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Precise measurement of total body water using trace quantities of deuterium oxide
Abstract
This study was undertaken to investigate the possibility of measuring total body water in human subjects to better than +/-0.5%. Accurate serial estimates of total body water were required to complement densitometric and anthropometric measurements used to monitor body compositional changes in obese patients undergoing dietary or surgical weight reduction therapy. The method required the oral administration of 1-2 g of deuterium oxide and the analysis of pre-dose and respective equilibrated samples of urine, plasma or saliva. The sample size required for analysis was 5 microliter and the conversion of gaseous phase was accomplished using a uranium reduction furnace. Isotopic enrichment of samples was measured using a mass spectrometer incorporating several features designed to cope with problems inherent in H2/H2H isotopic analysis. Reproducibility of sample preparation and accuracy of the mass spectrometer were tested using international standards and shown to give an overall sensitivity of 2 parts in 10(7) for the determination of deuterium in H2O/H2HO mixtures. This precision has enabled us to demonstrate that isotopic fractionation of deuterium with respect to hydrogen occurs within the body and expands the potential use of this isotope for quantitative biochemical studies in the human subject.
... However, in vivo, the amount of FM can be measured by a number of techniques including: underwater weighing (hydro densitometry), air displacement (bod pod), bioelectrical impedance analysis (BIA), dual energy X-ray absorptiometry (DEXA), computerised tomography (CT) and magnetic resonance imaging (MRI) and isotope dilution technique (deuterium oxide, D2O). Most of these techniques have proven their validity in determining FM [1,7,[8][9][10]. ...
... 1. Bioelectrical impedance analysis (BIA): BF% was estimated using commercially available BIA analyser system (Bodystat Quad scan 4000, British ISLES) in all studied groups in accordance with the manufacturer's instruction manual between 9 and 10 h in the morning. The reliability and validity of this system in measuring BF% has been previously verified in multiple ethnicities [8,9]. BF% was calculated from the whole body impedance value and the preentered personal data (age, gender, height and weight) of the corresponding women. ...
... Each woman received orally a dose of D2O (0.05 g/kg body weight) (99.8% atom present excess; Cambridge Isotope D2O laboratories, Inc, United Kingdom). The saliva samples were taken at baseline, after an overnight fast and at 3 h after ingesting the D2O (endpoint), assuming that the plateau was reached at 3 hours [9]. Absorbent salivates (sarstedt, Rommelsdorf, Germany) were used to collect the saliva. ...
Purpose: Obesity is a common health problem in both developed and developing countries. BMI is commonly used to identify obesity. However, there is increasing evidence that the relationship between BMI and BF% differs among various ethnicities. The main objectives of this study are (1) to evaluate the correlation between BF% as determined by BIA, DEXA, Deuterium oxide (D2O) and BMI, (2) to assess the accuracy of currently used WHO´s BMI cut-off points to identify overweight and obesity among Syrian women. Material and Methods: A total of 908 healthy Syrian women aged 18-60 years participated in this study. Weight, height, BMI, BF% assessed by BIA and DEXA, and D2O have been determined. Results: BF% results obtained by BIA and DEXA, and D2O revealed strong correlations. BMI showed a statistically significant correlation with BF% determined by BIA, DEXA and D2O. Obesity when defined as BMI ≥ 30 and as BF% > 35% (derived from BIA, DEXA and D2O) classified 43%, 52.5%, 75.9% and 72.7% of women as obese, respectively. ROC analysis defined BMI cut-off points for overweight and obesity of 22.5 and 25.7, respectively. Using the new BMI cut-off point, the prevalence of obesity among Syrian women was increased by 24%. Conclusions: The current BMI cut-off points recommended by WHO underestimate the prevalence of overweight and obesity among Syrian women. Our data suggests that it is important to lower the proposed WHO´s BMI cut-off points for the Syrian women.
... The kinetic ,differences between water and the 2H20 or 3H20 dose cause lower baseline and post-dose tracer levels in RW samples than exist in the body, and thus an overestimate of TBW occurs. Deuterium fractionation factors have been estimated in vitro (26) and in vivo (18,27), but have been determined based on analysis in small samples (Appendices C-D). Furthermore, these fractionation effects were determined for baseline, pre-dose abundances in plasma, which may not reflect isotope enrichment after equilibration with the tracer dose. ...
... The first purpose of this investigation was to identify an appropriate isotopic fractionation factor for TBW from 2H20 enrichment in RW compar~d to TBW from 2H20 enrichment in S. Previous studies had reported fractionation factors of 0.946 and 0.944 ± 0.004 (mean ± SD) (18,27), but were based on analysis of small numbers of subjects (n = 6 and 20) and had examined 2H20 abundances only in baseline, pre-dose fluid samples. This study compared 2H20 abundances in post-dose RW and S samples and TBW volumes . ...
... Analytical techniques differ among laboratories. Isotope-ratio mass spectrophotometry (IRMS) was used in the original analysis of fractionation effects (18,27), but is expensive, and thus not available for routine use in most laboratories. The use of infrared spectrophotometry (IR) was described by ...
... Body composition was measured non-invasively using one of two stable isotope dilution procedures: deuterium 19 for the majority of children (n ¼ 72 children with CP) or oxygen-18 (n ¼ 13 children with CP and all 16 TDC). 20 This was due to a small subset of the children with CP and all TDC being involved in a concurrent study investigating total energy expenditure. ...
... For the deuterium-dilution technique, a second urine sample was collected at approximately five hours after dosing. 19 When using oxygen-18, daily samples were collected for the 10 days following the appointment. 20 Parents of children with poor or no bladder control were instructed to collect samples using either urine bags or absorbent cotton wool balls placed in the nappy, from which urine was extracted. ...
... All urine samples were analysed using a Dual Inlet Isoprime isotope ratio mass spectrometer (Isoprime Dual Inlet IMRS e IonVantage Software, Isoprime, Manchester, UK) to determine isotopic enrichments. Dilution spaces for both deuterium and oxygen-18 were calculated according to standard equations, 19 and adjusted by 4% and 1% respectively to correct for overestimation when compared to the body water pool and give consistent total body water measures. 19,20 The subsequent total body water values were divided by age and gender specific hydration factors to give a result for FFM. ...
Background/Aims
Altered body composition is evident in school children with cerebral palsy (CP). Fat free mass and fat mass amounts differ according to functional ability and compared to typically developing children (TDC). The extent to which body composition is altered in preschool-aged children with CP is unknown. We aimed to determine the fat free mass index (FFMI) and body fat percentage (BF%) of preschool-aged children with CP and investigate differences according to functional ability and compared to TDC.
Methods
Eighty-five children with CP (68% male) of all functional abilities, motor types and distributions and 16 TDC (63% male) aged 1.4 to 5.1 years participated in this cross-sectional study. Body composition was determined via isotope dilution. Children with CP were classified into groups based on their gross motor function classification system (GMFCS) level. Statistical analyses were via ANOVA, ANCOVA, post-hoc Tukey HSD tests, independent t-tests and multiple regressions.
Results
There were no significant differences in FFMI or BF% when comparing all children with CP to TDC. Children classified as GMFCS levels III, IV and V had significantly lower FFMI levels compared to children classified as GMFCS I and II (p<0.05). Children of GMFCS IV and V had the highest mean (±SD) BF% of all children (24.6% (±10.7%)), significantly higher than children of GMFCS I and II (18.6% (±6.8%), p<0.05).
Conclusions
Altered body composition is evident in preschool-aged children with CP, with a trend towards lower FFMI levels and greater BF% across functional ability levels from GMFCS I to V. Further research is required to determine optimal body composition parameters and investigate contributing factors.
Clinical trial registry
Australian New Zealand Clinical Trials Registry (ANZCTR) number: ACTRN12611000616976
... Deuterium oxide is a suitable isotope that fulfils these criteria and can be used in combination with isotope ratio mass spectrometry (Halliday and Miller, 1977) to determine TBW to an accuracy of ± 0.5%. However the assumption that the water concentration of lean tissue is similar in SS and AA patients and constant with age (although children have a higher water content) may be a source of error since the composition of LBM may change in disease states and with growth. ...
... Anthropometry was measured as previously described and LBM derived in fasting subjects from the measurement of total body water using deuterium oxide dilution (Halliday and Miller, 1977). After the bladder had been emptied and urine collected to determine background enrichment, subjects were given a loading dose (2 ml/kg) of a 10% deuterium oxide solution. ...
