Vitamin E on the Moon By Wilfrid E. Shute
|
||
When the first wan to walk on the surface of the moon returned to earth, their physical condition was checked with meticulous care. Special attention was paid to medical problems that had developed during previous, shorter flights into space, notably bone demineralization, the development of hemolytic or red cell-destroying anemia, and general weakening of the cardiovascular system evidenced by a highly accelerated pulse rate.
Unlike previous space voyages, the Apollo II Moon Walk Crew, Armstrong, Aldrin and Collins, were provided a food supply that had been substantially enriched with vitamin E.
Only preliminary medical information has been released at this writing, and that has appeared in newspapers; hut it is noteworthy that there has been no mention at all of the "blood deconditioning process" -a euphemism for hemolytic anemia-that was reported after earlier space voyages of a duration of more than eight days, notably the Borman-Lovell Gemini 7 Hight in December, 1965.
Actually, in view of the fact that spacecrafts up to now have carried pure oxygen atmospheres, it is strange that it should have taken so long to recognize the need for vitamin E. it was determined many years ago, at the very beginning of the U.S. program of manned space flights, that crews are better able to withstand the fantastic accelerations required to break free of the earth's gravitational pull in an atmosphere of pure oxygen than in any other type of atmosphere.
Yet it is no secret to any scientist that pure oxygen rapidly begins to demonstrate toxic effects. As early as 1935, Behnke, Johnson, Poppen, and Motley, writing in the American Journal of Physiology (HO: 565, 1935) showed that pure oxygen is toxic and that as the atmospheric pressure increases, the toxicity of pure oxygen increases also. The hyperbaric administration of oxygen demonstrated toxic effects that quickly became well known; and by 1964 it was possible for a research team writing in Aerospace Medicine to assume that the toxic effect of pure oxygen was generally recognized by readers.
This particular paper, titled "Oxygen Toxicity and Vitamin E," was presented by the authors, Drs. Kann, Mengel, Smith, and Horton, at an Aerospace Medical Association meeting in May, 1964. Their paper should have received much wider attention than it did.
At the time their study was performed, it had already been found that when space capsule environments were simulated, with high oxygen concentrations, the volunteers who were subjected to such environments tended to develop convulsions and hemolytic anemia. Kann, Mengel, Smith, and Horton speculated that the toxic effect might derive from the peroxidation of unsaturated fatty acids, a condition that is best prevented in a normal environment by the presence of enough vitamin E in the bloodstream.
It ought to be apparent that just as an abnormal supply of unsaturated fatty acids requires additional vitamin E to prevent their peroxidation, so an abnormally large supply of oxygen would set up the same requirement. Nevertheless such a conclusion is better demonstrated than theorized about, and the Duke University research team set about performing an objective study with mice. They were able to demonstrate that vitamin E-deficient mice in a hyperbaric oxygen unit did develop hemolytic anemia and convulsions, whereas those whose diets were supplemented with vitamin E did not.
In conclusion the authors pointed out that their studies suggested that "certain manifestations of oxygen toxicity can be avoided in humans exposed to hyperoxia by pretreatment with vitamin E."
Thus vitamin E should not have been exactly unknown to those planning the diets of astronauts. A year after the report of the Duke University study, it was reviewed in Clinical Pharmacology and Therapeutics by Captain Carlos J. G. Perry of the U. S. Air Force Medical Corps. Captain Perry pointed out that, in addition to protection against peroxidation, vitamin E also has protective properties against extremes of temperature, hypoxia, and radiation exposure.
Yet in December of that same year, 1965, when Gemini 7 took off, the diet of the astronauts was supplemented with one gram of calcium a day to help counteract bone demineralization, but there was no vitamin E to protect them against the reductions in red cell mass and in blood plasma that had already been found after the Gemini 4 mission of McDivitt and White and the Gemini 5 mission of Cooper and Conrad.
It should have been known that the problem was bound to recur. Studies at the U, S. Army Medical Research and Nutrition Laboratory in Denver, Colorado, have shown very well that under conditions of high stress, it is not necessary for the diet to be high in polyunsaturates for the level of free fatty acids in the bloodstream to rise. They are mobilized from the triglyceride pool of adipose tissue. Their peroxidation in a pure oxygen atmosphere represented an obvious hazard, the answer to which was known but apparently ignored until 1969.
According to stories that appeared in the Toronto newspapers, the crew that circled the moon at Christmas 1968, again commanded by Colonel Barman, returned to earth showing a lass of between 20 and 30 per cent of their red blood cell mass. And so it was finally decided in preparing for the moon walk flight of Armstrong, Aldrin, and Collins, to supplement their diets with vitamin E as well as with calcium. In fact, they were given a full range of vitamins, since it was theorized that the dehydrated diet given them to save weight might be responsible for multiple vitamin deficiencies. In fact, the stripping of vitamin E from the diet during food processing is so universal that nearly everyone suffers from a vitamin E deficiency regardless of whether or not his food is dehydrated. if not, I have shown in the introductory chapter, there would probably be no coronary thrombosis.
In any case, we can probably be sure that the astronauts of the future will be well supplied with vitamin E on their voyages, and as a result, not only will they be spared the hemolytic anemia that has afflicted earlier crews, but they will also avoid the general weakening of the cardiovascular system that has been such a puzzle to the Aeronautics and Space Administration doctors.
Source: Vitamin E for Ailing & Healthy Hearts
|
   Beauty HealthVitamin E on the Moon
Fashion Travel |
|
