Prostate Cancer, Vitamin D, and Skin Color
Prostate cancer occurs more frequently in men with African-American ancestry. Prostate cancer is the second most common cause of death in American men; lung cancer is number one (American Cancer Society). Today, Murphy and colleagues link prostate cancer risk to low vitamin D status and race.
People with darker, more pigmented skin need to spend more time in the sun to synthesize and maintain normal vitamin D levels. With the advent of air conditioning, more indoor jobs, a paucity of vitamin D-rich foods, and guidance to use sunscreens to prevent skin cancer, many people have suboptimal vitamin D levels.
Murphy and colleagues measured serum 25-hydroxyvitamin D concentrations in 667 men, 40-79y, with prostate biopsy results following detection of abnormal prostate-specific antigen and/or digital rectal examinations. Regardless of race, men have suboptimal 25-OH D levels was significantly associated with high-grade disease on biopsy: 3.7 times higher in European-Americans below 30 nmol/L and 4.9 times higher in African-Americans below 50 nmol/L. In both cases and controls, approximately 40% of the men were found to be vitamin D deficient (< 50 nmol/L). [Please note that the authors defined 50 nmol/L as deficient whereas the Institute of Medicine defines deficient as ≤30 nmol/L and ≥50 nmol/L as sufficient ]. Only 13% of the men were using a vitamin D supplement. “
The authors wrote, “If normal serum 25-OH D is between 30 to 80 ng/mL, then no one in our sample had elevated serum levels of 25-OH D.” Because our diet isn’t particularly rich in vitamin D (and laws prohibit food and beverage manufacturers from fortifying many products with vitamin D), supplementation and/or spending time in the sun are important. Marshall and associates reported that 4000 IU vitamin D3 daily significantly reduced the risk of negative biopsies at 1 year reduced the risk of prostate biopsies with positive cores or the Gleason score in men being monitored for prostate cancer. The average baseline serum 25-OH D concentrations was 82 nmol/L in this cohort.
Murphy and colleagues report that severe vitamin D deficiency is positively associated across racial groups with higher Gleason grade disease and higher prostate tumor stage. African-American men had higher rates of vitamin D deficiency than their European counterparts.
Vitamin D isn’t an option; it is an essential nutrient. Boys, listen up. Maintaining optimal serum vitamin D concentrations is important for prostate health.
Murphy AB, Nyame Y, Martin IK, Catalona WJ, Hollowell CMP, Nadler RB, Kozlowski JM, Perry KT, Kajdacsy-Balla A, Kittles R. Vitamin D deficiency predicts prostate biopsy outcomes. 2014 Clin Cancer Res doi: 10.1158/1078-0432.CCR-13-3085
Weaver CM, Dwyer J, Fulgoni III VL, King JC, Leveille GA, MacDonald RS, Ordovas J, Schnakenberg D. Processed foods: contributions to nutrition. 2014 Am J Clin Nutr doi: 10.3945/ajcn.114.089284
Hall LM, Kimlin MG, Aronov PA, Hammock BD, Slusser JR, Woodhouse LR, Stephensen CB. Vitamin D intake needed to maintain target serum 25-hydroxyvitamin D concentrations in participants with low sun exposure and dark skin pigmentation is substantially higher than current recommendations. 2010 J Nutr doi: 10.3945/jn.109.115253
Marshall DT, Savage SJ, Garrett-Mayer E, Keane TE, Hollis BW, Horst RL, Ambrose LH, Kindy MS, Gatton-Celli S. Vitamin D3 supplementation at 4000 international units per day for one year results in a decrease of positive cores at repeat biopsy in subjects with low-risk prostate cancer under active surveillance. 2012 JCEM doi: 10.1210/jc.20132.1451