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Food Components to Enhance Performance: An Evaluation of Potential Performance-Enhancing Food Components for Operational Rations
1
Introduction and Background
THE COMMITTEE’S TASK
The Committee on Military Nutrition Research (CMNR) of the Food and Nutrition Board (FNB), Institute of Medicine (IOM), National Academy of Sciences (NAS), was asked by the Division of Military Nutrition, U.S. Army Research Institute of Environmental Medicine (USARIEM), U.S. Army Medical Research and Development Command (USARMRDC), to review the potential for specific food components to enhance the performance of military personnel under the stress of field settings. The committee was thus charged with providing a thorough review of the literature in this area and with interpreting these diverse data in terms of military applications.
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Food Components to Enhance Performance: An Evaluation of Potential Performance-Enhancing Food Components for Operational Rations
The committee was also asked to address six general questions that dealt with enhancement of performance.
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?
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?
Which food components, if any, would be the best candidates to enhance military physical and mental performance?
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?
Are there specific ethical issues that need to be considered with this type of research?
What regulatory issues must be considered with the types of food components that are being evaluated by the Army?
Within this context the CMNR was charged with specifically evaluating the potential of selected amino acids, carbohydrates, structured lipids, choline, carnitine, and caffeine to enhance performance. The committee was also asked to provide its recommendations regarding which, if any, of these compounds should be developed further within the current “Soldier as a System” initiative (Army Science Board, 1991).
The CMNR realized that there was a large amount of research—of variable quality—devoted to enhancement of performance. In addition, questions about dose levels, informed consent, time span, and timing of administration were raised with regard to the application and desired outcome within a combat setting. To help focus the objects of its report, the committee requested that the Army develop several scenarios that illustrated the hypothetical application of these food components. Seven scenarios written by Drs. Harris Lieberman and Mary Mays, USARIEM, are included in Appendix A.
To assist the CMNR in responding to these questions and developing their recommendations, a workshop was convened on November 16–17, 1992. This workshop included presentations from individuals familiar with or having expertise in cognition, endocrinology, exercise physiology, food engineering,
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Food Components to Enhance Performance: An Evaluation of Potential Performance-Enhancing Food Components for Operational Rations
food science, immunology, metabolism, neuropsychology, nutrition, nutritional biochemistry, performance psychology, and sports medicine. The invited speakers discussed their presentations with committee members at the workshop and submitted the contents of their verbal presentations as written reports. The committee met after the workshop to discuss the issues raised and the information provided. The CMNR later reviewed the written reports and drew on its collective expertise and the scientific literature to develop the summary, conclusions, and recommendations that appear in Chapters 1 and 2.
Terms Used in This Report
For the purposes of this report, the Committee on Military Nutrition Research defines the term enhancement to include both an avoidance of reduction in performance decrement during stress and improvement of performance above the baseline. Both physical and mental performances measured by a wide variety of tests are explored. Improvements over baseline performance and prevention of performance decrements during stress are admittedly widely different problems, but ones with similar overall military objectives. Possible approaches to each of these problems are also explored. Ergogenic aid, (“work-producing”) is used to refer to any substance, whether in a food or not, that enhances physical performance.
Report Organization
This summary begins with an overview of the specific military issues and research that led to interest in performance enhancement. The committee then provides a summary of information related to nutrition and stress. This is followed by a review and interpretation of the available data on the food components proposed for consideration by the Army. Chapter 1 concludes with a discussion of the safety and regulatory aspects of performance-enhancing food components.
MILITARY RESEARCH ON NUTRITIONAL ENHANCEMENT OF SOLDIER PERFORMANCE
History and Current Research
The introductory chapter by COL Eldon W.Askew summarizes the interest of the Army in enhancing soldier performance (see Chapter 3). In the
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past, the focus for maximizing soldier performance has largely been on efforts to improve training, doctrine, and equipment, with little research emphasis on how the physical and cognitive abilities of individual soldiers may be enhanced through nutritional supplementation or design of rations. Military rations are designed in accordance with the nutritional standards established by the Military Recommended Dietary Allowances (MRDAs) (AR 40–25, 1985), which are intended to ensure that soldiers are receiving nutritionally adequate rations.
