Abstract ED07-01: Vitamin D and the Cancer Connection: A D-Lightful Story
Authors: Holick Michael 
Published: May 2012

ED07-01

Abstract: ACCR

Vitamin D and the Cancer Connection: A D-Lightful Story

In the 1930’s, it was first appreciated that living at higher latitudes and having minimum exposure to sunlight increased risk of dying of cancer. This was followed by the observation by Apperley who reported that living at higher latitudes increased risk of dying of common cancers. He speculated that non-melanoma skin cancer, which is easy to detect and easy to treat, may be providing some immunity against more deadly cancers for people who live in southern United States. These data were followed by several epidemiologic studies suggesting that living at higher latitudes or being at risk of vitamin D deficiency increases risk of developing and dying of colon, prostate, and breast among other deadly cancers. Recently Iit’s has been recently reported that increased exposure to sunlight reduces risk of breast cancer in young women. Furthermore, women who ingested 1,500 milligrams of calcium and 1,100 IU of vitamin D3/d reduced their risk of developing all cancers by 60% in four years. It is now recognized that most tissues in the body not only have a vitamin D receptor but have the enzymatic machinery to produce the active form of vitamin D, 1,25-dihydroxyvitamin D3. 1,25(OH)2D3 is one of the most potent hormones for inhibiting cell growth and inducing terminal differentiation. It is believed that the local production of 1,25(OH)2D3 acts as a sentinel hormone to maintain cell growth and maturation. It’s has been estimated that more than 200 genes, many of which control cellular proliferation, differentiation, apoptosis and angiogenesis, are directly or indirectly influenced by 1,25(OH)2D3. Animal studies have revealed that vitamin D deficiency enhances colon tumor growth by as much as 40%. Novel vitamin D analogues with two side arms known as Gemini analogues have been tested in a mouse colon cancer model and have been shown to be up to 1,000 times more effective in not only reducing tumor growth and volume, but also tumor invasion when compared to 1,25(OH)2D3. In addition, these novel analogues have little calcemic activity when compared to 1,25(OH)2D3.

Studies have reported that by increasing intake of vitamin D to 1,000 IU/d could reduce risk of developing colorectal cancer by 50%. WIn women who had a blood level of 25(OH)D of at least 48 ng/ml reduced risk of developing breast cancer by 50%. Men with prostate cancer and metastatic disease who received 2,000 IU of vitamin D3/d for up to 18 months either had a significant reduction in their PSA levels or had less increase in their PSA doubling time.

The major source of vitamin D for most humans throughout evolution hasd been exposure to sunlight. However, for more than 40 years, there has been a campaign recommending that no one should be exposed to direct sunlight because it increases risk of skin cancer. Although it is true that chronic excessive exposure to sunlight increases risk of non-melanoma skin cancer, these cancers are often easy to detect and easy to treat with cure. Melanoma, however, is an aggressive deadly cancer. Because it originates in the skin, it is often included as one of the skin cancers that is caused by exposure to sunlight. However, when put into perspective, it is known that most melanomas occur on the least sun exposed areas, and, more importantly, two large studies have reported that occupational sun exposure reduces risk of malignant melanoma. Furthermore, children and young adults exposed to the most sunlight who develop melanoma are less likely to die of this deadly disease. The major risk factors for melanoma include bad genetics, red hair color and fair skin, the number of sun burning experiences especially as a child and young adult and those that have the largest number of moles on their body.

For every 100 IU of vitamin D that an adult ingests, the blood levels of the major circulating form of vitamin,[25(OH)D increases by 1 ng/ml. Most experts agree that a blood level of &gt; 30 ng/ml for 25(OH)D will provide health benefits including reducing risk of deadly cancers. It is essentially impossible to get a 1,000 IU of vitamin D/d from dietary sources. Thus, there needs to be a conscience effort to take a vitamin D supplement of at least 1,000 IU of vitamin D/d. An adult in a bathing suit exposed to 1 minimal erythemal dose of sunlight is equivalent to ingesting approximately 15,000 to 20,000 IU of vitamin D. Thus, sensible sun exposure is an excellent source of vitamin D. Indeed, even today most children and adults blood levels of 25(OH)D is seasonal in nature, with it peaking at the end of the summer and is at its nadir at the end of the winter. In the absence of any sun exposure, 2,000 IU of vitamin D/d is required for both children and adults to maintain a 25(OH)D of &gt; 30 ng/ml. Thus, all health care professionals should be vigilant about their patient’s’ vitamin D status. Either measurement of 25(OH)D once as year, preferably at the beginning of winter, with treatment for vitamin D deficiency or making certain that both children and adults are ingesting at least 1,000 IU of vitamin D/d, are two good methods to assure vitamin D sufficiency. For patients, I find that 50,000 IU vitamin D2 every two weeks for up to six years maintains their blood level of 25(OH)D at ~ 40-50 ng/ml with no toxicity.

Citation Information: Cancer Prev Res 2008;1(7 Suppl):ED07-01.