Growth impairment in homozygous sickle cell (SS) disease emerges as early as age six months but the mechanisms for this deficit are unknown. Analysis of longitudinal growth data suggested that adolescent growth and pubertal maturation of Jamaican SS children was delayed but final height was normal. This observation, delayed skeletal maturation, reduced weight for height, and lower subcutaneous fat reserves are consistent with the hypothesis that chronic childhood malnutrition retards growth in SS children. Competition from erythropoiesis may limit the availability of nutrients for growth and this hypothesis was supported by observations that high fetal haemoglobin levels, which reduce the haemolytic rate and therefore erythropoiesis, were associated with more normal growth, and that reducing erythropoiesis in SS patients with chronic hypersplenism by splenectomy was followed by an acceleration in linear growth. High erythropoietic activity may increase metabolism and the mean resting metabolic rate (RMR) relative to lean body mass of 16 post-pubertal SS adolescent boys was 22% greater than age and sex matched controls with a normal (AA) haemoglobin genotype. Adjusting for the higher visceral to somatic mass ratio of SS boys reduced the increase in RMR in SS disease to 8%. The RMR of prepubertal SS boys was also increased (relative to predicted values) but this increase did not correlate significantly with growth or serum transferrin receptor concentrations (a measure of erythropoietic activity). Faced with higher metabolic demands, SS patients have the option of increasing calorie intake or reducing energy expenditure for physical activity. The physical activity level of SS adolescent boys was 30% lower than age and sex matched AA controls suggesting that either the availability of calories or a poor appetite prevented an energy intake sufficient to maintain physical activity. It is therefore postulated that correction of suboptimal childhood nutrition could benefit the physical and mental development of children with SS disease.
... Before the exercise intervention, each participant emptied his bladder and provided a saliva sample for analysis of deuterium abundance. Saliva was chosen due to the ease and non-invasive nature of its collection, as well as the fact that saliva has been shown to be a valid and convenient sampling medium for determining total body water using the diluted isotope technique (Halliday & Miller, 1977;Schoeller, Kushner, Taylor, Dietz, & Bandini, 1985;Wong et al., 1988). Furthermore, it has been documented that enrichments of deuterium oxide in saliva and plasma samples were identical and reached a 2-h plateau after administration of an oral 2 H. W. Nolte et al. ...
... However, due to the influence of body composition, specifically individual variances in fat-free mass, the range has been reported to be approximately 45-75% (Schoeller et al., 1985) of total body water. Total body water (TBW) was calculated using the preferred method of Halliday and Miller (1977) according to the following equation: ...
... Isotope enrichments were converted to CO 2 production for each individual using a two-pool model (i.e.,considering respective individual dilution spaces for 18 O and 2 H), best suited for larger animals including pinnipeds (Speakman, 1987;Schoeller, 1988;Sparling et al., 2008). Initial isotope dilution spaces were calculated using the plateau method (Halliday and Miller, 1977). ...
... All methods for analyses and calculations of the energy expenditure of female fur seals using the doubly-labeled water are detailed in Chapter 2. In short, the isotope ratios 18 O: 16 O and 2 H: 1 H were analysed using gas source isotope ratio mass spectrometry (Optima, Micromass IRMS and Isochrom µG, Manchester, UK). Isotope enrichments were converted to CO 2 production for each individual using a two-pool model and initial isotope dilution spaces were calculated using the plateau method (Halliday and Miller, 1977). I used the equation from Speakman et al. (1993) to calculate metabolic rates from DLW concentrations and a respiratory quotient of 0.80. ...
Efficient extraction of energy from the environment is key to the survival and reproductive success of wild animals. Understanding the ratio of energy gained to energy spent of different foraging strategies (i.e., foraging efficiency) can shed light on how animals cope with environmental changes and how it affects population trajectories. I investigated how female foraging strategies during the breeding season impact the foraging efficiencies and reproductive successes of two fur seal species—one declining (NFS–northern fur seals, St. Paul Island, Alaska) and one increasing (AFS–Antarctic fur seals, Kerguelen Island, Southern Ocean). I also sought to develop new accelerometry-based methods to easily determine fine-scale energy expenditure at sea (VeDBA and flipper stroke metrics). Twenty lactating females of each species were captured and equipped with biologging tags to record GPS locations, depth and tri-axial acceleration. Energy expenditure for each foraging trip was measured using the doubly-labeled water method, and energy gained while foraging was determined from 1) diet composition (scat hard-parts and DNA) and blood stable isotope ratios; and 2) numbers of prey capture attempts (from head acceleration). Maternal investment in pups was determined from pup growth rates or from energy content of milk samples. Results showed acceleration metrics were only accurate at predicting energy expended by fur seals when time-activity budgets were taken into account (i.e., time spent performing different types of activity). Foraging strategies of AFS females resulted in efficiencies of ~3.4, with more efficient females producing bigger pups at weaning that had greater chances of survival. NFS females employed two foraging strategies with very different efficiencies (~1.4 vs ~3.0) that were associated with different foraging habitats and diet qualities. However, NFS with the more efficient strategy (3.0) undertook longer foraging trips than the other NFS (1.4) or AFS (3.4), and thus fed their pups ~20% less frequently. As a consequence, the declining NFS (unlike the increasing AFS) had to compromise between the rate of energy acquisition and the pup feeding frequency. Such reductions in energy intake and time allocated to nursing pups can ultimately lower juvenile survival, and may explain the population decline of NFS in Alaska.
... Samples are usually corrected for the exchange with non-aqueous hydrogen [71]. Analysis is carried out with the use of a ratio mass spectrometer [72] for the stable isotopes, and with a scintillation counter for tritiated samples [54,73]. Colt et al. [54] utilized 3 H during exercise and stated that 3 H might not be the best tracer to use because of the increase in 3 H space as the result of an increase in non-aqueous hydrogen-exchange in the postexercise period. ...
... The authors of that paper also utilized an incorrect value for metabolic water production during exercise. D 2 O tracers used to measure TBW have an accuracy of 0.5 % [72]. Bartoli et al. [65] found that TBW measurements are repeatable with an *4 % coefficient of variation (CV), of which 60 % is inherent in the dilution technique. ...
The prescription of an optimal fluid intake during
exercise has been a controversial subject in sports science for
at least the past decade. Only recently have guidelines
evolved from ‘blanket’ prescriptions to more individualised
recommendations. Currently the American College of Sports
Medicine advise that sufficient fluid should be ingested to
ensure that body mass (BM) loss during exercise does not
exceed [2 % of starting BM so that exercise-associated
medical complications will be avoided. Historically, BM
changes have been used as a surrogate for fluid loss during
exercise. It would be helpful to accurately determine fluid
shifts in the body in order to provide physiologically appropriate
fluid intake advice. The measurement of total body
water viaD2O is the most accurate measure to detect changes
in body fluid content; other methods, including bioelectrical
impedance, are less accurate. Thus, the aim of this review is to
convey the current understanding of body fluid allostasis
during exercise when drinking according to the dictates of
thirst (ad libitum). This review examines the basis for fluid
intake prescription with the use of BM, the concepts of
‘voluntary and involuntary dehydration’ and the major routes
by which the body gains and loses fluid during exercise.
... Samples are usually corrected for the exchange with non-aqueous hydrogen [71]. Analysis is carried out with the use of a ratio mass spectrometer [72] for the stable isotopes, and with a scintillation counter for tritiated samples [54, 73]. Colt et al. [54] ...
... The authors of that paper also utilized an incorrect value for metabolic water production during exercise. D 2 O tracers used to measure TBW have an accuracy of 0.5 % [72]. Bartoli et al. [65] found that TBW measurements are repeatable with an *4 % coefficient of variation (CV), of which 60 % is inherent in the dilution technique. ...
The prescription of an optimal fluid intake during exercise has been a controversial subject in sports science for at least the past decade. Only recently have guidelines evolved from 'blanket' prescriptions to more individualised recommendations. Currently the American College of Sports Medicine advise that sufficient fluid should be ingested to ensure that body mass (BM) loss during exercise does not exceed >2 % of starting BM so that exercise-associated medical complications will be avoided. Historically, BM changes have been used as a surrogate for fluid loss during exercise. It would be helpful to accurately determine fluid shifts in the body in order to provide physiologically appropriate fluid intake advice. The measurement of total body water via D2O is the most accurate measure to detect changes in body fluid content; other methods, including bioelectrical impedance, are less accurate. Thus, the aim of this review is to convey the current understanding of body fluid allostasis during exercise when drinking according to the dictates of thirst (ad libitum). This review examines the basis for fluid intake prescription with the use of BM, the concepts of 'voluntary and involuntary dehydration' and the major routes by which the body gains and loses fluid during exercise.
... stable) isotopes of hydrogen that are provided orally to participants as 2 H2O, reaching a near steady state of equilibrium throughout TBW within a few hours (Westerterp, 1999 (Schoeller et al., 1980). This approach has excellent measurement precision, with a validity and reliability of 2 and 0.5% reported within adult male populations (Halliday & Miller, 1977;Ellis, 2000). ...
