Executive Summary

The success of military operations depends to a large extent on the physical and mental status of the individuals involved. The physical demands of combat combined with the mental stress of long days, even if for short-term periods, take a unique toll on soldiers. Extreme environmental stressors encountered by military personnel during combat add further complexity. During sustained operations (SUSOPS), for example, combat foot soldiers carry loads in excess of 50 kg for three to seven days during missions that often last for about a month under weather conditions that vary from cold, mountainous to humid, tropical climates; rest between missions may be as short as two to three days.

An individual’s physiological and nutritional status can markedly affect one’s ability to maximize performance in sustained high-stress operations and may compromise mission effectiveness. Appropriate nutrition before and during missions can reduce adverse consequences of physical and mental stress, but optimizing soldiers’ nutritional status is a continuous challenge. First, from a practical standpoint, it is not possible to implement a single recommended dietary regime before missions. Second, individuals under stress often have diminished appetites. Soldiers usually burn about 4,500 kcal/day but consume only about 2,400 kcal/day during combat, leaving them in a state called “negative energy balance.” Finally, the nature of the ration is only one of many factors that determine eating habits during combat. Many less controllable and unpredictable factors, such as individual preferences and climate, come into play to reduce appetite, as was described in the Institute of Medicine (IOM) report, Not Eating Enough.

The consequences of being in negative energy balance while under the strenuous circumstances of SUSOPS range from weight loss to fatigue and



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Nutrient Composition of Rations for Short-Term, High-Intensity Combat Operations Executive Summary The success of military operations depends to a large extent on the physical and mental status of the individuals involved. The physical demands of combat combined with the mental stress of long days, even if for short-term periods, take a unique toll on soldiers. Extreme environmental stressors encountered by military personnel during combat add further complexity. During sustained operations (SUSOPS), for example, combat foot soldiers carry loads in excess of 50 kg for three to seven days during missions that often last for about a month under weather conditions that vary from cold, mountainous to humid, tropical climates; rest between missions may be as short as two to three days. An individual’s physiological and nutritional status can markedly affect one’s ability to maximize performance in sustained high-stress operations and may compromise mission effectiveness. Appropriate nutrition before and during missions can reduce adverse consequences of physical and mental stress, but optimizing soldiers’ nutritional status is a continuous challenge. First, from a practical standpoint, it is not possible to implement a single recommended dietary regime before missions. Second, individuals under stress often have diminished appetites. Soldiers usually burn about 4,500 kcal/day but consume only about 2,400 kcal/day during combat, leaving them in a state called “negative energy balance.” Finally, the nature of the ration is only one of many factors that determine eating habits during combat. Many less controllable and unpredictable factors, such as individual preferences and climate, come into play to reduce appetite, as was described in the Institute of Medicine (IOM) report, Not Eating Enough. The consequences of being in negative energy balance while under the strenuous circumstances of SUSOPS range from weight loss to fatigue and

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Nutrient Composition of Rations for Short-Term, High-Intensity Combat Operations mental impairments, such as confusion, depression, and loss of vigilance. The military has devoted great efforts to improve the quality of the food rations with the objectives of providing a palatable ration, encouraging consumption, and ensuring proper nutrition for soldiers. First Strike Rations (FSRs) are being developed in collaborative effort by the Combat Feeding Directorate (CFD), Research, Development, and Engineering Command (RDECOM), Natick Soldier Center (NSC) and the US Army Research Institute of Environmental Medicine (USARIEM) and were conceived as a new strategy to optimize the nutritive value of rations created for foot combat soldiers. FSRs are being developed as lightweight rations that contain all essential nutrients and food components with the idea of sustaining physical performance, postponing fatigue, and minimizing other adverse health consequences experienced while in SUSOPS. With the number of SUSOPS increasing, the optimization of these assault rations has become a high priority. The Department of Defense asked the IOM to appoint a committee to guide the design of the nutritional composition of the ration for SUSOPS. Although the focus of this report is soldiers, the recommendations may be applicable to physically fit nonmilitary personnel under similar conditions of high-stress, intense physical activity, especially those experiencing negative energy balance for the repeated, short periods of time outlined here. This may include firefighters, peacekeepers, and other civilian emergency personnel. COMMITTEE’S TASK AND APPROACH Under the auspices of the Standing Committee on Military Nutrition Research, the Committee on Optimization of Nutrient Composition of Military Rations for Short-Term, High-Intensity Situations was appointed to recommend the nutritional composition of a new ration designed for short-term use by soldiers during high-tempo, stressful combat missions. The ration is meant to be used for repetitive, three- to seven-day missions that include recovery periods of about 24–72 hours between missions. The nutritional composition of this new ration should be optimized to best sustain physical and cognitive performance and should prevent possible adverse health consequences, focusing on dehydration, the gastrointestinal gut processes, and the function of immune system as health issues of highest concern. Specifically, the committee was asked to respond to questions about the energy content, about levels and types of specific macronutrients and micronutrients, and about amounts of other bioactive substances that may enhance performance during combat missions. To address this task, the committee convened a workshop hosted by the USARIEM and the NSC in Natick, Massachusetts, August 11–13, 2004, at which speakers addressed the issues brought to the committee by the USARIEM. These presentations were the basis for the committee’s deliberations and recommendations and are included in this report as individually authored papers.

