Opinion

  1. Auburn Auburn United States says:

    The SELECT study demonstrated only that a synthetic form of one of the eight forms of vitamin E and a form of selenium different than the form of selenium that had previously shown significant reduction of prostate cancer showed no reduction in the SELECT study.

    SELECT is a phase III randomized, placebo-controlled trial of selenium (200 microg/day from L-selenomethionine) and/or vitamin E (400 IU/day of all-rac--tocopheryl acetate) supplementation for a planned minimum of 7 years (maximum of 12 years) for prostate cancer prevention.

    The panel of investigators reconsidered the possibility of using the yeast form of selenium because results with yeast would compare directly with the results of the NPC study, which provided the major rationale for selenium in SELECT. Therefore, in July and October 2000, an expanded panel of selenium experts reexamined the decision to use selenomethionine and reevaluated the issue of whether high-selenium yeast may be a preferable source of  selenium. However, after reviewing new evidence that indicated substantial batch-to-batch variations in both the presence and relative levels of specific organoselenium compounds in samples of NPC yeast the panel reaffirmed the original decision to use selenomethionine at 200 microg/day.

    Compared with the selenium formulation considerations, the decision to use vitamin E in the form of all rac--tocopheryl acetate was made relatively easily, given both its activity in the ATBC Study and its absorption and metabolism in humans. Supplements made from naturally occurring RRR--tocopherol that have approximately twice the biologic activity of synthetic forms exist, but because there have been no controlled trials of this form in disease prevention, RRR--tocopherol was excluded as a potential choice for SELECT.

    (See Designing the Selenium and Vitamin E Cancer Prevention Trial (SELECT) JNCI Journal of the National Cancer Institute 2005 97(2):94-102; doi:10.1093/jnci/dji009 )

    Yes, you read correctly.  The committee EXCLUDED  the forms of vitamin E and selenium previously shown to be effective.  The medical expert’s remarks were incomplete and misleading.  Not an uncommon experience with media reports on supplements.

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