My patients (both with and without prostate cancer) have an insatiable desire for information regarding foods, vitamins, nutritional supplements, and other non-prescription “stuff” that they can add to their daily diets to help improve the odds of them beating or avoiding prostate cancer. At a recent community outreach program that highlighted new advances in cancer, the vast majority of the questions from the audience dealt with food, nutritional supplements, and vitamins. Intelligent answers to these questions require balance and an understanding that not all the answers are in yet. So what advice can be offered in the meantime?
Selenium and Vitamin E
I was dismayed and disappointed by the recent announcement that two widely used supplements―selenium and vitamin E―which had been touted to reduce the risk of prostate cancer showed no such effect. In fact, there is even the possibility that they increase the risk of prostate cancer and diabetes. A large, government-sponsored study found these results.
This study should not only impact your decisions about selenium and vitamin E, it should also increase your skepticism of other, yet unproven, remedies that are widely used. Let’s take a look at some of them.
What Supplements and Foods are Thought to Reduce Prostate Cancer Risk?
A recent roundtable of Harvard experts was convened to categorize substances that reduce prostate cancer risk or increase the risk. Among substances that were thought to reduce risk were selenium and vitamin E―though we now know that not to be the case. Others on the list were:
· Fish, with the theory being that omega 3-fatty acid, a substance present in certain fatty fishes, may block the development of certain types of cancer.
· Cooked tomatoes, which contain a substance called lycopene that has anti-oxidant properties.
What Needs More Study?
Substances that have been thought to have some protective effect on prostate cancer development, but which have not been subject to many rigorous scientific studies, include:
· Members of the beta carotene family (carotenoids), melatonin and pomegranate juice. All of these are thought to have anti-oxidant properties.
· Soy and vitamin D, which have been able to block or stop the growth of cancer cells in laboratory situations and have gained popularity as food supplements.
What Increases Risk?
On the opposite side of the equation are substances that can actually increase the risk of prostate cancer. These include:
· Ingesting high levels of calcium (greater than 1,500 mg per day)
· Eating red meat
· Zinc supplements.
My Advice on Prostate Cancer and diet, supplements
On a practical level, I advise my patients not to ingest more than 1,000 mg of dietary calcium per day, and to avoid red meat or decrease the amount of red meat to once a month.
The specific advice related to the other substances listed above is still in a state of flux. In my opinion, encouraging people to eat fish high in omega 3-fatty acids makes sense because anti-oxidants are thought to provide a host of benefits, including, perhaps, reducing the risk of cancer. Keep in mind that pomegranate juice has quite a lot of calories, so people who are watching their weight need to take this into consideration. If you are a believer in lycopene ingestion, get it from cooking tomatoes with a little bit of oil; the bottled variety that you can buy for the nutritional supplement stores is unlikely to work since very little of that form of lycopene is absorbed into the blood stream.
The sobering news from the selenium and vitamin E study again bears emphasizing. While we thought that taking these substances was promoting enhanced prostate health, that turned out not to be true. We simply had not yet performed the necessary studies to make definitive conclusions.
When the newspaper reports a new finding about some substance that has a positive effect on cancer, please react with caution. While the claim may indeed have some merit, the benefit is likely to be modest at best and the substance may not be as effective as other tried and true things such as a good, healthy diet and exercise.
When my patients want additional information about supplements, I generally refer them to one of several websites. These include the National Cancer Institute’s Office of Cancer Complementary and Alternative Medicine www.cancer.gov/cam and the National Institutes of Health website on Complementary and Alternative Medicine, www.nccam.nih.gov
Do you take supplements to reduce your risk of prostate cancer? Please let me know if you have specific questions about the supplements you are taking.
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Comments: 10
Why don't we get some rigorous scientific studies on radiation and chemotherapy? These treatments are very expensive and dangerous, but they seem popular because the drug companies make a lot of money. I would like to see double blind studies on these treatments.
If radiation can cause cancer, why is it used as a treatment? Isn't that like putting out fire with gasoline?
I believe that it is far better to eat fresh fruits, salads and home made soups than it is to consume processed foods and red meat plus many, mahy supplements.
The first is a 'natural' diet, whereas the latter is simply a drug culture diet. Chemically made food.
There would equal enthusiasm to use dietary supplements as well if these agents underwent the same testing. Unfortunately, when many supplements have been tested, they have not measured up – and hence the skepticism.
One good example of a nutritional supplement was something called PC Spes- a Chinese Herbal remedy that was touted as a “cure all” for prostate cancer. Unfortunately, there were a variety of adulterated substances that were contained in this unregulated substance, necessitating its removal from the market. Other supplements, such as saw palmetto, for benign prostate disease, was shown to be no more effective than placebo. Thus, I am all for supplements and nutricueticals, as long as there are data to support their safe use.
The issue about using radiation to treat cancer when it can cause cancer is a very important issue. Again, we come to risk benefit ratios. The potential for a second cancer to develop from the use of radiation is a daily issue cancer specialists face. However, the greater good and benefit of the use of radiation to eliminate the cancer outweighs the possibility of a second cancer developing, perhaps decades later.
The pomegranate intake is probably ok with either the juice or fruit form, but further research needs to be done to fully understand how the body handles this substance in its differing forms.
The habits of our other readers are commendable -- ingestion of a good diet, with fruit, vegetables and other nutritious goodies makes excellent sense to me.
Please continue to share your thoughts with us. And let us know if you have any other questions about nutrition and cancer and its prevention.
Marc B. Garnick MD
Years ago a relative was dying from lung cancer. His wife, in trying to help was giving him mega doses of vitamin E. I understand, now there is evidence vitamin helps the cancer grow.
To me the supplement industry is as sleazy as a loan shark.