A number of studies suggest dark-skinned people who live far from the equator or those who get little sun exposure or consume little vitamin D, have lower levels of the vitamin.
“Yes. We think that's why African Americans develop more prostate cancerdefinedefine, breast cancer and colondefine cancer and get more aggressive forms of those cancers," says Michael Holick, a Boston University professor and leading vitamin D researcher.
According to the scientists, low levels of vitamin D can boost chances of premature death and development of cancer, diabetes, heart disease and other ailments.
John Flack, principal investigator at the Center for Urban and African American Health at Wayne State University, Detroit, says, "I think it's potentially a very important explanation for some of the differences, from hypertension to cancer to heart failure. The actual proof is not there, but it's plausible."
But there are many other factors like reduced access to health care, pervasive barriers to healthful living (for example, neighborhoods that lack fresh groceries), differences in income and education and the stress of racial inequality, which contribute to poorer health of the African Americans, Flack adds.
Also, people with pale sin can get adequate amount of the sunshine vitamin by exposing their body to the sun for 10 to 15 minutes twice a week in the summer while people with dark skin might need about two hours of exposure each time, Holick maintains.
Excessive exposure to sun can have ill effects like extra-darkening of skin, photo-ageing, wrinkling and risk of skin cancer, warn dermatologists.
Holick says sensible and limited sun exposure can be smart option but at present, it’s important that everyone, regardless of skin color, take a daily vitamin D supplement of at least 1,000 international units (IU).
Many scientists have raised doubts about the recommendation made by Holick.
However, an expert panel at the non-profit Institute of Medicine is reviewing the recommended daily intakes, which at present are 200 IU for people up to age 50, 400 IU for people ages 51 to 70 and 600 IU for those over age 70. An 8-ounce glass of fortified milk contains 100 IU.
Adit Ginde, a researcher at the University of Colorado Denver School of Medicine, holds that all Americans, especially people with darker skin, should pay attention to new guidelines due next year.
A recent study led by Ginde revealed that vitamin D levels are low in all racial groups but are particularly low in African Americans. The study was published in the Archives of Internal Medicine.
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