Prostate cancer affects 1 in 6 men, and is estimated to be the cause of 29% of all new cancer diagnoses. The incidence is increasing due to increased screening with both the Prostate Specific Antigen (PSA) blood test and the digital rectal exam (although controversy remains about the value of the PSA test used alone). Because prostate cancer accounts for 9% of all male cancer deaths, it is important to know preventive strategies.
Additionally, the incidence of many types of cancer is higher in men who also have Type 2 diabetes mellitus. Prostate cancer risk may not exactly be higher in men with diabetes, but survival is markedly reduced. Additionally, drinking coffee decreases the risk of getting Type 2 diabetes.
Those who study prostate cancer all over the world see that the incidence and mortality differ between countries and between men of different ethnicities. Part of the differences may be due to genetics, environment, socioeconomic status and inflammation; another part may be explained by diet.
Demonstrated benefits on prostate cancer have been found with plant foods like vegetables and fruits that have phytochemicals and antioxidants. Prostate cancer involves oxidative stress: both increased reactive oxygen species and loss of antioxidant enzymes cause genomic damage that precedes prostate cancer. Therefore, antioxidants and supplements have been studied for effect. Generally, study results are inconsistent, with some showing positive, negative, or no effect.
Among the most studied compounds are selenium, carotenoids lycopene and beta-carotene, vitamins E and C, and phenols (found in coffee and tea):
5 Supplements Studied with Prostate Cancer
- Selinium. Selinium is an essential trace element and an antioxidant found in seafood, cereals and meat. Brocolli and garlic contain selinium in the form of Se-methylselenocysteine. After a diagnosis of nonmetastatic prostate cancer, a 2014 study by Kenfield et al showed selinium supplementation of 140 mcg/day may increase mortality, and a 2018 review by Ballon-Landa shows selinium to be ineffective in prostate cancer prevention. The suggested daily dose is 200-400 mcg of methylselenocysteine per day (the US diet may provide 60-100 mcg/day).
- Carotenoids: Lycopene and B-carotene. From the neo-Latin Lycopersicum tomato, lycopene has a red pigment and is the optimal delivery method, at 20-30 mcg/day. In a recent 2017 study, Morgia et al showed neither a prostate cancer risk benefit nor a detriment from taking lycopene together with selenium (selinium-deficient patients who were optimized may have a decreased risk of getting prostate cancer). B-carotene. Studies with only B-carotene show no changes or reduced risk in prostate risk.
- Vitamin E. Found in nuts, oils, fruits and vegetables, gamma-tocopherol is the most common form of Vitamin E in the US. Alpha-tocopherol is the most studied due to its being the most abundant biologic form in humans as well as the most common form in supplements. D-alpha tocopherol is a synthetic form found in supplements. Different doses of alpha-tocopherol have been studied with or without other compounds like Vitamin C, D and A, selemium or B-carotene, finding mixed results. Gamma-tocopherol (found in sunflower seeds, almonds, spinach, swiss chard, and avocado) may be the ideal delivery method, decreasing risk of prostate cancer. The recommended dose is 200 mg of gamma-tocopherol in its natural form (not supplements); it may show benefit with prostate cancer.
- Vitamin C. Vitamin C prevents oxidative damage by scavenging free radicals, recycling vitamin E in the form of alpha-tocopherol, and inhibiting both the growth and viability of prostate cancer cells. While research shows vitamin C to protect against many types of cancer, there are mixed or ineffective results for prostate cancer prevention. Total vegetable and fruit intake may be more important than vitamin C consumption.
- Phenols. In a 2013 review, Terrence et al showed tea and coffee appear to offer protection against prostate cancer. In 5,035 men with prostate cancer in the Health Professionals Follow-Up Study, Wilson et al showed that drinking 6 cups of coffee per day had a decreased risk of lethal prostate cancer. Other studies have shown inconsistent results.
Lifestyle choices affect all areas of health, especially prostate cancer risk. Certainly, keep a healthy weight, eat antioxidant foods like fruits and vegetables, and avoid red meat, sugar, processed foods, animal fat and refined carbs.
While dietary supplements may have mixed results for prostate cancer risk, whole food intake may be most important.
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