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Committee on Military Nutrition Research: Activity Report Appendix I Conclusions and Recommendations from the Workshop Report: Food Components to Enhance Performance Submitted May 1994
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Committee on Military Nutrition Research: Activity Report This page in the original is blank.
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Committee on Military Nutrition Research: Activity Report Conclusions and Recommendations CONCLUSIONS As stated in Chapter 1, the Committee on Military Nutrition Research (CMNR) was asked to respond to six specific questions dealing with the potential for food components to enhance performance for military personnel in combat settings. The committee's responses to these questions appear below. The committee further reviewed the current knowledge base regarding specific categories of food components that were identified by Army scientists as having potential to enhance performance in light of the classification of ergogenic aids and the mechanisms of action as discussed by John Ivy (Chapter 12). Substances that may optimize physical performance are frequently referred to as ergogenic aids (Chapter 12). These may be divided into five categories: (1) mechanical, (2) psychological, (3) physiological, (4) pharmacological, and (5) nutritional. The mechanisms by which foods or food components may act as ergogenic aids as discussed by Ivy are (1) acting as central or peripheral stimulants, (2) increasing the storage or availability of limiting substrates, (3) acting as a supplemental fuel source, (4) reducing or neutralizing metabolic by-products, and (5) enhancing recovery. Each food component was also reviewed in light of the time frames and military scenarios drawn up by Army scientists (see Appendix A). The recommendations and conclusions drawn about the potential for these food components to enhance performance are included in the specific committee recommendations that follow.
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Committee on Military Nutrition Research: Activity Report GENERAL CONCLUSIONS General Concepts of Performance Enhancement The first consideration in maintaining or enhancing performance is to endeavor to insure that troops are in a well-hydrated, rested and well-nourished state-including optimal amounts of all essential micronutrients, plus the best in military training, both physical and mental, in advance of anticipated periods of stress. Under these circumstances performance is unlikely to be improved in the absence of the imposition of military operations which impose physical or mental stress. Obviously battlefield situations are not free of stress. Under these conditions troops are frequently deprived of sleep, apprehensive, haven't eaten sufficient food to meet their energy expenditures, dehydrated to varying degrees and exposed to environmental extremes of heat, cold, altitude, etc. which impacts on their physical and mental state. Given these conditions, enhancement of performance is more likely to be restoring performance to non-stressed baseline than to improvement over that expected from well-nourished and well-rested troops. The military Science and Technology Objective (STO) of enhancing performance by 10-15 percent is more realistic in short term enhancement of performance under stress than to obtain super performance from troops in a well-fed, well-rested state. While some of the food components considered in this report may be used at usual dietary levels (caffeine, carbohydrate) others are likely to be at levels of intake that may be considered pharmacological. These components may be provided in operational ration items designed to be used at specific times and provide short-term enhancement through increased vigilance, reduced feeling of fatigue, improved mental state, etc. The enhancement capability of a component likely will have a threshold which must be met to have a benefit and will also likely have a “wear out” when the stimulus can no longer overcome the adverse effect of the stress. In researching the effectiveness and safety of these pharmacological components it will be important to determine these levels and time periods to evaluate both safety and efficacy. It is also noted that some of these helpful nutritional effects may be maximized by the additional use of conventional over-the-counter drugs that block the intracellular formation of stress-induced prostaglandins, which contribute importantly to many symptoms and the ill effects of stress.
