weight while continuing to enjoy better erectile function and an improvement in urinary function.

See The Prostate Diet

Another benefit seen in the study: the high-protein, low-fat diet reduced inflammation throughout the body, which helped sustain the improvements in sexual, urinary, and endothelial function. What’s endothelial function? Glad you asked.

The inside of blood vessels, including those in the penis, have a lining called the endothelium. When a man becomes aroused, the endothelium in the blood vessels in the penis release nitric oxide, a substance that allows the surrounding muscles to relax, and then from there, things start to look up.

See How Do Erections Work?

The endothelium can be damaged by various factors, including high blood pressure, diabetes, oxidative stress, and excess weight. When the endothelium is damaged, blood flow can be impaired and a man may find it difficult or impossible to get or maintain an erection.

So although the sample size in this study was small, its results suggest—and other evidence supports them—that overweight diabetic men could do themselves and their partners a big favor by losing weight.

Study: Khoo J et al. Comparing effects of a low-energy diet and a high-protein low-fat diet on sexual and endothelial function, urinary tract symptoms, and inflammation in obese diabetic men. J Sexual Med 2011 Aug; doi: 10.1111/j.1743-6109.2011.02417x

While a healthy diet is certainly important in the fight against many diseases, adding dietary supplements is not a sure-fire way to prevent problems from occurring.  Most recently, researchers from the University Health Network in Toronto, Canada found that three hopeful contenders in the fight against prostate cancer – vitamin E (as alpha-tocopherol), selenium, and soy – were not found to be effective, even after three years of taking them daily.

For the study, Dr. Neil Fleshner MD, FRCSC, MPH, the head of the urology department at UHN, and colleagues randomly assigned 303 men to take either a combination of the three nutrients or a placebo every day.  The experimental group received 40 grams of soy (equivalent to about 1/3 of a cup), 800 IU of vitamin E (as alpha-tocopherol) (35 times the recommended dietary levels), and 0.2 grams of selenium (4 times the RDA).

All of the men had a precancerous condition called high-grade prostatic intraepithelial neoplasia (HGPIN) that placed them at a higher risk for developing prostate cancer.  After three years, twenty-six men out of every 100 developed prostate cancer regardless of whether they took the dietary supplement or the placebo control.

Selenium and vitamin E (principally, as alpha-tocopherol) are two nutrients that were also studied in the large SELECT prevention clinical trial funded by the National Cancer Institute.  Both are antioxidants which are thought to help control cell damage that can lead to cancer.  Over 35,000 men participated in the study however, the researchers found that selenium, either alone or combined with vitamin E (as alpha-tocopherol), did not prevent the development of prostate cancer. The researchers did observe a statistically nonsignificant increased risk of prostate cancer with vitamin E alone and newly diagnosed type 2 diabetes with selenium alone. (Lippman 2009) A post-SELECT Trial analysis, however, has suggested that further research is needed to determine whether selenium should still be considered in the fight against prostate cancer. (Ledesma 2010)

“I think in the absence of more compelling scientific data for vitamin E and selenium that we should move on” said Dr. Eric Klein.  Dr. Klein was not involved with the Canadian study, but is the chair of the Glickman Urological and Kidney Institute at the Cleveland Clinic and headed previous research into the nutrients’ potential affects against prostate cancer.

It should be noted that the studies that have evaluated the potential benefit of vitamin E supplements and health conditions use the form alpha-tocopherol, which is the most common form of the vitamin in both body tissues and dietary supplements.  Emerging research is taking into consideration another form of vitamin E, known as gamma-tocopherol which is the major form of vitamin E found in plant seeds and the diet.  According to a study published in 2001 in the American Journal of Clinical Nutrition, gamma-tocopherol may well be more effective of an antioxidant than alpha-tocopherol and it has been shown that alpha alone, without gamma is not as effective as when higher concentrations of gamma exist in the right ratio.  Researchers are looking into the gamma form for benefits in preventing both prostate cancer and heart disease and the results to date are encouraging.

On the other hand, previous research has shown a beneficial association between soy and prostate cancer.  Genistein is an antioxidant and isoflavone found primarily in soybeans and has been shown in test tube and animal studies to interfere with the growth of prostate cancer cells and help prevent metastasis.  Observational studies note that men in countries such as China in Japan who regularly eat soy products such as tofu and miso have lower rates of prostate cancer incidence, although the type and quantity of soy consumed in those countries is much different than consumed in the West.

Dr. Fleshner notes that the study may not have shown positive benefits because taking the dietary supplements for just three years may not have been enough to prevent HGPIN from progressing to prostate cancer.

