Vitamin D Shines in Cancer Protection

Do you have your blood vitamin D level checked on a regular basis? You should, a plethora of research demonstrates that adequate blood levels are associated with a reduced risk for several cancers. However, studies demonstrate that about 40% of the American adult population has insufficient vitamin D levels. If you are elderly or living in a nursing home the likelihood of a vitamin D deficiency is about 60%.


Vitamin D is a fat-soluble vitamin that is found naturally in foods, such as salmon, herring, sardines, cod liver oil, butter, egg yolks, and shiitake mushrooms. Vitamin D is formed in the skin when it is exposed to sunlight.



Vitamin D supplements are used in conventional medicine for the prevention and treatment of osteoporosis and rickets. In addition, many studies have demonstrated that vitamin D plays a role in many body processes, including cardiovascular, respiratory, blood sugar regulation, joint, cognitive, and muscular, while supporting a healthy functioning immune system and normal cell division.



The liver converts vitamin D3 from foods, skin production from sunlight, and from supplements into a substance known as 25(OH)D, also known as 25-hydroxyvitamin D. It is then converted by the kidneys and other tissues into activated vitamin D (1,25 OH2D3), also known as 1,25-dihydroxyvitamin D3, or calcitriol. This active form has several anticancer mechanisms, which include the suppression of cancer cell proliferation, stimulation of apoptosis (cell death), regulation of immune cell function, inhibition of angiogenesis (reducing blood supply to tumors), reduction of prostaglandin metabolism and action (reducing inflammatory compounds that stimulate cancer growth), antioxidant effects, DNA repair, interference with growth factors (such as IGF) that are involved in cancer cell growth, and influencing the expression of genes that control cell growth and other signaling factors involved with cancer formation. The active form of vitamin D targets enzymes that break down vitamin D, making it more available to tissues for its antitumor effects.



Several population studies suggest that vitamin D deficiency increases the risk of adults developing cancer. In a study of 790 female breast cancer survivors, 75.6 percent had low blood vitamin D levels. A review of studies found that postmenopausal women with low levels of vitamin D had a higher risk of developing breast cancer compared to postmenopausal women with high levels of vitamin D. In women with a history of breast cancer, vitamin D status has been strongly associated with better breast cancer survival.


Several studies have demonstrated high blood vitamin D levels associated with a lower risk of developing colon cancer, including a review in the Journal of Clinical Oncology, which found that higher vitamin D intake and blood vitamin D levels were associated with a lower risk of colorectal cancer. A review of studies involving people with colorectal cancer found that those who had normal vitamin D levels were more likely to survive than those with low levels of vitamin D.

A study completed in the United States involved men with a diagnosis of low-risk prostate cancer who were supplemented with 4000 IU of vitamin D3 for one year. Of these men, 24 of the 44 (55 percent) showed an improvement in their biopsy results, 5 (11 percent) had no change, and 15 (34 percent) showed a worsening of their biopsy results.


A study involving prostate cancer and vitamin D published in the Journal of the National Cancer Institute found that men with the highest blood vitamin D levels had less than half the risk of lethal prostate cancer compared to men with the lowest levels.



Side effects are uncommon when blood levels of vitamin D are within the normal range. Vitamin D toxicity for prolonged periods of time may lead to high blood calcium levels, which can result in bone loss, kidney stones, and calcifications of organs. Studies demonstrate that Vitamin D toxicity is very unlikely in healthy people at daily intake levels lower than 10,000 IU.



There are two forms of supplemental vitamin D: D2 (ergocalciferol) and D3 (cholecalciferol). D3 is the type found in foods and manufactured in the skin from sunlight. It is the preferred supplemental form, especially for cancer prevention. A typical adult’s daily dosage is 5000 IU (equivalent to 125 mcg) daily taken with food. The dosage will vary depending on one’s blood levels. Current research suggests that a serum level of vitamin D (25-dihydroxyvitamin D) should be at least 40 ng/ml in order to reduce the risk of developing cancer. I recommend my patients achieve a blood level of around 50 ng/ml.



I also recommend products that combine vitamin K2 with vitamin D3, since D3 improves calcium absorption through the intestines and K2 has the action of directing calcium to the bones. Many people have low K2 levels.



Excerpted with permission from the book Outside the Box Cancer Therapies by Dr. Mark Stengler and Dr. Paul Anderson (Hay House).

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