Use of Doubly-Labeled Water Measured Energy Expenditure as a Biomarker of Self-Reported Energy Intake
Dale A. Schoeller, Margriet S. Westerterp-Plantenga in Advances in the Assessment of Dietary Intake, 2017
The doubly-labeled water method was pioneered and validated in small animals by Nathan Lifson and coworkers over 60 years ago (Lifson et al. 1955). The method was based on the observation that the oxygen atoms in carbon dioxide were in equilibrium with the oxygen in water (Lifson et al. 1949). Thus it was reasoned that if a loading dose of water labeled with 2H and 18O, the 2H and 18O elimination kinetics could be used to calculate an animal’s carbon dioxide production. The elimination of the 2H in body water results from the daily ingestion of beverages containing water, food moisture, and metabolic water that dilute the excess tracer from the loading dose followed by excretion of water to maintain a steady state. The elimination of 18O from body water is not only by the dilution and excretion of water, but also by dilution from the oxygen atoms in carbon dioxide produced during respiration (Figure 10.1). This can be stated mathematically using a single pool mathematical model. The elimination rate of 2H from the total body water pool times the pool size is directly proportional to water flux, and the elimination rate of 18O from the total body water times the pool size is directly proportional to the sum of water flux and twice the carbon dioxide flux (Figure 10.1). The carbon dioxide flux is doubled because there are two atoms of oxygen in each carbon dioxide molecule for each atom of oxygen in water.
Fats and Cardiovascular Disease
Stephen T. Sinatra, Mark C. Houston in Nutritional and Integrative Strategies in Cardiovascular Medicine, 2015
Kidney, liver, and heart use ketones as their preferred fuel even with high blood glucose levels. FAs can be utilized to make ketones on site in normal cells, but the liver generally makes ketones for the heart and other tissues. The liver is a large organ and has a good oxygenated blood supply. When consuming a ketogenic diet, the liver makes ketones from the dietary fats consumed and sends them out to all other tissues of the body. This process has several beneficial effects. Liver has large blood supply that carries oxygenated blood. The oxygen required for making ketones is readily available in the liver and spares other tissues with a less oxygenated blood supply. Thus, when the ketones arrive at the peripheral tissues, they are ready to use and can pass through the cell membrane and into the mitochondria without carriers, insulin, oxygen, or any need to be modified for use by the mitochondria to be converted to energy. Furthermore, there are no waste products to be disposed of by the cells. All body tissues are capable of converting to a “ketone economy” within a few days of becoming ketonic. The brain can change in a few days but takes a little longer to completely adapt. Because ketones “burn” to carbon dioxide and water, the body actually produces metabolic water when using ketones for energy. The hump on a camel is fat to provide metabolic water when on long trips in the dessert. Marathon runners maintaining a ketogenic diet find that they do not “hit the wall” as severely as runners practicing carbohydrate loading (personal communication).
The Metabolic Cart
Michael M. Rothkopf, Jennifer C. Johnson in Optimizing Metabolic Status for the Hospitalized Patient, 2023
The ultimate purpose of consuming calories is to convert food from plants and animals into usable energy for ourselves. In our bodies, this is done by burning carbohydrates, fats and proteins and capturing some of the energy released into the high-energy phosphate bonds of ATP. Heat and water are also produced. The heat maintains our body temperature. The metabolic water contributes to our fluid balance (excess heat and water is dissipated and eliminated). Our cells perform this remarkable biologic combustion by utilizing oxygen as an electron acceptor. With it we enable aerobic respiration and the production of much more ATP than is possible through anaerobic processes.
Handgrip Strength and Its Association With Hydration Status and Urinary Sodium-to-Potassium Ratio in Older Adults
Published in Journal of the American College of Nutrition, 2020
Joana Mendes, Patrícia Padrão, Pedro Moreira, Alejandro Santos, Nuno Borges, Cláudia Afonso, Rita Negrão, Teresa F. Amaral
Free water reserve (FWR) (mL/24-h) is determined by various parameters of water metabolism: beverages and food water intake, metabolic water, urine volume, and obligatory urine volume (22). It was calculated as follows: [24-hour urine volume − obligatory urine volume] (22). The obligatory urine volume is a theoretical volume defined as the water volume necessary to excrete 24-hour urine solutes at the age-related lower limit of maximum urine osmolality (mean (−2 standard deviations)) (22). Based on literature data of standardized tests of renal concentration capacity in subjects in industrialized countries, the lower limit of maximum urine osmolality has been estimated to be 830 mOsm/kg minus 3.4 mOsm/kg per year starting from an age of 20 years (22). Obligatory urine volume was calculated by the following formula: [solutes in urine 24-hour (mOsm/day)]/[830–3.4 × (age-20)] (22). This calculation implies that the obligatory urine volume to excrete the same amount of 24-hour urine solutes increases with aging, reflecting the poor ability to concentrate urine in the elderly (22). The hydration status was evaluated based on FWR and participants were considered at risk of hypohydration in case of negative FWR values (22).
Integrating inert dusts with other technologies in stored products protection
Published in Toxin Reviews, 2021
Masumeh Ziaee, Asgar Ebadollahi, Waqas Wakil
It was reported by Le Patourel (1986) that S. granarius, O. surinamensis, C. pusillus and Tribolium castaneum Herbst (Coleopteran: Tenebrionidae) exhibited tolerance to sorptive dust, Sipernat 22S when provided with food commodity. The adult beetles absorb moisture from wheat grains resulted in metabolic water production and more survival. Similarly, Loschiavo (1988) mentioned that Oryzaephilus mercator (Fauvel) (Coleoptera: Silvanidae) provided with food after a 5-d exposure to the silica aerogel Dri-Die 67 (SG-67) indicated a significantly higher survival. It could be attributed to the beetles’ ability to ingest water from food source and restore the lost by desiccation (Loschiavo 1988, White and Loschiavo 1989).
The Na/Ca Exchange as a Target for Antitumor Effect of 4Hz Pulsing Magnetic Field
Published in Electromagnetic Biology and Medicine, 2020
Yerazik Mikaelyan, Naira Eloyan, Sinerik Ayrapetyan
The obtained result on spleen tissue hydration in TCM which has a time-dependent character starting from the first two hours of tumor transplantation (Figure 2) not having temperature sensitivity in in vitro state (Figure 3) indicates that the increase of spleen tissue hydration is due to the osmotic water uptake by cells because of the impairment of metabolic water efflux from the cells. The fact that lactate concentration in blood of TCM is significantly higher than that of HM (Figure 4) could serve as a supporting data on the impairment of mitochondrial function in spleen of TCM.