Supplemental and dietary vitamin E intakes and risk of prostate cancer in a large prospective study.

Divisions of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, DHHS, Bethesda, Maryland, USA. mewright@uic.edu

Supplemental vitamin E (alpha-tocopherol) has been linked to lower prostate cancer incidence in one randomized trial and several, although not all, observational studies. The evidence regarding dietary intake of individual vitamin E isoforms and prostate cancer is limited and inconclusive, however. We prospectively examined the relations of supplemental vitamin E and dietary intakes of alpha-, beta-, gamma-, and delta- tocopherols to prostate cancer risk among 295,344 men, ages 50 to 71 years and cancer-free at enrollment in 1995 to 1996, in the NIH-AARP Diet and Health Study. At baseline, participants completed a questionnaire that captured information on diet, supplement use, and other factors. Proportional hazards models were used to estimate relative risks (RR) and 95% confidence intervals (95% CI) of prostate cancer. During 5 years of follow-up, 10,241 incident prostate cancers were identified. Supplemental vitamin E intake was not related to prostate cancer risk (for >0-99, 100-199, 200-399, 400-799, and > or = 800 IU/d versus never use: RR, 0.97, 0.89, 1.03, 0.99, and 0.97 (95% CI, 0.87-1.07) respectively; Ptrend = 0.90). However, dietary gamma-tocopherol, the most commonly consumed form of vitamin E in the United States, was significantly inversely related to the risk of advanced prostate cancer (for highest versus lowest quintile: RR, 0.68; 95% CI, 0.56-0.84; Ptrend = 0.001). These results suggest that supplemental vitamin E does not protect against prostate cancer, but that increased consumption of gamma-tocopherol from foods is associated with a reduced risk of clinically relevant disease. The potential benefit of gamma-tocopherol for prostate cancer prevention deserves further attention.

PMID: 17548674 [PubMed - indexed for MEDLINE]

Bron: Medscape: http://www.medscape.com/viewarticle/582788_print

The Data and Safety Monitoring Committee said that "the data could not exclude a small chance that the study supplements might have effects later in the men's lives." However, the antioxidants selenium and vitamin E, taken alone or together for an average of 5 years, did not prevent prostate cancer, according to the committee............

Participants were randomized to 1 of 4 groups (2 capsules a day): selenium (200 μg) and vitamin E (400 mg); selenium and placebo; vitamin E and placebo; or 2 placebos. The 35,000-plus participants consisted of African-American men who were 50 years or older, and men of other races and ethnicities who were 55 years or older. The eligibility age was lower for African Americans because of the earlier average onset of the disease.

Selenium is a nonmetallic trace element found especially in plant foods, such as rice, wheat, seafood, meat, and Brazil nuts. Selenium is an antioxidant that may help control the cell damage that can lead to cancer, according to the NCI.

Vitamin E is found in a wide range of foods, especially vegetables, vegetable oils, nuts, and egg yolks. Like selenium, vitamin E is an antioxidant.

According to the NCI, selenium was selected for study in part because of results from the Nutritional Prevention of Cancer Trial, which was a skin cancer trial of 1312 men and women that incidentally revealed prostate cancer data; the results showed that men taking selenium for more than 7.5 years had about 52% fewer new cases of prostate cancer than men taking placebo.

Vitamin E was selected for the trial in part because of results from a 1998 study of 29,133 male smokers in Finland; men in the study who took vitamin E to prevent lung cancer had 32% fewer new cases of prostate cancer and 40% fewer deaths from prostate cancer than men taking placebo.

Bron: http://www.naturalnews.com/z024639.html Lees daar hele artikel hier enkele citaten:

Useless Vitamin E Used in Study

The SELECT trial used non-natural and chemically-derived vitamin E (dl-alpha tocopherol acetate) at a dose of 400 IU per day. Any time you see an "l" after the "d" in a vitamin E product throw it in the trash where it belongs. This vitamin E molecule is synthesized from coal tar and typically made by German pharmaceutical companies like Bayer and BASF. It has little or no antioxidant activity and is useless for human health - which was obvious long before the SELECT trial was started.

