I was privileged to attend a wonderful session on Vitamin D presented by Dr. Michael Holick, PhD, MD, and Professor of medicine, physiology and biophysics. Dr. Holick has been studying Vitamin D for 30 years and was granted General Clinical Research Center Excellence in Clinical Research Award by the National Center for Research Resources at the NIH in 2006.
Vitamin D has long been used to prevent the bone disease rickets in children and to promote bone health. Current research now links vitamin D to reduced cancer risk. Dr. Holick presented extensive research evidence to support his claims of a vitamin D-cancer connection. A recent study, the Creighton Study showed a 60% decrease in cancer risk over four years in middle-aged women taking 1100 units of Vitamin D3 daily. Vitamin D is now known to regulate 200 different genes and to inhibit cancer cell growth. As it turns out, the most aggressive and dangerous form of skin cancer, melanoma, occurs most on areas of the skin not exposed to sunshine and is a cancer has been found to be a associated with a vitamin D deficiency.
Vitamin D is actually a hormone. All cells in the body have receptors for Vitamin D. Vitamin D deficiency is very common as it is almost impossible to obtain adequate Vitamin D from the foods we eat. Our body’s main source of vitamin D is sunshine. Fourteen different cancers have incident rates inversly proportional to the amount of ultraviolet radiation(rays found in sunlight)in the environment. These cancers occur more frequently in areas with less sunlight and less frequently in areas with greater sunlight. As early as 1941 it was discovered that cancer incidence was higher in the northern United States. Vitamin D deficiency is being associated with several types of cancer including breast, colon and prostate. There is much evidence that Vitamin D affects the immune system.
We live in an age where sun exposure is avoided as it has been thought to promote skin cancer and cause wrinkles. In the US Vitamin D deficiency is most pronounced for those who live in the northern United States (anyone living north of Atlanta, Georgia) as we do not have enough sun exposure in northern winter months to create Vitamin D; the sun’s rays in the winter are not sufficient for producing Vitamin D. We are also a generation that stays indoors and out of the sun as we spend so much time in front of our televisions and computers. When we do venture out, we are wearing sun screen, which prevents our skin from manufacturing Vitamin D. Our body can produce enough Vitamin D to meet our needs with just 15-20 minutes of summer sun exposure to arms and legs 3 times a week. It is now recommended that you put your sun block on in the summer after you have been outside for 15-20 minutes.
Sixty percent of us are also overweight, so may not be able to utilize the Vitamin D we do take in as vitamin D tends to become trapped in the fat cells. Also among those at particular risk for vitamin D deficiency are those with dark-skin and the elderly as darkly pigmented and elderly skin does not as easily manufacture Vitamin D from sunlight. A 70 year old only makes 1/4 as much vitamin D as a 20 year old exposed to the same amount of sunshine. Current vitamin supplementation through multivitamins is less than what is felt to be sufficient, Dr. Holick suggests about 1000 units per day. Additional supplementation may be recommended in the winter in northern latitudes or for those over 50 years of age.
Vitamin D deficiency is felt to be epidemic in our society, and is now also being associated with the development of diabetes and several autoimmune disorders such as MS and rheumatoid arthritis.
Interesting, I have a new oncologist. I asked him his thoughts on vitamin D and cancer. He said he is now testing his patients for vitamin D deficiency, and almost 50% of his cancer patients have a severe vitamin D deficiency.
The blood test to determine if you are vitamin D deficient is 25-hydroxyvitamin D. Normal levels should be at least should be at least 30-60 ng/mL. Toxic levels are those above 150 ng/ml.
For more information, you can go to the website The UV Advantage
You can view Dr. Holick’s excellent lecture online at The Vitamin D Pandemic and its Health Consequences