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Abstract Background Cachexia complicates many chronic diseases. In chronic or congestive heart failure (CHF), cachexia independently contributes to decreased survival. Although diuretics have long been part of standard treatment of CHF, the addition of angiotensin and aldosterone antagonists to the standard treatment regimen has considerably improved the outcome of CHF. Both loop diuretics and the up‐regulation of the renin–angiotensin–aldosterone system caused by CHF induce loss of total body potassium (TBK). Hypothesis In addition to the causal association of loss of muscle mass with loss of TBK, we propose that the reverse mechanism also exists. The known beneficial effects of angiotensin and aldosterone inhibition may partly result from preserved TBK with consequent muscle mass preservation. Conclusion We propose that monitoring of muscle mass, potassium balances, and TBK should be included in future CHF studies to verify this hypothesis and allow further optimization of therapy.

Background The 2007 World Health Organization/Food and Agriculture Organization/United Nations University (WHO/FAO/UNU) recommendation for the Estimated Average Requirement (EAR) of additional protein during pregnancy for a gestational weight gain (GWG) of 12 kg (recalculated from a GWG of 13.8 kg) is 6.7 and 21.7 g/d in the second and the third trimester, respectively. This EAR is based on measurements of potassium accretion in high-income country (HIC) pregnant women. It is not known if low- to middle-income country, but well-nourished, pregnant women have comparable requirements. Objective We aimed to estimate total body potassium (TBK) accretion during pregnancy in Indian pregnant women, using a whole-body potassium counter (WBKC), to measure their additional protein EAR. Methods Well-nourished pregnant women (20–40 y, n  = 38, middle socioeconomic stratum) were recruited in the first trimester of pregnancy. Anthropometric, dietary, and physical activity measurements, and measurements of TBK using a WBKC, were performed at each trimester and at birth. Results The mid-trimester weight gain was 2.7 kg and 8.0 kg in the second and the third trimester, respectively, for an average 37-wk GWG of 10.7 kg and a mean birth weight of 3.0 kg. Protein accretion was 2.7 and 5.7 g/d, for an EAR of 8.2 and 18.9 g/d in the second and the third trimester, respectively. The additional protein EAR, calculated for a GWG of 12 kg, was 9.1 and 21.2 g/d in the second and the third trimester, respectively. Conclusion The additional protein requirements of well-nourished Indian pregnant women for a GWG of 12 kg in the second and third trimesters were similar to the recalculated 2007 WHO/FAO/UNU requirements for 12 kg. [ABSTRACT FROM AUTHOR]

Body composition measurements are used to evaluate surgical treatment, such as bariatric surgery in overweight patients. Nowadays, there are many different methods to measure body composition available. However, none of them has been validated for use in patients after operation. The aim of the present study was to compare the amount of surgically removed fat with two different methods, bioelectrical impedance analysis (BIA) and total body potassium (TBK). Amount of removed fat during liposuction was measured 1, 2, 3, 4, 14 days, and 1 year postoperatively in 27 obese patients after liposuction. The results were compared with actual removed fat during the operation. The median fat mass removed was 4020 grams (range 1954-9655). Postoperatively there was a varying reduction in fat mass, as measured with BIA and with TBK. There was a clear difference between the range of amounts removed measured with BIA and the range of amount removed measured with TBK. This study indicates that BIA, but not TBK, is an appropriate method to measure fat mass in obese subjects in a surgical setting. BIA seems to underestimate the amount of fat removed, whereas TBK seems to overestimate it. [ABSTRACT FROM AUTHOR]

Objective: This investigation provides information about changes of TBK and BCM during growth from infancy to adolescence inclusive. Methods: Compilation of results from several semi-longitudinal studies of 476 males and 528 females were accomplished on Caucasian children. Results: TBK and BCM were slightly higher in boys who were also taller and heavier from infancy to about 12 years of age. TBK and BCM were significantly different at P < 0.05 level in favor of boys at ages 13 to 15 years and at P < 0.01 level at ages 16 to 18 years compared to girls of the same age periods. Points of acceleration of BCM -- TBK during adolescence of both genders were found using regression with intersection of two-lines analyses, which occurred when boys reached height of 139.9 cm compared to 128.8 cm in height of girls. Conclusions: TBK percentile tables of both genders based on semi-longitudinal approach can be used objectively for evaluations of BCM using Wang's formula BCM(Kg) = TBK(g) × 9.20/39.1 compared to Moore's equation BCM(gr) = Ke(mEq) × 8.33 which underestimates BCM. [ABSTRACT FROM AUTHOR]