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Nutrient Composition of Rations for Short-Term, High-Intensity Combat Operations Box ES-1 Assumptions Regarding Assault Missions Population Soldiers deployed to assault missions are male with an average body weight of 80 kg, approximately 16 percent body fat who are relatively fit and within an age range of 18–45 years (average < 25 years). Prior to Assault Mission Soldiers may be using dietary supplements and caffeine. Immediately prior to a mission soldiers are well hydrated, not abusing alcohol, but may be using tobacco products. During Assault Mission Soldiers may be on a mission for as many as 24 out of 30 days, with each mission lasting three to seven days. There may be as much as 20 hr/day of physical activity, with an average of 4 hr/day of sleep. Total daily energy expenditure will be approximately 4,500 kcal. Soldiers are likely to have an average energy intake of 2,400 kcal/day. Soldiers are likely to have access to 4–5 L of chlorinated water per day. Some soldiers may experience diarrhea, constipation, or kidney stones during the assault mission. Soldiers have different electrolyte intakes before a mission than during a mission; thus, during a mission a period of biological adjustment may occur. Ration The daily ration must fit within 0.12 cubic feet and weigh 3 lb or less. It will be approximately 12–17 percent water but varying greatly from one item to the other; most items will be energy dense and intermediate in moisture. There will be no liquid foods in the rations, although gels and powders may be provided. The food available during recovery periods will provide, at a minimum, the nutritional standards for operational rations. To provide context for the recommendations, the committee also formulated some basic assumptions about the characteristics of the soldiers’ diets and health, the missions, and other issues, compiled through open sessions and available literature (see Box ES-1). The committee used the Dietary Reference Intakes (DRIs) established by the IOM for active young men as the starting point for nutrient content in formulating the assault ration because these values are the most authoritative, up-to-date standards available. Further adjustments were then made to meet the unique needs of soldiers involved in assault conditions.

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Nutrient Composition of Rations for Short-Term, High-Intensity Combat Operations ANSWERS TO THE MILITARY’S QUESTIONS 1. Should the energy content of the ration (energy density) be maximized so as to minimize the energy debt, or is there a more optimal “mix” of macronutrients and micronutrients, not necessarily producing maximal energy density? The committee recommends that the basic ration’s energy content be approximately 2,400 kcal/day. While this level does not maximize energy density, this is the average daily energy intake that has frequently been reported for soldiers during training. Choosing this caloric level minimizes the possibility of discarding food items that might result in inadequate intakes of necessary micronutrients; however, in case ration items are discarded, micronutrients should be distributed as evenly as possible throughout the food items in the ration (rather than clustering them in a few items) to prevent significant amounts of individual micronutrients from being discarded. It should also be emphasized that rations should only be used over intermittent short terms (three to seven days) that, together, may last for a total of no more than a month. To develop the recommendation on the total caloric intake of the ration, the committee considered health risks and benefits and information regarding the actual situation in the field. The data included food preferences, degree of satisfaction, and actual consumption of current rations. Data collected during training exercises of various military groups indicate that under stressful field conditions soldiers consume an average energy intake of 2,400 kcal. This level of intake is not enough to maintain body weight; however, the weight loss is moderate if the period of low energy intake is not sustained. Taking this information into account, the committee concluded that a ration with a caloric content of 2,400 kcal—if designed with adequate macronutrients and micronutrients and eaten entirely and for short periods of time such as three to seven days for up to a month—would not pose any health risks. In addition to the basic ration, the committee recommends provision of high-carbohydrate supplements for energy (400 kcal) in the form of gels, candy, or powder to add to fluids. These may also contain electrolytes to maintain balance. These supplements could serve individuals whose energy intake or need is higher than the one in the basic ration and could also be used at times during the day when physical activity peaks and more energy is needed. They could also be used by individuals who lose excess electrolytes or at times when the climatic conditions may cause higher electrolyte losses than usual. Although soldiers would still be in a negative energy balance, little evidence exists to suggest that a periodic hypocaloric diet, if otherwise adequate in protein and other essential nutrients, is likely to be harmful when consumed over brief periods of time, even if some weight loss occurs (< 10 percent of body weight). It is recommended that weight loss be measured after one month of use, and if

