Vitamin D – Is it a Black and White Matter?

Vitamin D, the so-called “sunshine vitamin,” has been in the news a lot recently, as more and more research suggests that the majority of Americans have lower-than-optimal levels of this important vitamin in their blood.  While we’re designed to make Vitamin D in our skin when exposed to the sun’s UV rays, the fact is that between our increasingly indoor lifestyles, use of sunscreen to protect against skin cancer, lack of exposure to sunlight for many months during the wintertime, and diets deficient in the few foods that contain Vitamin D (like fortified milk and fatty fish)… we’re coming up short on Vitamin D.

Moreover, individuals with dark skin have been shown to have even lower blood levels of Vitamin D than lighter-skinned people, causing some experts to consider whether regular Vitamin D supplementation should be recommended for darker-skinned people–and African Americans in particular– across the board.

New research in last month’s Journal of Clinical Endocrinology and Metabolism, however, suggests that the safety of taking a Vitamin D supplement may not be the same in blacks as in whites.  According to the study, higher Vitamin D status (as defined by higher levels of Vitamin D in the blood) in African Americans with diabetes was significantly associated with more calcified plaque in certain arteries (atherosclerosis); a condition which has long been recognized as a leading risk factor for heart attack and stroke.  The average blood level of vitamin D among participants in the study would be considered “insufficient,” but not overtly deficient, by currently emerging standards.
This study is the first to uncover a possible association between higher Vitamin D status and increased risk of atherosclerosis, and paints a much different picture than has been suggested in the last decade of Vitamin D research.  Most emerging research has shown that along with supporting healthy bone structure, sufficient Vitamin D status may also reduce the risk of high blood pressure, diabetes, autoimmune diseases, excess fat accumulation around vital organs, and gastrointestinal cancers.  What’s more, the overwhelming majority of research has shown Vitamin D supplementation to be exceptionally safe.
But since most of the existing research has used white subjects, the new study’s authors propose that perhaps it may not be applicable to the entire population.  For example, blacks have been shown to process calcium more efficiently than whites, which may explain the lower rates of osteoporosis in black Americans than white Americans, despite lower average dietary intakes of calcium.  This phenomenon would suggest that if a micronutrient, like calcium, is uniquely processed by individuals and across ethnic groups, who’s to say that Vitamin D – or any other vitamin or mineral for that matter – is any different?
Without a doubt, more research is needed to support this new finding and if it is validated, to explore whether it applies more broadly to African Americans without diabetes as well. But until then, the study suggests that blacks and African Americans should consult their doctor to weigh the benefits and risks of taking a Vitamin D supplement first.

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