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Committee on Military Nutrition Research: Activity Report Food Components or Nutrients that Offer Potential to Enhance Performance The following food components have potential for enhancing performance under certain circumstances that may be encountered in military operations. Carbohydrates. The role of carbohydrate as a fuel source for extended physical activity is well-known. Increased storage of glycogen prior to extended physical performance through consumption of high-carbohydrate meals and consuming carbohydrates during an extended physical activity as a means of increasing performance is well established. Studies with soldiers in military activities are less clear but likely relate to the more intermittent nature of the physical activity, in comparison with the extended moderate-to high-level physical activities of athletic competition. The value of carbohydrate supplementation in extending physical performance is usually demonstrated after 60–90 minutes of continuous activity at 60 to 70 percent of maximal oxygen uptake . Moderate to heavy physical activity of a lesser time period followed by rest or reduced activity does not usually demonstrate a value for carbohydrate supplementation during the activity. The potential role for carbohydrates in affecting such behaviors as mood, performance, and satiety, with emphasis placed on sensorimotor and cognitive performance as discussed in Chapter 18, is worthy of further consideration. Mood changes that may affect motivation to operate under stressful conditions are an important consideration. These stressful situations, such as combat, may unmask performance deficits that are not apparent under nonstressful conditions. It also should be emphasized that meals containing protein and carbohydrate demonstrate more beneficial effects than meals that are nearly protein-free. The behavioral effects seen are usually time context dependent. Snacks (providing combinations of protein and carbohydrate) may have utility in enhancing performance between meals. Research in evaluating the benefits of supplemental carbohydrates on performance should include the more subtle evaluations of motivation and coping in addition to the simple cognitive and sensorimotor measures. Evaluation should be made of the potential performance-enhancing benefits of supplemental carbohydrate and carbohydrate-containing snacks on physical and cognitive performance, including mood and motivational effects. Caffeine. Caffeine exerts its central nervous system-mediating effects by blocking adenosine receptors. Its stimulant effects when compared with those of other drugs such as amphetamines are weak, but most studies to date suggest that caffeine tends to delay sleep and reduce the deterioration of performance associated with fatigue and boredom. Caffeine at higher doses
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Committee on Military Nutrition Research: Activity Report reverses sleep deprivation-induced degradation in cognitive performance, mood, and alertness—important considerations in extended military operations in subjects who report low levels of caffeine intake. The principal side effects include nervousness/jitteryness and decreased sleepiness, which may persist for several hours. Caffeine definitely should be considered in developing performance-enhancing rations or ration components. Caffeine is safe as a component of food at doses required to overcome sleep deprivation and has been included in diets in coffee and many soft drinks. Since many soldiers may not normally drink coffee, a mechanism for including caffeine in another ration component that can be selectively used when the situation requires should be evaluated. It appears that doses of 300–600 mg/70-kg person will achieve the desired stimulus in those nonhabituated to caffeine; additional research needs to be conducted to determine the effects of this level of caffeine in those with higher habitual intakes. Tyrosine. The amino acid tyrosine is the precursor of the neurotransmitters dopamine, norepinephrine, and epinephrine. Under highly stressful conditions, the availability of tyrosine may be rate limiting for the synthesis of these neurotransmitter products. The observation that the functioning of catecholaminergic neurons can be precursor dependent is the basis for the hypothesis that tyrosine will mitigate the adverse effects of acute stress, because such neurons regulate, in part, the behavioral, cardiovascular, and neuroendocrine consequences of stress. A series of studies in animals has demonstrated that the performance decrement observed in highly stressed animals can be restored by tyrosine supplementation. Studies in humans as well as animals suggest that the amino acid tyrosine may have beneficial effects on humans that are subject to acute stressors. The adverse effects of hypoxia, cold, body negative pressure, and psychological stress have been reduced by treatment with tyrosine. Research is needed to define methods of administration and the effective and safe levels of tyrosine required. Choline. Choline and choline-containing compounds are critical for a wide variety of processes within the body, including acting as a messenger within the cells and as neurotransmitters in the nervous system controlling muscle contraction, providing methyl groups in a variety of intracellular reactions, acting as a component of triglyceride transport, and participating in the immune response. The best-known function of choline is as a component of acetylcholine, an important neurotransmitter. Free choline and choline-containing esters are present in a wide variety of foods in the human diet. The usual intake is estimated to be in the range of
