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Vitamin D and Cancer
January 18, 2004

Cancer Maps and Vitamin D
   
The National Cancer Institute's cancer incidence maps show a 2-to-1 increase in the incidence of breast and prostate cancer as you go from the southern U. S. to the northern U. S. Cancer maps of Europe show the same 2-to-1 increase as you go from sountern Europe to northern Europe, with a gradient in cancer incidence as you move north. This phenomenon has been traced to differences in exposure to sunlight, and tissue levels of vitamin D. The fact that southern Europe is at the latitudes of the mid-Atlantic to northern U. S. suggests that this effect might be even greater than 2-to-1 in Europe as you go from North Africa to Scandinavia. (North Alabama is at the same latitude as Morocco; Panama City, Florida, is at the same latitude as Cairo, and the southern tip of Florida is at the same latitude as Nigeria, Chad, and the northern Sudan. A ratio of 3-to-1 or greater might be a reasonable extrapolation of these effects as we go from South Florida north to northern Sweden, central Alaska, and central Greenland.
   When you consider that many Swedish families probably take multivitamin tablets and/or cod liver oil, and that some men and women in south Florida who work in offices all day may not get much sunlight during the winter months, with their shortened hours of daylight, you realize that the actual span of cancer incidence as a function of vitamin D may be considerably larger than the cancer maps are indicating. .
Cancer Risk Reduction Due to Vitamin D Supplementation Should Be Independent of NSAID Cancer Risk Reduction
   It also suggests to me that the mechanism(s) underlying vitamin D's role in preventing cancer is/are independent of the anti-inflammatory mechanisms of NSAID's COX-2 inhibitors, such as Celebrex and Vioxx, and the anti-inflammatory properties of the omega-3 oils. This is because, presumably, there's no geographical variation in the frequency with which people take aspiring or ibuprofen. You'd have as many people taking them in New England or Minnesota as you would in Alabama or Florida. Since they're also associated with a 2-to-1 decrease in breast and prostate cancer incidence, this suggests that the two effects are independent. In other words, someone in Alabama who takes ibuprofen every day, would have roughly one-fourth the cancer risk as someone in New England who rarely takes ibuprofen or aspirin.
Comparing NSAIDs with the Long-Chain Omega-3 Fatty Acids.
   The NSAID's block the effects of both the COX-1 prostaglandins requisite to normal cellular functioning, and the COX-2 prostaglandins that seem to be almost specific to abnormal inflammation.
   By contrast, the omega-3 oils upregulate the production of anti-inflammatory prostaglandins, and down-regulate the production of the arachidonic-acid-based pro-inflammatory prostaglandins.
    Both are necessary to a properly functioning organism, with the pro-inflammatory prostaglandins fighting infections and aiding in wound-healing, and the anti-inflammatory prostaglandins keeping the pro-inflammatory prostaglandins in balance, particularly when the inflammatory responses attack the body and cause auto-immune diseases, as well as cardiovascular disease and cancer.
   NSAIDs block the effects of the pro-inflammatory prostaglandins, while the omega-3 oils encourage the production of anti-inflammatory prostaglandins at the expense of the pro-inflammatory prostaglandins.
   Prolonged use of NSAIDs can cause liver damage and gastric disturbances (including ulcers in 2%-to-4% of the population). They act as blood thinners, particularly in the case of aspirin. Also, they can't cross the blood-brain barrier.
   The omega-3 oils are recognized by the body as essential fatty acids. Like the NSAIDs, they can also act as blood thinners. Unlike the NSAIDs, they can cross the blood brain barrier, and don't cause gastrointestinal bleeding or ulcers.
   They can cause free-radical damage unless their use is coupled with an intake of antioxidants.
Vitamin D Protects Against Other Types of Cancer As Well
   Vitamin D protects against a variety of other types of cancer, including colorectal and skin cancers.
Vitamin D Requirements Rise with Age
    Vitamin D supplementation is recommended at a daily level of 200 IU for those under 30, 400 I. U. for ages 30 to 70, and 600 IU for ages above 70.
   Obviously, a five-foot-tall woman weighing 100 pounds will need less vitamin D than a six-foot, four-inch linebacker weighing 200 pounds.
   One study author is calling for elevating the RDA for vitamin D to 1,000 I. U. a day.

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