By Jimmy Downs

Saturday April 6, 2013 (foodconsumer.org) -- A new review published in the Jan 2013 issue of Pigment Cell & Melanoma Research suggests that maintaining a high level of serum vitamin D can help cancer patients reduce their risk of dying from a variety of cancers including breast cancer, colorectal cancer, gastric cancer, head and neck cancer, lymphoma and leukemia, lung cancer,  melanoma, prostate cancer, and cancer in the upper Aerodigestive tract. 

Cited in the review, one study led by S. Tretli and colleagues in Norway and published in Cancer Causes and Control shows that breast cancer patients who had greater than 81 nm of 25(OH)D were 63 percent less likely to die from breast cancer, compared with those having 46 nm of vitamin D or less in their blood.

Similarly, Tretli et al. also found that patients with greater than 81 nm of vitamin D were 60 percent less likely to die from colorectal cancer, compared with those who had less than 46 nm.

Tretli et al. and other groups of researchers, according to the reviewers, found men and women who had the highest levels of vitamin D were up to 41%, 15%, 67%, 81%, 76%, and 11% less likely to die from gastric cancer, head and neck cancer, lymphoma and leukemia, lung cancer, melanoma, prostate cancer, and cancer in the upper aerodigestive tract, respectively, compared with those having the lowest levels of vitamin D.

Is it safe to take vitamin D supplements and how much should a person take per day?

The reviewers say the National Academy of Sciences defines a maximum daily intake of 2000 IU of vitamin D3 as the upper safe limit. However, all reports of vitamin D toxicity suggest that the vitamin D level required to cause hypercalcemia, a sign of vitamin D toxicity is above 200 nM, which requires a daily intake of greater than 40,000 IU and could be considered the lowest observed adverse effect vitamin D level.

The reviewers say vitamin D intoxication is observed when serum vitamin D levels are above 150 ng/mL (374 nM), which requires intake of 50,000 IU per day to raise such a high level of 25-hydroxyvitamin D in the blood at which hypercalcemia and hyperphosphatemia are observed.

A person who exposes his hands and face to the sun for 15 minutes in the hottest hours of the day can get him 10,000 IU.  The current daily allowance recommended by the Institutes of Health is 600 IU per day for both infants and most adults.   

Vitamin D experts criticize the recommendation saying that it is irrational to recommend the same dosage both for small children and adults and the dosage per se is ridiculously low.   The Vitamin D Council says that only high levels of vitamin D have protective effects against more than 100 diseases such as heart disease, diabetes, cancer, depression.  It suggests that adults should take 4000 to 5000 IU of vitamin D daily to maintain healthy levels of vitamin D.

Reference

Guerrieri-Gonzaga, A. and Gandini, S. (2013), Vitamin D and overall mortality. Pigment Cell & Melanoma Research, 26: 16–28. doi: 10.1111/pcmr.12036