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Committee on Military Nutrition Research: Activity Report 200–1,000 mg per day. There is no Recommended Dietary Allowance (RDA) for choline in humans, but intake of 500 mg/day results in decreased plasma choline and phosphatidylcholine concentrations. Diets deficient in choline produce liver dysfunction within 3 weeks, resulting in massive triglyceride accumulation in the liver and abnormalities of plasma levels of liver enzymes. There is evidence that diets low in choline reduce muscle performance. Dietary choline supplementation of individuals with normal intakes during a 20-mile (32-km) run improved the run time by 5 minutes and prevented the drop in plasma choline levels normally associated with the run. Placebo-controlled, randomized, double-blind trials are needed to determine whether choline supplementation will enhance performance of military personnel undergoing rigorous activity in the field. Choline supplementation enhances memory and reaction time in animals, particularly aging animals, and enhances memory in humans. Although the mechanisms for this are unclear, there are indications of alterations of the anatomy of brain cells. Carefully controlled laboratory studies with human subjects may suggest field studies to evaluate cognitive performance enhancement in stressful field situations. With the diversity of functions of choline in the body, there is ample reason for interest in reviewing its possible value in maintaining or enhancing performance of the soldier. Since choline is a normal constituent of many foods and can safely be used at the high usual levels of intake, it is worthy of evaluation to determine whether it may enhance either the physical or the cognitive performance of soldiers who are functioning in a stressful environment. Other Food Components of Theoretical Importance but Low Probability of Improving Performance On the basis of a review of information presented at the workshop and review of background materials, it is concluded that the following materials have some theoretical importance but offer a very low probability of demonstrating an improvement in performance under conditions anticipated in military operations. Carnitine. Carnitine is important metabolically in exercising muscle. Carnitine functions as a transportable high-energy compound that can be reformed without the use of ATP. It acts as a storehouse of high-energy compounds, stimulates fatty acid oxidation, transports acylcoenzyme A (acyl-CoA) across membranes, prevents the accumulation of lactate, and stimulates carbohydrate and amino acid utilization. These functions have led to the
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Committee on Military Nutrition Research: Activity Report hypotheses that supplementation of free carnitine, acetylcarnitine, or propionylcarnitine theoretically might enhance the oxidation of fatty acids during exercise, thus sparing the use of muscle glycogen, delaying the onset of fatigue, and enhancing exercise performance. Most Americans consume 50–100 mg of carnitine per day, with some consuming three times that amount. Carnitine appears to be safe, but there is little evidence to suggest that higher amounts are beneficial to healthy individuals. Carnitine has been extensively researched, and at this time there is no conclusive evidence that carnitine supplementation is helpful in enhancing physical performance during exercise. Its importance metabolically in exercising muscle indicates that research on its use should be followed. It is not recommended for consideration in military ration development at this time. Structured lipids. Structured lipids are defined as fats that are synthesized from mixtures of long- and medium-chain fatty acids. Therefore, they are differentiated from typical dietary fats by the presence of medium-chain fatty acids (5–10 carbon atoms). Their potential as a performance-enhancing ingredient is based on the hypothesis that glycogen utilization during exercise may be spared by the rapid oxidation of the medium-chain fatty acids. Since the medium-chain fatty acids in the diet are delivered directly and rapidly to the liver via the portal circulation, their metabolism in the liver produces the ketone bodies acetoacetate and ß-hydroxybutyrate, which would circulate to the muscle and be oxidized, sparing glycogen. The nutritional advantages of structured lipids have been demonstrated mostly in individuals with such stresses as burns, trauma, and infection. Research to date has not supported the hypothesis that the supplements of structured lipids will spare glycogen utilization during exercise, which is more closely related to the objective of enhancing physical or mental performance during military operations. In the absence of new data that demonstrate potential in this area, the inclusion of structured lipids in rations or food components for improving performance is not recommended. ANSWERS TO THE QUESTIONS POSED TO THE COMMITTEE The committee has answered the six questions posed by the Army in light of the general conclusions described above. These answers are further elaborated in the recommendations that follow.