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Nutrient Composition of Rations for Short-Term, High-Intensity Combat Operations weight loss is greater than 10 percent for a soldier, he should not be sent on assault missions until weight is regained to within 5 percent of initial weight. Also, the ration should not be substituted for Meals, Ready-to-Eat or food services that provide a more appropriate diet for longer periods. 2. What would be the optimal macronutrient balance between protein, fat, and carbohydrate for such an assault ration to enhance performance during combat missions? 3. What are the types and levels of macronutrients (e.g., complex versus simple carbohydrates, proteins with specific amino acid profiles, type of fat, etc.) that would optimize such an assault ration to enhance performance during combat missions? Answers to questions two and three will be discussed together. The recommendations regarding distribution, level, and type of macronutrients for the ration were developed by considering the major health risks that might be posed by eating a hypocaloric diet in a combat situation. The typical energy deficit of 50 percent seen in combat operations leads to a negative nitrogen balance that can result in muscle loss, fatigue, and loss of performance. To minimize these potential consequences, the committee recommends that the protein level of the ration be 100–120 g total protein (based on 1.2–1.5 g/kg of body weight for an 80 kg average male soldier). This level will likely spare muscle protein loss as well as attenuate net nitrogen loss and adequately provide for synthesis of serum proteins while the individual is in a hypocaloric state. In addition, this level of protein will likely maintain the immune and cognitive functions requiring protein or amino acids. The committee recommends that the protein added to the ration be of high biological value. At this time, there is insufficient evidence to believe that the addition of specific amino acids or specific proteins with rapid rates of absorption will be of any additional benefit; more evidence is necessary before making a recommendation in this respect. The carbohydrate content of the ration is an important energy source and also helps maintain gastrointestinal health. Strong evidence that carbohydrate enhances cognitive function is still lacking; however, numerous data suggest that supplementing the diet with carbohydrate throughout periods of continuous physical exercise and stress not only increases energy intake but also optimizes physical performance. The committee recommends that the carbohydrate in the basic ration be 350 g to optimize physical performance. An additional 100 g of carbohydrate should be available as a supplement. Therefore, the overall recommendation is for 450 g. The committee considers palatability to be the major consideration in designing the food products to ensure ration consumption; thus, the food items and the carbohydrate supplement should provide a variety of

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Nutrient Composition of Rations for Short-Term, High-Intensity Combat Operations flavors. The amount of fructose as a monosaccharide in the ration should be limited to avoid the possibility of osmotic diarrhea. Dietary fiber should be 15–17 g and should include both nonviscous, fermentable fiber (e.g., gums, pectin, β-glucans, soy polysaccharides) and viscous, nonfermentable fiber (e.g., cellulose, lignin, hemicellulose). The primary reason for adding fat to the ration is to provide a readily digestible food source of high energy density. In addition to the essential fatty acids, fat is required to provide palatability and improve taste so that the ration is fully consumed. Among the macronutrients, protein and carbohydrate in adequate levels were considered the priority; the remainder of the macronutrients (up to the energy level of 2,400 kcal) should be provided as fat. The committee recommends that, after protein and carbohydrate needs are met, the ration should provide 58–67 g of fat (22–25 percent of energy intake) to be distributed across a variety of foods. The ration should provide a balance of dietary fatty acids between monounsaturated, polyunsaturated, and saturated fats, with at least 17 g of linoleic acid and 1.6 g of α-linolenic acid, recognizing essential fatty acid needs as well as the undesirable pro-oxidant properties of large amounts of unsaturated fatty acids. This balance can be determined by food formulation criteria. There is no recognized benefit to modifying fatty acid type in or adding structured lipids to the ration. 4. What are the types and levels of micronutrients such as direct antioxidants (e.g., vitamins C and E, carotenoids), cofactors in antioxidant and other biochemical reactions with high metabolic flux (e.g., B vitamins, zinc, manganese, copper), or other bioactives (e.g., caffeine) that could be added to such rations to enhance performance during combat missions? Table ES-1 shows the recommended levels of micronutrients and other bioactives. The committee followed a general approach to establish these levels as described here. They were primarily based on DRIs and then modified by the committee after considering data about sweat losses and utilization under high energy expenditure and stress. To provide food developers some flexibility, a range of levels was recommended for most micronutrients. In most cases, the ranges are based on the recommended dietary allowance (RDA) or adequate intake and the 95th percentile of intake of the US population. When the 95th percentile dietary intake was higher than the tolerable upper level (UL), then the UL was used as the upper limit of the recommended range. Exceptions to this general approach include the following: (1) for thiamin, the committee considered the importance of energy expenditure when setting the recommendations, while for vitamin B6, negative energy balance and the loss of protein were considered; (2) for vitamin C, the committee added 35 mg to the RDA to account for the needs of smokers; and (3) for vitamin A, the committee

