Approximately one third of adults in the United States take multivitamin and multimineral supplements, and the main reasons for doing so are to support their health or to be sure they are getting all the nutrients they need. Yet there are questions about whether taking these supplements is always a good idea. These questions arise in part because there are uncertain if not conflicting reports on multivitamin use and cancer, particularly in men. Here are a few of those reports, including a look at whether multivitamins prevent cancer.
Multivitamins and cancer prevention
One example is a new study (October 2012) by researchers at Brigham and Women’s Hospital and Harvard Medical School, who followed nearly 15,000 male doctors (age 50 or older) for more than 10 years. Half of the participants took a brand name multiple supplement (Centrum Silver) while the other half took placebo. Centrum Silver is actually a multivitamin/mineral combination that includes vitamins A, B6, B12, C, D, E, K, and other B vitamins (i.e., biotin, folic acid, niacin, pantothenic acid, riboflavin, and thiamin) as well as the minerals boron, calcium, chloride, chromium, copper, iodine, lutein, lycopene, magnesium, manganese, molybdenum, nickel, phosphorus, potassium, selenium, silicon, vanadium, and zinc.
According to the authors of the study, men who took the multivitamin/multimineral showed an 8 percent reduction in cancer compared with men in the placebo group. Dr. John Michael Gaziano, chief of the Division of Aging at Brigham and Women’s Hospital, noted in a press release that the study “suggests, at least for men, that there might be benefits to taking multivitamins in terms of cancer.”
But as Dr. Ernest Hawk, vice president and division head for the Division of Cancer Prevention & Population Sciences at MD Anderson Center, remarked in a CNN article that “it will be difficult to make generalizations to the broad public from this one study.” The study’s authors were not able to identify which types of cancer use of multivitamin/minerals may prevent, nor if the results would apply to smokers or women. It also should be noted that the men in the study were generally healthy, non-smokers, and not overweight or obese.
The findings of this latest study have introduced some new information for experts to mull over regarding the benefits and risks of taking multivitamins and multiminerals, especially given the questions it did not answer. Among those questions are the risks associated with taking multivitamins, which have been reported in previous research.
Multivitamins and cancer risks
Several previous studies have pointed out an increased risk of cancer associated with multivitamin use. Perhaps the most notable one is the National Institutes of Health and AARP Diet and Health Study, in which 395,344 men, who were cancer-free when they enrolled in the study, were followed for five years. During follow-up, 8,765 men were diagnosed with localized prostate cancer and an additional 1,476 were given a diagnosis of advanced prostate cancer. When investigators then conducted a six-year follow-up, 179 men were found to have terminal prostate cancer.
Upon closer evaluation, the investigators discovered that men who took multivitamins more than seven times per week had an increased risk of advanced and terminal prostate cancers when compared with men who never took multivitamins. The greatest risk for prostate cancer among men with high multivitamin use was seen among men with a family history of the disease or who took supplements in addition to the multivitamin, such as carotene, selenium, and zinc. However, among men who took multivitamins regularly, there was no association between the risk of localized prostate cancer and supplement use.
In another study, which was conducted by the American Cancer Society, a total of 475,726 men who were cancer-free at the start of enrollment in the Cancer Prevention Study in 1982. The investigators reported a total of 5,585 deaths associated with prostate cancer during the 18 years of follow-up, and an evaluation of multivitamin use revealed the following:
- Death rate from prostate cancer was higher among men who had taken a multivitamin at least 15 times per month when compared with men who had not taken the supplement
- The increased risk of prostate cancer was only significant among multivitamin users who had not taken additional supplements
- The authors concluded that regular use of multivitamins was associated with a small increase in the rate of prostate cancer deaths.
If you are a man who is considering taking a multivitamin or multimineral, first evaluate your reasons for doing so. Would some minor improvements in your diet eliminate the need for a multivitamin supplement?
Eating whole, natural foods is a better way than supplements to get the nutrients your body needs. If you follow the Prostate Health Diet, you may find your need for a multivitamin or multimineral disappears.
You can also discuss your dietary needs with a knowledgeable nutritionist or your healthcare provider who can help you evaluate your needs. If it is determined you can benefit from a multivitamin or multimineral supplement, then you can work together to determine the best product for you. Be sure to look for brands from reputable manufacturers and products that have been evaluated for quality by an independent source, such as ConsumerLab.com and/or the Natural Products Association.
Read more in our Prostate Cancer Health Center.
Gaziano JM et al. Multivitamins in the prevention of cancer in men. The Physicians’ Health Study II randomized controlled trial. JAMA 2012; 308(18): 1871-80
Lawson KA et al. Multivitamin use and risk of prostate cancer in the National Institutes of Health–AARP Diet and Health study. Journal of the National Cancer Institute 2007; 99 (10): 754-64.
Stevens VL et al. Use of multivitamins and prostate cancer mortality in a large cohort of US men. Cancer Causes and Control 2005 Aug; 16(6): 643-50