By Marc Sorenson, EdD, Sunlight Institute…
A short time ago, we posted a blog showing that little boys who had high sunlight exposure were about 82% less likely to develop prostate cancer than those who were not exposed. Now let’s take a look at additional interesting science on sunlight and prostate cancer.
Norwegian research has also demonstrated an inverse correlation between prostate cancer and sunlight when death rates from prostate, breast and colon cancer were compared to the season in which the cancer was diagnosed.[i] [ii] Over 36 months, study subjects diagnosed during summer and fall (times of the greatest sunlight exposure and vitamin D production) had much lower death rates than those diagnosed in winter and spring.
Another indication of the influence of sunlight on prostate cancer is research on prostate specific antigen (PSA). The higher the PSA level in the blood, the greater is the chance of cancer. When the prostate gland is undergoing changes that may lead to cancer, PSA levels generally rise. Men with the lowest levels of lifetime sunlight exposure have higher PSA levels than those with the highest levels of sunlight exposure.[iii]
Nevertheless, a recent meta-analysis of studies of serum vitamin D levels and prostate cancer showed no relationship between prostate cancer and vitamin D.[iv] The reason for the discrepancy between a lowered risk of prostate cancer correlating to higher sunlight exposure but not correlating to a higher serum level of vitamin D is unknown. It is probable that the beneficial influence of sunlight on prostate cancer goes beyond its stimulation of vitamin D production in skin. And according to Dr. Cannell, the reason for the lack of a relationship between blood levels of vitamin D and prostate cancer may be because the subjects in the studies received much of their vitamin D from cod-liver oil, high in vitamin A, which has been shown to thwart the beneficial effect of vitamin D on cancer,[v] possibly due to the fact that retinol (vitamin A) competes with activated vitamin D for receptor sites.[vi] Suffice it to say that sun exposure is the safest and surest way to reduce the risk of prostate cancer. Men, protect your health and your love-life by getting your share of the wonderful sun.
[i] Robsahm TE, Tretli S, Dahlback A, Moan J. Vitamin D3 from sunlight may improve the prognosis of breast-, colon- and prostate cancer (Norway). Cancer Causes Control 2004;15:149-58.
[ii] Lagunova Z, Porojnicu AC, Dahlback A, Berg JP, Beer TM, Moan J. Prostate cancer survival is dependent on season of diagnosis. Prostate 2007;67(12):1362-70.
[iii] Weinrich S, Elliaon, E, Weinrich, M, Ross, K, Reis-Starr, C. Low sun exposure and elevated serum prostate specific antigen in African American and Caucasian men. AM J Health Stud 2001;17:148-55
[iv] Lu Yin, Elke Raum, Ulrike Haug, Volker Arndt, Hermann Brenner. Meta-analysis of longitudinal studies: Serum vitamin D and prostate cancer risk. Cancer Epidemiology 2009;33: 435–45.
[v] Cannell, J. Vitamin D newsletter: February 28, 2010.
[vi] Bao Y, Ng K, Wolpin BM, Michaud DS, Giovannucci E, Fuchs CS. Predicted vitamin D status and pancreatic cancer risk in two prospective cohort studies. Br J Cancer 2010;102(9):1422-7.