There has been a concern that the development of sophisticated equipment and the increasing demands that are made on the soldier, both physically in load carrying and in the cognitive abilities required to use the more sophisticated weaponry, place additional burdens on the nutritional needs of the individual. This has raised the question of whether soldier performance can be improved through design of special rations. USARIEM and the U.S. Army Natick Research, Development and Engineering Center (NRDEC), located at Natick, Massachusetts, share responsibility for implementing the new Science and Technology Objective (STO) that is principally directed at the sustainment or enhancement of soldier performance through the use of performance-enhancing food components (see description of this STO in question 2 on page 4). In this context, if soldier performance that may be reduced under the stress of sustained field operations could be sustained at preoperational levels, it would be considered an enhancement of performance.
COL Eldon W.Askew (Chapter 3) briefly summarizes the research that USARIEM has conducted in the past few years in three areas, dietary macronutrients (carbohydrates), nutritional pharmacology (caffeine), and nutritional neuroscience (tyrosine). These areas are reviewed in more depth in the chapters that follow (Chapters 15–17 and 20). Although some responses have been measured under carefully controlled laboratory conditions, the results have not always been transferable to field operations. The difficulty in obtaining precise measures in the field, the considerable variations frequently experienced among subjects, and the difficulty of actually duplicating conditions imposed either in the laboratory or in the field affect the outcome of this research.
The issues considered in the workshop and this report center around the identification of potential performance-enhancing nutrients or food components that may be used to supplement or improve the operational rations that already provide liberal allowances of nutrients as established by the MRDAs.1 Soldiers who consume these military rations are thus presumed to be in a state of good nutrition.
1
The Military Recommended Dietary Allowances (MRDAs) are being revised. The current edition is included in its entirety in Appendix B.
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Design Issues for Rations
There are two primary tasks in meeting the objective of enhancing performance by using rations. The first requires the identification of food components that may, through prior research or consideration of metabolic pathways, appear to be candidates for evaluation. This task is further complicated by the need to design the appropriate environmental stresses and identify the physical and cognitive measures that may be sufficiently sensitive to evaluate their influence on performance.
The second requires the development of the appropriate delivery system to supply the components to the soldier in the proper amount and at the appropriate time.
Two introductory chapters (Chapters 4 and 5) by Irwin A.Taub and C. Patrick Dunne, of the Food Engineering Directorate, Natick Research, Development and Engineering Command (NRDEC), provide an excellent review of the complexity of developing operational rations for the military. These rations must meet special nutritional needs, be acceptable to the soldier, have sufficient shelf-lives under the storage time and conditions imposed for the ration system, and meet the safety and performance criteria established for the ration when used possibly 3 to 4 years after manufacture. The capability of NRDEC and the extent of the challenge this task presents are eloquently discussed in Taub and Dunne’s chapters.
Biochemical Strategies and Issues
Biochemists may identify nutrients or food components that are important sources of energy or that function as metabolic regulators at the cellular level for which changes in the supply or concentration may affect metabolism at that site. However, in the complex functioning of the various tissues and organs and metabolic regulation, these cellular observations may not be transferable to performance enhancement of the individual. Therefore, it is important in selecting potential performance-enhancing components for study to carefully evaluate (1) the physiological basis for the potential performance enhancement at the functional site(s); (2) the potential for being able to deliver such a component through the physiological processes of digestion, absorption, and circulation; and (3) the delivery of the food component to the functional site at a concentration that will be effective and not adversely affect the complex interactions in the overall metabolism. With all of the complexities of human metabolism, it is important to carefully evaluate food components or nutrients as potential performance enhancers (physical and/or cognitive) on the basis of their demonstrated potential in studies on the functioning tissue or organ.
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As discussed in the chapters by Drs. Dunne and Taub, the ration developers are acutely aware of these problems and are looking to the CMNR for guidance on the selection of components for evaluation in the appropriate food delivery systems.