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Nutrient Composition of Rations for Short-Term, High-Intensity Combat Operations TABLE ES-1 Ration Nutrient Composition Recommended by the Committee Nutrient or Energy Intake Recommended Amount Comments Energy Intake 2,400 kcal in basic ration Additional 400 kcal should be supplemented as carbohydrate in form of candy, gels, or powder to add to fluids, or all three. Macronutrients Protein 100–120 g Protein should be of high biological value. Preferable to add sources of protein with low-sulfur amino acids and low oxalate levels to minimize risk of kidney stone formation. Carbohydrate 350 g 100 g as a supplement Additional 100 g should be supplemented as carbohydrate in form of candy, gels, or powder to add to fluids, or all three. Amount of fructose as a monosaccharide should be limited to < 25 g. Fiber 15–17 g Naturally occurring or added. A mix of viscous, nonfermentable and nonviscous, fermentable fiber should be in the ration for gastrointestinal tract function. Fat 22–25% kcal 58–67 g Fat added to the ration should have a balanced mix of saturated, polyunsaturated, and monounsaturated fatty acids with palatability and stability the prime determinants of the specific mixture. Fat should contain 5–10% linoleic acid and 0.6–1.2% α-linolenic acid. Vitamins Vitamin A 300–900 µg RAE1 Could be added as preformed vitamin A or provitamin A carotenoids. Vitamin C 180–400 mg Highly labile in processed food. If added to foods, encapsulation should be considered to prevent degradation through interaction with pro-oxidants. Vitamin D 12.5–15 µg Estimates of dietary intake are not available. Range based on ensuring serum levels of 25-hydroxy-vitamin D. Vitamin E (α-tocopherol) 15–20 mg Should be added to foods since natural foods are mainly sources of γ- rather than α-tocopherol. Vitamin K No recommended level Amount in foods would be adequate provided ration is at least 50% whole foods.2

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Nutrient Composition of Rations for Short-Term, High-Intensity Combat Operations Nutrient or Energy Intake Recommended Amount Comments Thiamin 1.6–3.4 mg Dependent on energy use and intake. Amount in foods would be adequate provided ration is at least 50% whole foods. Riboflavin 2.8–6.5 mg Dependent on energy use. Niacin 28–35 mg Dependent on energy use. The amount added to the ration should not be over 35 mg. Vitamin B6 2.7–3.9 mg Dependent on negative energy balance and loss of lean tissue. If a higher protein level is provided, the amount of vitamin B6 should be increased proportionally. Folate 400–560 µg Fortification may be needed. Vitamin B12 No recommended level Amount in foods would be adequate provided ration is at least 50% whole foods. Biotin No recommended level Amount in foods would be adequate provided ration is at least 50% whole foods. Pantothenic Acid No recommended level Amount in foods would be adequate provided ration is at least 50% whole foods. Choline No recommended level Amount in foods would be adequate provided ration is at least 50% whole foods. Minerals Calcium 750–850 mg Major concern for higher levels is the potential formation of kidney stones. Chromium No recommended level Amount in foods would be adequate provided ration is at least 50% whole foods. Copper 900–1,600 µg If added to foods, encapsulation should be considered due to its pro-oxidant activity. Iodine 150–770 µg Could be added as iodized salt. Iron 8–18 mg If added to foods, encapsulation should be considered due to its pro-oxidant activity. Palatability should determine the amount in ration foods.