The primary aim of this thesis was to evaluate the dietary intake, energy expenditure and energy balance of young professional male rugby league players across the season.
... However, their study was limited to 1 laboratory and a small sample size (n = 5). Further evidence suggests the enrichment time of urine (taking up to 5 h), compared with that of saliva (3-4 h), yielded a similar concentration upon reaching the enrichment plateau (12,36). These findings provide evidence for researchers to assume that specimen type and technology have no significant differences. ...
Background
Deuterium oxide (D2O) dilution is the criterion method for total body water (TBW) measurement, but results may vary depending on the specimen type, analysis method, and analyzing laboratory. Bioelectrical impedance (BIA) estimates TBW, but results may vary by device make and model.
Objectives
We investigated the accuracy and precision of TBW estimates and how measurement conditions impacted the accuracy of body composition using multicompartment body composition models.
Methods
Eighty collegiate athletes received duplicate TBW measures acquired from three BIA devices (S10, SFB7, and SOZO) and from unique D2O combinations of specimen type (saliva, urine), analysis methodology [Fourier transform infrared spectrophotometry (FTIR), isotope-ratio mass spectrometry (IRMS)], and three different laboratories. TBW measures were substituted into two (2C) and five-compartment (5C) body composition models. Criterion measures were compared using Lin's Concordance Correlation Coefficient (CCC) cutoff of Poor (<0.90), Moderate (0.90 to 0.95), Substantial (0.95 to 0.99); Almost Perfect (>0.99).
Results
Fifty-one participants (26 female) completed the protocol. Using IRMS saliva as the criterion TBW, all other measures produce a substantial or almost perfect agreement, except for SFB7 (poor) and SOZO (moderate). The 2C body composition measures using D2O and BIA produced poor agreement except for moderate agreement for Lab 3 FTIR saliva. The 5C body composition measures using D2O produced a substantial agreement, whereas the BIA device S10 and SOZO had a moderate agreement, while the SFB7 had a poor agreement to the criterion. Test-retest precision varied between techniques from 0.3 to 1.2% for TBW.
Conclusion
Small differences in TBW measurement led to significant differences in 2C models. 5C models partially mitigate differences seen in 2C models when different TBW measures are used. Interchanging TBW measures in multicompartment models can be problematic and should be performed with these considerations.
... Isotope dilution space was calculated by the plateau method (Halliday and Miller, 1977), ...
Many different physiological changes have been observed in wild waterfowl during the flightless stage of wing moult, including a loss of body mass. Previously we established that captive barnacle geese (Branta leucopsis) underwent this characteristic decrease in body mass during their wing moult, even though they had unlimited and unrestricted access to food. In the present study we aimed to determine if this body mass loss during moult comprised mainly a reduction in fat stores, and to ascertain if the captive geese undergo pre-migratory and pre-winter fattening over a similar temporal scale to their wild conspecifics. The non-destructive technique of deuterium oxide isotope dilution was employed to provide repeated measurements of estimated fat deposition from a captive flock of fourteen barnacle geese. Birds were injected with deuterium oxide at 7 distinct intervals for one annual cycle. During the flightless period of the moult, body fat decreased by approximately 40% from the pre-moult value. During late-September and early October, body fat reached its highest point in the annual cycle, both as an absolute value and as a percentage of total body mass. We propose that while the energetic cost of wing moult is not the ultimate cause of fat loss in moulting barnacle geese, the approximate 212 g of fat catabolised during moult would provide sufficient energy to cover the cost of the replacement of the flight feathers, estimated to be 6384 kJ, over an approximate 42 day period. We conclude that the previously recorded increase in metabolism during moult in the geese, led to the use of endogenous fat reserves because the birds reduced rather than increased their food intake rates owing to the increased risk of predation when flightless. We also conclude that captive barnacle geese do undergo pre-winter and pre-migratory fattening, providing further evidence of the innate nature of these fat deposition cycles.
... where A is the oral dose (g) of isotope administered, and a is the amount (g) of the dose diluted for mass-spectrometric analysis in T (g) of tap water and Ea is the enrichment of the portion, Et is the enrichment of tap water, Es is the mean enrichment of the 4-6 hour post dose samples and Ep is enrichment of the predose saliva sample [12]. Isotopic composition was determined by mass spectrometry, using platinum catalysed equilibration with hydrogen gas [13]. ...
Background: Metabolic acidosis in chronic kidney disease (CKD) is often treated with oral sodium bicarbonate. There is limited evidence around the effects of sodium bicarbonate on extracellular fluid and blood pressure in CKD. Methods: In a double blind randomised comparison patients with stage 3-5 CKD were randomised to either oral sodium bicarbonate 1.5 g three times a day (n=18) or placebo (n=21) for 4 weeks. Assessments performed at 0 and 4 weeks included: body weight, office blood pressure and assessment for peripheral/pulmonary oedema; serum creatinine, electrolytes and venous bicarbonate; 24-hour urine for sodium excretion; extracellular fluid volume and total body water determined by sodium bromide and deuterium oxide dilution respectively; extracellular fluid volume and total body water by bioimpedance. Differences between the active and placebo groups at week 4 were analysed by ANCOVA. Results: At week 4, serum bicarbonate was higher (25.6±2.4 vs 23.3±3.1 mmol/l) and blood urea lower (14.2±5.6 vs 17.0±5.8 mmol/l) in the active treatment group. Urine sodium concentration was also higher (82.7±25.3 vs 59.0±21.9 mmol/l). Extracellular fluid volume (20.0±4.3 vs 18.0±2.9) and total body water (42.3±9.6 vs 39.0±6.8) measured by bioimpedance and total body water by deuterium dilution (41.7±8.3 vs 39.4±6.2) were significantly greater in the treatment arm at week 4. Differences in systolic and diastolic blood pressure did not reach statistical significance. Conclusions: Oral sodium bicarbonate has a biological effect and increases body water content, without evidence of a clinical consequence. This may reflect the fact that some of the ingested sodium is excreted in the urine.
... The 7-day 24-h fluid intake diary is the only validated methodology for assessing TFI [46], and weighing and duplicate portion method for assessing FWI [26,47]. Referring to the methods of assessing body fluid, bioelectrical impedance spectroscopy, bioelectrical impedance analysis, trace quantities of deuterium oxide and ultrasound are commonly used [28,[48][49][50][51]. It was widely recognized that human body composition analyzer based on bioelectrical impedance theory could be used to record body fluid distribution with high accuracy [52,53]. ...
Abstract Background Normal distribution of body fluid is important for maintaining health through the balance of water metabolism. Studies have shown that disease states and diuretics perturb the balance and then induce abnormal intracellular/extracellular fluid ratio. However, there are relatively few researches on the associations between water intakes and body fluid. The objective of this study was to explore the association between body fluid and water intake. Methods A total of 159 young adults in Baoding, China were recruited in this cross-sectional survey and completeness of follow-up was 98.1%. A 7-day fluid specific diary was used to record total fluid intake (TFI). Water intake from foods (FWI) for 3 days was measured using the methods of weighting, duplicate portion method and laboratory analysis by researchers. Body fluid was measured using bioelectrical impedance analysis. Results Total body water (TBW), intracellular fluid (ICF) and extracellular fluid (ECF) of participants were 32.8[28.0,39.2], 20.5[17.3,24.5] and 12.4[10.7,14.7], (kg). This represented 55.2 ± 6.2, 34.4 ± 4.0 and 20.8 ± 2.3 (%) of body weight (BW), respectively. ICF, ECF and TBW among male participants who drank more than or equal to adequate TFI was higher than those who drank less (Z = -1.985, p = 0.047; Z = -2.134, p = 0.033; Z = -2.053, p = 0.040). Among both males and females, the values of TBW/BW in participants whose TWI met or exceeded the AI were higher than those with TWI less than AI (t = − 2.011, p = 0.046; t = − 2.716, p = 0.008). Among all participants, there was moderate correlation between water intakes (TFI/BW, FWI/BW and TWI/BW) and body fluid (ICF/BW,ECF/BW and TBW/BW) (p
... However, its frequency of use in these studies was low, a factor that can be explained by its limitation to predict bone mineral density and bone mineral content, being variables present in a larger proportion of the reviewed studies. Isotope dilution was the least utilized method, at 5.5%. is method verifies the deuterium, oxygen eighteen, and tritium concentration, thus determining the total water, fat mass, and fat-free mass for the whole body [56]. Despite having good precision, the technique is very difficult to analyze, [47] being a possible cause for its restricted use. ...
