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At 05:27 PM 12/9/95 -0500, you wrote: >At 3:12 PM 12/8/95, IANTD wrote: > > >> > >> Vit E has been proven as a benfit >> in reducing probability to Oxygen hits and DCI. Other s such as Vit C >> etc are felt to be good. If in fact free radicals are one of the major >> producers of oxygen hits as current research reflects antioxidants >> should be the most effective means of avoiding tox. Also avoiding fats >> as they cause sluding of the blood is advisable . Exercise when not >> diving and being in good shape also go along way towards prevention >> Tom mount>-- > > >Tom, while the concept you're espousing makes SENSE, and a lot of people >think they have anecdotal evidence supporting the idea...the original >question was for STUDIES supporting the theory > >do you know of any to cite? William, I have to agree with you and John Comly. I also have problems with Tom's statement that Vit E "...has been PROVEN as a benfit in reducing probability to Oxygen Hits and DCI." I especially have a problem with the inclusion of DCI in the statement, as I know of NO published reports on Vit. E and DCI, let alone any that PROVE that Vit. has a beneficial effect. As to anti-oxidants and their effects on tolerating oxygen exposure, there are enough studies (animal) to make me feel that they fall into the "worth trying and probably no real reason not to use them" area. However, I tend to worry about conclusions drawn from studies on animals that are deficit in a substance. A healthy diver (not vitamin deficit) who takes extra Vit. E may not see any beneficial effect, and in the case of fat soluble vitamins, may actually run the risk of developing Vit. E toxicity (if the dosage is high enough for a long enough duration.) At least with Vitamin C (being water soluble) we cannot accumulate excess stores and thus the problem of potential toxicity. We have already seen how some folks in the technical dive community jumped to erroneous conclusions in the past about oxygen toxicity and neuro-transmitters, going so far as to take research out of context and recommend to their students that taking oral GABA (gamma amnio butyric acid) suppliments would be protective against CNS Oxygen toxicity. This is one of the problems when you have people with no medical or physiologic education begin making recommendations based on old, out of date research that they poorly understand (ie, gaba, taken orally, is digested before it is absorbed, and thus no significant intact GABA ever reaches the blood stream. Even if it did, there is always the blood-brain barrier that prevents many substances from crossing from the blood to the brain). As to oxygen toxicity in man, considering the extreme variability that Donald and others have reported (not only between subjects, but in the same subject on different trials), it would require enormous numbers of experimental exposures to document any significant differences between the control group (ie, those with normal Vit. E levels) versus the experimental group (those receiving Vit. E at above the RDA doses.) John
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