This is very similar to an earlier attack on beta-carotene, implying that beta carotene caused an increase in lung cancer in smokers who took it. Once again the "study" used a chemically-derived synthetic beta carotene made from acetylene gas produced by BASF, masquerading as a dietary supplement.

 

Natural Vitamin E is a Powerful Cancer Prevention Tool

Vitamin E is a required nutrient for immune system function. If you lack it, especially as you age, it is not technically possible that your immune system will work at optimal capacity. Thousands of studies confirm this statement, as well as fully documented molecular pathways relating to vitamin E and immune system function. Many Americans over the age of 50 are lacking vitamin E because it is destroyed in food processing and many people don't eat enough of the fattier vitamin E containing foods - making vitamin E supplementation a necessity for immunologic health.

Unlike drugs that kill cancer cells with "overwhelming toxic force," that is if they can be killed at all before killing the person with the treatment, the majority of anti-cancer nutrients such as green tea and vitamin E have a level of intelligence in human physiology. They are smart enough to know the difference between a healthy cell that should stay alive and a diseased cell that should die. This means the very same nutrient will help keep a healthy cell alive by protecting it while helping to kill cancer cells. This is truly a marvel of Mother Nature at work. No drug is even on the same playing field as nutrients provided by nature.

This does not mean that nutrients alone are a treatment for cancer. It does mean they are a powerful player in the natural immune toolbox, nothing to be discredited by bogus or incompetent "science."

There are eight natural forms of vitamin E, 4 tocopherols (alpha, beta, gamma, and delta) and 4 tocotrienols (alpha, beta, gamma, and delta). While d alpha tocopherol is the most common form of vitamin E in dietary supplements, it is actually gamma tocotrienol that is one of the most powerful anti-cancer nutrients known to Mankind. Why didn't NCI test natural gamma tocotrienol in their study instead a synthetic and useless form of vitamin E?

There are at least three known mechanisms by which gamma tocotrienol, unlike plain vitamin E, knocks out cancer cells. The first is by directly inducing death signals in cancer cells, which has been demonstrated in prostate and breast cancer cells. It also activates the well-known tumor suppression gene, p53, which in turn governs the cell cycle to prevent cancer. And it even shuts off the flow of blood to tumors to help starve them of nutrition. It does all this while simultaneously keeping healthy cells alive and assisting in the flow of blood to healthy cells! This is not a miracle; it is simply Mother Nature at work to aid survival.

Selenium and Cancer

Selenium is needed to form glutathione, which is the backbone of life in all cells in your body. Adequate cellular glutathione is required to keep cells healthy, and like vitamin E, is required for immune system competence. Vitamin E and selenium work synergistically to support immunity, antioxidant defense systems, and cancer prevention. No bogus study will ever discredit these simple facts.

The form of selenium used in the SELECT study was l-selenomethionine at a dose of 200 mcg. This form of the nutrient is fine; although the dose of the nutrient may have needed to be three or four times the amount tested. The study should have had various selenium dosage groups.

But if the form of the nutrient is fine, then why didn't the dose given seem to do anything useful? Researchers at NCI should have the brains to control for drug variables that would obviously influence the outcome of a selenium study - based on known principles of selenium biochemistry. In this case we are talking about a study group of 35,000 men at an age where they are at risk for prostate cancer. The number one drug that directly interferes with the metabolism of selenium is the widely prescribed statin drugs to lower cholesterol. The researchers should have (and still probably could) divide the selenium-taking men into those taking statins (at various dosages) and those not taking statins (if there even are any in the group). The higher the dose of statin, the greater the suppression of selenium-containing antioxidant enzymes will be. Lees hier hele artikel verder