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Nutrient Composition of Rations for Short-Term, High-Intensity Combat Operations Nutrient or Energy Intake Recommended Amount Comments Magnesium 400–550 mg No more than 350 mg of magnesium salts should be present to meet the minimum daily amount of magnesium recommended. The rest should come from food sources. Also, if salt needs to be added and taste becomes objectionable, encapsulation should be considered. Manganese No recommended level Amount in foods would be adequate provided ration is at least 50% whole foods. Molybdenum No recommended level Amount in foods would be adequate provided ration is at least 50% whole foods. Phosphorus 700–2,500 mg Because inorganic phosphates may cause diarrhea, it is recommended that they are added only up to 700 mg. Intakes above this amount should come from food sources only. Potassium Aim to 3.3–4.7 g Foods naturally high in potassium should be included in ration; if added to foods to achieve recommended levels, taste problems might be encountered. Selenium 55–230 µg No clear evidence of effects as an enhancer of immune function or performance. Sodium ≥3 g up to 12 g as supplement For individuals who lose salt in excess or when in extremely hot or strenuous situations, sodium could be supplemented up to 12 g total. Part of this amount should be included in the form of candy, gels, or powder to add to fluids. Palatability will limit addition of sodium to these products; therefore, salt tablets should also be provided under medical guidance. Zinc 11–25 mg If it needs to be added and taste becomes objectionable, encapsulation should be considered. Ergogenics Caffeine 100–600 mg Not more than 600 mg in a single dose. There is no evidence of dehydration at this level. 1RAE = retinol activity equivalents. 2Whole foods = food items prepared to preserve natural nutritive value.

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Nutrient Composition of Rations for Short-Term, High-Intensity Combat Operations recommends a minimum of 300 µg retinol activity equivalents to minimize the risk of night blindness. One factor that would affect the micronutrient requirements is sweat and urine losses. Among factors causing increased sweat volume are exercise intensity and environmental temperature. When there were specific data or estimated amounts for additional micronutrient losses in sweat or urine during intense exercise in the heat (e.g., zinc, copper, sodium), then the amount was added to the recommended upper end level. The committee recommends the micronutrients be provided in whole foods and that fortification or the use of supplements be limited to the extent possible. In cases such as potassium, however, it was recognized that food alone would not provide enough of a particular nutrient and that some form of supplementation might be needed. In other cases, such as for the trace elements molybdenum, manganese, and chromium, no level is recommended because those minerals are widely distributed in foods and a deficiency is not anticipated during the short period of intake of these rations. The committee cautions about the potential for oxidation or interactions with other nutrients in the ration. Therefore, in addition microbiological tests, chemical analysis should be performed on the final ration following appropriate shelf-life studies. Other Bioactive Substances The committee reviewed the effects of several bioactive substances other than nutrients because of their potential benefits in physical or cognitive performance. Caffeine is the only component for which there are compelling data showing effectiveness for combat soldiers; therefore, only caffeine received the endorsement of the committee. Some other bioactives (e.g., creatine) are consumed already by soldiers with the goal of increasing physical endurance. For the most part, their effects are not clear. The committee recommends that randomized, blinded trials be undertaken to elucidate the risks, including withdrawal effects, and potential benefits of creatine and other popular bioactives; ideally, these trials should be conducted under conditions that mimic combat situations. The flavonoids are a class of compounds that might provide some benefit as antioxidants against the oxidative stress occurring during intense exercise and mental activities. Until more in vivo studies are conducted, foods such as fruits, vegetables, tea, and chocolate, which contain significant amounts of flavonoids, should be included in rations. WATER NEEDS Although the committee was not asked to make recommendations regarding water needs, the close links between diet, hydration status, and physiological