PERFORMANCE ISSUES AND MEASUREMENT APPROPRIATE TO THE MILITARY
Physical Performance
The performance of physical tasks in any job setting requires the confluence of physiological and psychological processes. As discussed by James A.Vogel (Chapter 6), many of these processes and related factors can be viewed as potential targets for performance enhancement through ergogenic aids. Although experimental studies can focus on measurement of physical performance at levels ranging from the isolated muscle cell to the whole organism, the issue for the military is the performance of the soldier in physically demanding tasks, often under stressful conditions. Review of food components that may enhance physical performance through psychological factors that contribute to performance of all tasks, such as arousal, concentration, and motivation (see Dishman, 1989, for a review), will be reviewed in the following sections. In Chapter 6, Vogel focuses on the four categories of physiological factors that are involved in physical task performance: metabolic capacity, neuromotor control, energy substrates, and tissue homeostasis. The various physical performance tasks in the military involve several or all of these physiological categories,
The physical task of firing a rifle is predominantly determined by neuromotor control factors, while that of running for long distances is predominantly determined by the other three groupings of factors (Chapter 6, p. 114).
Vogel contends that to evaluate the effectiveness of ergogenic aids, the specific target of action among these categories must be identified and then appropriately measured using well-validated techniques. A careful review of the most appropriate methodologies for each category is provided by James A.Vogel in Chapter 6. Evaluation of the effectiveness of any food component on performance would then optimally be tested in experiments that isolated the target categories in several stages: in a controlled laboratory setting, in a single field task, and as part of an operational scenario. Appendix A provides several
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scenarios that depict militarily relevant physical performance tasks in which ergogenic aids might prove effective.
Mental Performance
The issues of mental performance that are of concern to military personnel in a combat setting do not differ from those in a regular workplace, with the exception of the severity of the levels and types of stress superimposed on the situation. The ability to perceive, attend to, and respond appropriately to cues, as well as make appropriate decisions, and to remain vigilant are critical in military combat settings. These areas of cognitive performance also form the basis for many physical performance tasks, such as positioning and loading artillery shells or moving through a mine field. Laboratory studies in many settings have shown that well-trained personnel will typically sacrifice speed for accuracy in cognitive performance tests in stressful situations. Although in the workplace this may reduce monetary cost-effectiveness, in a field combat situation a significant decrease in speed of performance could be life-threatening.
Sleep deprivation is a major overlying factor that can further lead to performance degradation in the workplace (Commission on Sleep Disorders Research, 1993). This problem has long been recognized by the Army and thus has been the focus of laboratory and field research in military settings. In Chapter 7, Belenky et al. present a review of recent research on sleep deprivation and its effects on performance during continuous combat operations. Belenky et al. state that the “The ability to do useful mental work declines by 25 percent for every successive 24 hours awake” (p. 128). In laboratory and field studies, although psychomotor performance, physical strength, and endurance do not appear to be less affected by sleep deprivation, complex mental functions such as the ability to perceive and understand changing situations, adapt to changes, and plan alternative strategies are significantly degraded. For example, soldiers were able to maintain accuracy at fixed targets after 90 hours without sleep, but they exhibited poor performance with targets that appeared at random time intervals and in changing locations (Haslam and Abraham, 1987, see Belenky et al.; Chapter 7).
An extended, uninterrupted sleep (7-plus hours) appears to provide the best means of restoring cognitive performance. Sleep that is fragmented, however, has been shown to provide little recuperative value in terms of cognitive performance (Bonnet, 1987). Unfortunately, fragmented sleep—interrupted by noise, lights, and nearby movements—is more typical of combat settings than an uninterrupted rest. The trade-offs for commanders in allowing more sleep for their troops or making increased forward progress in an operation were
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addressed by McNally et al. (1989) through integration of experimental data from Thorne et al. (1983) into models of military performance under different conditions of sleep deprivation. The results indicate that restricting a unit’s sleep is unproductive. The total output on any given task of units with mild to moderate sleep deprivation would be expected to drop as the days pass. During this time, the more complex reasoning and decision-based tasks would be expected to suffer the greatest decline in performance. In Chapter 7, Belenky et al. illustrate these types of problems with accounts of experiments using simulated artillery fire (Banderet et al., 1981) and after-action debriefings from Operation Desert Storm.