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Committee on Military Nutrition Research: Activity Report Is enhancement of physical and mental performance in “normal,” healthy, young adult soldiers by diet or supplements a potentially fruitful approach, or are there other methods of enhancing performance that have greater potential? Emphasis should be given to making sure that troops are adequately hydrated and fed prior to military operations. There is little evidence from current nutrition research to suggest that soldiers already consuming nutritionally adequate rations as specified in the Military Recommended Dietary Allowances (MRDAs) will show significantly improved performance when nutritional supplements are added (as differentiated from pharmaceutical levels of some food components). Troops going into operational situations are presumably in good physical condition and have been consuming adequate amounts of military rations to meet their nutrient needs. Individual vitamin and mineral supplements are unlikely to improve performance under these circumstances. Soldiers who have been deprived of adequate food intake for a period under the pressure of military operations would likely benefit from receiving additional food to overcome the caloric deficit before entering another operation. Similarly, if they have been deprived of adequate sleep or rest because of extended physical activity, an opportunity to sleep or physically rest would help restore performance to normal levels. Stimulants such as caffeine may help in the short term to overcome the effects of physical and mental fatigue when continuous operations are required. The Army Science and Technology Objective (STO) states: By FY98 demonstrate a 10–15 percent enhancement of soldier performance in selected combat situations through the use of rations/nutrients that enhance caloric utilization and/or optimize the physiological levels of neurotransmitters. (Army Science Board, 1991). Is the level of enhancement identified in this STO reasonable with the current scientific knowledge? The Army Science and Technology Objective (STO) of demonstrating a 10–15 percent enhancement of performance through specific ration or nutrient consumption by Fiscal Year 1998 is overly optimistic, particularly if this is expected as enhancement over the level achieved by normal, well-fed, physically fit soldiers. However, if enhanced performance is defined as restoring or preventing all or part of the decrease in performance that is usually encountered over extended field operations, then there may be opportunities to achieve this objective. Current studies of troops in extended field operations show that troops tend to reduce food intake, lose weight, and in some instances dehydrate. Overcoming these deficits is more likely to maintain performance. Since only modest dehydration will result in reduced performance, ensuring adequate fluid
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Committee on Military Nutrition Research: Activity Report intake offers the best opportunity to overcome potential performance deficits. Adequate food intake to meet caloric needs also will help maintain high levels of performance. Under conditions of extended moderate physical activity, carbohydrate supplementation to maintain muscle glycogen levels can extend the ability to perform at this activity level. Simply eating frequent meals may accomplish this. Stimulants such as caffeine may also temporarily maintain physical and cognitive performance. Which food components, if any, would be the best candidates to enhance military physical and mental performance? Food components that would help provide energy sources to large muscles would be most likely to enhance or maintain performance. The proper use of carbohydrate supplements for persons engaged in continuous, moderate physical activity over at least 1.5 to 2 hours has the ability to extend the time to exhaustion. Caffeine has also been demonstrated to improve physical and cognitive performance. Tyrosine may also benefit cognitive performance under certain circumstances. Choline has shown some possible benefit in improving performance over extended periods of physical activity. Studies with marathon athletes need to be carefully reviewed relative to these applications to military operations. Soldiers in military operations seldom are required to perform at a similar continuous level of physical activity and over the extended time period as athletes in marathon events. Should the mode of administration be via fortification of the food in rations, supplemented via a separate food bar or beverage component, or administered in a “vitamin pill mode”? Is palatability a significant issue in this type of supplementation? The answer to this question depends not only on what food component or individual nutrient is under consideration but also on issues of safety and efficacy that have not yet been addressed. Depending on the circumstances, carbohydrate supplements can be delivered effectively in either beverages or snack bars. Caffeine is currently widely consumed either in beverages or in pill form, as a means of enhancing wakefulness and alertness. It could easily be added to snack bars or food items, but because of adverse reactions to caffeine in some individuals as well as religious proscriptions, this would be less desirable. It is premature to answer the question for individual nutrients such as tyrosine, tryptophan, and choline. Their effectiveness depends on large increases in plasma levels and is reduced when consumed as part of a normal meal containing protein and carbohydrate. Conversely, their safety is likely to be highest when these substances are consumed as supplements to a meal. The safety of these substances as single supplements when given in large enough doses to be effective has not yet been demonstrated.
