When it comes to cancer – prostate or otherwise – people often have questions about what could have caused it, if there’s anything they could have done to prevent it, or whether certain dietary changes or supplements can cure it.
Why Study Multivitamins?
Multivitamin use is very common: 34%-49% of older adults report regular use, and thus it’s important to know what effect this might have on the development of various conditions, including prostate cancer.
In prostate cancer, there has been conflicting information. One large randomized clinical trial showed no link between multivitamin use and risk of developing prostate cancer overall. Other studies following large numbers of men over time showed inconsistent results, with some studies finding no association and others suggesting an increased risk of advanced prostate cancer.
Now, results of a new study led by Dr. Yiwen Zhang of the Harvard T.H. Chan School of Public Health, along with PCF-funded researcher Dr. Lorelei Mucci, are shedding new light on the relationship between multivitamin use and the development of prostate cancer.
Zhang and team analyzed data on more than 48,000 men in the Health Professionals’ Follow-Up Study, which has followed male health professionals since 1986. The study collects detailed information on health conditions and lifestyle habits, including the key variables (multivitamin use and frequency, and diagnosis of prostate cancer), other dietary supplement use, intake of foods such as tomatoes and fish, body mass index (BMI), PSA testing, family history of prostate cancer, and more.
Among the 48,000 men, about 30,000 were current or past users of multivitamins. There were approximately 7,000 cases of prostate cancer over 30 years of follow-up. Using mathematical modeling, Zhang and team found no association between multivitamin use and risk of prostate cancer overall or of advanced or fatal prostate cancer. In other words, men who reported regular use of multivitamins (7 or more tablets per week) had a similar risk of prostate cancer compared with men who never took multivitamins. Long-term multivitamin use of 15 years or more was also not linked to diagnosis of or death from prostate cancer. The researchers further considered how other factors (e.g., other supplement use, BMI, PSA testing) may also be related to multivitamin use and diagnosis of prostate cancer. Accounting for these factors did not change the conclusions.
The study has several strengths, including collection of multivitamin use data at multiple timepoints, extensive data on other relevant factors, and long follow-up time. One limitation is that because the study population consists of highly-trained health professionals (mostly white) who were expected to be already well-nourished, the results might not be generalizable to populations with different nutritional status or ethnic groups.
Prostate Cancer Prevention
So, if a multivitamin is not the answer, what CAN you do to prevent prostate cancer, or reduce the risk of recurrence if you’ve been diagnosed? Research suggests that certain dietary factors may help. To lower your risk of fatal prostate cancer, avoid whole milk, opt for healthy vegetable fats (like olive oil), choose fish over red and processed meat, and include cooked tomatoes and cruciferous vegetables (like broccoli) in your diet. If you smoke, ask your doctor for support to quit. And many studies have shown that exercise is a powerful tool to lower the risk of prostate cancer recurrence – by as much as 60%. For more, see our series of articles with Dr. Lorelei Mucci on lifestyle and prostate cancer.
Do You Need a Multi?
What about taking a multivitamin for general wellness? You may not need one if you follow a whole-foods diet with plenty of brightly-colored vegetables and whole grains, varied proteins (emphasizing plant-based), and minimal packaged “snack foods” and sugars. (A multivitamin is also not going to “make up” for a nutrient-poor diet: whole foods contain fiber and cancer-fighting antioxidants not found in a pill!) Everyone’s health situation is different, so check with your doctor or a nutritionist about whether you are getting the right kind of nutrients in your diet. For example, if you are on hormone therapy for prostate cancer treatment, your doctor may recommend calcium and vitamin D supplements to maintain bone health. For more nutrition and lifestyle tips, download PCF’s guide, The Science of Living Well, Beyond Cancer.