Compelling Reasons to Study Vitamin E Status
Earlier this year, the US and Canadian governments established Federal Dietary Reference Intake (DRI) Committees to prioritize nutrients for government-funded reviews and subsequent commissioning to establish reference values. The announcement was published in the Federal Register.
Sixteen nutrient substances were nominated. Five of these are fat/fatty acids: saturated fat, stearic acid, and the long-chain polyunsaturated acids - arachidonic acid (ARA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). The remaining 11 were: choline, chromium, fiber (viscous and fermentable), magnesium, niacin, potassium, protein, sodium, vitamin B6, vitamin E, and zinc. According to the process, the committees will be evaluating to see if sufficient new and relevant information is available, whether a review would address an important public health concern, and if there are unresolved methodological issues which would impede a DRI review.
Hopefully, the committee takes a good look at vitamin E. Three national surveys (NHANES 1988-1994, NHANES 1994-1996, NHANES 2001-2002) and four more recent surveys (NHANES 2003-2004, NHANES 2005-2006, NHANES 2007-2008, NHANES 2009-2010)find that the diets of most Americans provide less than the RDA levels of vitamin E. Yet there hasn’t been a government review of the science on vitamin E since 2000.
The 2010 Dietary Guidelines Advisory Committee recognized that only 7% of Americans had a vitamin E intake above the Estimated Average Requirement (EAR, Figure D2.14). Similar proportions (Figure D2.15) were identified for 4 nutrients which only had Adequate Intakes (AI), not EARs - dietary fiber 4%, potassium <3%, vitamin D 31%, calcium 36%. These four nutrients, but not vitamin E, were identified as nutrients of concern.
After a meta-analysis of high-dosage vitamin E supplementation (≥400IU/d) in 2005, recommendations were made to avoid vitamin E supplements with little regard for the fact that baseline blood α-tocopherol concentrations exceeded 25μmol/L in these studies. There is little evidence adding nutrients to nutritionally replete individuals will affect health outcomes.
Do most people have these levels of vitamin E? No. According to Valtuena and colleagues and Duly and colleagues, optimal blood α-tocopherol concentrations to prevent cardiovascular disease and cancer are ≈30 μmol/L. By this standard, > 50% of Americans are vitamin E insufficient, even among individuals with glaucoma.Finally, vitamin E supplementation may be a low-cost, easy-to-use approach to decrease the risk of developing cardiovascular disease in some (≈37%) individuals with diabetes.
It is time for the Federal Dietary Reference Intake (DRI) Committees to recommend a new review of vitamin E.
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