The article discusses a study that assessed total body potassium (TBK) and body cell mass (BCM) in healthy men over a 21-year period, and evaluated changes with age. From baseline to end of study, the prevalence of overweight and obesity rose significantly, with no change in TBK observed over the duration of the study. Subjects with a low maximum BCM at an early age showed tendency to exhibit decreased body mass index (BMI) as they aged, while those with a high maximum BCM at an early age tended to show increased BMI as they aged.

The advent of liver transplantation for end-stage liver disease (ESLD) in children has necessitated a major rethink in the preoperative preparation and management from simple palliative care to active directed intervention. This is particularly evident in the approach to the nutritional care of these patients with the historical understanding of the nutritional pertubations in ESLD being described from a single pediatric liver transplant center. ESLD in children is a hypermetabolic process adversely affecting nutritional status, metabolic, and non-metabolic body compartments. There is a complex dynamic process affecting metabolic activity within the metabolically active body cell mass, as well as lipid oxidation during fasting and at rest, with other factors operating in conjunction with daily activities. We have proposed that immediately ingested nutrients are a more important source of energy in patients with ESLD than in healthy children, among whom energy may be stored in various body compartments. [ABSTRACT FROM AUTHOR]

Aim: Protein energy malnutrition is common in children with chronic renal failure (CRF) and may negatively impact on clinical outcome. Although the aetiology of malnutrition is multifactorial, descriptive information on body composition may guide nutritional interventions aimed at optimising nutritional status. Methods: This prospective cohort study in children with CRF was conducted from April 1999 to November 2000. Patients were categorised according to their glomerular filtration rate (GFR) into CRF and end-stage renal failure (ESRF). Body composition was assessed based on anthropometry, total body potassium (TBK), total body protein (TBP) and dual X-ray absorptiometry (DEXA). Results: Fifteen patients (10 male, 5 female; mean age: 13.4 ± 4.3 years) were studied, including eight patients with CRF (mean GFR: 17.0 ± 7.2 mL/min/1.73 m2) and seven patients with ESRF (mean GFR: 6.4 ± 1.7 mL/min/1.73 m2). Patients in both groups ( n = 15) had deficits in height and TBP (mean z-score height-for-age: −1.19 ± 1.05, P < 0.01; mean z-score TBP: −0.71 ± 0.71, P < 0.05). There were no significant differences in weight, height, fat-free mass, TBK and TBP between patients with CRF and ESRF. Conclusions: Linear growth impairment and decreased TBP are common in children with chronic and ESRF. TBK and DEXA may underestimate the degree of malnutrition in these patients. [ABSTRACT FROM AUTHOR]

The proportion of fat-free mass (FFM) as body cell mass (BCM) is highly related to whole body resting energy expenditure. However, the magnitude of BCM/FFM may have been underestimated in previous studies. This is because Moore's equation [BCM (kg) = 0.00833 × total body potassium (in mmol)], which was used to predict BCM, underestimates BCM by 11%. The aims of the present study were to develop a theoretical BCM/FFM model at the cellular level and to explore the influences of sex, age, and adiposity on the BCM/FFM. Subjects were 112 adults who had the following measurements: total body water by ²H2O or ³H2O dilution; extracellular water by NaBr dilution; total body nitrogen by in vivo neutron activation analysis; and bone mineral by dual-energy X-ray absorptiometry. FFM was calculated using a multicomponent model and BCM as the difference between FFM and the sum of extracellular fluid and solids. The developed theoretical model revealed that the proportion of BCM to FFM is mainly determined by water distribution (i.e., E/I, the ratio of extracellular to intracellular water). A significant correlation (r = 0.90, P < 0.001) was present between measured and model-predicted BCM/FFM for all subjects pooled. Measured BCM/FFM [mean (SD)] was 0.584 ± 0.041 and 0.529 ± 0.041 for adult men and women (P < 0.001), respectively. A multiple linear regression model showed that there are independent significant associations of sex, age, and fat mass with BCM/FFM. [ABSTRACT FROM AUTHOR]

