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--> A Review of Antioxidants and Oxidative Stress in Military Personnel The Office of the Surgeon General (OSG), through the U.S. Army Medical Research and Materiel Command (USAMRMC), requested CMNR to provide interim guidance on the potential value of supplemental antioxidants for the health and readiness of service members. The questions posed by the OSG related to the value of specific supplements (Vitamins C, E and β-carotene) administered proactively to protect individuals against hazards in the military environment which may not be typical of exposures in the general U.S. population. To address this issue, the CMNR held a workshop in Washington, D.C. on July 29–31, 1998 and produced a letter report with conclusions, recommendations and responses to the following three key questions: What is the strength of the evidence to suggest that oxidative stress is a concern for service members during extremes of physical activity and other stresses encountered in training and operations? What is the strength of the evidence that vitamin C, vitamin E, and/or β-carotene are likely to protect health and performance of service members exposed to multiple environmental stresses during military training and operations (e.g. severe air pollution in some urban environments; radiation hazards to crew at altitude; radio frequency radiation hazards on ships and around communications facilities; lung and tissue blast overpressure effects and physical and psychological stresses in extreme training courses such as Ranger training and USMC crucible training)? Is there evidence, of any health risk associated with supplementing intakes of vitamin C, vitamin E, and β-carotene by service members, with the
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--> intention of maintaining health and performance in adverse military training and operational environments? Conclusions Information presented at this meeting, in earlier CMNR reports, and other scientific literature provided evidence that military service leads to exposure to unique oxidative stresses that may have adverse health consequences. Some of these stresses are reasonably well characterized, such as those associated with strenuous exercise, work in extremes of environmental temperatures, and at altitude. Much less is known about other sources of oxidative stress, such as radiofrequency and microwave radiation hazards, exposure to blast overpressure, and psychological stress related to extreme training courses or deployment. Military rations formulated in accordance with the MRDAs provide nutrients in amounts consistent with meeting nutrient needs—including the antioxidant nutrients—when these rations are consumed at levels required to maintain body weight in the usual range of physical activity for military task requirements. There is little evidence that supplementation with vitamins C, E or with β-carotene in normal conditions (i.e. in garrison) would enhance overall health. There is little evidence currently available to indicate that supplementation of vitamins C and E and β-carotene would be beneficial in protecting against short term, acute oxidative stress. In addition, the use of antioxidant compounds to minimize this stress is not without risk. Recommendations Effective methods of promoting lifestyle changes as outlined in Diet and Health (NRC, 1989a), Healthy People 2000 (DHHS, 1991) and Healthy People 2010 (in draft) should be developed as these have the greatest potential of maintaining health and performance of military personnel and their dependents, particularly in view of the introductory comments of Lt. General Blanck concerning the transition of military medicine to a health promotion emphasis. Aggressive educational efforts should be directed to military personnel engaged in operations of various intensities and in stressful environments on the importance of striving to maintain food intakes consistent with physical demands and energy requirements to avoid excessive weight loss. Emphasis should be placed on meeting the recommendations of the Dietary Guidelines for Americans (USDA/DHHS, 1995) rather than supplementing with individual nutrients. Supplementation should not be considered except in specific high stress situations where intake is likely to be markedly inadequate. If supplementation is determined to be necessary, however, data on the benefits of doses exceeding 100 mg/day of vitamin C and 50 mg/day of vitamin E as alpha tocopherol are
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--> not definitive and need to be confirmed. Supplementation of β-carotene for military personnel is NOT recommended at this time. As study results become available in trials of the interrelationships of vitamin E and vitamin C to muscle soreness and to immunological function, these recommendations should be reviewed again. Future Research Recommendations Research focused on the protective effects of antioxidants against acute oxidative stress is strongly encouraged as information is most lacking in this area. Validation of a battery of biomarkers for detecting oxidative tissue damage in human subjects in ambulatory or field situations. Evaluation of the extent to which the presence of tissue oxidative damage impacts performance. The extent and duration of oxidative stress that might be associated with hyperoxia, prolonged exposure to ionizing radiation, radiofrequency, blast overpressure, and psychological stress. Supplementation of vitamins C, E and β-carotene in a controlled, randomized way so that their true efficacy in decreasing oxidative tissue damage based on validated biomarkers can be determined. This research is essential both with respect to optimizing health and performance of personnel, and optimizing cost effectiveness. <><><><><><><><><><><><> The full text of the letter report plus the responses to the questions are in Appendix K.
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