Prostate Cancer and Nutrition
Prostate cancer is the most common cancer among men. It represents 13% of all new cancer cases in the US and >25,000 men will die from it this year. Risk factors for prostate cancer are: age, family history (genetics), and race.
Researchers search to determine if nutrition affects prostate cancer risk. A systematic review of 12 self-reported dietary intake and 9 biomarker studies finds no evidence of an association between prostate cancer risk and omega-3 long-chain polyunsaturated fatty acids (LCPUFAs). In the same issue of Nutrition and Cancer, Zhai and colleagues examined 13 case-control and 5 cohort studies and did not find an association between carbohydrate intake and prostate cancer risk. The initial report of the Selenium and Vitamin E Cancer Prevention Trial (SELECT) found no effect of vitamin E or selenium on prostate cancer risk.
These results are not surprising. As explained by the Prostate Cancer Foundation, prostate cancer is really several diseases with underlying causes and the impact of diet (eating too few vegetables) or behaviors (smoking) appear to be different in low-risk versus aggressive prostate cancers.
Our readers know we prefer studies measuring nutritional status. It is important, however, to remember that single time-point estimates do not reflect decades of dietary choices.
Understanding the causes of complex, multi-factorial diseases that develop over years is difficult. Some studies report beneficial effects of vitamin E supplementation whereas others don’t. It will take more than one meta-analysis to characterize beneficial or negative nutrient-disease relationships.
Differences in participant volunteers, their lifestyle behaviors, and genetics will affect the impact of nutrition on prostate cancer risk. The effect of our choices is often unknown. We do know that consuming recommended amounts of vitamins and minerals is good for our health.
Alexander DD, Bassett JK, Weed DL, Cernkovich Barrett E, Watson H, Harris W. Meta-analysis of long-chain omega-3 polyunsaturated fatty acids (LCω-3PUFA) and prostate cancer. 2015 Nutr Cancer doi: 10.1080/01635581.2015.1015745
Zhai L, Cheng S, Zhang D. Dietary carbohydrate and prostate cancer risk: A meta-analysis. 2015 Nutr Cancer doi: 10.1080/01635581.2015.1019639
Lippman SM, Klein EA, Goodman PJ, Lucia MS, Thompson IM, Ford LG, Parnes HL, Minasian LM, Gaziano JM, Hartline JA, Parsons JK, Bearden JD, Crawford ED, Goodman GE, Claudio J, Winquist E, Cook ED, Karp DD, Walther P, Lieber MM, Kristal AR, Darke AK, Arnold KB, Ganz PA, Santella RM, Albanes D, Taylor PR, Probstfield JL,, Jagpal TJ, Crowley JJ, Meyskens FL, Baker LH, Coltman CA. Effect of selenium and vitamin E on prostate cancer and other cancers: The Selenium and Vitamin E Cancer Prevention Trial (SELECT). 2009 JAMA 301:39 doi:10.1001/jama.2008.864
Brasky TM, Darke AK, Song X, Tangen CM, Goodman PJ, Thompson IM, Meyskens Jr FL, Goodman GE, Minasian LM, Parnes HL, Klein EA, Kristal AR. Plasma phospholipid fatty acids and prostate cancer risk in the SELECT trial. 2013 J Natl Cancer Inst doi: 10.1093/jnci/djt174
The Alpha-Tocopherol Beta Carotene Cancer Prevention Study Group. The effect of vitamin E and beta carotene on the incidence of lung cancer and other cancers in male smokers. 1994 NEJM doi 10.1056/NEJM199404143301501
Cui R, Liu Z-Q, Xu Q. Blood α-tocopherol, γ-tocopherol levels and risk of prostate cancer: A meta-analysis of prospective studies. 2014 PloS ONE doi: 10.1371/journal.pone.0093044