As the U.S. military faces the twenty-first century, it must contend with changes in the nature of warfare and deployment that have significant implications for individual performance. The more frequent redeployment of soldiers (necessitated by downsizing and by changing military strategies) mandates greater concern for their physical health and well-being and, therefore, the development of cutting-edge techniques for field assessment of health and nutritional status. Such assessment tools must demonstrate reproducibility and reliability in field tests, must be noninvasive, and must cause minimal interference with battlefield operations. Reliance upon techniques that are tied to laboratories must give way to ambulatory assessment. Budgetary constraints, coupled with the need to stay at the forefront of research, dictate that careful consideration be given to identifying the best available and emerging technologies and making priority decisions regarding which ones should be undertaken directly by the military, which deserve investment of funds to foster military applications, and which are best left to the private sector.

In 1994, the Committee on Military Nutrition Research (CMNR) was asked by the scientists at the U.S. Army Research Institute of Environmental Medicine (USARIEM) to identify and evaluate new technologies to determine whether the technologies; will provide useful tools to help solve important issues in military nutrition research in the areas identified by USARIEM. The committee was requested: (1) to provide a survey of newly available and emerging techniques for the assessment and optimization of nutritional and physiological status and performance, and (2) to evaluate the potential of these techniques to contribute to future research efforts involving military personnel. In addition, the committee was asked to make recommendations regarding the practicality and the applica-

tion of such techniques in field settings and to include in its response the answers to the following six questions:

1. Will the technologies be a significant improvement over current technologies?
2. How likely are the technologies to mature sufficiently for practical use?
3. What is the cost/benefit ratio of the new technologies, and how expensive (in both monetary and personnel terms) will they be to employ compared with the importance of the information they will provide?
4. Are the technologies of such critical value that their development should be supported by Department of Defense funds—such as can be provided by the Small Business Innovative Research program?
5. How practical are the technologies? Will they require dedicated personnel and complex, exotic equipment? Will the data provided be difficult to analyze?
6. Can the technologies be used in the field (could they be used in the field or used to analyze samples collected in the field)?

Recognizing that there were a large number of technologies that could be reviewed and the need to limit the scope of this review to those areas of most interest to USARIEM, six relevant research areas for review were identified, with the primary criterion for inclusion being the possibility for application to field research: body composition, tracer techniques to evaluate metabolism and energy expenditure, ambulatory methods to determine energy expenditure, molecular and cellular approaches to nutrition and immune function, and functional and behavioral measures of nutritional status. To assist the CMNR in responding to the questions, a workshop was convened on May 22–23, 1995, in Washington, D.C., that included presentations from individuals with expertise in the aforementioned areas.

Committee members subsequently met with staff several times over the course of a year and a half and worked separately and together using the authored papers, additional reference materials provided by the staff, and personal expertise and experience with the methods to draft the overview, summary, conclusions, and recommendations, which were reviewed by an anonymous panel of peers according to National Research Council policy.

This report, Emerging Technologies for Nutrition Research: Potential for Assessing Military Performance Capability (IOM, 1997), looks at newer technologies that are being employed to identify and study basic issues that may be significant in nutrition research, with evaluation being limited to technologies discussed at the workshop. It provides responses to the questions posed to the CMNR, conclusions, and recommendations, as well 24 invited papers presented at the workshop.

• Methods of measuring body composition are relevant and important to the military to assure accuracy and fairness in the application of body composition measures to accession and retention of military personnel.
• Anthropometric measures are the most applicable methods for evaluating compliance with military standards of body fat. The more sophisticated technologies of computerized axial tomography scanning, magnetic resonance imaging (MRI), and dual-energy x-ray absorptiometry (DXA) are useful tools for developing application equations from anthropometric measures to estimate body fat.
• Bioelectrical impedance analysis is a less-reliable method of measuring body fat, but the methodology may be useful in answering specific questions concerning hydration state and function of cell membranes.
• Tracer methodology, particularly the use of stable isotopes, is an important technology for understanding and measuring metabolic processes (the doubly labeled water technique currently is used in studies of energy expenditure in the field and is a cost-effective technology for this purpose). Stable isotopes that can be administered and measured noninvasively through easily obtained samples offer important opportunities to estimate metabolic processes in the field. Central analysis of samples increases the practicality of their use in field studies.
• Ambulatory monitoring techniques, such as the foot strike measurement, also show good promise as field measures of work and energy expenditure.
• The various molecular and cellular technologies are interesting as research methods but are strictly laboratory research tools at present. Observing the development of these techniques and their application will be important for USARIEM, but investing in their in-house development is not recommended at this time. Studies of immune function are potentially very important to the military. An understanding of the effect of the various stresses of military operations on the body's immune function and how these may be modified to aid soldier performance is an important area for investigation.
• The development of vaccines against various infectious diseases of unique significance to the military population but not necessarily of significance to the civilian population may be very important in sustaining the ability of the soldier to operate effectively in the field. Oral vaccines may be most effective as they tend to mimic the route of exposure to the infectious agents that cause problems in the field.
• The development and production of human antibodies by transgenic plants create dramatic new possibilities for short-term (weeks-to-months) pro-phylaxis, or therapy, of unusual infectious diseases or toxemias of potential military importance and for which no other forms of immunization currently are available.

• The ability to study the cognitive function of individuals while they perform their duties has great potential for improving soldier performance under stress. Current developments in computerized and miniaturized technology appear to permit expanded studies of real-time cognitive behavior. Support for the development of specific monitoring devices that are compatible with military field equipment may be necessary to implement this technology.

• Anthropometric equations remain the most practical tools for assessment of body composition in field situations. More sophisticated technologies such as DXA and MRI should be used to develop criterion measures for refinement of the equations.
• Tracer methodology is important for measuring energy expenditure and metabolism. Further development of stable isotope techniques in collaboration with the private sector is recommended for greater field applicability.
• A foot-contact method shows promise for ambulatory monitoring of energy expenditure.
• The military should keep abreast of research in the private sector that uses molecular cloning techniques to study the effects of nutritional and other stressors on gene expression, but this research should not be undertaken by the military at this time.
• Development of vaccines that are effective against infectious diseases of unique significance to military populations should be pursued.
• Noninvasive techniques for the assessment of cognitive function during operational task performance should be developed further.

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The committee's responses to the questions, conclusions, and recommendations from this report are included in Appendix H.