Vitamin D
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etiology of atherosclerosis, especially in non-Caucasians. Freedman et al. (2010) have found that serum vitamin D correlates in African Americans, but not in Euro-Americans, with calcified atheroscleratic plaque. "Higher levels of 25-hydroxyvitamin D seem to be positively correlated with aorta and carotid CP in African Americans but not with coronary CP. These results contradict what is observed in individuals of European descent". One study found an elevated risk of ischaemic heart disease in Southern India in individuals whose vitamin D levels were above 89 ng/mL. A review of vitamin D status in India concluded that studies uniformly point to low 25(OH)D levels in Indians despite abundant sunshine, and suggested a public health need to fortify Indian foods with vitamin D might exist. However the levels found in India are consistent with many other
studies of tropical populations which have found that even an extreme amount of sun exposure, such as incurred by rural Indians, does not raise 25(OH)D levels to the levels typically found in Europeans,
Mortality
Using information from the National Health and Nutrition Examination Survey a group of researchers concluded that having low levels of vitamin D (<17.8 ng/ml) was independently associated with an increase in all-cause mortality in the general population. The study evaluated whether low serum vitamin D levels were associated with all-cause mortality, cancer, and cardiovascular disease (CVD) mortality among 13,331 diverse American adults who were 20 years or older. Vitamin D levels of these participants were collected over a 6-year period (from 1988 through 1994), and individuals were passively followed for mortality through the year 2000. Shortening of leukocyte telomeres is a marker of aging. Leukocyte telomere length (LTL) predicts the development of aging-related disease, and length of these telomeres decreases with each cell division and with increased inflammation (more common in the elderly). Vitamin D can inhibit proinflammatory overeaction and slow the turnover of leukocytes, longer leukocyte telomere length is achieved by the body maintaining the optimal vitamin D concentration.
Complex regulatory mechanisms control metabolism, recent epidemiologic evidence suggests that there is a narrow range of vitamin D levels in which vascular function is optimized. Levels above or
Fatty fish, such as salmon, are natural sources of vitamin D.