This review compiled anthropometric data from 29 original articles, published between 1995 and 2015, corresponding to a total sample of 6368 celiac disease subjects. Body mass index was the main parameter for measuring anthropometry (82.1%), followed by body mass (78.6%), body fat (51.7%), bone mineral density and bone mineral content (46.4%), and fat-free mass (44.8%). The main evaluation method was dual x-ray absorptiometry (83.3%), followed by bioimpedance (16.6%), skinfold thickness (16.6%), and isotope dilution (5.5%). This compilation suggests that celiac disease patients without a gluten-free diet (WGFD) and celiac disease patients with a gluten-free diet (GFD) show a lower body mass than the control group, with inconclusive data about WGFD versus GFD. Body mass index is lower in WGFD and GFD compared to control group, and is lower in WGFD compared to GFD. We observed lower values of FM and FFM in WGFD and GFD versus the control group. No difference was found between WGFD versus GFD. BMD and BMC are lower in WGFD versus GFD and GFD versus the control group, with inconclusive data about WGFD versus GFD. The findings of this review suggest that celiac disease patients must be periodically evaluated through anthropometric parameters, since the pathology has the potential to modulate such values even in a gluten-free diet, with these variables reflecting their healthy status. In parallel, the screening of different anthropometric assessment methodologies can provide support for more accurate evaluations by scientists and clinical professionals who work with celiac disease patients.
... We are aware that our sweat samples are likely affected to some small degree by evaporative enrichment of the sweat drops on the skin as well as by condensation/isotope exchange with water vapour [7]. The 2 H enrichment of body water compared to drinking water was indeed already discovered and described over 40 years ago by Halliday and Miller [13]. It can be explained with (i) the uptake of hydrogen-bearing food including food water and fractionation processes during metabolism, (ii) the uptake of inhaled water vapour (iii) and to a large degree also with the respiratory loss of isotopically depleted water vapour [e.g. ...
Inspired by a previous ‘Sauna, sweat and science’ study [Zech et al. Isot Environ Health Stud. 2015;51(3):439–447] and out of curiosity and enthusiasm for stable isotope and sauna research we aimed at answering the question ‘do we sweat (isotopically) what we drink’? We, therefore, pulse-labelled five test persons in a sauna experiment with beverages that were ²H-enriched at about +25,600 ‰. Sweat samples were collected during six sauna rounds and the hydrogen isotope composition δ²Hsweat was determined using an isotope ratio mass spectrometer. Before pulse labelling, δ²Hsweat – reflecting by approximation body water – ranged from –32 to –22 ‰. This is ∼35 ‰ enriched compared to usual mid-European drinking water and can be explained with hydrogen-bearing food as well as with the respiratory loss of ²H-depleted vapour. The absence of a clearly detectable ²H pulse in sweat after pulse labelling and δ²Hsweat results of ≤+250 ‰ due to a fast ²H equilibration with body water are moreover a clearly negative answer to our research question also in a short-term consideration. Given that the recovery of the tracer based on an isotope mass balance calculation is clearly below 100 %, we finally answer the question ‘where did the rest of the tracer go?’
... The following equation is used to calculate the dilution space (Halliday and Miller, 1977): A correction is then applied to account for the non-aqueous exchange of hydrogen (Racette et al., 1994), giving TBW: ...
The ‘expensive-tissue’ hypothesis of Aiello and Wheeler is well-known in anthropology for positing that an increasingly small gut was a key factor in the evolution of the large hominin brain. The insight that organs and tissues in the body compete for energy resources was also central to the ‘thrifty phenotype’ hypothesis of Hales and Barker, which proposed that nutritional stress in fetal life resulted in differential growth of the brain and pancreas. Both hypotheses are consistent with life history theory, which assumes that energy allocation trade-offs occur in energylimited environments. The prediction that somatic traits trade off against one another in the context of the body’s fixed energy budget has, however, yet to be rigorously tested in humans. The current thesis project aimed to fill this gap by recruiting 70 healthy young women and obtaining comprehensive, high-quality data on their brain and body composition. This included, specifically, measures of brain gray and white matter volume, fat mass, skeletal muscle mass, and volumes of the heart, liver, kidneys and spleen. Additional outcomes included resting energy expenditure and two proxies of early-life growth: birth weight, a marker of fetal weight gain, and tibia length, a marker of linear growth indexing postnatal experience. With these data, three principal hypotheses were tested: 1) there is variation in the energy expenditure of tissues and organs; 2) trade-offs are observed between brain and body organs/tissues; and 3) trade-off relationships are mediated by early-life growth. Results suggest the metabolic cost of organs and tissues is variable, and that the brain – in particular its gray matter component – trades off against lean tissues in the body (i.e. skeletal muscle, the liver and kidneys), but not fat mass. However, less support was found for the prediction that trade-offs are mediated by fetal and infant growth.
... A single baseline urine sample was collected before administration of the dose, and parents were asked to collect another sample w5 h after the dose was given. Measurement of the isotopic enrichment of isotopes at this time enabled the calculation of the body water pool with the use of standard equations (28). Impedance (V) was collected with the use of a Bodystat 1500MDD device at 800 mA and a fixed frequency of 50 KHz. ...
Background:
Altered body composition in children with cerebral palsy (CP) could be due to differences in energy intake, habitual physical activity (HPA), and sedentary time.
Objective:
We investigated the longitudinal relation between the weight-for-age z score (WZ), fat-free mass (FFM), percentage of body fat (%BF), and modifiable lifestyle factors for all Gross Motor Function Classification System (GMFCS) levels (I-V).
Design:
The study was a longitudinal population-based cohort study of children with CP who were aged 18-60 mo (364 assessments in 161 children; boys: 61%; mean ± SD recruitment age: 2.8 ± 0.9 y; GMFCS: I, 48%; II, 11%; III, 15%; IV, 11%; and V, 15%). A deuterium dilution technique or bioelectrical impedance analysis was used to estimate FFM, and the %BF was calculated. Energy intake, HPA, and sedentary time were measured with the use of a 3-d weighed food diary and accelerometer wear. Data were analyzed with the use of a mixed-model analysis.
Results:
Children in GMFCS group I did not differ from age- and sex-specific reference children with typical development for weight. Children in GMFCS group IV were lighter-for-age, and children in GMFCS group V had a lower FFM-for-height than those in GMFCS group I. Children in GMFCS groups II-V had a higher %BF than that of children in GMFCS group I, with the exception of orally fed children in GMFCS group V. The mean %BF of children with CP classified them as overfat or obese. There was a positive association between energy intake and FFM and also between HPA level and FFM for children in GMFCS group I.
Conclusions:
Altered body composition was evident in preschool-age children with CP across functional capacities. Gross motor function, feeding method, energy intake, and HPA level in GMFCS I individuals are the strongest predictors of body composition in children with CP between the ages of 18 and 60 mo.
... The isotope ratios 18 O: 16 O and 2 H: 1 H were analysed using gas source isotope ratio mass spectrometry (Optima, Micromass IRMS and Isochrom μ G, Manchester, UK). Isotope enrichments were converted to CO 2 production for each individual using a two-pool model, and initial isotope dilution spaces were calculated using the plateau method 64 . We used the equation from Speakman et al. 65 to account for evaporation loss, and CO 2 production rates were converted into daily energy expenditure using a respiratory quotient (RQ) of 0.80 66,67 . ...
Flipper strokes have been proposed as proxies to estimate the energy expended by marine vertebrates while foraging at sea, but this has never been validated on free-ranging otariids (fur seals and sea lions). Our goal was to investigate how well flipper strokes correlate with energy expenditure in 33 foraging northern and Antarctic fur seals equipped with accelerometers, GPS, and time-depth recorders. We concomitantly measured field metabolic rates with the doubly-labelled water method and derived activity-specific energy expenditures using fine-scale time-activity budgets for each seal. Flipper strokes were detected while diving or surface transiting using dynamic acceleration. Despite some inter-species differences in flipper stroke dynamics or frequencies, both species of fur seals spent 3.79 ± 0.39 J/kg per stroke and had a cost of transport of ~1.6–1.9 J/kg/m while diving. Also, flipper stroke counts were good predictors of energy spent while diving (R² = 0.76) and to a lesser extent while transiting (R² = 0.63). However, flipper stroke count was a poor predictor overall of total energy spent during a full foraging trip (R² = 0.50). Amplitude of flipper strokes (i.e., acceleration amplitude × number of strokes) predicted total energy expenditure (R² = 0.63) better than flipper stroke counts, but was not as accurate as other acceleration-based proxies, i.e. Overall Dynamic Body Acceleration.
... Clearly both these approaches were unsuitable for humans. However, it was noted that if the exact amount of the dose is known and the first isotope enrichment in the body is measured after the dose has spread through the entire pool, then it is possible to estimate N from the dilution principle (Halliday and Millar, 1977). It had been known since the early 1970s that the dilution space for oxygen (N o ) is smaller than the dilution space for deuterium (N d ) by between 1 and 8%, averaging about 3% (reviewed in Sheng and Huggins, 1979) ...