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Committee on Military Nutrition Research: Activity Report Are there specific ethical issues that need to be considered with this type of research? The ethical issues depend upon the nature of the enhancement. When the safety of the use of the ration is not all issue, informing the soldiers about the ration and its purpose should suffice. If the component(s) is used at a pharmacological level, the criteria for evaluating the safety of the component as a drug should be met. Soldiers should be informed of its benefits, and possible side effects and should be educated concerning its condition of use. Research needs to proceed through proper stages of safety and efficacy evaluation before trials on large numbers of troops are conducted. Issues related to ethnicity, gender, and religious beliefs need to be considered, and evaluation and follow-up on any reported adverse or side effects must be conducted. The best guidelines for this research would be U.S. Food and Drug Administration (FDA) guidelines for research on proposed new drugs. What regulatory issues must be considered with the types of food components that are being evaluated by the Army? The considerations for the approval of food additives are well developed by John E. Vanderveen in Chapter 23. The most important consideration is the demonstrated safety of the material in question. The general approach to demonstrating safety is well spelled out in the FDA' s Red Book (Food and Drug Administration, 1982). A further consideration is the matter of whether the uses considered during this workshop represent usage as a “food” or as a “drug.” Different regulations control each class of materials. Further, if a substance is classified as a “drug,” then not only must safety be demonstrated but data showing efficacy must also be presented. It would seem critical for the military to follow the same requirements that the FDA would require for general use of a component in the civilian population. Therefore in considering the components other than caffeine and carbohydrates that have been discussed as agents capable of enhancing performance, it is important to recognize that none of these materials has been demonstrated to be “safe,” notwithstanding the fact that all of these agents exist in natural foods at levels required for potential effects. Importantly, the proposed uses (to enhance performance) require exposure levels that are in excess of what would be consumed in foods. It would seem that the intended uses as performance enhancers would classify the compounds in question in the drug category. The testing requirements are not necessarily more stringent for a drug; in fact, as noted by Dr. Vanderveen, a drug classification permits a benefit-risk consideration that is not possible for a food category consideration. Thus, it would be necessary
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Committee on Military Nutrition Research: Activity Report to generate data demonstrating minimal risk from the exposures expected and data clearly demonstrating a benefit from the proposed doses. RECOMMENDATIONS General On the basis of data presented at the workshop, the Army's prior selection of carbohydrate, caffeine, and tyrosine as food supplements that may enhance performance is fully justified. It is recommended that research with all three should continue. The utility of caffeine in reversing the degradation in cognitive performance, mood, and alertness associated with sleep deprivation that has been widely explored at USARIEM and elsewhere is well understood. It is recommended that future research with this compound explore and attempt to categorize individual differences in responses to caffeine as well as the issue of expectancy and placebo effects. Recommendations Regarding Food Components Proposed by the Army On the basis of the papers presented by the invited speakers, discussion at the workshop, and subsequent committee deliberations, the Committee on Military Nutrition Research recommends the following: The following components have clearly demonstrated their ability to enhance performance under appropriate simulated conditions and should be evaluated in appropriate delivery systems. Caffeine. Caffeine functions as a weak stimulant that, in low doses, tends to delay sleep and reduce the deterioration of performance associated with fatigue and boredom. At higher doses caffeine reverses the sleep deprivation-induced degradation in cognitive performance, mood, and alertness. The long experience with the use of coffee suggests that caffeine is safe at levels required to achieve the desired effects, and its effects are reversible over time. The primary issues that need to be answered in providing caffeine are the appropriate carrier that should be used to provide the supplement and the amount required to achieve the desired benefit in those both habituated and nonhabituated to it. Since it would not be desirable to inhibit
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Committee on Military Nutrition Research: Activity Report sleep when operations permit, the timing and availability of the caffeine-containing food component should be evaluated. Carbohydrate. Carbohydrate is an important fuel source and is particularly important for enhancing extended continuous physical activity. The potential role for carbohydrate in affecting such behaviors as mood, performance, and satiety relating to sensorimotor and cognitive performance has not been as thoroughly evaluated. Many studies have been carried out with carbohydrate supplements, with the major emphasis on physical performance. The committee recommends that this line of research at USARIEM should be continued. However, emphasis should be shifted to the effect of the macronutrient composition of meals and supplements on the affective domain, including such aspects as mood, perceived fatigue, and motivation. Hedonic properties and the timing and setting of meals and supplements are important variables to be considered, as are food preferences and aversions related to race, ethnicity, geography, and gender. Carbohydrate-containing snacks, which also provide sufficient protein, should be evaluated as a means of overcoming fatigue and improving mood and performance. Research to evaluate the performance-enhancing potentials of such products should be conducted not only as a means of potentially improving performance in the short term but also as an aid in overcoming some of the caloric deficits usually noted for troops in field operations. It is also suggested that the possibility of providing caffeine in such a product may define a product that could be used in a particularly stressful time to enhance performance. The following components are suggested for further research on the basis of their importance in energy metabolism and/or neurotransmitter actions in the body. Choline. On the basis of its diverse functions in the body, both in physical performance and in cognitive function, and limited studies demonstrating potentially improved performance in extended physical activity, in cognitive function in animals and humans, and its relative safety, the committee believes that choline should be evaluated for its performance enhancement potential. The committee recommends that choline should be added to the list of food supplements that have potential to enhance performance and that are being evaluated at the U.S. Army Research Institute of Environmental Medicine (USARIEM). It is suggested that carefully controlled laboratory studies with human subjects be conducted initially, the results of which may suggest field studies that could be used to evaluate enhanced physical and/or cognitive performance under stressful field conditions.
