Posted on August 5, 2010 -
Disclaimer: The opinions expressed in these newsletters are those of the author and do not necessarily reflect those of Nutristart Vitamin Company.
From the depths of winter darkness, we shall today discuss the “sunshine vitamin.” Though in days of yore it was known as the “antirachitic vitamin” due to its use as a treatment for rickets (a disease causing bones to become soft and bendable, leading to bowed legs, knock knees and other bone malformations). These days the winter blahs and the longing for a sunny tropical vacation may be more modern indicators of a vitamin D deficiency. It’s been estimated that as many as 80% of Canadians may have dangerously low levels of vitamin D, during our long winters. The supplement is now being prescribed for such problems as low energy, depression and joint pain. Even celiac disease (gluten-sensitivity) is indirectly linked to a deficiency of vitamin D.
Vitamin D is a fat-soluble nutrient that functions as both a vitamin and a hormone. Active metabolites of vitamin D are produced in the liver and kidney, and affect other tissues, primarily the intestinal mucosa and bone tissue. Up until recently it was believed that the only important function of vitamin D was to increase absorption of calcium and to increase calcium deposition into bones. Then we found that cultures below the equator had very little incident of Multiple Sclerosis, yet when those same peoples moved north of the equator, their levels rose to the same as those residing in the northern countries.
A recent issue of the Journal of the American Medical Association published a study done on white members of the U.S. Military. In this study the soldiers with the highest levels of vitamin D were 62% less likely to develop M.S. than those with low levels. (No link was found between blacks or Hispanics, possibly since there were so few in the study and possibly because dark skin doesn’t absorb sunlight as readily as pale skin.) Dr. William Finn, a vitamin D expert at the University of North Carolina stated “There is no question that vitamin D deficiency is an epidemic in the U.S.” and this study was “just one more reason to pay attention to it.”
Before long a link between low vitamin D levels and prostate cancer was established. “Our findings suggest that vitamin D plays an important protective role against prostate cancer, especially … aggressive disease,” said Haojie Li, MD, PhD, a researcher at Brigham and Women’s Hospital and Harvard University School of Public Health, in a recent news release. They found that men with the highest levels of vitamin D had significantly lower overall risk (45%) of devolping prostate cancer. Currently a study is under way to test a high dose vitamin D product (DN-101: Calcitriol) in conjunction with a chemotherapy drug, for treating those with prostate cancer. They hope to increase survival times and improve quality of life in those cancer patients studied, and have already noted that the patients have found the chemotherapy easier to tolerate.
Another new study published by the American Journal of Preventive Medicine, explored the link between blood levels of vitamin D and the risk of colon cancer, observing 1500 individuals over 25 years. They found that a daily intake of 2,000 i.u. of vitamin D3 could reduce the incidences of colorectal cancers by two-thirds. It has already been observed for some time now that death rates from breast, colon, ovarian and prostate cancer are considerably lower in countries with sunnier climates.
Now a new breast cancer study has found that individuals with the highest blood levels of vitamin D had the lowest risk of breast cancer. (Journal of Steroid Biochemistry and Molecular Biology.) Dr. Cedric Garland of the University of California went so far as to state: “It has more potential than any other vitamin or micronutrient to prevent cancer.” The doctors went on to say that by taking 2,000i.u. of vitamin D3 daily , one could maintain a serum blood level of D associated with a 50% reduction in breast cancer risk. They then suggest that spending 10 to 15 minutes daily in the sun will accomplish this.
For years we have been advised to stay out of the sun excessively, to avoid getting skin cancer. Ironically, it now appears that a deficiency of vitamin D may also be linked to skin cancer, as well as the aforementioned forms of cancer. The Cancer Society now suggests that you get “some” sun, but not “too much.” It was previously assumed that we got plenty of vitamin D from our limited exposure, and so they still maintain that 10 to 15 minutes is sufficient. We now know that this is not necessarily so: unless you run around naked and dirty, a lot, that is.
