Do vitamins impact prevalent causes of disease and
(Updated May 22, 2009)
Since we originally wrote this seires, there have been two updates.
A new article (reference 20) presents research on the effect of antioxidant intake, and the risk of age-related macular degeneration (a degeneration of part of the retina leading to blindness). The researchers find that intake of beta-carotine, vitamin E, vitamin C, and zinc reduced the risk of macular degeneration over the study duration of eight years. However, the intake is from food, not supplements, so there is no indication that indeed these particular dietary compononents are responsible for the improvement.
An article and editorial in the Journal of the National Cancer Institute (references 21 and 22) present data indicating that a low level of vitamin D correlates with higher incidence of cancer. They find that individuals that have a high vitamin D level, that is equivalent to adding 1500 International Units of vitamin D daily to one's diet, have a 17% reduction in overall cancer risk (Risk Ratio of 0.83, Margin of Error between 0.74 and 0.92). Likewise, there is a reduction in cancer mortality of 29% (Risk Ratio of 0.71, Margin of Error between 0.60 to 0.83). We note that the study does not claim that vitamin D supplementation reduces the risk - only that higher vitamin D levels (that may be achievable by a walk in the sun) are correlated with a reduced risk. Later research (reference 23) shows that vitamin D supplementation does not reduce invasive breast cancer incidence in postmenopausal women. In addition, the findings of this study do not support a relationship between total vitamin D intake and breast cancer risk
Another recent study, "Vitamins E and C in the Prevention of Cardiovascular Disease in Men" (reference 24) again demonstrates the lack of positive effect of vitamins C and E on cardiovascular health. This is a (trustworthy!) double blind placebo controlled study that tracked almost 15,000 male physicians for 10 years. There is one detrimental finding worth noting: vitamin E was associated with a 74% increased risk of hemorrhagic stroke, although the Margin of Error is between 4% and 191%, possibly borderline significant. However total mortality is not impacted by either vitamin.
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Modification - May 22, 2009