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Nutrient Composition of Rations for Short-Term, High-Intensity Combat Operations function cannot be overlooked. Proper hydration is a major factor in maintaining sustained mental and physical performance. Water needs are governed by sweat volume and metabolic rate as well as nutrient intake—primarily protein and salt intake. In this sense, the nature of the ration will also influence the water needs during combat; that is, protein and salt intake provide most of the excreted osmoles as urea and sodium with accompanying anions and, thus, additional fluid is needed for their excretion. The recommendation for 100–120 g of protein per day will result in 0.2–0.4 L more urine than would occur with 80 g of protein. While the protein recommended might add to the needs of water, the comparatively high level of carbohydrate in the ration compensates for some of those needs through improved protein utilization and limitation in the need to excrete sodium salts. While the committee did not provide specific recommendations for water, adequate amounts of water must be consumed with this ration to maintain and optimize physiological function and performance. Considering the expected level of stress and sweat volumes, and the nature of the ration, water in excess of 4–5 L/day must be available to ensure optimal performance in combat missions in which energy expenditure is high or carried out in hot and humid environments. FOOD MATRIX CONSIDERATIONS Food rations that provide complete nutritional needs for short-term, high-intensity military operations present a unique challenge to the product developer and nutritionist. Although the nutrient composition recommended by the committee (see Table ES-1) will place some constraints on the food forms and matrixes used, with careful planning it should be possible to provide complete nutritional needs in a ration with a restricted size and shelf-life of two to three years. For example, although whole foods should be used to the extent possible, the recommended levels for some nutrients may dictate the use of fortification with labile vitamins such as vitamin C as well as with other nutrients such as folate that are likely to be low in the ration due to the types of foods included. Fortification with labile nutrients presents a unique challenge because of the potential interaction with other compounds and decreased bioavailability. Food developers need to carefully consider the shelf-life of the ration to ensure that levels of these labile micronutrients are neither above (if storage period is shorter than anticipated) nor below (due to interactions with other components) the range of recommended levels. To minimize decreased bioavailability due to interactions, the use of encapsulated forms for some nutrients may be necessary. Because taste is an important factor when soldiers rate foods and because this ration is meant to be eaten entirely, providing a variety of acceptable, palatable products becomes a primary concern. Electrolytes (sodium and potassium) and other minerals (zinc, calcium, and magnesium) are known to have objectionable tastes to some, possibly at the levels recommended. The use of appropriate

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Nutrient Composition of Rations for Short-Term, High-Intensity Combat Operations chemical forms with better taste or technologies to mask the objectionable taste should be a high priority for food developers. In addition to palatability, satiety and food form should also be taken into consideration for this ration. A mix of carbohydrate-rich and fat-rich foods is needed to provide a satiating balance in the ration and to avoid overconsumption of the less-satiating foods. Foods that are included in a ration should have variety in flavors and textures and should be easy to consume. They should include familiar items in addition to foods that are already available for athletes, such as carbohydrate gels or powders to add to fluids for carbohydrate and electrolyte supplementation. Packaging is also an important consideration for stability, protection, and for ease of consumption. Overall, the use of existing and familiar products, packaging, and technologies is advised. FUTURE NEEDS The ration recommended by the committee was designed with the best available data. The majority of the data, however, were derived from studies in which the environment or the subjects were substantially different from the ones for which this ration is targeted. The committee believes that further work needs to be conducted to confirm that the ration provides optimal performance and maintains health or to have the opportunity of improving the ration by making necessary adjustments. The committee finds that, where gaps in knowledge exist, additional data in the following areas of investigation should prove particularly beneficial to future development and refinement of an optimal ration: (1) additional knowledge regarding the unique nutrient requirements during combat operations, (2) deeper understanding of food preferences under high-stress situations, (3) additional information on the actual use of the ration in the field, and (4) methods to identify individuals at greater risk of excess electrolyte loss and kidney stone formation. Some of the questions that will help advance knowledge regarding nutrient requirements during combat operations are: (1) What are effects of hypocaloric, high-carbohydrate, high-protein diets on performance and health? (2) What are the effects of micronutrients (e.g., vitamins C and E, B vitamins, zinc, selenium, iron, and copper), combination of antioxidants, or single amino acids on health and performance? (3) What are the potential benefits and risks of taking bioactives to enhance performance? When conducting such research, the physical and cognitive performance outcome measurements should be relevant and appropriate for those conditions (e.g., shot pattern tightness, complex reaction time, vigilance rather than objective or self-reported measurements of mood states). Furthermore, the committee emphasizes the importance of conducting such studies under conditions that approximate circumstances under combat operations.

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Nutrient Composition of Rations for Short-Term, High-Intensity Combat Operations The committee finds that the USARIEM and the CFD, RDECOM, NSC should continue to follow the existing systematic approach to ration development for combat missions. The approach should incorporate early in the design process issues of palatability and food preferences of end users. To that effect, the military should consider performing studies to test the performance and acceptability of the ration under the real circumstances of combat and under different environments with attention to actual duration of use of such rations. For a continuous improvement of the ration’s acceptability, more studies could be conducted to create strategies for the addition of specific nutrients to foods without compromising palatability. Other critical factors that need studying are stability of the rations over the long shelf-life required, for which nutrient interactions and packaging should be considered. Because this ration was designed to be used under unique circumstances, the actual use of rations with respect to duration and frequency should be monitored to ensure that they are not used when individuals are in garrison or in other types of extended missions.

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