logical stress, or energy deficit? What are the risks of amino acid supplements and high-protein diets?
In considering the questions posed by the Army, the CMNR collaborated with the Subcommittee on Body Composition, Nutrition, and Health of Military Women. The two committees convened a workshop in March 1997, in Washington, D.C., to bring together experts in protein metabolism, exercise physiology, and cognitive psychology, as well as military nutritionists familiar with historical and recently completed nutritional assessment surveys. Each of the workshop speakers was asked to prepare a review paper. After the workshop, the committees summarized the presentations, and drawing upon their summaries of the workshop, the commissioned papers, background materials provided by the speakers, focused literature searches by the staff, and their own expertise in the field of protein metabolism, they prepared an overview of the pertinent issues, responses to the sponsor's questions, conclusions, and recommendations. These form chapters 1 and 2 of this report. The authored papers, which can be found in Chapters 3 through 16, were not subject to review.
Current estimates of protein and amino acid requirements are based on studies employing the technique of nitrogen balance assessment. A 1985 report of the Food and Agriculture Organization, in collaboration with the World Health Organization and the United Nations University (FAO/WHO/UNU, 1985) proposed a protein requirement of 0.625 g per kilogram of body weight per day (g/kg BW/d) for egg or beef protein, so-called high-quality proteins. The current recommended dietary allowance (RDA) for protein in the U.S. diet is 0.8 g/kg BW/d for adults (Table ES-1; NRC, 1989).
Consensus exists for the current adult protein requirement but not the adult requirement for total essential (indispensable) amino acids (IAAs). Based on nitrogen balance data, the recommendation for IAAs as a percentage of total protein intake is 43 percent for children and only 11 percent for adults (FAO/WHO/UNU, 1985). Since the 1985 report, Young and colleagues have presented data showing that the FAO/WHO/UNU pattern cannot maintain