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Overindulgence of Multivitamins Heightens Risk of Fatal Prostate Cancer |
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Written by Theresa Maher
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Wednesday, 16 May 2007 |
Multivitamins are recommended in a routine fashion for the elderly in an effort to supplement their diet with an addition of essential nutrients.
However a new study finds an excessive intake of multivitamins heightens the risk of developing advanced or sometimes fatal prostate cancer in men.
The risk of prostate cancer is especially high for men with a family history of the disease, according to researchers at the National Cancer Institute. The dietary supplements industry is very lucrative in the United States and millions of Americans pop these pills in the hope of improving their health. However experts have always questioned the benefits of these pills especially in the context of preventing cancer.
Earlier trials have also linked overindulgence of multivitamins to the development of prostate cancer. In 2005 a study by researchers at the American Cancer Society had found a higher mortality from prostate cancer among men who used multivitamins.
The study involved nearly 500,000 men and had lasted for almost 18 years. Researchers said the death rate from the cancer was slightly higher in men who used multivitamins for 15 or more times a month as compared to those who never took the supplements.
Prostate cancer is the most common cancer in men in the United States. It is also the second leading cause of cancer deaths in the country. According to the American Cancer Society, 218,890 new cases of prostate cancer will be diagnosed in the United States this years and lead to at least 27,050 deaths.
The cancer is fully curable if detected early. However in the present study, consuming multivitamins for seven or more times a week was not linked to localized prostate cancer, but was associated with an advanced one where the risk of death was relatively high.
Researchers from the National Cancer Institute followed 295,344 men who participated in the National Institutes of Health-AARP Diet and Health Study. During the study period of five years, 10,241 men were diagnosed with prostate cancer. Of them 8,765 had localized tumors, while 1,476 had advanced prostate cancer.
Excessive multivitamin usage was not linked to the risk of localized prostate cancer, the researchers said. However men who consumed selenium, beta-carotene, or zinc supplements and had a family history of prostate cancer were at an increased risk of developing lethal prostate cancer. Typically these men took multivitamins for seven or more times in a week.
Researchers said taking multivitamins for seven times a week caused 32 percent increased risk of advanced prostate or fatal prostate cancer as compared to men who did not consume multivitamins.
In an accompanying editorial published in the Journal of the National Cancer Institute, Goran Bjelakovic of the University of Nis in Serbia, and Christian Gluud of Copenhagen University Hospital weigh the benefits and adverse effects of multivitamin supplements.
They write that the study "adds to the growing evidence that questions the beneficial value of antioxidant vitamin pills in generally well-nourished populations and underscore the possibility that antioxidant supplements could have unintended consequences for our health."
However the study authors led by Karla Lawson of the National Cancer Institute in Bethesda admit they are not sure which vitamin or nutritional supplement is linked to the risk of advanced prostate cancer.
This is because multivitamin supplements contain multiple components and unless studies are conducted based on specific component; it would be difficult to pinpoint one specific vitamin/supplement as being responsible for prostate cancer risk.
Dr. Michael F. Leitzmann of the National Cancer Institute, who was a part of the study, said they would not be altering any recommendations for multivitamins based on this study.
Consumers must realize that while the above study is critical of multivitamins, these supplements have a variety of benefits. This study cautions against excessive use of these supplements and does not endorse quitting them altogether.
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