Vitamins, Minerals and Cancer
By Miguel Pelayo, MD // June 25, 2012
BREVARD COUNTY–One of the most frequent questions I am asked by my patients, and even by my family and friends, is: What vitamins or supplements are there to combat cancer, prevent it, or to enhance the immune system during chemotherapy, and are there any natural products that are helpful in those scenarios?
Coming from a Hispanic background, I have to admit that I drank my fair share of “cocimientos” cooked up by a concerned grandmother when I was sick. These questions are very difficult to answer, and unfortunately there is not much data on some supplements, but I can speak on those that have been studied in detail.
No Benefit From Vitamin A
When it comes to Vitamin A and cancer, studies have shown mixed results. In the early 90s there were some suggestions that diets high in Vitamin A or beta-carotene could decrease the risk of cancer. Interestingly, in 1994 a study published in the New England Journal of Medicine actually showed a possible increase in lung cancer in people who take these supplements. In a separate study it was noted that there was a higher incidence of prostate cancer, and higher death rate from the cancer in people taking the supplement compared to patients not taking the supplement.
Although there are no clinical trials with Vitamin A and breast cancer, there have been some suggestion of decreased risk in certain populations, although there also have been many studies not showing any relation at all. It goes without saying that no recommendations can be made at this time due to the conflicting data.
Calcium, Selenium, Vitamin E
Calcium supplementation appears to prevent the recurrence of colorectal adenomas. This was evident from combined data compiled from three placebo-controlled trials involving people who were taking supplemental calcium compared to those that were not. Calcium supplementation is endorsed by the American College of Gastroenterology for adenoma prevention. However, despite these benefits in adenoma prevention trials, the data on colorectal cancer prevention is currently conflicting, as one study did show benefit, and another did not.
A large study of over 35,000 men looked at Selenium and Vitamin E in relation to prostate cancer. This study was stopped after seven years because no decreased risk was noted. In fact, an increase in cancer incidence was noted for Vitamin E and suggested for Selenium.
Go to any health store and there are walls covered with bottles that claim their contents support and enhance the immune system. Currently there are neither randomized controlled trials nor peer-reviewed research that clearly validates immune-enhancing properties of natural supplements.
It can be argued that zinc may decrease the length and reduce the symptoms of a common cold, as was concluded from a compilation of several studies, but this is the extent of it. Vitamin C and the commonly used Echinacea were both proved to be no better than placebo in preventing or treating the common cold.
Imperative to Discuss Supplements With Physician
Any supplement must be used with caution in patients on chemotherapy for cancer. Many supplements interact detrimentally with chemotherapy, either causing increased side effects or decreasing the effectiveness of the treatment.
It is always a good idea to use caution when you are taking supplements of any kind. If you take any over the counter supplements make sure that you have discussed them with your physician. Not only may the supplements have inherent risks and side effects, they may also cause dangerous interactions with your prescription medications.
ABOUT THE AUTHOR
Dr. Miguel Pelayo graduated from the Universidad Central del Caribe, a United States accredited school in Bayamon, Puerto Rico. He completed his residency in internal medicine at the University of South Florida in Tampa and did his fellowship training in Hematology and Oncology at H. Lee Moffitt Cancer Center and Research Institute in Tampa, Florida. He is Board Certified in Internal Medicine and is a member of the American College of Physicians, the American Society of Hematology and the American Society of Clinical Oncology. Dr. Pelayo is fluent in both English and Spanish. To reach Dr. Pelayo call 855-894- 4673 or log on to SpaceCoastCancer.com