Preliminary data indicate that decrements in cognition-based performance are paralleled by decreases in glucose metabolism in specific areas of the brain (Thomas et al., 1988). The effects of dietary glucose supplements on performance enhancement under conditions of sleep deprivation have not been fully examined.
The scenarios in Appendix A provide additional direct examples of the types of cognitive performance changes that are of concern in military settings. Reduction in performance degradation through ingestion of food components that may affect neurotransmitters, more general neuronal excitability, or the specific brain regions involved in cognitive activities will be discussed in the sections that follow.
PROVIDING FOOD IN THE CONTEXT OF MILITARY COMBAT SETTINGS
Many contextual factors are influential in the amount and type of food that individuals consume. An individual’s expectations (Cardello and Sawyer, 1992), the time of day (Kramer et al., 1992), the effort needed to obtain food (Collier, 1989; Engell et al., 1990), the amount and diversity of available food (Engell, 1992; Rolls et al., 1992), the appropriateness of the meal to the time of day (Birch et al., 1984; Kramer et al., 1992), food acceptability (Meiselman et al., 1988), food presentation (Cardello and Sawyer, 1992), and the dynamics of the social situation while eating (de Castro and Brewer, 1992; Goldman et al., 1991) all affect the amount eaten and what is selected. Since appropriate food intake is essential for performance, these contextual factors are recognized by the Army as important; however, the manner of food delivery in combat settings is necessarily constrained by the food engineering concerns that were previously described. As Meiselman and Kramer mention in Chapter 8, the long-term storage requirements for rations contribute to difficult demands for production as well as for the consumer. In addition, soldiers typically eat considerably less than the total ration that is provided for them (of the 3,900
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kcal per day for moderate activity in a temperate climate, soldiers eat 2,000–3,000 kcal, on average). This reduction in intake does not appear to be related to food acceptance, since soldiers consistently give good ratings to military rations (see Chapter 8 for review). The stress of the training or combat situation is another mediating factor for consideration. Although a hungry individual may not eat if fearful, once eating does occur the level of intake will most likely be enhanced (Gray, 1987). Individual responses differ greatly, however, and although the “typical” response may be to reduce food intake under stressful conditions, some subgroups of the population increase food intake under the same conditions (see discussion in Chapter 8).
In Chapter 8 Meiselman and Kramer review the history, methodological approaches, and methodological issues related to research in food intake, contextual factors, and performance enhancement. In the military setting these authors point out that performance science has yet to resolve many methodological questions. Provision of food in a military setting and its impact on soldier performance are presented as complex multifactorial problems that require an initial resolution of the definition of performance. The authors refer to the military initiative that calls for soldier performance enhancement in the following five capabilities: lethality, mobility, command and control, survivability, and sustainment. Translating these capabilities into reliably measurable components of cognitive and physical performance that can be enhanced by food component intake in the context of military rations is no easy task. As discussed by these authors, not only will the contextual issues of food component provision require careful examination but new methodologies will most likely require development or refinement. In addition, physical and cognitive performance measurement need to be well-integrated—an area where there is little previous research.
In summary, although an individual’s food intake in the military is influenced by the same set of factors that influence food intake in nonmilitary settings, the stress of military training or combat settings, the shelf life requirements, the packaging and delivery constraints of military rations, and the added performance capability demands result in a highly complex set of problems for performance enhancement. Research in this area will not only require careful attention to the issue of context in food item delivery—similar to standard military rations—but also to the integration of physical and cognitive performance measurement and most likely the development of new methodologies that would test the performance capabilities valued in soldier field settings.
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STRESS AND NUTRIENT INTERACTIONS
The Central Nervous System
Primary neurotransmitters in the central nervous system include the monoamines dopamine, norepinephrine (NE), and serotonin (also called 5-hydroxytryptamine or 5HT). The catecholamine norepinephrine is believed to be an important neurotransmitter involved in the sleep-wake cycle, pain, anxiety, and arousal, whereas the indoleamine serotonin is thought to be important in many central processes, including pain perception, memory, appetite, thermoregulation, blood pressure control, heart rate, and respiration.
