Could vitamin D deficiency explain the disparity between cancer rates in black and white people?
Why Cancer Rates (and Deaths) are Higher for Black People
The research was carried out by a chap from the Sunlight, Nutrition and Health Research Center in San Francisco (ah, do I want to work there or what?!), and another dude from the Department of Internal Medicine at Eastern Tennessee State University (sounds a little less appealing if I’m honest). These doctors have concocted a theory that vitamin D deficiency is a possible cause for the, as yet, unexplained disparity in cancer survival rates between black and white Americans. They acknowledge that other factors (such as socioeconomic status, cancer stage at diagnosis, and treatment) are primary explanations for the difference in survival rates between patients but found that there was still a missing factor, or factors, influencing the outcome of cancer across racial groups.
Cancer and Vitamin D
William, B. Grant, PhD, and Alan N. Peiris, MD, considered the idea that biologic differences could be at play in survival from cancer and that vitamin D, whilst increasingly acknowledged as important to health, is often overlooked in these analyses. Disparities between cancer survival rates in blacks and whites focus on thirteen cancer types: bladder, breast, colon, endometrial, lung, ovarian, pancreatic, prostate, rectal, testicular, and vaginal cancer; Hodgkin’s lymphoma; and melanoma.
UVB, Vitamin D, and Cancer
Other studies have found a correlation between the incidence of these thirteen types of cancer and/or death from these cancers and the patients’ serum 25(OH)D concentrations and ultraviolet B light exposure (from the sun). For other cancer types, such as bladder, lung, and ovarian cancer, the same correlation is not as significant, although it is unclear as to why (later diagnosis, dietary factors, smoking, and so on might be more important for these, perhaps).
Sun is Most Important Vitamin D Source
London 2012 Olympic rules allow beach volleyball players to cover up in tshirts and shorts rather than bikinis. No great loss for vitamin D in London but...
There are numerous studies noting a beneficial effect of vitamin D for reductions in cancer occurrence and death from cancer and some 80-90% of our vitamin D is gained from the sun as the UVB light acts on pre-vitamin D on our skin. Although many processed foods contain added vitamin D there are no naturally vegan foods that are rich in vitamin D and so, if we don’t get sufficient sun exposure, we have to accept that we need vegan vitamin D supplements, such as Deva’s Vegan Vitamin D2, to maintain adequate vitamin D levels.
Statins and Vitamin D
A personal hypothesis, unsubstantiated as yet, is that as vitamin D is based on cholesterol it could also be that levels have dropped due to the increasing use of statins (which were recently linked to fatigue in another research paper). Cardiovascular disease is more prevalent in black people, meaning that they are more likely to be prescribed statins as a preventative medicine, thus affecting vitamin D synthesis and making a bad situation worse. Also, fatigue equals less motivation to get outside and get sun exposure to produce that vitamin D – triple whammy!
Vitamin D for Black Vegans?
Let’s make that a quadruple whammy as this latest paper also claims that black Americans are less likely to have as much vitamin D from oral intake than white peers. Their recommendation is that black Americans should take vitamin D as most are deficient. If modern medicine is to be truly preventative then we might consider scrapping the statins and going for serum vitamin D checks and prescribed supplements instead. The difficulty in proving this theory is that any research would necessarily be long-term and complex. It would need to follow healthy participants and monitor their vitamin D levels and then assess the incidence of cancer and the survival rates in different cancers amongst a select population. Slightly simpler studies could look at the effect of vitamin D levels on cancer survival in patients already diagnosed and being treated.
How Much Vitamin D to Take
The authors note that immediate action might be worthwhile, and Dr Grant recommends raising vitamin D levels to 40ng/mL through vitamin D3 supplements of 1000 to 4000IU/day. Tackling vitamin D deficiency, amongst both black and white people, may also reduce the risk of cardiovascular disease, chronic and infectious diseases, autoimmune disease such as multiple sclerosis, respiratory infections, and diabetes mellitus. Taking vitamin D2 is not as effective at raising serum 25(OH)D levels but manufacturers are starting to make vegan vitamin D3 more accessible and affordable.
Vegan Vitamin D3
Black vegans, and vegans who have a family history of diseases with a possible connection to vitamin D deficiency might wish to talk to their doctors about supplements, as might with those who live at more northerly latitudes, such as Canadian and British vegans. Despite being an ‘English rose’ I’m off to take my vitamin D2 drops, and look for some vegan D3. If vitamin D deficiency is the cause of increased cancer rates and deaths in black people, waiting for clinical trial results might not be an option for some.
Reference
William B. Grant and Alan N. Peiris, Review: Differences in vitamin D status may account for unexplained disparities in cancer survival rates between African and White Americans, Dermatoendocrinol. Volume 4, Issue 2 April/May/June 2012. Abstract
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Do Black people get skin cancer at all ?
Hi Allison,
Black people do get skin cancer and are actually more likely to die from it as it is often diagnosed much too late to provide effective treatment. According to the National Cancer Institute “in African Americans, melanomas are most often found under the nails, on the palms of hands, and on the soles of the feet,” i.e. those places with less pigment generally.
So sun-safety is paramount for all, as is vigilance about unusual skin blemishes and vitamin D levels!
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