Do Sunlight and Vitamin D Increase Cancer Survival Time?


sunny day at a state parkFor years we have been told that sunlight causes cancer, and that we should work hard to avoid any sun exposure. This sun-cancer connection certainly seems to hold true for many types of skin cancer, especially for fair-skinned individuals. If we need proof that the sun causes skin cancer, we need only look at the increasingly alarming rate of skin cancer among teenagers. However, all of this said, maybe the sun is not completely bad after all, as new research suggests that sunlight may actually benefit those who already have internal cancer. Read the full story over at Cancer Decisions, a website run by Dr. Ralph Moss.

Allow me to summarize the study. Research conducted at Boston area hospitals by Harvard scientists showed that those who had cancer surgery in the summer were almost 25% more likely to survive five years than those who had their cancer surgery in the winter, spring, or fall. Why is this? Well, right now nobody can be absolutely sure, but the researchers tied the increased survival time to sunshine and the only vitamin our bodies make from sunshine: vitamin D.

Vitamin D is also known as cholecalciferol, and acts as hormone. It is best known as a bone-strengthening agent and preventer of Ricketts. It is present in fatty fish like salmon and herring, as well as in many milk products. Of course, most people get their vitamin D from the sun. According to the Cholecalciferol Council, most of us make about 20,000 IU (international units, one of which equals .025 mcg of Vitamin D) after being in the sunlight for 20 minutes. This is the vitamin D in 500 glasses of milk, and 50 times the current RDA. It is not recommended you get this amount in supplemental form, because vitamin D from sunlight will not accumulate to toxic levels like Vitamin D from supplements can. However, this illustration shows the importance of sunshine in getting adequate levels of vitamin D. It is easy to see how lack of sun in the winter can affect our serum vitamin D levels.

Now let us return to the cancer study. When vitamin D was added to the research criteria, the results were even more stunning. The study showed that "patients with the highest vitamin D intake who had surgery in the summer had a threefold better disease-free survival and a four-fold better overall survival than patients with the lowest vitamin D intake who had surgery during winter." Also, The five-year disease-free survival was 83 percent for those with high levels of vitamin D in the summer, versus 46 percent for those winter patients with low levels, and the five-year overall survival rate was 72 percent compared to 30 percent, respectively.

That vitamin D and sunlight might prevent cancer and prolong survival time of those with cancer is backed by other studies. Various studies have shown that sunlight correlates with lower rates of colon, breast, and prostate cancers, although some studies have found no correlation. Interestingly, the research shows that vitamin D and sun exposure seem to only work with regard to internal cancers, while sunlight increases the rate of external cancers.

I remember once remarking that vitamin D was one of those boring supplements with no therapeutic use. I often wondered why companies even bothered manufacturing it. However, recent years have proven me wrong! The lesson from this study (which is still preliminary, so it is too early to draw too many lessons)? Getting out in the sun for a little bit and enjoying your summer may actually be beneficial, especially if you are undergoing cancer treatment. However, remember, it is a fact that too much sun exposure increases your risk of skin cancer so use common sense. This means using sunblock if you are going to be out in the sun for longer than 20 minutes, and avoiding sun exposure during peak daylight hours. Of note, many doctors recommend consuming no more than 800 IU/day of vitamin D from all supplement and food sources, and even then some suggest taking fat soluble vitamins like Vitamins A and D every other day to prevent toxic build-up.

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For more information on studies relating to vitamin D, sunshine, and cancer, click here. Remember that Vitamin D (and sunshine) is not to be used as a primary treatment for cancer, or without a doctor's supervision.

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