Tyrosine hydroxylation is the rate-limiting step in the synthesis of all major catecholamines including NE and dopamine, while serotonin is synthesized from tryptophan. Several lines of investigation have examined the effects of administration or manipulation of these or other precursors on various physiological functions and behaviors. Protocols have included acute (short-term, i.e, minutes to hours) manipulations as well as chronic (usually long-term -days to months- diet-related) administration.
Studies using acute paradigms have examined the behavioral consequences of altered neurotransmitter precursor availability and, hence, neurotransmitter synthesis. Alterations in brain amino acids and neurotransmitter levels are seen within 15–20 minutes after administration of amino acids such as L-tyrosine (TYR), or after feeding diets high in carbohydrates (CHOs) or protein to experimental animals (see Chapter 9 by John D.Fernstrom).
In addition, both serotonin and NE have been examined for their effects on macronutrient selection (see Chapter 13 by Richard J.Wurtman). In experimental animals pharmacological doses of NE (either central or peripheral administration) have been reported to enhance CHO consumption relative to protein or fat consumption, whereas central or peripheral administration of 5HT appears to inhibit CHO consumption while sparing protein and fat intake (see Blundell, 1986 for a review). In one example, with a two-diet choice (protein-rich versus CHO-rich), a small dose of 5HT introduced into the parventricular nucleus of experimental animals selectively suppressed the CHO-rich diet (Shor-Posner et al., 1986).
In Chapter 9, John D.Fernstrom reviews the biochemical basis underlying L-tyrosine (TYR) administration to counter stress. Results from several studies suggest that TYR administration enhances dopamine (DA) and NE synthesis in the brain and reverses deficient performance in rats and humans (Lehnert et al., 1984; Banderet and Lieberman, 1989). However, the author cautions that while TYR administration may increase transmitter (DA and NE) synthesis and release and may potentially affect brain functions, the exact consequences of TYR administration are unknown. Further study would be essential to
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understanding the usefulness of TYR or other pharmacological or nutritional agents that stimulate DA or NE release.
The studies of Levine and colleagues (Levine et al., 1990) further illustrate the effects of different types of stressful stimuli on increasing the activity of NE-containing neurons in the brain. Acute stress appears to have little effect on NE receptors in the brain. Chronic stress, however, is associated with increased NE synthesis and turnover (Stanford et al., 1984; Thierry et al., 1968). Chronic stress may also be associated with marked decrements in the number of activated beta receptors, in that a stress-induced increase in NE release by brain neurons via stimulation of beta receptors on target neurons and the production of second-messenger-mediated effects leads to beta receptor down regulation (Torda et al., 1981). The available evidence thus suggests that NE receptor responsiveness is changed following chronic stress and that these changes are different from those accompanying acute stress. Data also suggest that such changes are not uniform; i.e., NE receptors and subtypes as well as activity in different brain regions may differ. Therefore, agents such as TYR that enhance NE synthesis and release following acute stress may have different effects under chronic stress.
Stress also affects brain DA neurons, although there is some controversy whether all DA neurons or only some are activated by stress. Again, further research is needed to determine whether administration of TYR in animal models under acute stress stimulates DA synthesis and release and improves functioning. Stress also reportedly increases the brain levels of the major DA metabolite dihydroxyphenylacetic acid (DOPAC) (Dunn, 1988). There are few available studies on brain DA neuronal activity under chronic stress, but several suggest increased levels of DOPAC. Although one cannot determine at present whether DA receptor sensitivity is influenced by chronic stress, administration of TYR should stimulate DA receptor synthesis and release; this is again suggestive of enhanced performance.
Although stress does not influence the activity of the serotonin precursor neurons, stress does increase brain concentrations of the essential amino acid tryptophan (TRP)—possibly as a consequence of increased serotonin (5HT) synthesis and turnover. The mechanism responsible for the stress-induced increase in 5HT synthesis and turnover differs from those in DA and NE (see Fernstrom, 1990). In animals, with 5HT administration through a large dose of valine (or TYR), the stress-induced rise in brain TRP levels or the rise in brain 5HT may be blocked, with unknown consequences to brain function.
