Vitamin D Can Increase Cancer Survival Rates For Black Americans

Main Category: Cancer / Oncology
Also Included In: Dermatology;  Public Health
Article Date: 09 Mar 2006 - 0:00 PDT

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Black Americans often have lower survival rates for cancer even for the same stage at discovery and same type of treatment. A study published in the March issue of the Journal of the National Medical Association (JNMA) suggests that one of the reasons for this difference is that Black Americans have lower levels of serum 25-hydroxyvitamin D [25(OH)D] than white Americans due to lower amounts of vitamin D from all sources. Black Americans have about 40 to 60% of the serum 25(OH)D levels of white Americans.

Vitamin D has been found to reduce the risk of developing breast, colorectal, ovarian, and prostate cancer and/or non-Hodgkin’s lymphoma and increasing the survival rates of these cancers as well as lung cancer, melanoma, and/or Hodgkin’s lymphoma in Australia, Canada, Europe, Japan, and the U.S. Solar UVB, an important source of vitamin D, has also been found associated with reduced risk of mortality for another dozen types of cancer for white Americans.

In the study published in the JNMA, it was found that summertime solar UVB doses were inversely associated with colon, esophageal, gastric, lung, and rectal cancer for Black American males, but just breast and gastric cancer for Black females. Lung cancer mortality rates, used in this ecologic study as the index for the adverse health effects of smoking, were highly correlated with these cancers (other than gastric cancer) as well as ovarian cancer, so the associations found in this study may not be solely due to smoking. However, lung cancer mortality rates are also linked to dietary fat, genetics, and vitamin D. Black women generally have lower serum 25(OH)D levels than Black men, which may have affected the findings.

A recent meta-analyses of colorectal cancer risk with respect to oral vitamin D intake and serum 25(OH)D found that about 1000 I.U. of vitamin D per day reduces the risk of colorectal cancer incidence by 50%. Black Americans have been found to have about one-third to one-half the serum levels of serum 25(OH)D corresponding to these reductions in cancer risk on average, while white Americans have about one-half to two-thirds of such levels on average.

Since Black Americans have darker skin, it takes them 2-4 times as long in solar UVB to make the same amount of vitamin D as white Americans do. The easiest way for Black Americans to increase serum 25(OH)D levels would be through supplements, with 1000 to 2000 I.U. per day recommended. Increasing vitamin D intake and serum 25(OH)D levels to these levels by Black and white Americans would likely reduce overall cancer incidence rates by 30% for Black Americans and 10% for white Americans and increase cancer survival rates by 20-30%.

The paper, Grant WB. Lower vitamin D production from solar ultraviolet-B irradiance for black Americans compared to white Americans may explain some of the difference in cancer survival rates. J Natl Med Assoc. 2006;98:357-64, can be downloaded from here (PDF)

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