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Vitamin D and Cancer Prevention Featured

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  Vitamin D is essential for the formation, growth, and repair of bones and for normal calcium vitamin_dabsorption and immune function. Two major forms of vitamin D are vitamin D2 and vitamin D3. Vitamin D2 is made naturally by plants, and vitamin D3 is made naturally by the body when the skin is exposed to ultraviolet radiation. Vitamin D2 and vitamin D3 can also be manufactured. Health Benefits of Vitamin D Vitamin D deficiency is associated with muscle strength decrease, high risk for falls, and increased risk for colorectal, prostate and breast and other major cancers. Vitamin D deficiency can impact 36 organ tissues in the body whose cells respond biologically to vitamin D. The list includes bone marrow, breast, colon, intestine, kidney, lung, prostate, retina, skin, stomach and the uterus.

In the August issue of the American Journal of Clinical Nutrition, identifies vitamin D’s potential for contributions to good health in the adaptive and innate immune systems, the secretion and regulation of insulin by the pancreas, the heart and blood pressure regulation, muscle strength and brain activity. In addition, access to adequate amounts of vitamin D is believed to be beneficial towards reducing the risk of cancer. Let’s look at vitamin D to see how much vitamin D is needed for optimal health and how vitamin D deficiencies may affect you and increase your risk of cancer.  

Effects of Vitamin D Deficiency


Vitamin D deficiency can impair normal bone metabolism, leading to Rickets, Osteomalacia andrickets Osteoporosis.

Getting More Vitamin D

Get Sunshine for Vitamin . Most vitamin D is made in the body after the skin is exposed to sunlight. Despite the known and potential health benefits of vitamin D, increasing sun exposure increases the risk of skin cancer. In general, most experts believe that people should continue to use sun protection when UV levels are moderate or higher. Some researchers have suggested that brief daily exposure to UV rays will ensure adequate vitamin D production.

Vitamin D in Fortified Foods and Supplements. Fortification of foods with vitamin D in the United States is carefully regulated. Vitamin D fortification is allowed for milk and milk products, cereal flours and related products, margarine, and fruit juices and fruit juice drinks. Some yogurts are now fortified with vitamin D. Cheese, ice cream, and other dairy products made from milk are generally not fortified with vitamin D. The amount of vitamin D in multivitamins and other dietary supplements typically ranges from 400 IU to 2,000 IU.  

Vitamin D Supplements and Toxicity


Vitamin D toxicity is more likely to occur from high intakes of dietary supplements than from high intakes of vitamin D-fortified foods. For most children and adults, the recommended upper limit of vitamin D intake from foods and supplements is 1,000 IU per day for those less than 1 year of age and 2,000 IU per day for older individuals. The upper limit is the highest average daily intake level that is likely to pose no risk of adverse health effects.

Vitamin D May Have a Role in Cancer Prevention

A large number of scientific studies of many types have provided evidence suggesting that vitamin D may have a role in cancer prevention. The first evidence came from geographic correlation studies. In these studies, an inverse relationship was found between sunlight exposure levels and the rates of incidence and death for certain cancers. Individuals living in southern latitudes were found to have lower rates of incidence and death for these cancers than those living at northern latitudes. Because sunlight/UV exposure is necessary for the production of vitamin D3, researchers hypothesized that differences in vitamin D levels accounted for the observed relationships.  

Mechanisms by Which Vitamin D May Modify Cancer Risk

Laboratory studies have shown that vitamin D promotes cellular differentiation, decreases cancer cell growth, and stimulates apoptosis.  

Vitamin D and Breast Cancer

  Several studies have suggested an increase association between vitamin D intake and the risk ofself_breast_exam breast cancer, others have shown no association or even a positive association. However, most women in these studies had relatively low vitamin D intakes. When the analysis was restricted to women with the highest vitamin D intakes (400 IU, per day), their breast cancer risks were lower than those of women with the lowest intakes (typically < 50 IU, per day).  

Vitamin D and Prostate Cancer

Geographic correlation studies have suggested that men exposed to higher levels of sunlight may have a lower risk of prostate cancer. Although some epidemiologic studies have suggested that higher vitamin D levels are associated with increased prostate cancer risk, most studies have not shown such an association.

Vitamin D and Pancreatic Cancer

Participants in the Health Professionals Follow-Up Study and the Nurses' Health Study (more than 120,000 total), were followed for 16 years for the incidence of pancreatic cancer, and 365 cases were identified. Compared with participants with the lowest vitamin D intakes, those with higher intakes had progressively lower risks of pancreatic cancer.

Vitamin D and Colorectal Cancer

Some studies suggest that higher intakes of vitamin D from food and/or supplements and higher levels of vitamin D in the blood are associated with reduced risks of colorectal cancer. In the American Cancer Society's Cancer Prevention Study, lifestyle of more than 120,000 men and women were analyzed. Men who had the highest intakes of vitamin D through both their diet and supplement use had a slightly lower risk of colorectal cancer than men who had the lowest vitamin D intakes. However, this association was not observed among women. In the Women's Health Initiative randomized trial, healthy postmenopausal women took daily supplements that contained both calcium and 400 IU of vitamin D or a placebo for an average of 7 years. Supplementation did not reduce the incidence of colorectal cancer. Some scientists have raised the possibility that the relatively low level of vitamin D supplementation and the short duration of participant follow-up might account for the negative results.

Recommended Daily Intakes of Vitamin D

Currently, the recommended daily intake of vitamin D is 200 IU for people up to 50 years old; 400 IU for people 51 to 70 years old; and 600 IU for people over 70 years old. On November 13, 2008, Professor Anthony Norman of UC Riverside was joined by seventeen other UC researchers in declaring that the government’s current recommended daily allowance for vitamin D is inadequate and have ask the government to re-examine its recommendation. UC scientists suggest the recommended intake should be 2000 IU per day of vitamin D3 is the appropriate intake for most adult Americans. 2000 IU daily intake of vitamin D can be achieved by a combination of sunshine, food, supplements, and limited tanning exposure.

Bottom Line On the use of Vitamin D Supplements to Prevent Colorectal or Other Cancers


The National Cancer Institute (NCI) does not yet recommend the use of vitamin D supplements to reduce the risk of colorectal or any other type of cancer. Although some evidence suggests that vitamin D may provide some protection against colorectal and possibly other cancers, the evidence of potential benefit is limited and inconsistency.

Last modified on Wednesday, 23 February 2011 00:19
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