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Committee on Military Nutrition Research: Activity Report Tyrosine. Research has demonstrated that tyrosine may be rate limiting for the synthesis of neurotransmitter products under highly stressful conditions. Animal studies and limited human studies have demonstrated that tyrosine may have beneficial effects in overcoming the adverse effects of acute stressors. These data are encouraging and demonstrate that additional research should be conducted under carefully controlled conditions to further define when tyrosine may be beneficial in reversing acute stress. The research with tyrosine currently being carried out at both USARIEM and the Naval Medical Research Institute is exciting. The committee recommends that this research be expanded, with more emphasis placed on safety, interactions with ration consumption, stress, and field studies. Data are required on the safety of tyrosine use at levels required for efficacy. Since the effect of tyrosine appears to be pharmacological, the FDA protocols for demonstrating safety and efficacy should be considered. Evaluation of the proper method of delivering an effective dose of tyrosine to affected troops would also be required. The following compounds have a low probability of enhancing performance through their use in military rations. Carnitine. Because of its importance metabolically in exercising muscle, research in the exercise physiology literature should be monitored, but carnitine is not recommended for consideration in performance enhancement ration development and evaluation by the military until it is demonstrated that carnitine supplementation over that normally supplied in usual military rations has some value. Structured lipids. There are no data to support the fact that structured lipids spare glycogen utilization during exercise and therefore support improved performance. It is recommended that structured lipids not be further evaluated as a performance-enhancing component of operational rations. Specific Recommendations Tyrosine. Although tyrosine has been demonstrated to reverse the effects of certain acute stressors, some critical issues remain to be addressed before it can be recommended for use in enhancing the performance of acutely stressed military personnel. These issues, as outlined by Harris R. Leiberman (Chapter 15), are as follows: demonstrating the generalizability of tyrosine effects across a wider range of stressors,
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Committee on Military Nutrition Research: Activity Report establishing a dose-response function for tyrosine's beneficial effects, determining whether tyrosine has efficacy in chronic stress paradigms, determining the safety of tyrosine administration, assessing the risks and benefits of acute versus chronic administration of tyrosine, and determining the most appropriate method for providing tyrosine supplementation. Choline. Both clinical and basic research into choline and its effects on the body may have relevance for the military. Several clinical studies are obvious: studies to determine whether choline supplementation enhances endurance and muscle performance, and studies to determine whether choline supplementation enhances intellectual performance and whether this alters performance of soldiers in the field. Carbohydrate supplements. Since carbohydrate supplements have been shown to enhance performance in athletes performing at moderate to heavy levels of physical activity for extended periods of time, it is desirable to evaluate various military operational scenarios to determine whether and when a carbohydrate supplement would be advantageous. Suggested areas are: continuous load carrying at 50–70 percent maximal oxygen uptake for 1–2 hours without resting, and sleep-deprived states when moving into simulated-combat situations. Another possible area of research would be to determine the amount of protein needed in relation to carbohydrate to prevent the “perceived fatigue” effect reported with carbohydrate intake. Other Areas that Offer Research Potential While tryptophan was extensively used by many individuals, serious safety concerns led to its being banned from use. Depending upon federal regulatory guidelines, tryptophan may at some point offer research potential in the area of sleep promotion. Issues of mode of administration and dose would be areas of significant concern for military research with tryptophan. Laboratory research indicates heightened self report of fatigue after ingestion of high-carbohydrate, low-protein supplements. Studies of carbohy