The doubly-labelled water (DLW) method provides the ability to measure the energy expenditure of free-living animals based only on the injection of two isotopes in water (one of oxygen and one of hydrogen) and traditionally the collection of 2 blood samples. We review here the fundamental basis of how the method works, and highlight how the choice of the appropriate calculation equation can have a large impact on the resultant estimates, particularly in species where the difference between the isotope elimination constants is small. This knowledge is not new, but is worth reiterating given the potential for error by making the wrong choice. In particular, it is important to remember that for mammals weighing less than 5kg, and birds weighing less than 2kg, the single pool models perform best in validation studies, while in mammals above 15kg the two-pool models perform best. Above 2kg in birds and between 5 and 15kg in mammals, however, the model superiority is uncertain. Even where the choice based on body mass would appear clear, the decision may need to be tempered by species specific information regarding potential additional sources for hydrogen turnover, such as de novo lipogenesis or methanogenesis. Recent advances in the technique have included attempts to make the method less invasive by using innovative methods for dosing and sample collection. In addition, the advent of laser spectroscopy, as a replacement technology for mass spectrometry, may open up many new opportunities in the field. These potentially include direct sampling of breath in the field and tracking background isotope drift using (17)oxygen levels.
... The mean SD deuterium analyzed was <2%. The equation used for the calculation of deuterium dilution space (N) was as follows (Halliday and Miler 1977): N = (TA/a)•((Ea -Et)/(Es -Ep)). ...
There is no data on the prevalence of overweight and obesity in young Syrian boys. Therefore, the present study aimed to provide baseline and reference data on the prevalence of overweight and obesity among young Syrian boys using skin-fold thickness measurements and deuterium dilution (DD) as a reference method. The sample of 2470 healthy Syrian 18- to 19-year-old boys were enrolled in this study. SFTs were measured at the biceps (B), triceps (T), subscapular (SI) and suprailiac locations (SS) were done and validated using the DD technique as a reference method. Receiver operating characteristics (ROC) curve was drawn to determine appropriate cut-off points of the Σ
... The isotope ratio 2 H: 1 H was analysed using gas source isotope ratio mass spectrometry (Isoprime IRMS and Isochrom mG; Micromass, Manchester, United Kingdom). The isotope dilution space was calculated using the plateau method [43]. Previous studies have found that hydrogen isotope dilution overestimates the total body water (TBW) pool [44], as such, the isotope dilution space was corrected by 3% to take this into account. ...
Sexual size dimorphism is widespread throughout seabird taxa and several drivers leading to its evolution have been hypothesised. While the Australasian Gannet (Morus serrator) has previously been considered nominally monomorphic, recent studies have documented sexual segregation in diet and foraging areas, traits often associated with size dimorphism. The present study investigated the sex differences in body mass and structural size of this species at two colonies (Pope's Eye, PE; Point Danger, PD) in northern Bass Strait, south-eastern Australia. Females were found to be 3.1% and 7.3% heavier (2.74 ± 0.03, n = 92; 2.67 ± 0.03 kg, n = 43) than males (2.66 ± 0.03, n = 92; 2.48 ± 0.03 kg, n = 43) at PE and PD, respectively. Females were also larger in wing ulna length (0.8% both colonies) but smaller in bill depth (PE: 2.2%; PD: 1.7%) than males. Despite this dimorphism, a discriminant function provided only mild accuracy in determining sex. A similar degree of dimorphism was also found within breeding pairs, however assortative mating was not apparent at either colony (R2 < 0.04). Using hydrogen isotope dilution, a body condition index was developed from morphometrics to estimate total body fat (TBF) stores, where TBF(%) = 24.43+1.94*(body mass/wing ulna length) - 0.58*tarsus length (r2 = 0.84, n = 15). This index was used to estimate body composition in all sampled individuals. There was no significant difference in TBF(%) between the sexes for any stage of breeding or in any year of the study at either colony suggesting that, despite a greater body mass, females were not in a better condition than males. While the driving mechanism for sexual dimorphism in this species is currently unknown, studies of other Sulids indicate segregation in foraging behaviour, habitat and diet may be a contributing factor.
... considering respective individual dilution spaces for 18O and 2H), best suited for larger 574 animals including pinnipeds (Schoeller 1988, Sparling et al 2008, Speakman 1987. Initial isotope 575 dilution spaces were calculated using the plateau method (Halliday & Miller 1977). There are several 576 approaches for the treatment of evaporative water loss in the calculations (Visser & Schekkerman 1999). ...
We investigated differences in foraging efficiencies of lactating northern fur seals (Callorhinus ursinus) and their potential links to pup survival on the Pribilof Islands. Foraging efficiency is key to determining whether animals extract enough energy from their environment to survive and reproduce, but is seldom estimated in the wild. In this study, we measured foraging efficiency of lactating fur seals by determining 1) foraging locations and behaviors using tracking data, 2) energy expenditure at sea using the doubly-labeled water method and accelerometer data, and 3) the energy gained while foraging using diet data from collected scats and number of prey capture attempts from head acceleration. We also developed a dynamic bioenergetic model for females nursing pups to compare theoretical energy requirements with field estimates of energy acquired by our tracked females. We found that females foraging off the Bering Sea shelf traveled for longer times and greater distances than those that stayed over the shelf. However, the females that travelled off shelf had higher foraging efficiencies than females that foraged over the shelf. Females that travelled off-shelf preyed on smaller but more numerous and higher energetic quality prey compared to on-shelf females. We calculated overall dynamic body acceleration (as a proxy for energy expenditure) and found it had limited power to predict total energy expenditure. Energy required as predicted by our bioenergetics model compared favorably with the average energy acquired by the fur seals we tracked from St. Paul. However, the range of field estimated consumption was wide, and a significant portion of the seals we tracked consumed less than the required threshold. Our findings help assess whether lactating females are obtaining adequate nutrition during summer to successfully rear pups in the Bering Sea, and provide insight into why the Pribilof population has declined. As such, our study provides a research framework that can be applied to other species and serve as a stepping-stone for future research on impacts of environmental changes on top marine predators
... Additionally extracellular water (ECW) can be analyzed via the dilution of a sodium bromide solution, even though this widely used method lacks precision [55]. Another method measures the total body water (TBW) using deuterium oxide dilution method (DMM) via urine, plasma or saliva analysis, which is not applicable for a durable monitoring of the hydration state, especially in spec of private users [39,66]. Besides, a wellestablished method, which is often used for cosmetically purposes, is corneometry. ...
The demographic change and the growth of mankind are challenging worldwide, especially for healthcare systems. One strategy that is and will in future further be employed to keep humans healthier at all ages coeval fighting disease related consequences, offer modern technologies for personalized disease treatment and health monitoring. New technological advance in personalized disease treatment and health monitoring using sensor-based technologies (eHealth) help people to recover from illness or stay healthy, to monitor the health state of patients in need and to assist care staff during their daily routine. This review aims to give an overview on current technologies and trends that are used to treat diseases or measure vital parameters with focus on hydration monitoring as a particularly important parameter, which can be catalyst for several secondary diseases. Further we reveal the trend towards individually tailored therapy of disease and preventive monitoring of health parameters via new technologies in a wireless area body network. There are some already existing technologies but there is not yet a way to monitor the entire health state and especially hydration as one of the most crucial vital parameters. In combination with advanced therapeutic medicinal products and companion diagnostics, wireless area body networks may help to pave the way for personalized medicine and improve healthcare systems in acute and preventive manners as well as individual physical fitness.
... Lazarus et al. 30 showed that BMI had a true positive rate of 67% and false positive rate of 6% for predicting high FM in a group of 4-20 year old children and adolescents. Correlation coefficient of 0.85 was seen between BMI and FM assessed by DEXA in a group of [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] year old Italian children 31 . The correlation between FM and BMI in our study (Sri Lankan children) was 0.84 (p<0.001), ...
... Total body water for each patient was calculated from the difference between the baseline and the first sample collected after dosing using the formula of Halliday and Miller (1977). ...
... Doubly-labelled water: Total body water: Deuterium measurement: "0 measurement The dilution of isotopically labelled water with body water to determine, for example, body composition, breast milk output and energy expenditure is a commonly used technique. However, although it is well established that available measurement techniques are accurate and precise for International Water Standards (Coleman et al. 1982;Wong et al. 1984Wong et al. ,1992Kendall & Coplen 1985;Tanweer et al. 1988) and the dilution of isotopes in water (Halliday & Miller 1977), with the exception of the studies of Wong et al. (1987,1992), there is no corresponding mass of data to indicate that isotope dilution can be measured correctly in body water and biological fluids such as plasma, saliva, urine or milk. ...