In summary, there are few studies that clearly define the catecholamine receptor responses to stress. In addition, there is marked diversity among the various catecholamines suggesting the need for additional animal studies to examine differences in acute and chronic stress on catecholamine receptors in particular brain regions, and their correlations with function.
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did not employ carnitine supplementation, there was little evidence that endurance conditioning had an effect on skeletal muscle carnitine concentrations, nor were there correlations between total carnitine concentration in muscle at rest and finishing time or between muscle carnitine and maximal aerobic power or duration of training. In another study, following carnitine supplementation for 5 days, the ratio of acylated to free carnitine increased from preexercise values during exercise and remained elevated for 40 minutes postexercise (Soop et al., 1988).
In summary, while carnitine functions as a transportable high energy compound that can be reformed without the use of ATP, carnitine supplementation has not been demonstrated to improve physical or mental performance in well-nourished individuals. Basic research on the effects of various forms of carnitine in exercise may be in order. These will be facilitated by the development of simple methods that permit measurement of various acylcarnitines in large numbers of samples. There is no conclusive evidence to date that carnitine supplementation is helpful in enhancing physical performance during exercise. The status of carnitine research is such that, at present, no recommendation to increase levels of carnitine in rations are called for.
SAFETY AND REGULATORY ASPECTS OF POTENTIAL PERFORMANCE-ENHANCING FOOD COMPONENTS
Safety of Amino Acids
Military rations exceed the RDAs for protein and the protein source provides an adequate intake of the essential amino acids. Therefore, the supplementation of military rations with amino acids at the usual range of dietary intakes would not be expected to improve performance. Amino acid intakes at several times the usual dietary intakes must be evaluated for safety as well as effects on performance. Several of the chapters address the use of tyrosine supplements to enhance performance. Such use is pharmacological rather than nutritional and therefore presents different concerns with regard to safety. In Chapter 22, Timothy J.Maher discusses the recent issue associated with supplements of L-tryptophan. In this incident, the occurrence of eosinophilia-myalgia syndrome (EMS) was associated with the use of L-tryptophan supplements. It was subsequently shown that the induction of EMS was associated with one or more impurities in one particular product and was not the result of L-tryptophan ingestion per se. Nonetheless, this experience raised safety concerns about the use of amino acid supplements specifically and more generally the use of all nutrients as supplements at physiological levels. It is clear that these types of supplements must be highly
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purified before they can be considered safe for use. The safety of amino acid supplements has been the subject of a recent review by the Life Sciences Research Office (LSRO) of the Federation of American Societies of Experimental Biology (Anderson and Raiten, 1992).
Much research has been published on the important nutritional roles of amino acids as the essential building blocks for proteins and as precursors of other physiologically important compounds such as hormones and neuroactive peptides. These needs are normally met by the quantities of amino acids supplied by ingested foods and are presented to the body as a mixture of many amino acids. These levels of exposure are generally recognized as presenting no safety concerns. However, amino acid supplements, particularly methionine and lysine, can provide much greater quantities of single amino acids, which raises the potential of direct toxic effects or the possibility of creating “imbalances” of amino acids that could have deleterious consequences.
Amino acid supplements proved to be a boon in poultry and swine production by permitting the upgrading of low-quality plant proteins to allow for maximal growth rates. In these circumstances the exposure levels were of the same order of magnitude as expected from normal diets, and the likelihood of toxicities or imbalances was nil. More recently, over-the-counter (OTC) availability of amino acid supplements and their potential use in pharmacological quantities have created concern. The LSRO report (Anderson and Raiten, 1992) reviews in detail the literature on animal and human studies that can shed light on the safety of supplements. It is clear from the LSRO report that many amino acids can have toxicological effects, that there is a paucity of information to establish safe use levels for individual amino acid supplements, and that there is adequate evidence to raise concern about certain vulnerable population groups.
