Higher vitamin E levels predict improved prostate cancer survival

An article published in the May 1, 2009 issue of the journal Cancer Research reported the discovery of researchers at the National Cancer Institute of an improvement in prostate cancer survival among men with high vitamin E levels. The effect was particularly strong among those who supplemented with the vitamin.

Joanne L. Watters and colleagues analyzed data from 29,133 participants in the Alpha-Tocopherol, Beta-Carotene (ATBC) Cancer Prevention Study, which evaluated the effect of vitamin E and beta-carotene on the risk of cancer in male Finnish smokers enrolled between 1985 and 1988. Blood samples collected upon enrollment and at three years were analyzed for serum levels of beta-carotene, retinol (vitamin A), and alpha-tocopherol (vitamin E). Although the trial concluded in April, 1993, on-going follow-up documented 1,891 prostate cancer cases and 395 deaths due to the disease through April, 2005.

Men whose serum alpha-tocopherol levels at the beginning of the study were among the top one-fifth of participants were found to have a 33 percent lower risk of dying of prostate cancer compared with those whose levels were in the lowest fifth. For those whose levels were highest at the third year of the study, a 20 percent lower risk existed. Men who received alpha-tocopherol supplements in the trial and whose baseline levels of vitamin E were highest experienced the lowest risk of prostate cancer mortality, which was 49 percent less than the risk experienced by those in the lowest 20 percent of serum alpha-tocopherol levels. This risk declined after three years to 74 percent less than the risk of those among the lowest fifth.



When all-cause mortality was analyzed among those diagnosed with prostate cancer, participants in the top one-fifth of serum vitamin E levels were shown to have a 33 percent lower risk of death over the course of follow-up, suggesting, according to the authors, "a possible effect for alpha-tocopherol on other causes of death in men with prostate cancer." Continue Reading

Greater omega-3 fatty acid intake associated with decreased risk of advanced prostate cancer

In an article published online on March 24, 2009 in the American Association for Cancer Research journal Clinical Cancer Research, scientists from the University of California, San Francisco report a protective effect of long chain omega-3 polyunsaturated fatty acids against advanced prostate cancer risk.

Professor of epidemiology and biostatistics John S. Witte, PhD and his associates compared 466 men with aggressive prostate cancer to 478 healthy men matched for age and ethnicity. Dietary questionnaire responses were evaluated for omega-3 fatty acid intake, and blood samples were analyzed for nine variants in the gene that controls cylooxygenase-2 (COX-2), an enzyme involved in fatty acid metabolism, inflammation and cell proliferation. Earlier research has demonstrated decreased expression of COX-2 among animals fed high omega-3 fatty acid-containing diets, as compared to high omega-6 diets.




Advanced prostate cancer risk declined with increasing omega-3 fatty acid intake. Men whose intake of omega-3 fatty acids was among the top 25 percent of participants had a 63 percent lower risk of aggressive prostate cancer compared with those whose intake was in the lowest fourth.


This association was stronger among men with a particular modification of the gene that controls COX-2 expression, resulting in an over five times greater risk of advanced prostate cancer in men with this variant who reported a low intake of omega-3 fatty acids. "Previous research has shown protection against prostate cancer, but this is one of the first studies to show protection against advanced prostate cancer and interaction with COX-2," Dr Witte stated. "The COX-2 increased risk of disease was essentially reversed by increasing omega-3 fatty acid intake by a half a gram per day." Continue Reading

Zinc from supplements associated with reduced risk of advanced prostate cancer

The March, 2009 issue of Nutrition and Cancer published the finding of Seattle's Fred Hutchinson Cancer Research Center of an association between long term consumption of zinc supplements and a reduced risk of advanced prostate cancer in men.

Prostate tissue contains ten times the level of zinc than other soft tissues in the body, while adenocarcinoma cells from prostate tumors lose the ability to concentrate the mineral. These and other factors led Emily White and colleagues to hypothesize that prostate cancer risk could be lowered by increased zinc intake.

For the current study, they evaluated data from 35,242 men between the ages of 50 to 76 who participated in the VITamins and Lifestyle (VITAL) study of the impact of dietary supplements on cancer risk. Questionnaires completed upon enrollment provided information concerning diet and nutritional supplement intake over the past ten years, as well as demographic characteristics and health history. Eight hundred thirty-two of these participants developed invasive prostate cancers over a four year follow-up period, categorized as local, regional or distant invasion. Continue Reading

Genistein prevents prostate cancer metastasis in animal model

The March 15, 2008 issue of the journal Cancer Research published the finding of a team from Northwestern University in Illinois that genistein, an antioxidant compound that occurs in soybeans, almost completely prevented prostate cancer from spreading in mice in whom cancerous human tissue was implanted.

The study is the first to show that genistein can halt prostate cancer metastasis in a living organism. Raymond C. Bergan, MD of Northwestern’s Robert H. Lurie Comprehensive Cancer Center and his colleagues implanted an aggressive human form of prostate cancer into several groups of mice and gave some of the animals an amount of genistein that elevated blood concentrations to levels comparable to those measured in humans following the consumption of soy foods. While genistein did not reduce prostate tumor size, spread of the disease to the lungs, a common site of metastasis, was reduced by 96 percent compared with animals that did not receive genistein. A repeat of the experiment elicited the same result. Continue Reading

Lifestyle improvements enhance telomerase activity

An article appearing online on September 16, 2008 in The Lancet Oncology reports a pilot study conducted by Dean Ornish, MD and colleagues which found that adopting positive lifestyle changes increases the activity of telomerase, the enzyme responsible for maintaining telomeres. Telomeres are DNA-protein complexes that cap the ends of chromosomes, aiding in their stabilization.

Telomere length is associated with cellular age, and adequate telomere length is vital to maintaining cells, including immune system cells which protect the body against a number of diseases, such as cancer. Longer telomere length has been associated with increased resistance to disease and premature death in prostate, breast, lung and colorectal cancer.

The current study involved 24 patients with low-risk prostate cancer. Dr Ornish, of the Preventive Medicine Research Institute in Sausalito, and his associates at the University of California, San Francisco, conducted a three day intensive residential retreat followed by a three month comprehensive lifestyle modification program.

Participants were asked to adopt diets that limited fat to 10 percent of their calorie intake, and which contained a low amount of refined carbohydrates, abundant amounts of whole grains, fruit and vegetables, and supplemental soy protein powder, fish oil, vitamin E, selenium, and vitamin C. The subjects were also asked to engage in moderate aerobic exercise for one half hour per day and one hour stress management periods for six days per week, in addition to a one hour weekly group support session. Blood samples were analyzed for telomerase activity and other factors, and psychological distress was evaluated at the beginning of the study and at the end of the three month treatment period. Continue Reading