SUN AND PROSTATE CANCER
No doubt, you’ve heard about the dangers of sun exposure and the risk of skin cancer. But new research suggests that getting sunshine can help prevent another of the most common cancers- prostate cancer.
Paul Marsolini is very cautious about getting skin cancer, and protects himself from the sun. “I use 30 SPF sun block. I’ll go out to the beach and spend an hour or two but I really do limit my exposure.”
While he may have protected himself from skin cancer, Paul didn’t expect that he would be diagnosed with prostate cancer.
The researchers believe the link between sunshine and prostate cancer lies in Vitamin D. They noticed that people at a high risk of prostate cancer were similar to people at risk for Vitamin D deficiency i.e. they often lived in northern latitudes, they had darker skin and were rarely young. Previous research had shown that the prostate uses Vitamin D to promote the normal growth of prostate cells, and it blocks the ability of prostate cancer cells to spread to other parts of the body and invade healthy tissue. Vitamin D is produced in the skin as a reaction to ultraviolet light and it subsequently metabolizes in the liver and kidneys to form active Vitamin D.
Dr. John Philips, a prostate cancer expert at Beth Israel Medical Center, says, “Vitamin-D is an anti-growth vitamin. We have good data with cancer cell lines and other tumors that vitamin D is anti cancer.”
The researchers compared 450 white patients who had advanced prostate cancer--cancer that had spread beyond the prostate--with a control group of 455 men who did not have prostate cancer. Sun exposure between the two groups was measured by comparing pigmentation of underarm skin, which is usually not exposed to sunlight, with forehead pigmentation, which is affected by sunlight.
There was no difference in the underarm measurement between the two groups.
But when the forehead color was compared to the underarm color, the control group had significantly darker pigmentation than the cancer patients. In all, the men with high sun exposure had half the risk of prostate cancer than did men with low sun exposure.
And in those with certain gene variants, risk was reduced even further, to as much as 65%. Apparently the genes involved determine the type of receptor the individual has for Vitamin D. The receptors vary in their ability to bind Vitamin D.
Numerous studies have unearthed a link between sunny lifestyles and reduced prostate cancer risk. But most researchers either relied on broad geographical trends or on subjects recalling specific memories of sun exposure. Further research in large populations, including non-whites, is warranted to confirm the combined effects of sun exposure and genotype, and define the exposure period that is important in influencing prostate cancer risk.
“Dietary Vitamin D, which is present in milk, milk proteins and soy can give people their dietary supplements without the risk of ultra violet radiation,” states Dr Philips.
The researchers say that men should not try to reduce their risk of prostate cancer by sunbathing because that increases the risk of sun-induced skin cancer, especially melanoma. But getting enough Vitamin D through foods and vitamins might be a safe, inexpensive and convenient method to ward off prostate cancer in men.
For most people, it usually takes just a few minutes of sun-exposure for skin to make a large quantity of Vitamin D, much less time in fact than it takes for the skin to burn. But exactly how long is needed will depend on skin type, age, location and time of day and year. It is not exactly known how much Vitamin D in supplement form one should get, but 400 international units (IU) per day is the Recommended Dietary Allowance. And 2000 IU is safe, so one might want to aim for the higher amount.
For more information on this study, click here:
http://www.nccc.org/news/prostate_cancer_sunlight_061505.html
http://ods.od.nih.gov/factsheets/vitamind.asp
Related Stories Links:
|