Measurement of energy expenditure with doubly-labelled water and of body composition and breast milk output with 2H or 18O requires accurate and precise techniques for measuring isotopic enrichments. The possibility of an inaccuracy in measurements of 2H and 18O isotopic enrichment arising from the matrix in biological fluids was investigated (1) by simulating a dilution experiment in both water and urine samples and (2) by reconstituting urine samples, ranging from 10 to 60 g/kg in solid concentration, from freeze-dried urinary solids mixed with either natural abundance or doubly-labelled water. Current techniques involved in measuring 2H and 18O isotopic enrichments were used (reduction of the samples to H2 gas with either Zn or U, and CO2/H2O equilibration or direct measurement of mass 20:18 ratios on water vapour for 18O analysis). All four methods accurately measured serial dilutions in both urine and water. Dilution space calculated from isotopic enrichments, compared with the water content of urine (determined by freeze-drying and accounting for exchangeable isotopes) was overestimated by about 2.4 % by the Zn technique whereas other methods were accurate. The urinary solids content of a water solution was related to that inaccuracy. The use of the Zn technique with biological samples is likely to create biases in 2H distribution space. Examination of recent literature supports this view. Caution should therefore be used when physiological conclusions have to be made from the relative size of 2H and 18O distribution spaces.
Study design:
Prospective, observational OBJECTIVES: To evaluate agreement between a reference method (doubly labelled water, DLW) of total energy expenditure (TEE) and published equations for estimating energy requirements in acute spinal cord injury (SCI).
Setting:
Victoria, Australia METHODS: Twenty participants (18 male) within 8 weeks of traumatic SCI completed DLW, anthropometric and dietary intake assessments. Energy requirements were predicted using Harris-Benedict, Schofield, Henry, Nelson, Buchholz and Chun equations, multiplied by a combined activity and stress factor of 1.3, and the ratio method (kJ/kg body weight). Fat-free mass (FFM) and fat mass (FM) were calculated from TBW-derived DLW and from bioelectrical impedance spectroscopy (BIS).
Results:
Median time since injury was 41 days. Median TEE was 9.1 MJ. Fair agreement was found between TEE and predicted energy requirements for the Chun (rc = 0.39), the Harris-Benedict equation (rc = 0.30), the ratio method (rc = 0.23) and the Buchholz (rc = 0.31) and Nelson equations (rc = 0.35), which incorporate measures of FFM and/or FM. Other equations showed weak concordance with DLW. When two hypermetabolic patients were removed, agreement between TEE and predicted energy requirements using the Buchholz equation increased to substantial (rc = 0.72) and using the Nelson (rc = 0.53) and Chun equations (rc = 0.53) increased to moderate. The Buchholz equation had the smallest limits of agreement (-2.4-2.3 MJ/d).
Conclusion:
The population-specific Buchholz equation that incorporates FFM, predicted from either BIS or DLW, demonstrated the best agreement in patients with acute SCI.
Sponsorship:
The study was funded by grants from the Institute for Safety, Compensation and Recovery Research (ISCRR Project # NGE-E-13-078) and Austin Medical Research Foundation. M Panisset was supported by an Australian Postgraduate Award.
Der demografische Wandel und das Populationswachstum stellen eine globale Herausforderung für die Gesundheitssysteme dar. Eine vielversprechende Lösungsstrategie liegt in der digitalen Überwachung, Prävention und Therapie akuter und chronischer Erkrankungen durch die Nutzung von innovativen Technologien aus dem Bereich der personalisierten Medizin. Die Digitalisierung in der Überwachung von Vitalparametern mittels Sensorik besitzt großes Potential für die längere Gesunderhaltung der Patienten und somit die Entlastung der Gesundheitssyteme im Ganzen. Da Wassermangel für eine Vielfalt von Krankheiten einen Katalysator darstellt, ist die Hydratation ein wichtiger aber bislang nur invasiv zugänglicher Vitalparameter. Zur Etablierung nicht invasiver Messungen des Wasserhaushaltes am Menschen wurde im Rahmen dieser Arbeit die Eignung der Mikrowellentechnologie untersucht. Dehydratation resultiert in der Veränderung des Osmolythaushaltes und beeinflusst biochemische Prozesse, was zur Entstehung von Morbidität führen kann. Im Rahmen der Arbeit werden Teilbereiche der Entwicklung eines Medizinproduktes abgebildet. Zu diesem Zweck wird die Machbarkeit der mikrowellenbasierten Analyse des Wasserhaushaltes in einer technischen Machbarkeitsstudie untersucht, um im zweiten Prozessschritt einen technischen Demonstrator in vitro und in vivo am Probanden erproben zu können. Hochfrequente elektromagnetische Wellen interagieren mit Molekülen, speziell Wasser. Enthält eine Probe freie Wassermoleküle, kann dies im reflektierten Signal detektiert werden. Zur Überprüfung des Sensorsystems in vitro dienen humane 3D-Vollhautmodelle mit spezifischer Hydratation und Gewebedichte der Matrixkomponenten als standardisiertes Modell zur Untersuchung definierter Exsikkoseszenarien und des Einflusses verschiedener Modellkomplexitäten. Die Eignungsüberprüfung des Systems mit einem technischen Demonstrator des künftigen Medizinproduktes belegt die Anwendbarkeit des Messsystems zur Erfassung des relativen Wassergehaltes. Die Technologie zeichnet sich durch eine hohe Sensitivität bei der Destinktion von Proben mittels Frequenz- und Signalreflektionsdifferenzen aus. Neben den In-vitro-Testungen wird das entwickelte Sensorsystem aus regulatorischer Sicht zur klinischen Leistungsüberprüfung vorbereitet und im Rahmen eines bewilligten Ethikvotums in vivo erprobt. Die Ergebnisse belegen die Machbarkeit der nichtinvasiven Erfassung des Wasserhaushaltes durch mikrowellenbasierte Messungen. Die Technologie birgt das Potential, in ein körpernahes Sensorsystem integriert zu werden, welches als Medizinprodukt zur persönlichen Gesundheitsüberwachung zugelassen werden kann.
A dietary source of energy must occupy a central place in any nutrition scheme, since energy requirements must be met even at the expense of protein requirements. However, dietary energy requirements are difficult to define in any species, and particularly so in human beings. The nutritional objective of livestock farmers is clear: they have to raise their animals as profitably as possible. For a given strain of pig, for example, a certain ration can be shown to be optimum to yield the most meat at least cost, but such criteria do not apply in human nutrition. The human nutritionist cannot play safe and recommend a minimum of energy in the diet. It is possible to define ‘enough’ vitamin C, and if the requirement is exceeded not much harm is done, but the same latitude does not apply to energy intake. Grossly excessive and grossly deficient energy intakes are both damaging to health.
Obesity is rising among adults and children worldwide, including populations living in developing countries. The published data related to Syria are insufficient to address this issue. Therefore, the aim of this study is to determine the prevalence of overweight and obesity, and to determine appropriate cut-off points of the body mass index (BMI) for defining overweight and obesity among Syrian adolescents. We record body weight (kg), height (m2), and body mass index (kg/m2). The total body fat mass (BFM) was determined by deuterium oxide dilution (DD). The total sample was used in a split-sample internal cross-validation. The BMI was integrated to multiple regressions and Bland and Altman's procedure was used to analyze the data. Receiver operating characteristics (ROC) curve was drawn to determine appropriate cut-off points of the BMI for defining overweight and obesity. The prevalence of overweight and obesity was 24.5% by BMI and 46.5% by body fat content. Receiver operating characteristics (ROC) curve analysis defined a BMI of 22.34kg/m2 as a cut-off for overweight with sensitivity of 84.0%, 80.9% specificity, and BMI of 24.71kg/m2 with 82.80% sensitivity and 93.0% specificity for obesity. The results of our study suggest lower BMI cut-offs for overweight and obesity in Syrian population than those of recommended by WHO.
Die Ermittlung der Körperzusammensetzung und des Fettgewebsanteils am Körpergewicht ist zur Abschätzung des Ernährungszustandes und für die Planung und Überwachung diätetischer Studien erforderlich. Für epidemiologische Untersuchungen wird eine einfache und schnell anwendbare Methode zur Bestimmung der Körperfettmasse benötigt, die für den Probanden keine Nachteile hat. Es wurden zahlreiche Untersuchungsmethoden entwickelt, die zum Teil sehr fehlerhaft (Gasverdünnungsmethode 13) oder sehr aufwendig sind (Messung des Gesamtkörperwassers [8] und des Gesamtkörperkaliums [11]). Die Bestimmung der subkutanen Fettschichtdicke und Kalkulation der Gesamtkörperfettmasse mittels Caliper war bisher die einfachste Methode [6]. Zahlreiche Arbeitsgruppen beschäftigen sich inzwischen mit der Ultraschallmessung der subkutanen Fettschichtdicken [1, 4, 7, 18]. Ziel unserer Untersuchungen ist es, Caliper- und Ultraschallmessung zu vergleichen und anhand der densitometrisch ermittelten Körperzusammensetzung die Fehler der jeweiligen Methode festzustellen.