Summary: Background: Cross-sectional data have shown that sarcopenia and fat accumulation are associated with aging and can be limited by structured physical training. However, it is often difficult to maintain a long-term compliance to training programs. It is not clear whether leisure-time physical activity is effective in preventing sarcopenia and fat accumulation. Objectives: (i) To investigate longitudinal body composition changes in a population of elderly people in good apparent health. (ii) To evaluate the impact of leisure-time physical activity on muscle mass and characteristic as reflected by total body potassium per fat-free soft tissue (TBK/FFST), and on fat accumulation. Design: Longitudinal evaluation over 3 years, of body composition changes in 74 healthy men and 66 women, over 65 years old. Body fat and FFST were analyzed by dual-energy X-ray absorptiometry and TBK by whole-body 40K counter. Physical activity was analyzed by a specific questionnaire. Results: Despite a stable total body weight, FFST and appendicular skeletal muscle mass slightly decreased (−0.3±1.4 and −0.2±2.2kg, , respectively) as well as the TBK/FFST (−4.1±6.3mmol/kg, ), over the 3-year period. Body fat increased significantly (0.6±2.2kg, ), and it accumulated mainly in the abdomen (0.4±1.5kg, ). Multiple regression analysis showed that body composition changes were related mainly to body weight changes. Nevertheless, positive linear correlations were observed between the degree of engagement in leisure-time physical activity and FFST (), appendicular skeletal muscle mass (), TBK/FFST (), whereas negative correlation was observed with total and truncal fat (). Conclusions: Mild but significant decline in muscle mass and its TBK content, and body fat accumulation were observed over a 3-year period in healthy elderly subject: leisure-time physical activity does not seem to prevent them. However, a higher level of physical activity is associated with higher muscle mass and TBK content, and less total and truncal fat. [Copyright &y& Elsevier]

The article presents a scientific research that investigated on whether large amounts of sodium are stored in an osmotically inactive form during sodium retention through balance studies in freely moving dogs. Results of the study showed that osmocontrol adjusts total body water to the body's present content of sodium and potassium and invalidates the hypothesis that large amounts of sodium are stored in an osmotically inactive form during sodium retention.

The assessment of potassium (K) effects in hypertension involves a history of complex research in cell K function and body K homeostasis. These studies provide evidence for the role of K ions in vascular and renal function, insulin resistance, glucose uptake, and the renin–angiotensin–aldosterone system; and there have been an impressive number of clinical and epidemiologic research relating dietary intake K and regulation of blood pressure. However, the usual technique by which K metabolism is assessed in clinical practice (plasma or serum K) provides no useful data for estimating disorders in cell K transport that occurs in hypertensive patients or that may follow the administration of diuretics, β-blockers, or nonsteroidal anti-inflammatory drugs. This fact becomes more crucial if associated with the physiologic decline in body K stores occurring after the age of 30 years, which may impair the long-term treatment of hypertensive individuals. In this context, this article presents a review of the clinical and research methods that can be used to assess more accurately K metabolism and cell K physiology in hypertensive patients, including a heritable defect in red blood cell K transport. [Copyright &y& Elsevier]

Background: We previously derived a whole-body resting energy expenditure (REE) prediction model by using organ and tissue mass measured by magnetic resonance imaging combined with assumed stable, specific resting metabolic rates of individual organs and tissues. Although the model predicted REE well in young persons, it overpredicted REE by ≈11% in elderly adults. This overprediction may occur because of a decline in the fraction of organs and tissues as cell mass with aging. Objective: The aim of the present study was to develop a cellular-level REE prediction model that would be applicable across the adult age span. Specifically, we tested the hypothesis that REE can be predicted from a combination of organ and tissue mass, the specific resting metabolic rates of individual organs and tissues, and the cellular fraction of fat-free mass. Design: Fifty-four healthy subjects aged 23-88 y had REE, organ and tissue mass, body cell mass, and fat-free mass measured by indirect calorimetry, magnetic resonance imaging, whole-body 40K counting, and dual-energy X-ray absoptiometry, respectively. Results: REE predicted by the cellular-level model was highly correlated with measured REE (r = 0.92, P < 0.001). The mean difference between measured REE (x±SD: 1487 ± 294 kcal/d) and predicted REE (1501 ± 300 kcal/d) for the whole group was not significant, and the difference between predicted and measured REE was not associated with age (r = 0.009, NS). Conclusion: The present approach establishes an REE-body composition link with the use of a model at the cellular level. The combination of 2 aging-related factors (ie, decline in both the mass and the cellular fraction of organs and tissues) may account for the lower REE observed in elderly adults. [ABSTRACT FROM AUTHOR]