Making vitamin D from the sun is not as simple as we thought. It begins when the oils produced by your skin are irradiated by the ultraviolet rays of the sun. An inactive sterol formed from cholesterol then converts to the substance cholecalciferol. At this point the compound enters the blood through the skin and is converted to the active form of D3, in the liver. However, creating vitamin D in the skin from sunlight is restricted by skin pigments and natural keratin, as well as synthetic sun-blocks which all screen out ultraviolet light. Sun block with an SPF of only 8, will inhibit more than 95% of vitamin D production in the skin. Clothing, smoke, fog, smog, and most glass screen out the UV light and interfere with vitamin D formation. Then there is the daily shower. By the time you get out of that hot, chlorine and detergent mix, all the oils on the surface of your skin have been washed away. Your moisturizer does not serve the same function, as far as the creation of vitamin D is concerned. Still, it is suggested that a Caucasian could generate enough vitamin D by exposing 50% of the skin to 15minutes of noontime sun on a clear day. Those with darker pigment would require closer to 25minutes under the same conditions.
Just recently researchers at the University of California, San Diego, found that the skin holds a fair bit of inactive vitamin D, until it is attacked by microbes or bacteria, it then activates the vitamin D in the skin converting it into the D3 form, in order to defend the skin against these invaders. “Our study shows that skin wounds need vitamin D3 to protect against infection and begin the normal repair process” said Dr. Richard Gallo in the Journal of Clinical Investigation. It has already been established that vitamin D will help fight infectious diseases of the lungs, such as influenza and tuberculosis. When we remember that psoriasis is often treated with ultraviolet light, it makes me wonder if high levels of D might not have a similar effect on skin disorders. Sure enough, my studies for this newsletter revealed that some early studies found patients with psoriasis to have low blood levels of vitamin D. As well, applying vitamin D topically to those with psoriasis has been shown to reduce the symptoms.
Supplemental vitamin D is usually defined as ergocalciferol (D2, from irradiated yeast) and cholecalciferol (D3, from irradiated sheep’s wool, or fish liver oil). It is now believed that only the D3 form is active, and so should be your choice when purchasing a supplemental form. As far as dietary sources of vitamin D, the only practical dietary source is vitamin D-fortified milk (other dairy products are not fortified), which only provides approximately 100i.u. of vitamin D per cup. D is found naturally occurring in cod and halibut liver oils, in the edible portion of oily fish (salmon, herring and sardines) egg yolk, butter and liver. Since plants are a poor source of vitamin D, strict vegetarians who cannot get daily exposure to sunlight should consider a supplemental form. The medical system maintains that taking more than 2,000i.u. of vitamin D per day can cause the body to absorb excessive calcium, possibly damaging the kidney and liver. Certainly, in those prone to kidney stones, high vitamin D levels can elevate their risk, due to increasing the levels of oxalates in their urine. On the other hand, those naturally treating conditions of Multiple Sclerosis take around 6,000i.u. of vitamin D per day. I am also aware of a physician, a pioneer in the field of “orthomolecular” nutrition, who has been advising some of his patients with depression to take 10,000i.u. of vitamin D per day, throughout the winter, suggesting that it is the equivalent of a tropical holiday.
Toxicity in adults occurs when they take 100,000i.u. daily for a few months. Yet in the only documented case of pharmacological overdose (www.vitamindcouncil.com) a man inadvertently took between 156,000i.u. and 2,000,000i.u daily for 2 years. Once properly diagnosed he recovered uneventfully, after treatment with steroids and sunscreen. To put the amounts of D required into perspective let’s consider what nature provides. Humans make at least 10,000i.u.of vitamin D within 30 minutes of full body exposure to the sun. Historically even those of us in the northern hemisphere would have spent considerably more time outdoors than 30 minutes per day.
If you think you are possibly deficient have your doctor do a blood test to confirm it. Almost all the articles I researched end with a warning not to self prescribe the vitamin, as indicated by the following quote from Dr. Kim Chi (working on the new vitamin D related drug for treating prostate cancer): “We don’t want people heading out there and taking boatloads of vitamin D. It can be very toxic and life-threateningly toxic.” I would beg to differ. I would suggest that compared to many of the pharmaceutical drugs casually dumped into the market place and readily prescribed (until the dangers manifest themselves in us, the real guinea pigs), you could hardly come close to that danger in self-prescribing most nutrients. Do a little research and find out how many people have died from vitamin overdoses in the last decade (only from Iron, in the past, before child-proof lids). Now compare that to deaths from prescription drugs: 106,000 annually in the U.S. (“a conservative number”). You do the math.