This study examined the relation between waist circumference (WC), hip circumference (HC), waist-to-hip ratio (WHpR), waist-to-height ratio (WHtR) and triceps skin-fold thickness and percentage body fat in young Syrian men. The aim was to develop equations that can use these anthropometric characteristics to estimate percentage body fat in this group of subjects. A total of 2470 healthy Syrian men aged 18–19 years were enrolled in the study in 2010–2011. The anthropometric characteristics of all subjects were measured. The percentage body fat of 213 of the subjects was determined using the deuterium dilution (DD) technique as a reference method. The validity of using WC, HC, WHpR and WHtR to calculate percentage body fat, in comparison with the reference method (DD technique), was assessed by calculating biases and limits of agreement. The estimates of percentage body fat using ‘WC’ and ‘WC with triceps skin-fold’ measurements ranged from 13.00±5.56% to 14.55±8.63%, and were lower than those determined using the reference method (21.32±6.42%). A better prediction equation is proposed for young adults, based on a multiple linear regression model using WC, HC and WHtR.
Nolte, HW, Nolte, K, and van der Meulen, J. Total body water, electrolyte, and thermoregulatory responses to ad libitum water replacement using two different water delivery systems during a 19-km route march. J Strength Cond Res 29(11S): S88-S93, 2015-Hands-free hydration systems are often advocated for improved hydration and performance in military populations. The aim was to assess whether such systems indeed result in improved hydration in exercising soldiers. Subjects were required to complete a route march while consuming water ad libitum from either a hydration bladder (BG) or traditional canteen (CG). Water intakes of 538 ml·h (BG) and 533 ml·h (CG) resulted in no differences for changes in body mass, serum [Na], plasma osmolality, total body water, or time required to complete the march. There were no differences between peak exercise core temperature of the BG (38.9° C) and CG (38.7° C) groups. There were no differences between the groups for fluid balance, thermoregulation, or performance. This is a not a surprising finding because the amount of fluid consumed ad libitum is determined by changes in serum osmolality and not the fluid delivery system as often proposed.
The volume of fluid ingested for rehydration is essential in determining the restoration of euhydration because it must be in excess of the water lost since the individual was last euhydrated. The formulation of any ingested beverage is also important as this affects the rate at which the fluid is emptied from the stomach, absorbed in the small intestine, and hence assimilated into the body water pool. This review highlights the essential role of the gastrointestinal tract in the maintenance of hydration status.
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The NanoSIMS (Cameca 'NanoSIMS 50' ion microprobe) is a new type of ion microprobe that can be used for elemental and isotopic studies on a sub-micrometer scale. The instrument is based on a design concept by G. Slodzian (Université de Paris-Sud) who was also responsible for the development of the very successful CAMECA ims3f-7f series, as well as the ims1270/1280. The NanoSIMS 50 was built by CAMECA in France and the first instrument of this type was delivered to Washington University in St. Louis (MO, USA) in December 2000. By now there are more than ten NanoSIMS instruments installed world-wide with applications ranging from cosmochemistry to biology and material sciences. The most significant innovation in the ion optical design of the NanoSIMS (Figure 12-0.6) is the normal primary ion incidence and a normal coaxial secondary ion extraction. This makes it possible to reduce the distance between the sample and the immer-sion lens to 400 mm, which results in a much smaller spot size than in other SIMS instruments at a given probe current. The diameter of the primary ion beam at the sample defines the smallest area whose chemical or isotopic composition can be determined without interference from neighboring regions. Obviously, a smaller spot size allows the analysis of smaller particles and gives more detailed information about the internal composition of a given sample of heterogeneous composition. In imaging mode, the primary beam diameter defines the lateral resolution of a secondary ion image. The typical Cs þ primary beam diameter of a CAMECA f-series ion microprobe is on the order of 1–3 mm although slightly smaller spot sizes can be achieved through careful tune-up and with significant loss of intensity. The NanoSIMS, in contrast, offers a routine Cs þ primary beam diameter of 100 nm (hence the instrument's name), but beam diameters as low as 30 nm have been achieved. In negative (O À) primary beam mode the best achievable probe diameter is around 150 nm.
AimMulti-frequency bioelectrical impedance analysis (MF-BIA) may provide a quick, cost-efficient method of total body water (TBW) assessment. We compared TBW estimates from the Biospace InBody 520, 720, and S10 MF-BIA devices to TBW estimates from isotopic deuterium dilution (D2O).MethodsTBW was measured in 25 men and 25 women, 18–49 years, 73.6 ± 15.4 kg on each of the three devices and from D2O analysis.ResultsAll MF-BIA devices significantly overestimated TBW compared to D2O TBW for men (4.7–5.4 kg, 10.8–12.4%; P < 0.01) and women (3.7–4.3 kg, 12.3–14.3%; P < 0.01). Regression analyses in men revealed R2 (0.86–0.90) and SEE (1.7–2.0 kg), and in women revealed R2 (0.82–0.86) and SEE (1.5–1.6 kg). Bland and Altman analyses revealed similar limits of agreement for men (3.5–3.9 kg) and women (3.4–3.7 kg).Conclusions
The Biospace InBody devices significantly overestimate TBW in men and women. The consistent bias for men and the increasing bias with increasing TBW for women may indicate that these devices are suitable for group TBW estimates in men only.
The sensitivity of gas-phase infrared spectrophotometry for the determination of deuterium in water is evaluated. Syringe injection of 20 /sup +/L of sample into a heated 10-cm-path-length cell is shown to provide a detection limit of about 60 ppm. The analytical response is found to be linear with concentration from natural abundance (150 ppm) to at least 1.8 atom % deuterium.
This chapter describes the theory of the 2H218O method, its assumptions, the analytical procedures and equations used in its calculation, and its validity compared to the energy balance method and indirect calorimetry when measuring the total energy expenditure (TEE) of humans. The 2H218O method is validated as an accurate method for estimation of TEE in small mammals and birds. In spite of the violation of many of the assumptions associated with the isotope method, with proper corrections, TEE estimated by the 2H218O method has proven accurate against TEE estimated by energy balance and indirect calorimetry in infants, children, and adults.The isotope method, being noninvasive, nonrestrictive, and does not expose the subjects to radiation, the 2H218O method is considered as the method of choice by the nutrition community for the estimation of energy requirements during infancy, growth, pregnancy, and lactation.
Introduction: To measure changes in body mass, total body water, running performance, fluid intake and blood biochemical variables in an ultra-marathon mountain race. Methods: 9 subjects (44.0 ± 9.2 years; 72.2 ± 9.0 kg) were measured 2-days before the race, immediately pre-race and post-race for body mass (BM), total body water (TBW), plasma osmolality, plasma sodium ([Na + ]), plasma potassium ([K + ]) and plasma total protein concentrations. Fluid intake and rating of perceived exertion (RPE) were also measured over the entire race. Results: Significant BM loss occurred from 2-days pre-race to post-race (-3.1 ± 1.2 kg; P<0.05) and pre-race to post-race (-3.7 ± 2.7 kg; P<0.01). A positive linear relationship was found between fluid intake and changes in BM during the race (r = 0.7; P<0.05). Rates of fluid intake (321-628 ml/hr) and total body mass loss varied substantially between individuals. Plasma osmolality and [Na + ] concentrations were well regulated and did not change significantly. There was a non-significant correlation between changes in body mass and race performance. Conclusion: We conclude that drinking rates vary substantially in athletes drinking ad libitum during an 80 km mountain race whereas plasma osmolality and [Na + ] are well regulated despite large changes in BM. Therefore, drinking ad libitum during prolonged endurance running seems to be an appropriate method to maintain fluid homeostasis during ultra-marathon mountain races.
A fast and easy method is described which uses Fourier transform infrared spectroscopy (FT-IR) to measure the 1H/2H ratio of aqueous samples of less than 100 μl with high precision (+ 0.2–0.5% in the range of 89 to 2680 μl/1). Using a thermostat-controlled CaF2 cell, low resolution absorption specta (8 cm-1) are measured. The integral of absorption in the range of 2600 and 2460 cm-1(02H vibration) is used to analyse the 2H content of the sample. For measurements at low enrichment five standards are used (SLAP: 89.00 μl/1, GISP: 126.3 μl/1, V-SMOW: 156.0 μl/1, all from the International Atomic Energy Agency, Vienna, Austria, standard 1: 183.3 μl/1, standard 2: 222.5 μl/1, both prepared by weighing and controlled by isotope ratio mass spectrometry (IR-MS)). For measurements at high enrichment three standards are used (standard 2: 222.5 μl/1, standard 3: 1323 μl/1, standard 4: 2680 μl/1, all prepared by weighing and controlled by IR-MS). Measured and reported 2H concentrations coincide very well, two samples for quality control (145 and 1612 μl/1) were measured with a precision of 0.3 and 0.4% corresponding to + 0.5 and 5.9 μl/1.