Energy expenditure and fat-free mass (FFM), as well as the relationships between these parameters, were investigated in thirteen pairs of monozygotic twins discordant for SCI. Basal energy expenditure (BEE) and resting energy expenditure (REE) were determined by indirect calorimetry. Measurements for FFM and fat mass were obtained by dual-energy x-ray absorptiometry. Total body potassium was determined by a 4-Pi whole-body counting chamber. Values are expressed as mean ± standard deviation. BEE and REE of the twins with SCI were significantly less than those of the able-bodied co-twins (1387 ± 268 vs. 1660 ± 324 kcal/d, p < 0.005, and 1682 ± 388 vs. 1854 ± 376 kcal/d, p < 0.05, respectively). Regardless of the group, direct and highly significant relationships were evident between BEE or REE and FFM or TBK. In summary, twins with SCI had lower energy expenditure than their able-bodied co-twins. Regardless of paralysis, direct linear relationships existed between energy expenditure and measures of lean mass. [ABSTRACT FROM AUTHOR]

Background: Protein is an important body component, and the presently accepted criterion method for estimating total body protein (TBPro) mass--in vivo neutron activation (IVNA) analysis-- is unavailable to most investigators and is associated with moderate radiation exposure. Objective: The objective was to derive a theoretical cellular level TBPro mass and distribution model formulated on measured total body potassium, total body water, and bone mineral and to evaluate the new model with the IVNA method as the criterion. Design: The new model was developed on the basis of a combination of theoretical equations and empirically derived coefficients. TBPro mass estimates with the new model were evaluated in healthy women (n = 183) and men (n = 24) and in men with AIDS (n = 84). Total body nitrogen was measured by IVNA, total body potassium by whole-body 40K counting, total body water by tritium dilution, and bone mineral by dual-energy X-ray absorptiometry. Results: The group mean (± SD) TBPro mass estimates in healthy women and men and men with AIDS (8.2 ± 0.9, 11.0 ± 1.8, and 10.5 ± 1.1 kg, respectively) with the new model were similar to IVNA criterion estimates (8.9 ± 0.9, 11.1 ± 1.6, and 10.9 ± 1.2 kg, respectively). TBPro mass estimates with the new model correlated highly with the IVNA estimates in all subjects combined (r = 0.92, P < 0.001). The new model suggests that the composite TBPro mass within each group consists mainly of cellular protein (75-79%) and, to a lesser extent, protein in extracellular solids (19-23%) and extracellular fluid (≈2%). Conclusion: The new model provides a non-IVNA approach for estimating protein mass and distribution in vivo. [ABSTRACT FROM AUTHOR]

Most reports of outcome following obesity surgery report weight and co-morbidity changes only. We studied body composition changes in 17 adult patients (15 F, 2 M, age 43±2 years, range 28–58 years), with morbid obesity (initial BMI 40.4±4.9 kg/m2, range 34.7–48.8) who were managed surgically by laparoscopically inserting an adjustable gastric band. Body composition was studied before and after surgery (mean interval of 909±51 days, range 441–1,155 days) using anthropometry (abdominal circumference, AC, sum of four skinfold thicknesses, SFSUM), whole-body potassium counting (TBK), in vivo neutron activation analysis total body nitrogen (TBProtein) and whole-body dual-energy ray absorptiometry (total body percent fat TBF%, and total body bone mineral density TBBMD). Weight loss over the study period was 23.4±2.5 kg. (p<0.0003) with an AC reduction of 20.0±4.5 cm (p<0.008). Both SFSUM and TBF% were significantly reduced (p<0.02 and p<0.0005 respectively). Both TBK and TBProtein after normalization for sex and height, were significantly (p<0.0054 and p<0.001 respectively) reduced, but the ratio of loss of fat mass to fat-free mass, at 4.4:1 was usual for weight loss, and there was no significant changes in the ratio of potassium to protein. TBBMD, after normalization relative to a young same sex adult, was not significantly changed. In this group of patients, most of the substantial weight loss over a 2- to 3-year period was due to loss of fat mass, with relatively less reduction in the components of fat-free mass. Adjustable laparoscopic gastric banding induces fat loss without significant other deleterious effects on body composition. [ABSTRACT FROM AUTHOR]

