Men who develop prostate cancer are usually diagnosed with the disease after the age of 70. This is exactly the time in their lives when vitamin D levels tend to be lowest. In addition, the dark skin pigment called melanin blocks ultraviolet light, which the body uses to produce vitamin D. And black men (who tend to have high levels of melanin) have a higher risk of prostate cancer than men with lighter pigmented skin. So could there be a connection between vitamin D deficiency and prostate cancer risk? According to a new study from Brigham and Women's Hospital and Harvard University School of Public Health (BWHU), that association is significant and may provide an important tool in preventing this cancer and in treating cases in which the disease is aggressive. But what's the best way for men to maintain adequate levels of vitamin D? Ah, there's the rub. Because you'll find quite a bit of vitamin D advice out there that ranges from misguided to just plain wrong. The BWHU team used blood samples taken from 2,400 men who had participated in the Physician's Health Study. During a 13-year follow up period, a little more than 1,000 of the subjects developed prostate cancer after the samples were taken, while more than 1,300 remained free of the cancer. Researchers measured blood plasma levels of vitamin D, and also analyzed variations in the vitamin D receptor (VDR) gene and its possible link to prostate cancer risk. The VDR gene determines how well vitamin D is utilized by the body. Analysis of the data produced two striking results:
1) Subjects who had the highest vitamin D levels cut their prostate cancer risk by nearly half, compared to subjects with the lowest D levels
2) Subjects who had a specific genotype that facilitates the benefits of vitamin D, and who also had high levels of D, were estimated to have a 55 percent lower risk of developing prostate cancer, and more than 75 percent lower risk of developing an aggressive form of the cancer
The researchers believe that their study is the first to confirm that vitamin D offers protection against prostate cancer, as well as a tendency to curb clinically aggressive forms of the disease. A NutraIngredients.com report on the BWHU study featured comments from a UK nutritionist who stated that the best way to get vitamin D is by eating fortified cereals. Our regular readers won't be surprised that I nearly jumped out of my shoes when I read that one. As I've noted in previous alerts, the best dietary sources of vitamin D are eggs, liver, fish liver oils, and oily fish such as salmon, sardines, trout, and tuna. But by far, the best source of vitamin D is through sun exposure. When your skin is exposed to ultraviolet light, your body responds by manufacturing vitamin D. Of course, the idea of sun exposure runs against the current popular "wisdom" that you should completely avoid sunlight unless covered scalp to ankles with sunblock. But as Dr. Jonathan V. Wright, M.D., has pointed out in his Nutrition & Healing newsletter, sun exposure is not only good, it's essential. The damage that can set the stage for skin cancer comes when exposure is extreme and results in sunburned skin. Unfortunately, the amount of sun needed to prompt the body to create vitamin D is only available in most of the U.S. during the summer months. For the remainder of the year - and for those who live in extreme northern and southern latitudes - the most accessible source of vitamin D is from fish oil supplements. Older men and black men should ask their doctors to check their vitamin D levels by monitoring blood tests for 25-hydroxyvitamin D (also known as 25(OH)D). This is the best way to be certain that they're getting enough vitamin D. According to natural physician Dr. Joseph Mercola, the optimal 25(OH)D value is 115-128 millimicromolar (nmol/L). A value below 50 is considered a serious deficiency that increases the risk of chronic diseases, including breast cancer. By some estimates, as much as 40 percent of the population is vitamin D deficient, with a relatively small percentage qualifying in the optimal 25(OH)D range. In a 1999 issue of the American Journal of Clinical Nutrition, Reinhold Vieth, M.D., of the University of Toronto laid out some guidelines for supplementing above the vitamin D recommended dietary allowance of 200 IU per day. Dr. Vieth wrote that in order for 25(OH)D to exceed 100 nmol/L, a daily vitamin D intake of 4,000 IU is necessary. And Dr. Vieth notes that, except for people who have a hypersensitivity to vitamin D, there are no adverse effects with 25(OH)D levels under 140 nmol/L. But to reach that upper level you'd need to take 10,000 IU per day. Before you begin taking fish oil supplements, there are two important details to keep in mind:
1) If you get regular, daily sun exposure during the summer, chances are you don't need a D supplement during those three months of the year
2) Choose a fish oil supplement that's "molecularly distilled" to insure that toxins are kept to a minimum
And, as always, talk to your doctor or health care provider before starting any new dietary supplement regimen.