Body fluid regulation in a simulated disabled submarine: effects of cold, reduced O2, and elevated CO2.

INTRODUCTION: Survivors awaiting rescue aboard a disabled submarine (DISSUB) lacking power and/or environmental control would potentially be exposed to cold and reduced O2 and elevated CO2 levels. We hypothesized that elevated CO2 levels would lead to hormone changes that would mitigate cold and hypoxia-induced body fluid losses. METHODS: Blood was drawn from seven men on three mornings: baseline (21% O2, 0.05% CO2), after 4 d of low O2, cold, and high CO2 (T101; 4 degrees C, 16.75% O2, 2.5% CO2), and following acute withdrawal of cold and high CO2 (T173, 16.75% O2, 0.05% CO2). Total body water (TBW) was measured using deuterium oxide dilution at baseline and at T148. Hormone analyses included atrial natriuretic peptide (ANP), aldosterone (ALDO), and plasma renin activity (PRA). RESULTS: TBW decreased by 0.4 +/- 0.4 L. Water turnover was 3.0 +/- 0.5 L x d(-1). ANP (pg x ml(-1)) was lower (p < 0.05) at T101 (3.46 +/- 1.17) and T173 (4.97 +/- 2.28) vs. baseline (8.19 +/- 3.40). PRA (pg x ml(-1)) was higher (p < 0.05) at T101 (10.43 +/- 4.90) and T173 (14.23 +/- 4.48) vs. baseline (6.81 +/- 3.43). ALDO, serum osmolality, and electrolytes were not different across time. Urine flow was lower at T101 and T173 vs. baseline, and urine osmotic clearance was lower at T173 vs. baseline. Free water clearance did not change across time. DISCUSSION: These data indicate that the combination of cold, low O2, and high CO2 for 5-7 d did not change total body water and hormone changes and urinary measures across the DISSUB were consistent with fluid retention.

Adequacy of Garrison feeding for Special Forces soldiers during training.

This study evaluated whether Special Forces (SF) soldiers training in garrison would meet nutrient intake recommendations using the available garrison dining facility. Dietary intakes were obtained by a visual estimation method and self-reported food records from 32 SF and 13 support soldiers for 9 days. Total energy expenditure (TEE) was measured in nine soldiers from each group using doubly labeled water. Mean (+/- SD) total energy expenditure of SF (4,099 +/- 740 kcal/day) was higher than support soldiers (3,361 +/- 939 kcal/day, p < 0.01). Energy intake did not differ between groups. Median energy intake for all soldiers was 3,204 kcal/day. The nutrient intake goals of SF soldiers were not fully met by eating in the dining facility. Extending meal times and providing additional meals or "take out" foods may allow energy needs of SF soldiers (approximately 4,200 kcal/day) to be met, while reducing the reliance on potentially less nutritious outside foods.

Iron deficiency is unacceptably high in refugee children from Burma.

Iron-deficiency anemia (IDA) in refugees is reported to be among the major medical problems worldwide. Because food rations are typically inadequate in iron, long-term reliance is a key predictor of anemia among displaced people. Comprehensive nutritional assessments of refugee children from Burma have not previously been completed. Refugee children aged 6-59 mo were studied to determine 1) the prevalences of anemia, iron deficiency (ID) and IDA and 2) the factors associated with anemia and ID. Cluster sampling in three camps and convenience sampling in two additional camps were used. Hemoglobin (Hb) levels were measured and micro mol zinc protoporphyrin/mol heme were determined in 975 children. Logistic regression analyses (95% CI) determined predictors of anemia and ID. The prevalences of IDA, anemia and ID in these refugee children were 64.9, 72.0 and 85.4%, respectively. Predictors of anemia included young age (P < 0.001), food ration lasting <1 mo (P = 0.001), daily consumption of dietary iron inhibitors (P < 0.05), weight-for-height Z-score of <-2 (P < 0.05), male gender (P < 0.05) and uneducated father (P < 0.001). Predictors of ID were young age (P < 0.001) and recently reported illness (P < 0.05). Laboratory tests confirmed that anemia and ID are major health problems among these refugee children and that ID is the leading cause of anemia. A comprehensive nutrition and public health-focused approach to combating anemia and ID is essential. Following the presentation of results to policy makers, the improvement of the micronutrient content of rations has been initiated.

Nutrition knowledge and supplement use among elite U.S. army soldiers.

A U.S. Army Special Forces (SF) unit was studied to determine characteristics of supplement users, assess nutrition knowledge, and identify nutrition information sources. SF-qualified (n = 119) and non-SF, support soldiers (n = 38) participated. Most soldiers (87%) reported current supplement use with more SF (90%) than non-SF, support soldiers (76%) using supplements (p < or = 0.05). Supplements SF reported using most were multivitamins, sports bars/drinks, and vitamin C. The mean nutrition knowledge score for all soldiers was 48.5 +/- 15.2% correct responses. Most soldiers incorrectly believe protein is used for energy for short-term athletic events (64%) and that vitamins provide energy (58%). The most common information sources reportedly used were popular magazines/books (75%), friends/teammates (55%), physicians/nurses, radio/television (34%), and the Internet (31%).