The objective of this study was to investigate the relationship between body mass index (BMI, kg/m2) and body cell mass (BCM) estimated from total body potassium (TBK) measured by whole body 40K counting in healthy 284 African-Americans (AA), 269 Asians (A) and 536 Caucasians (C) aged 18–107 years and to study the effects of age, sex, and race on the relationship. Body fat and fatfree mass (FFM) were measured by dual-energy X-ray absorptiometry (DXA). There was a significant positive correlation between BCM and BMI. For a given BMI, A had lower BCM but decreased less per year of age than AA and C, and males had higher BCM than females in each ethnic group. The fraction, BCM/FFM decreased with BMI in all subgroups by race, sex, and age, and males decreased more per age and AA decrease more than A and C. Not only the BCM–BMI relationship but also BCM/FFM vs. BMI is important to health. [ABSTRACT FROM AUTHOR]

Background: Total body potassium (TBK) is an index of fat-free mass. Data describing changes in TBK in African American, Asian, or Hispanic populations have not been reported. Objective: The aim was to investigate possible sex and racial differences in TBK in adults over an age range of 70 y. Design: The study used longitudinal and cross-sectional data collected in a body-composition unit from 973 men and 1368 women of African American, Asian, white, and Hispanic race-ethnicity. Random coefficient models in which baseline weight and height were taken into account were applied to estimate sex-specific changes in TBK among the 4 racial-ethnic groups. Results: The ages of 30 and 31 y were identified for women and men, respectively, as the cutoffs after which TBK began to decline. Both sexes had similar racial-ethnic patterns for expected mean TBK at the age cutoffs: African Americans had the highest value, followed by whites, Hispanics, and Asians. After the age cutoffs, the decline in TBK differed by race and sex. In women, African Americans showed the most rapid decline, whereas Asians had the lowest. In men, Hispanics had the most rapid decline in TBK, followed by African Americans, whites, and Asians. Conclusion: Significant sex and racial differences exist in the rate of change in TBK with age. Further studies are needed to explore the associations of declining TBK with health risks. [ABSTRACT FROM AUTHOR]

The body composition of 58 college women was determined by whole body 40K count; skinfold measurements at four sites; creatinine equivalence and from prediction equation of body water. Lean body mass (LBM) estimated from measurement with skinfold-thickness agreed quite well with the respective values estimated from the total body water prediction equation. Good agreement was also found with whole body 40K count only among obese females (BMI > 30 kg/m2). Whole body 40K counts tended to overestimate the LBM among females with normal BMI (18.5 − <25 kg/m2) and among overweight females (25-30 kg/m2). Measure of muscle mass from the urinary creatinine equations gave inferior values for all studied females compared with the respective mean values obtained with the other three methods. Comparison between the three methods, showed significant correlations. Method selection must thus be considered in the interpretation of inter-study comparisons and follow-up of sliming regimen. The present results suggest that additional studies should be done on subpopulation groups from the same community to assess small changes in body composition. [Copyright &y& Elsevier]

