An update on vitamins and “nutraceuticals” in prostate cancer

The desire to find vitamins and foods and similar products (“nutraceuticals” as compared to pharmaceuticals) that have significant and measurable clinical impact on the prevention and/or the actual treatment of prostate cancer has been a constant over the past 20+ years.

At the beginning of this year, Trottier et al. published a review on nutraceuticals and prostate cancer prevention in Nature Reviews Urology. For the purposes of their review they defined “nutraceuticals” as ” ‘natural’ substances isolated or purified from food substances and used in a medicinal fashion.”

Trottier and his colleagues note that, in the search for “natural” products that can be used to prevent the onset of prostate cancer we have already collected data from human studies on an extensive range of elements, chemicals, biochemicals, and actual foodstuffs, including, for example, vitamin E, selenium, vitamin D, green tea, soy, and lycopene. However, in most cases what we have available are data from retrospective analysis and epidemiological data as opposed to actual clinical studies. And where we have data from truly randomized, well-controlled clinical trials (e.g., the SELECT trial on the preventive effects of selenium and vitamin E), the results have invariably shown no beneficial impact of the products being tested.

Having said that, Trottier et al. make the point that the role of nutraceuticals in prostate cancer prevention is still under intense investigation. In a recent commentary on their earlier review in the Beyond the Abstract section on the UroToday web site, they draw particular attention to soy, pomegranate, and green tea as sources for preventive effects on the progression of prostate cancer. They emphasize that soy “has the most compelling evidence for benefit, albeit moderate in strength, in both primary prevention and patients on active surveillance.” They also note that there are now some 30 different clinical trials investigating the potential value of pomegranate-based products.

In another, more recent, review, Doneka et al. have also addressed vitamins and related chemicals and their potential in the management of risk from prostate cancer, placing emphasis on the anti-cancer activities of several such products through their actions as anti-oxidants, activators of transcription factors, or factors influencing epigenetic events. In addition, we recently commented on an article suggesting the potential of vitamin K1 in prostate cancer prevention and management.

The “New” Prostate Cancer InfoLink has long taken the view that a healthy diet that optimizes the relative quantities of naturally occurring vitamins and other essential biochemicals is likely to help optimize the capabilities of the immune system. A well-functioning immune system will often eliminate cancerous cells before they are able to find a micro-environment within the body where they can develop and grow into clinically significant tumors. However, it is also likely that if a specific individual has a high propensity for development of cancerous cells (for genetic or epigenetic reasons), then the probability that one of those cells will grow into a tumor capable of metastasis is significantly increased. In addition, the health of one’s immune system and one’s propensity to develop cancer cells may very well depend on things that happen early on in life (including in utero). If this is the case, it seems unlikely that dietary and nutritional changes carried out in one’s 40s or 50s are going to make a lot of difference to a man’s risk for prostate cancer (although it may still be possible to slow down progression).

We need a great deal more information about the biological growth and evolution of the immune system before we are likely to understand the real impact of diet and nutrition on prostate cancer risk and prostate cancer management. In the meantime, we intend to continue to suggest that a good, heart-healthy, and varied diet and a sensible daily quantity of that diet will be most likely to optimize overall life expectancy. If products like soy or green tea or pomegranate juice are a significant part of that diet, they may well help and they are unlikely to hurt. However, the excessive use of any one product, based on currently available information, tends to be associated with negative results.

We would like to think that future research into the potential of vitamins and nutraceuticals would be conducted with a good deal more scientific rigor than much of that seen in the past (and even the very recent past), but we predict a larger continuing stream of published data about the effects of such products on small numbers of mice than about randomized clinical trials in man.

One Response

  1. I had a patient tell me that he was taking a vitamin supplement that had a lot of lycopene, a substance in tomatoes that is thought to prevent prostate cancer, and he asked me if that would prevent prostate cancer in him.

    I love tomatoes. I love tomato sandwiches with lots of mayonnaise and lightly toasted white bread. I love tomatoes in sauce, juice, bloody marys. I love anything tomato. I have had a ton of tomatoes. I grow them. I raise them from seed. I love how they smell. I plant them on Good Friday. I have a hundred tomato cages. I have raised beds for my tomatoes. I root suckers. I know tomatoes, I love and eat tomatoes. I always have, it is something I got from my mother who loved tomatoes.

    I say to the patient, ”Yes, take the vitamin with lycopene to prevent prostate cancer. It may or may not help. I eat tomatoes every day and I got it.”

    So … take all of what you read, or have heard, or what’s on the internet with a grain of salt. I love salt on a tomatoes too.

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