Resources:

1.  Original Reports – Urologic Oncology:Progression From High-Grade Prostatic Intraepithelial Neoplasia to Cancer: A Randomized Trial of Combination Vitamin-E, Soy, and Selenium

Neil E. Fleshner, Linda Kapusta, Bryan Donnelly, et al. JCO May 2, 2011:JCO.2010.32.0994; published online on May 2, 2011;

http://jco.ascopubs.org/content/early/2011/04/26/JCO.2010.32.0994

2.  Medical News Today, Prostate Cancer: More Soy In Diet May Protect Against Deadly Disease, accessed May 5, 2011 at http://www.medicalnewstoday.com/articles/224373.php

3.  NCHS Data Brief, Number 61, April 2011

Dietary Supplement Use Among U.S. Adults Has Increased Since NHANES III (1988–1994), accessed May 5, 2011 athttp://www.cdc.gov/nchs/data/databriefs/db61.htm

4.  gamma-tocopherol, the major form of vitamin E in the US diet, deserves more attention.  Jiang Q, Christen S, Shigenaga MK, Ames BN.  Source:  University of California, the Department of Molecular and Cell Biology, Berkeley, USA.  Am J Clin Nutr. 2001 Dec;74(6):714-22.  accessed May 7 at http://www.ncbi.nlm.nih.gov/pubmed/11722951

5.  Dr. Neil Fleshner’s profile can be found at:

http://www.uhnresearch.ca/researchers/profile.php?lookup=1843

In a new review of the literature, J. Kellogg Parsons, MD, MHS, associate professor of surgery at the University of California, San Diego, Moores Cancer Center, outlined the modifiable lifestyle factors that contribute to the development of BPH and LUTS.  These two conditions are often studied together because BPH is the main cause of LUTS.

In the review, Parsons named three factors associated with an increased risk of both BPH and LUTS: obesity, diabetes, and consumption of meat and fat. He noted that most studies have found a relationship between obesity and an increased risk of both BPH and LUTS, including a Norwegian study of 21,700 men (Seim 2005) and the seven-year prospective analysis of 5,700 men who participated in the Prostate Cancer Prevention Trial. (Kristal 2007)

Parsons stated that “disruptions in glucose homeostasis have been strongly and robustly associated with a higher likelihood of prostate enlargement, BPH, and LUTS” in a variety of studies involving tens of thousands of men. Results from the Prostate Cancer Prevention Trial also show that meat and fat consumption are associated with an increased risk of BPH and LUTS. (Kristal 2008)

On the positive side, lifestyle factors found to help reduce the risk of BPH and LUTS include exercise, vegetable intake, and alcohol consumption. Regarding exercise, Parsons noted a 2008 study in which a meta-analysis of 11 studies involving 43,083 men found that moderate to vigorous exercise was associated with up to a 25 percent reduced risk of both BPH and LUTS. (Parsons 2008)

Vegetable consumption can reduce a man’s risk of BPH and LUTS, (Kristal 2008) and benefits are especially good for higher blood levels of carotene and lycopene, which are found in high concentrations in vegetables such as tomatoes, carrots, and greens. (Tavani 2005; Rohrmann 2004)

The research findings on alcohol consumption are mixed. While a meta-analysis of 19 studies involving 120,091 men found a 35 percent reduced likelihood of BPH among men who drank moderately daily, the study also found an increased risk of LUTS. (Parsons 2009)

Parsons also reported that research thus far has not reached any definite conclusions about the associations between cholesterol/triglycerides and BPH and LUTS, nor between smoking and both of these conditions.

This review suggests that modifiable lifestyle factors, including exercise, obesity, diabetes, diet, and alcohol consumption have a substantial impact on the development of BPH and LUTS. Parsons thus noted “there is little, if any, downside to promotion of healthy lifestyle interventions—weight loss, exercise, decreasing meat and fat intakes, and increasing vegetable intake—among BPH and LUTS patients.”

Sources

Kristal AR et al. Race/ethnicity, obesity, health related behaviors and the risk of symptomatic benign prostatic hyperplasia: results from the prostate cancer prevention trial. J Urol 2007; 177:1395–1400.

Kristal AR et al. Dietary Patterns, Supplement Use, and the Risk of Symptomatic Benign Prostatic Hyperplasia: Results from the Prostate Cancer Prevention Trial. Am J Epidemiol 2008; 167:925–34.

Parsons JK. Lifestyle factors, benign prostatic hyperplasia, and lower urinary tract symptoms. Curr Opin Urol 2011; 21:1-4

Parsons JK, Im R. Alcohol consumption is associated with a decreased risk of benign prostatic hyperplasia. J Urol 2009; 182:1463–68.

