Alpha-Tocopherol Supplements May Reduce Gamma-, Delta-Tocopherol Levels

Alpha-Tocopherol Supplements May Reduce Gamma-, Delta-Tocopherol Levels

BALTIMORETakingalpha-tocopherol supplements may reduce serum levels of gamma- anddelta-tocopherol, according to researchers at Johns Hopkins University. Theirrandomized, placebo-controlled trial was printed in the October issue of the Journalof Nutrition (133, 10:3137-40, 2003) (www.nutrition.org).

Despite promising evidence from in vitro experiments andobservational studies, supplementation of diets with alphatocopherol has notreduced the risk of cardiovascular disease and cancer in most large-scaleclinical trials, researchers wrote. One plausible explanation is that thepotential health benefits of alphatocopherol supplements are offset bydeleterious changes in bioavailability and/or bioactivity of other nutrients.

To test their theory, researchers assigned 184 adultnon-smokers to take 400 IU/d of RRR-alpha-tocopheryl acetate (a natural,esterified form of alpha-tocopherol) or placebo for two months. At the end ofthe study period, researchers measured changes in serum concentrations of gamma-and delta-tocopherol from baseline. Compared with placebo, supplementation withalphatocopherol reduced serum gamma-tocopherol concentrations by an average of58 percent and reduced the number of individuals with detectabledelta-tocopherol concentrations.

Researchers concluded alpha-tocopherol supplementation may notbe efficacious due to reducing serum levels of the other two vitamin E isomers,and they stated further research is clearly warranted.

Andreas Papas, Ph.D., president of YASOO Health Inc., adjunctprofessor at the College of Medicine at East Tennessee State University andsenior scientific advisor at the Institute Harvard School of Epidemiology,agreed with the Johns Hopkins researchers. Taking the whole complex is the way to get the full benefit[of vitamin E], he said. That is now becoming quite a mainstream thesis.