Background: A substantial proportion of total body potassium (TBK) in humans is found in skeletal muscle (SM), thus affording a means of predicting total-body SM from whole-body counter-measured 40K. There are now > 30 whole-body counters worldwide that have large cross-sectional and longitudinal TBK databases. Objective: We explored 2 SM prediction approaches, one based on the assumption that the ratio of TBK to SM is stable in healthy adults and the other on a multiple regression TBK-SM prediction equation. Design: Healthy subjects aged ⩾ 20 y were recruited for bodycomposition evaluation. TBK and SM were measured by wholebody 40K counting and multislice magnetic resonance imaging, respectively. A conceptual model with empirically derived data was developed to link TBK and adipose tissue-free SM as the ratio of TBK to SM. Results: A total of 300 subjects (139 men and 161 women) of various ethnicities with a mean (± SD) body mass index (in kg/m2) of 25.1 ± 5.4 met the study entry criteria. The mean conceptual model-derived TBK-SM ratio was 122 mmol/kg, which was comparable to the measurement-derived TBK-SM ratios in men and women (119.9 ± 6.7 and 118.7 ± 8.4 mmol/kg, respectively), although the ratio tended to be lower in subjects aged = 70 y. A strong linear correlation was observed between TBK and SM (r = 0.98, P < 0.001), with sex, race, and age as small but significant prediction model covariates. Conclusions: Two different types of prediction models were developed that provide validated approaches for estimating SM mass from 40K measurements by whole-body counting. These methods afford an opportunity to predict SM mass from TBK data collected in healthy adults. [ABSTRACT FROM AUTHOR]

Background: Total body potassium (TBK) is known to decline throughout adulthood. The relations between physical activity, age, anabolic hormones, and TBK have rarely been considered. Objective: We sought to describe the relation between habitual physical activity, age, serum estradiol, and insulin-like growth factor I (IGF-I) and TBK in postmenopausal women. Design: TBK, fat-free mass (FFM), moderate-to-vigorous-intensity physical activity (MVPA; assessed with use of a semistructured interview), and serum concentrations of estradiol, IGF-I, and IGF binding protein 3 (IGFBP-3) were quantified in 51 healthy white women aged 54-76 y. Results: The potassium content of FFM declined curvilinearly with age, indicating an accelerated loss of skeletal muscle after 65 y of age. With the data split into high (n = 25) and low (n = 26) MVPA groups, the active women had 6.5% more potassium per FFM than did their less-active counterparts (P < 0.01). In multiple regression analysis, MVPA was the major determinant of the potassium content of FFM (P = 0.02), such that an active 70-y-old had the potassium content value of a 55-y-old sedentary woman. Serum estradiol, IGF-I, and IGFBP-3 were not significant determinants of the potassium content of FFM. Conclusions: These data suggest that 1) habitual physical activity can significantly influence FFM potassium content; 2) physical activity must, therefore, be considered if the effect of aging per se on TBK is to be clarified; and 3) MVPA, such as that pursued by the active women in the present study (eg, walking, dancing, floor exercises, and swimming), can assist in preventing sarcopenia in older women. [ABSTRACT FROM AUTHOR]

OBJECTIVES: To evaluate body composition parameters, including fat-free mass (FFM), appendicular skeletal muscle mass (ASMM), relative skeletal muscle mass (RSM) index, body cell mass (BCM), BCM index, total body potassium (TBK), fat mass, percentage fat mass (FM), and their differences between age groups and to evaluate the frequency of sarcopenia in healthy older subjects DESIGN: Cross-sectional, nonrandomized study. SETTING: Outpatient clinic. PARTICIPANTS: Ninety-one healthy men and 100 healthy women age 60 and older. MEASUREMENTS: FFM, ASMM, FM, and percentage fat mass by whole-body dual-energy x-ray absorptiometry; TBK, BCM, and TBK/FFM ratio by whole body potassium-40 counter. RESULTS: All lean body mass parameters were significantly (P < .05) lower in subjects age 80 and older than in those age 70 to 79, except ASMM in women. Mean FFM was 4.2 kg (7.3%) lower in men age 80 and older than in those younger than 70 and 2.9 kg (6.8%) lower in women age 80 and older than in those younger than 70. The skeletal muscle mass, reflected by ASMM, decreased more than FFM. This suggests that nonskeletal muscle mass is proportionally preserved during aging. Forty-five percent of men and 30% of women were sarcopenic by definition of BCM index and 11.0% of men and women by definition of RSM index. CONCLUSIONS: Significant age-related differences exist in body composition of older men and women between age 60 and 95. The greater decrease in TBK and BCM than the decrease in FFM and skeletal muscle mass suggests changing composition of FFM with age. Lack of agreement between two independent sarcopenia indexes suggests that further refinement in the definition of a sarcopenia index is necessary. [ABSTRACT FROM AUTHOR]