Introduction: To measure changes in body mass, total body water, running performance, fluid intake and blood biochemical variables in an ultra-marathon mountain race. Methods: 9 subjects (44.0 ± 9.2 years; 72.2 ± 9.0 kg) were measured 2-days before the race, immediately pre-race and post-race for body mass (BM), total body water (TBW), plasma osmolality, plasma sodium ([Na + ]), plasma potassium ([K + ]) and plasma total protein concentrations. Fluid intake and rating of perceived exertion (RPE) were also measured over the entire race. Results: Significant BM loss occurred from 2-days pre-race to post-race (-3.1 ± 1.2 kg; P<0.05) and pre-race to post-race (-3.7 ± 2.7 kg; P<0.01). A positive linear relationship was found between fluid intake and changes in BM during the race (r = 0.7; P<0.05). Rates of fluid intake (321-628 ml/hr) and total body mass loss varied substantially between individuals. Plasma osmolality and [Na + ] concentrations were well regulated and did not change significantly. There was a non-significant correlation between changes in body mass and race performance. Conclusion: We conclude that drinking rates vary substantially in athletes drinking ad libitum during an 80 km mountain race whereas plasma osmolality and [Na + ] are well regulated despite large changes in BM. Therefore, drinking ad libitum during prolonged endurance running seems to be an appropriate method to maintain fluid homeostasis during ultra-marathon mountain races.
A mass spectrometric method for the accurate determination of the hydrogen-deuterium ratio has been developed. It is possible to determine this ratio to ± 0.10% using material of “normal abundance”, i.e., 1 part D in 6700 parts H. Samples as small as 0.1 mg H2 (0.001 ml H2O) can be run. Natural evaporation and condensation that have been shown to fractionate the oxygen isotopes also fractionate the hydrogen isotopes. The ratio of these two fractionations is equal to the ratio between the ratios of the vapour pressures of and of .Ocean waters range from 0.0153 to 0.0156 mole % deuterium, whereas fresh waters of the United States range from 0.0133 to 0.0154 mole % deuterium. A measurement of Yellowstone Park fumarole gases gives a minimum temperature of 400° for the equilibrium H2O + HD = HDO + H2 in the gases.
1. The synthesis of long-chain fatty acids de novo was measured in the liver and in regions of adipose tissue in intact normal and genetically obses mice throughout the daily 24h cycle. 2. The total rate of synthesis, as measured by the rate of incorporation of 3H from 3H2O into fatty acid, was highest during the dark period, in liver and adipose tissue of lean or obese mice. 3. The rate of incorporation of 14C from [U-14C]glucose into fatty acid was also followed (in the same mice). The 14C/3H ratios were higher by a factor of 5-20 in parametrial and scapular fat than that in liver. This difference was less marked during the dark period (of maximum fatty acid synthesis). 4. In normal mice, the total rate of fatty acid synthesis in the liver was about twofold greater than that in all adipose tissue regions combined. 5. In obese mice, the rate of fatty acid synthesis was more rapid than in lean mice, in both liver and adipose tissue. Most of the extra lipogenesis occurred in adipose tissue. The extra hepatic fatty acids synthesized in obese mice were located in triglyceride rather than phospholipid. 6. In adipose tissue of normal mice, the rate of fatty acid synthesis was most rapid in the intra-abdominal areas and in brown fat. In obese mice, all regions exhibited rapid rates of fatty acid synthesis. 7. These results shed light on the relative significance of liver and adipose tissue (i.e. the adipose 'organ') in fatty acid synthesis in mice, on the mino importance of glucose in hepatic lipogenesis, and on the alterations in the rate of fatty acid synthesis in genetically obese mice.
The concentration of deuterium oxide in urine can be determined rapidily by infrared spectroscopy applied to urine purified by treatment with charcoal at alkaline pH. The method is sensitive to 0.5 v v per cent D2O. Total body water can be measured to ± 1.5 per cent with the same results as obtained using tritium oxide as the tracer.
A procedure is described for the determination of total body water content of human subjects using 11- to 12-gm. doses of deuterium oxide (D2O), vacuum sublimation of serum samples, and quantitation of the deuterium by infrared spectrophotometry at 2510 cm.-1. The coefficient of variation based on day-to-day procedure reproducibility is less than 2%. D2O added to serum is completely recovered in the sublimation and assay operations. The D2O dilution procedure compares favorably with the tritium dilution technic, with values obtained on 45 out of 46 individuals falling within the ±3 combined S.D. limits for the two methods. The significance of the total body water data is discussed.
The suggestion is made that isotope tracing be carried out by monitoring the natural variations in deuterium concentrations.
As an example, the natural variations in deuterium concentrations between food and water collected in Illinois and food and
water collected in Colorado were used to determine the residence time of water in the blood and urine of rats. We observed
not only a 5½-day turnover time of water in the blood and urine, but also evidence for the influx of water vapor from the atmosphere through
the lungs into the blood.
Determination of total body water based on volume distribution of deuterium oxide is facilitated by use of a slightly modified osmometer. Linearity of values for standards is evident. Recovery experiments indicate the sensitivity of the method. Determinations of deuterium oxide content of standards and of plasma water by osmometry are in close agreement with values determined by falling drop technique.
Our opinion of the present state of jejunoileal shunt in the treatment of obesity may be summarized as follows: (1) A jejunoileal shunt is of distinct benefit in selected patients for whom the obese state has become a hazard to health. (2) It is not the procedure one does because an obese patient is 25 to 50 pounds overweight. (3) Inasmuch as a high degree of cooperation is essential, a relationship of mutual respect, trust, and responsibility must be present between the physician and patient. A hostile attitude on the part of the patient cannot be tolerated. (4) Although long-range benefits from the control of factors leading to aggravation of cardiovascular disorders may be expected, it may be dangerous to subject patients with well established cardiovascular disease to this procedure. (5) A jejunocolic shunt should not be used for control of obesity. (6) A jejunoileal shunt should definitely be considered as an investigative procedure, for the present, and should not be undertaken unless facilities are available to handle complications and to conduct significant research into the mechanism of obesity and its attendant complications over a long period of time.
The quantitative relationship between fatty acid synthesis de novo and production of plasma lipoproteins by perfused liver has been investigated. Livers of rats were perfused in situ for 3–5 hours with a suspension of erythrocytes in one of three perfusing media: rat plasma, buffer containing albumin, or a mixture of plasma and buffer. Tritium oxide (2 mC) was added in each case. Livers were from young rats fed adlibitum or fasted and re-fed. Rates of hepatic fatty acid synthesis ranged from 1.4 to 14.1 μmoles/gm liver/hour, as determined from the tritium content of fatty acids in the liver plus perfusate. A high correlation was found between the number of micromoles of fatty acid synthesized by livers and the number of micromoles of esterified fatty acid released by livers into the perfusing medium. When the perfusate was prepared with only plasma, 0.9 mole of total fatty acid was released per mole synthesized. With all perfusing media, net release of triglycerides, and to a lesser extent cholesterol, was highly correlated with rate of fatty acid synthesis. The additional amounts of triglycerides and cholesterol resulting from accelerated fatty acid synthesis were all released into the perfusate β-lipoprotein fraction, identified immunochemically and by ultracentrifugation. Livers with similar rates of fatty acid synthesis released more triglyceride, cholesterol, and newly synthesized fatty acid when the perfusing medium contained plasma. Net release of phospholipids was nearly independent of the rate of fatty acid synthesis or the presence of plasma in the perfusate. The rate of fatty acid synthesis de novo, which varied widely among even carefully selected rats, is an important determinant of lipid release by the perfused liver.
Data are tabulated on the saliva/serum ratios of tritium after the
administration of tritiated water in human subjects. (C.H.)
TOTAL body water may be estimated by administering a known weight of deuterium oxide and, after equilibration has occurred, determining its concentration in water obtained from some body fluid. Faller et al.1 have shown that, within the limits of experimental error, the same values are obtained for total body water whether the deuterium oxide is administered orally or intravenously. Serum is the usual source of body water containing the equilibrium concentration of deutrium oxide. If, however, urine or saliva could be used, the whole procedure could be carried out without venipuncture; this would be an advantage when serial estimations are to be made or when other investigations involving venipuncture are undertaken in the same subject.
- Soberman