Nutrients for a Healthy Prostate
Recent studies have revealed a strong link between diet and prostate cancer. Men concerned about prostate cancer may benefit by increasing their intake of five key nutrients. These nutrients can be obtained by eating certain foods or taking nutritional supplements.
Selenium is a trace mineral that is essential for good health. It functions as an antioxidant in our bodies, helping to prevent and repair cellular damage. The best dietary sources of selenium include Brazil nuts, bread, meat and seafood, and plant foods.
Studies link low selenium levels with an increased risk of prostate cancer. A recent review found that prostate cancer risk decreased as selenium increased, up to a certain level in the blood.1
Clinical trials with high-dose selenium supplements have shown mixed results. In one trial, men who took 200 mcg of selenium (as high-selenium yeast) a day had a 49% reduction in risk of prostate cancer.2 In the more recent SELECT study, 200 mcg of selenium (as selenomethionine) did not affect the risk of prostate cancer among healthy men.3
It is important to get an adequate amount of selenium. Look for a prostate health supplement that contains the recommended daily value of 70 mcg a day.
Vitamin E is a fat-soluble vitamin found in fats and oils such as salad dressings, margarine, and cooking oil. Other food sources include green leafy vegetables, peanuts, and almonds. Vitamin E’s main role in our bodies is as an antioxidant, protecting cells from the damaging effects of free radicals. Vitamin E is made up of a family of compounds called tocopherols. There are four tocopherols: alpha, beta, delta, and gamma. Although gamma-tocopherol is the primary source of vitamin E in the American diet, most vitamin E supplements contain only alpha-tocopherol.
One study showed that men who took 50 IU of alpha-tocopherol reduced their incidence of prostate cancer by 32% and their risk of death from prostate cancer by 41%.4 In the SELECT trial, high-dose alpha-tocopherol (400 IU a day) did not decrease prostate cancer risk.3 It is thought that this dose was likely too high, and did not provide the various tocopherols found in vitamin E-rich foods. High-dose supplements with only alpha-tocopherol lower the body’s level of gamma-tocopherol.5 Lowering those levels might not be beneficial, since research indicates that gamma-tocopherol may play an important role in decreasing prostate cancer risk.6-8
Based on this and other research, a supplement for prostate health should contain gamma tocopherol, along with a mixture of vitamin E from other natural “mixed” tocopherols.
Vitamin D is a fat-soluble vitamin that helps regulate the body’s calcium balance. Research over the last decade shows that vitamin D is not only important for bone health but also benefits the immune system and reduces the risk for a variety of health conditions.9 Vitamin D deficiency has been linked to more aggressive prostate cancer,10 and in one study, 2,000 IU of vitamin D a day resulted in a decrease in the rate of PSA rise in men with a prostate cancer recurrence.11
Adequate vitamin D levels depend on sun exposure and dietary intake. It is not surprising that the incidence of prostate cancer is higher in the northern U.S. than in the south. African Americans, who cannot produce as much vitamin D due to their skin pigmentation, have higher rates of prostate cancer than do white men. African Americans appear to require a higher vitamin D intake to reach and maintain normal vitamin D blood levels than do Caucasians.
According to the National Institutes of Health, older men need more vitamin D than younger men. Since most do not get enough in their diet or from sun exposure, taking a supplement is recommended.
Lycopene is a carotenoid, or plant pigment, that gives tomatoes their red color. Lycopene acts as a powerful antioxidant in our bodies, and studies have revealed a link between an increased intake of lycopene and a reduced risk of prostate cancer. Lycopene is most abundant in tomatoes, but is found in lesser amounts in pink and red grapefruit, guava, and watermelon. Interestingly, cooked tomatoes provide more lycopene than raw tomatoes.
In two small clinical trials, men with newly diagnosed prostate cancer were treated with either 30 mg lycopene a day (from Lyc-O-Mato®, a whole tomato extract) or placebo before undergoing radical prostatectomy. In these studies, lycopene supplementation decreased the growth and spread of prostate cancer cells and decreased PSA levels.12,13
China, Japan, and Korea have the lowest prostate cancer death rates in the world. Diet is believed to play a large role in this decreased risk. A traditional Asian diet is low in fat and rich in soy, fish, and green tea. The average Asian diet contains 50 mg of soy isoflavones a day, compared to the average Western diet, which contains less than 5 mg a day.
Soy foods, which include tofu, soy milk, and soy nuts, contain compounds known as isoflavones, or plant estrogens. These compounds may decrease the growth of prostate cancer cells, and in men who have been treated for prostate cancer, may decrease the rate of PSA rise.14 In men being treated with radiation therapy, soy isoflavones may decrease side effects and make the prostate cancer cells more sensitive to the treatment.15,16
1. Hurst et al. Selenium and prostate cancer: systematic review and meta-analysis. Am J Clin Nutr. 2012; 96(1):111-22.
2. Duffield-Lillico et al. Selenium supplementation, baseline plasma selenium status and incidence of prostate cancer: an analysis of the complete treatment period of the Nutritional Prevention of Cancer Trial. BJU Int. 2003; 91(7):608-12.
3. Lippman et al. Effect of selenium and vitamin E on risk of prostate cancer and other cancers: the selenium and vitamin E cancer prevention trial (SELECT). JAMA. 2009; 301(1):39-51.5.
4. Heinonen et al. Prostate cancer and supplementation with a-tocopherol and b-carotene: incidence and mortality in a controlled trial. J Natl Cancer Inst. 1998; 90:440-446.
5. Ju et al. Cancer-preventive activities of tocopherols and tocotrienols. Carcinogenesis. 2010; 31(4):533-42.
6. Jiang et al. Gamma-tocopherol or combinations of vitamin E forms induce cell death in human prostate cancer cells by interrupting sphingolipid synthesis. PNAS. 2004; 101(51):17825-30.
7. Helzlsouer et al. Association between alpha-Tocopherol, y-Tocopherol, selenium, and subsequent prostate cancer. J Natl Cancer Inst. 2000; 24: 2018-2023.
8. Wright et al. Supplemental and dietary vitamin E intakes and risk of prostate cancer in a large prospective study. Cancer Epidemiol Biomarkers Prev. 2007; 16(6):1128-35.
9. Holick. Vitamin D deficiency. N Engl J Med. 2007; 357(3):266-281.
10. Murphy et al. Vitamin D deficiency predicts prostate biopsy outcomes. Clin Cancer Res. 2014; 20:2289-99.
11. Woo et al. Pilot study: potential role of vitamin D (cholecalciferol) in patients with PSA relapse after definitive therapy. Nutr Cancer. 2005; 51(1):32-36.
12. Kucuk et al. Effects of lycopene supplementation in patients with localized prostate cancer. Exp Biol Med. 2002; 227(10):881-885.
13. Hussain et al. Soy isoflavones in the treatment of prostate cancer. Nutr Cancer. 2003; 47(2):111-7.
14. Kumar et al. The specific role of isoflavones in reducing prostate cancer risk. Prostate. 2004; 59(2):141-7.
15. Hillman and Singh-Gupta. Soy isoflavones sensitize cancer cells to radiotherapy. Free Radic Biol Med. 2011; 51(2):289-98.
16. Ahmad et al. Soy isoflavones in conjunction with radiation therapy in patients with prostate cancer. Nutr Cancer. 2010; 62(7):996-1000.