Protein and Water Balances of Young Adults during Prolonged Exposure to High Altitude (4,300 Meters)

Consolazio, C. Frank; Matoush, LeRoy O.; Johnson, Herman L.; Daws, Ted A.

doi:10.1093/ajcn/21.2.154

Cited by 57 publications

(22 citation statements)

References 11 publications

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“…Because water deficits and excesses are triggering compensatory changes in either water gain or losses until water balance is re-established, water balance studies with water available ad-libitum can be used for the estimation of the daily water requirement under the specific conditions of observation. Water balance studies in infants, children and adults (Ballauff et al, 1988;Consolazio et al, 1968;Goellner et al, 1981) demonstrate that infants require more water on a body weight basis than adults but about the same amount of water per unit of energy intake for the production of urine of similar osmolarity (or specific gravity) (80 to 210 mL of water per 100 kcal for urinary specific gravity of 1.006 and 1.030, respectively).…”

Section: Body Water Balancementioning

confidence: 99%

Scientific Opinion on Dietary Reference Values for water

Products¹

2010

EFS2

326

114

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This Opinion of the EFSA Panel on Dietetic Products, Nutrition, and Allergies (NDA) deals with the setting of dietary reference values for water for specific age groups. Adequate Intakes (AI) have been defined derived from a combination of observed intakes in population groups with desirable osmolarity values of urine and desirable water volumes per energy unit consumed. The reference values for total water intake include water from drinking water, beverages of all kind, and from food moisture and only apply to conditions of moderate environmental temperature and moderate physical activity levels (PAL 1.6). AIs for infants in the first half of the first year of life are estimated to be 100-190 mL/kg per day. For infants 6-12 months of age a total water intake of 800-1000 mL/day is considered adequate. For the second year of life an adequate total water intake of 1100-1200 mL/day is defined by interpolation, as intake data are not available. AIs of water for children are estimated to be 1300 mL/day for boys and girls 2-3 years of age; 1600 mL/day for boys and girls 4-8 years of age; 2100 mL/day for boys 9-13 years of age; 1900 mL/day for girls 9-13 years of age. Adolescents of 14 years and older are considered as adults with respect to adequate water intake. Available data for adults permit the definition of AIs as 2.0 L/day (P 95 3.1 L) for females and 2.5 L/day (P95 4.0 L) for males. The same AIs as for adults are defined for the elderly. For pregnant women the same water intake as in non-pregnant women plus an increase in proportion to the increase in energy intake (300 mL/day) is proposed. For lactating women adequate water intakes of about 700 mL/day above the AIs of non-lactating women of the same age are derived. KEY WORDSWater, total body water, hydration, osmolarity, water balance, regulation, distribution, consumption, water loss, water requirement, adequate intake SUMMARYFollowing a request from the European Commission, the EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA) was asked to deliver a scientific Opinion on Population Reference Intakes.Water is consumed from different sources, which include drinking water (tap and bottled water), beverages, moisture content of foods, and water produced by oxidative processes in the body. Water intake from beverages and foods is defined as total water intake, while the sum of total water intake and oxidation water constitutes total available water.Water is essential for practically all functions of the body and is particularly important for thermoregulation.A water intake which balances losses and thereby assures adequate hydration of body tissues is essential for health and life.The water content of the body and the distribution of body water over the intracellular and extracellular compartments of the body changes with age, but is under tight homeostatic control for an individual in a given stage of life.Loss of body weight, denoting loss of body water, of about 1% is normally compensated within 24 hours. Without compensation and furthe...

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Section: Body Water Balancementioning

confidence: 99%

Scientific Opinion on Dietary Reference Values for water

Products¹

2010

EFS2

326

114

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“…At high altitude, humans experience a loss of body water via altitude-cold diuresis, high energy expenditures, and often poor access to water (Askew 1989;Consalazio et al 1968). Many studies have shown that such dehydration is associated with impaired physiological performance (e.g.…”

Section: Introductionmentioning

confidence: 99%

The effect of drinking tea at high altitude on hydration status and mood

Scott

Rycroft

Aspen

et al. 2004

European Journal of Applied Physiology

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The effect of drinking tea on hydration status and mood was studied in nine male and four female members of expeditions based at Mt. Everest base camp at an altitude of 5,345 m. Whilst exposed to altitude-cold diuresis, participants were subjected to a crossover experimental design comprising two 24-h dietary interventions. In the "tea" condition, hot brewed tea formed a major part of fluid intake, whereas in the "no-tea" condition tea was excluded from the diet. Subjects were prohibited in both cases from consuming other caffeinated beverages, caffeinated foods, and alcoholic drinks. Mean fluids ingested [mean (SE); tea=3,193 (259) ml versus no tea=3,108 (269) ml] and urine volume (tea=2,686 (276) ml versus no tea=2,625 (342) ml] were similar under both conditions. Statistical analysis found no difference in urine stimulated as a result of the tea intervention (P=0.81). Several markers of hydration status were also taken immediately pre and post each condition, including measures of urine specific gravity, urine electrolyte balance (K+, Na+), and urine colour. None of these measures indicated a difference in hydration status as a result of the dietary intervention in either the control or tea condition. A difference was, however, found in mood, with subjects reporting reduced fatigue when tea was included in the diet (P=0.005). The study shows therefore that even when drunk at high altitude where fluid balance is stressed, there is no evidence that tea acts as a diuretic when consumed through natural routes of ingestion by regular tea drinkers, but that it does have a positive effect on mood.

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“…There is now ample evidence that both long-term and short-term exposure to HA induces weight loss in humans (Boyer & Blume, 1984;Guilland & Klepping, 1985;Consolazio et al, 1968;Rose et al, 1988). The weight loss in humans recorded at extreme altitudes is due, at least partly, to drastic reduction of lean body weight and muscle wasting (Kayser, 1994).…”

Section: Discussionmentioning

confidence: 99%

“…With the durations of these sojourns varying from a few days to many months, the inherent problems of Acute Mountain Sickness (AMS) viz., reduced food intake, headache, nausea, dizziness, insomnia, etc., are also encountered. This altitudeinduced hypophagia (Consolazio et al, 1969;Hannon et al, 1976;Rose et al, 1988;Guilland & Klepping, 1985;Askew, 1989) and the resultant body weight loss (Consolazio et al, 1968;Boyer & Blume, 1984;Butterfield et al, 1992;Kayser, 1994) have been the focus of many studies over the years. Food intakes are usually reduced by 10±50% during acute altitude exposure.…”

Section: Introductionmentioning

confidence: 99%