One of the amino acids that was discussed at length during this workshop and that forms the basis for this report is tyrosine, which was reported to have beneficial effects in response to stress by virtue of its role as a precursor for catecholamines. Tyrosine appears to be well tolerated by rats consuming a high-protein diet, but in animals fed low-protein diets, a distinct syndrome is observed involving cataracts, skin lesions, and histopathological changes (Anderson and Raiten, 1992).
In summary, the available evidence, while inadequate to establish safety, does raise concerns about the indiscriminate use of amino acid supplements. These data make it clear that before advocating any use of supplements, appropriate safety studies should be conducted. The LSRO, in its report (Anderson and Raiten, 1992), has proposed a two-tiered approach to animal testing for individual amino acids or mixtures of amino acids. Human clinical studies were also recommended by LSRO, again involving a two-tiered
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approach (see Anderson and Raiten, 1992). These recommendations represent a sound starting point for establishing the safe use of amino acid supplements.
Regulation of Food Components by the U.S. Food and Drug Administration1
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 delineated in the U.S. Food and Drug Administration’s (FDA) Red Book2. A further consideration is the matter of whether the uses considered during the CMNR workshop in November, 1992 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 in the civilian population. Therefore, in considering any of the materials 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. 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, with the exception of candy bars or CHO supplements, 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 John E.Vanderveen, a drug classification permits a benefit-risk consideration that is not possible for a food category consideration. Thus, it would be necessary to generate data demonstrating minimal risk from the expected exposures and data clearly demonstrating a benefit from the proposed doses.
1
The views expressed in this section reflect the policy of the Food and Drug Administration at the time of the CMNR workshop in November, 1992. In the future, the policy may be revised to meet legislative mandates or public health needs.
2
This document is currently under revision. On March 29, 1993 the FDA issued a notice (58 FR 16536) announcing the availability for comment of a draft revision of Toxicological Principles for the Safety Assessment of Direct Food Additives and Color Additives Used in Food.
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SUMMARY
The increasing sophistication of weapon systems and the complexity of military operations place heavy demands on the soldier to effectively use these systems in military operations. Although thorough training can prepare the individual for effective use of these systems, these sophisticated weapons and the associated training do not eliminate and, in fact, may not reduce the physical demands on the individual soldier in combat. Also, although computers and other information processing aids may help the soldier to process information for effective decision making, the consequences of errors in cognition are multiplied. Therefore, maintaining or enhancing physical and mental performance of the individual engaged in combat is an important objective and deserves a major effort in the identification and evaluation of systems for delivery of those components that pass the rigorous tests for enhancing performance. Although the November 1992 workshop and this report form a good starting point in the selective evaluation of nutrients or food components, it is important that there be a continuing evaluation of the basic nutrition, biochemical, and neuroscience research literature to further identify possible candidates for evaluation. In the following chapter, the CMNR discusses the specific evaluation of the nutrients or components covered in this workshop and makes recommendations for their evaluation. Future research recommendations are also presented.
REFERENCES
AMAC American Medical Association’s Council on Scientific Affairs 1984 Cafffeine labeling, a report on the safety of dietary caffeine. JAMA 252:803–806.
Anderson, S.A., and D.J.Raiten, eds. 1992 Safety of Amino Acids Used as Dietary Supplements. Bethesda, Md.: Life Sciences Research Office.
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.
Banderet, L.E., and H.R.Lieberman 1989 Treatment with tyrosine, a neurotransmitter precursor, reduces environmental stress in humans. Brain Res. Bull. 22(4):759–762.
Banderet, L.E., J.W.Stokes, R.Francesconi, D.M.Kowal, and P.Naitoh 1981 Artillery teams in simulated sustained combat: Performance and other measures. Pp. 581–604 in Department of Health and Human Services National Institute for Occupational Safety and Health Report 81–127: The Twenty-Four Hour Workday: Proceedings of a Symposium on Variations in Work-Sleep Schedules, L.C.Johnson, D.I.Tepas, W.P Colquhon, and M.J Colligan, eds. Washington, D.C.: U.S. Government Printing Office.
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Representative terms from entire chapter:
food components