Parsons JK, Kashefi C. Physical activity, benign prostatic hyperplasia, and lower urinary tract symptoms. Eur Urol 2008; 53:1228–35.

Rohrmann S et al. Association between serum concentrations of micronutrients and lower urinary tract symptoms in older men in the Third National Health and Nutrition Examination Survey. Urology 2004; 64:504–9.

Seim A et al.  The prevalence and correlates of urinary tract symptoms in Norwegian men: the HUNT study. BJU Int 2005; 96:88– 92.

Tavani A et al. Intake of selected micronutrients and the risk of surgically treated benign prostatic hyperplasia: A Case–Control Study from Italy. Eur Urol 2005. http://www.sciencedirect.com/ and http://www.europeanurology.com/.

He was introduced to Dr. Eliaz who found that an old injury in Vietnam was the missing piece that needed to be addressed. Read more

In the new study, which was conducted by Sanoj Punnen, MD, and colleagues at the University of California San Francisco, 512 men who had aggressive prostate cancer were evaluated. Aggressive prostate cancer was defined as having a tumor stage of T2c or greater, a PSA (prostate-specific antigen) level of 10 ng/mL or higher, and a Gleason grade of 7 or higher. The patients were compared with 470 healthy controls.

All the men completed a self-administered food frequency questionnaire that included information on meat consumption, how the meat was prepared, and level of doneness. Based on the responses, the investigators found that men who ate an average of two or more servings per week of grilled or barbecued red meat that was well done or very well done had a twofold increased risk of advanced prostate cancer than men who did not eat hamburgers or other red meat.

Investigators did not find the same increased risk for advanced prostate cancer associated with men who ate red meat prepared rare or medium. It is possible these findings indicate that the relationship between meat consumption and prostate cancer is limited to advanced disease, or that the main factor is not meat but how it is prepared.  Dr. Punnen noted that past epidemiological studies regarding prostate cancer risk and meat consumption have yielded mixed results.

Source: American Urological Association Annual Meeting

Dark colas, such as Coke and Pepsi, use a coloring that is manufactured through a chemical reaction between sugars, ammonia, and sulfates.  According to CSPI Executive Director Michael Jacobson, these reactions produce two carcinogens:  2-methylimidazole (2-MEI) and 4-methylimidazole (4-MEI).  Studies by the National Toxicology Program have identified these two chemicals as causing cancer in animals – specifically of the lung, liver, thyroid, and blood (leukemia).

California has added 4-MEI to its list of carcinogens and is pursuing legislation that would require a product that elevated levels of the chemical to carry a warning on the label.  Levels higher than 16 micrograms per person per day would require a warning.  Jacobson says some sodas have levels eight times higher than that.  A 12-ounce can of cola contains up to 130 micrograms, according to CSPI.

Clear sodas such as Sprite do not contain the caramel coloring.

Jacobson has petitioned the FDA to ban the artificial colorings, which have no nutritional or preservative value, and move toward natural colorings such as from beets or carrots.

Of course, to every story, there is two sides.  The American Beverage Association contends that there is no evidence yet that shows that 4-MEI causes cancer in humans.  Take the case of saccharin, which carried a warning level for years because it caused bladder cancer in rats.  However, it was later discovered that rats respond to saccharin differently than humans, and over time, an increased risk of cancer was not found to occur in humans.

Medpage Today, a news service for physicians developed in part by the University of Pennsylvania School of Medicine, notes that while there was “clear evidence” that 4-MEI caused cancer in mice, the studies in rats were less clear.  They also note that the significant increases in leukemia were found in females and not males.

Even if future studies find no risk in humans, excessive intake of soda is still concerning for other health reasons.  First, regular soft drinks can contribute a significant amount of calories to the diet.  Obesity is rampant now in our country, with over two-thirds of Americans over their ideal body weight.  Excess body weight increases the risk for heart disease (the number one killer of American adults), diabetes, respiratory problems such as sleep apnea, and some types of cancer including those of the colon and pancreas.

But diet soda may be no better.  Another recent study highlighted this month found that diet sodas may potentially increase the risk of strokes by as much as 60%.  In background information for this study, conducted at the University of Miami, notes that those who drink more than one type of soft drink per day, regular or diet, are at a greater risk of metabolic syndrome (a cluster of cardiovascular risk factors) and that this may be contributing to the increase in stroke risk.

The bottom line for health – decrease the amount of soft drinks you consume – regular or diet, brown or clear – and increase your intake of water.  After all, as Dr. Jennifer Ashton says to CBS News, “our bodies are about 60% water, not 60% soda.”