Humans respiratory quotient

Extending these foregoing studies to the controversial problem of the value of sorbitol in the diabetic diet, Ellis and Krantz carried out typical tolerance tests with the compound. In normal human subjects, 50 g. of sorbitol increased the respiratory quotient above the normal basal level. Within an observation period of two hours, the effect was similar to that produced by an equal quantity of n-glucose. The blood sugar level was not significantly altered by the administration of sorbitol but was markedly elevated by n-glucose. In thirteen moderately severe diabetic... 

Regulation of NADPH Production Fatty Acid Synthase Respiratory Quotient Data from Human Studies... 

RESPIRATORY QUOTIENT DATA FROM HUMAN STUDIES... 

FIGURE 5.16 Respiratory quotient measurements of human subjects (O) food quotient values ( ). Human subjects consumed a low-fat diet for 6 days, followed by a high-fat diet for 7 days. Subjects lived inside separate respiratory chambers for days 4-10, then left the chambers, and returned for days 12-14. Each respiratory chamb was a small room ventilated at a measured rate with air. In-going air was sampled and measured every 15 min, and outgoing air was sampled and measured every 5 min, for the entire period that the subjects lived in the chambers. The RQ values for each subject was calculated for each day, as indicated in the figure. (Redrawn with permission from Schrauwen et al, 1997.)... 

Whole room calorimetry is considered the gold standard for measuring energy expenditure in humans. Although the subject is free to move around in the calorimetric chamber, spontaneous physical activity is greatly reduced. Furthermore, the measurement is carried out under strictly controlled, artificial environmental conditions and often is of short duration (<24 hr). However, indirect calorimetry does provide important information about the basal metabolic rate, respiratory quotient, sedentary energy expenditure, and sleeping metabolic rate. 

Li, X, Jin, L. Z., Wang, S. Zhu, J. 2010. Respiratory quotient calculation of the human body at a confined space in coal mines. Journal of University of Science and Technology Beijing, 32, 963-967. 

Another goal of the USDA study was to determine whether CLA enhanced energy expenditure, lipolysis, or fat oxidation in humans, similar to the effects observed in animals. Accordingly, measurements of metabolic rate and respiratory quotient were made by indirect calorimetry, and stable isotope tracers of palmitate and glycerol were used to measure the rate of appearance of free fatty acids and glycerol as well as whole body lipolysis and apparent reesterification. CLA supplementation had no effect on metabolic rate or whole-body fat oxidation rate during rest or exercise. Similarly, CLA did not change lipolytic rate, fatty acid release from adipose tissue, or apparent FFA reesterification rates under conditions of rest or exercise (33). 

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