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Committee on Military Nutrition Research: Activity Report drate/protein ratios in supplements also offer research potential for sleep promotion. Limited data from laboratory studies suggest that the buffering effects of sodium bicarbonate ingestion on muscle pH changes during physical exercise offer potential for further research. Glycerol is another substance that, although not specifically covered in this workshop, may warrant further investigation as a dietary supplement to enhance performance. Likewise, while not specifically discussed in the CMNR workshop, there are reports that carbohydrate supplementation is beneficial in improving performance at high altitude. Although this report has emphasized the specific isolated food components identified by the U.S. Army, and thereby focused recommendations regarding these components on a component-by-component basis, further research would need to include careful investigations of the interactions among any components as well as the interactions of regular dietary levels of caffeine and carbohydrates with performance-enhancing food components. Symptoms that frequently occur during stress (including headaches, myalgias, somnolence, and reduction in food intake) contribute importantly to decrements in performance. Carefully controlled studies should be considered during military-type stresses of the ancillary use, prophylactic and/or therapeutic, of common, symptom-treating, over-the-counter drugs that block the cytokine-induced intracellular production of prostaglandins, that is, drugs such as aspirin or ibuprofen. Prostaglandin blockade with such drugs could not only reduce symptoms to improve performance but could also have the ancillary nutritional benefits of improving appetite and reducing the hypermetabolic loss of body nutrients and muscle protein known to be associated with prostaglandin release. AREAS FOR FUTURE RESEARCH The Committee on Military Nutrition Research recognizes the potential value for performance enhancement in combat settings and suggests a number of areas for future research within the military. The CMNR believes that the military services, through their pool of volunteer personnel, offer an excellent and often unique opportunity to generate research data and statistics on the nutrition, health, and stress reduction in service personnel. These findings can be directly applied to improving both the health and the performance of military personnel and those of the general U.S. population.
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Committee on Military Nutrition Research: Activity Report Much of the research needed to establish the safety of large doses of tyrosine and potentially choline needs to be carried out with rats. Amino acid, neurotransmitter, and metabolite levels need to be measured in specific brain nuclei, and many other animal studies are needed including gross and microscopic pathologies in both short-and long-term experiments. Possibly this could be accomplished through the Army funded neuroscience research at the Pennington Biomedical Research Center, Baton Rouge, Louisiana, in support of the human studies at USARIEM. Performance, including cognitive, emotional, and physical aspects, is of crucial importance to all service branches. It is recommended that an interservice committee be established to coordinate and facilitate research and development activities in this area. A final general recommendation is to focus nutrition/performance research on diet/stress/immune function relationships in both acute and chronic situations. It would be desirable to relate the research, at least in part, to researchable issues raised by the two Ranger studies. Immunological studies should include studies of humoral immunity, cellular immunity, and plasma cytokine concentrations before, during, and after the period of stress. The Committee on Military Nutrition Research is pleased to participate with the Division of Nutrition, U.S. Army Research Institute of Environmental Medicine, U.S. Army Medical Research and Development Command, in programs related to the nutrition and health of U.S. military personnel. The CMNR hopes that this information will be useful and helpful to the U.S. Department of Defense in developing programs that continue to improve the lifetime health and well-being of service personnel. REFERENCES Army Science Board 1991 Soldier as a System. 1991 Summer Study Final Report. Assistant Secretary of the Army Research, Development and Acquisition. Washington, D.C.: U.S. Department of the Army. Food and Drug Administration 1982 Toxicological Principles for the Safety Assessment of Direct Food Additives and Color Additives Used in Food. Washington, D.C.: U.S. Department of Health and Human Services.