Total Body Potassium and Body Fat Estimation in Relationship to Height, Sex, Age, Malnutrition and Obesity

1975 ◽  
Vol 48 (5) ◽  
pp. 431-440 ◽  
Author(s):  
C. J. Edmonds ◽  
B. M. Jasani ◽  
T. Smith

1. Total body potassium was estimated by 40K measurement with a high-sensitivity whole-body counter in normal individuals over a wide age range and in patients who were obese or were grossly wasted as a result of various conditions which restricted food intake. 2. Potassium concentration (mmol/kg body weight) fell with increasing age over 30 years in both normal males and females, but when individuals of different age groups were matched for height, a significant fall in total body potassium with increasing age was observed only in males. Total body potassium of females was about 75% that of males of similar height when young, the sex difference decreasing with ageing. In the normal population, total body potassium was significantly correlated with height and with weight; regression equations for various relationships are given. 3. Fat-free mass was estimated from total body potassium, values of 65 and 56 mmol of potassium/kg fat-free mass being used for males and females respectively. Body fat estimated by this method correlated well with skinfold measurements over a wide range of body weight but in malnourished individuals having inadequate food intake there was considerable discrepancy and present formulae for estimating fat-free mass from total body potassium appear unsatisfactory in malnutrition. Considerable differences between expected and observed values of total body potassium were found in muscular individuals and in normal individuals who were thin but whose body weight was relatively constant. 4. The patients with malnutrition were low both in body fat as estimated by skinfold thickness and in total body potassium estimated on the basis of height. Plasma potassium was, however, normal and potassium supplements did not increase the total body potassium. 5. Total body potassium of obese individuals was not significantly different from that of normal weight individuals on the basis of height. Total body potassium fell on weight reduction with a very low energy diet of 1260 kJ (300 kcal.) daily but changed little with a 3300 kJ (800 kcal.) diet over several months' observation. 6. For overweight, obese individuals, total body potassium was best predicted from the individual's height. For those whose body weight was less than expected, the use of weight gave the best prediction but the error was considerable when the weight deviation was large.

2017 ◽  
Vol 11 (2) ◽  
pp. 15-27
Author(s):  
Tomáš Hadžega ◽  
Václav Bunc

The aim of our observation was to measure selected anthropometric characteristics and to analyze actual body composition in children of younger school age from elementary schools in Prague. The group consisted of a total of 222 probands, boys (n-117) and girls (n-105) aged 8–11 years (average boys age = 9.0 ± 1.0 years, body height = 139.9 ± 8.6 cm, body weight = 32 ± 7.5 kg, BMI = 16.3 ± 2.4 kg.m–2). Average age girls = 8.9 ± 0.9 years, body height = 137.3 ± 8.8 cm, body weight = 30.5 ± 7.3 kg, BMI = 15.9 ± 2.4 kg.m–2). The BIA 2000 M multi-frequency apparatus (whole-body bioimpedance analysis) was used to analyze the body composition. Children of younger school age showed higher TBW values – total body water (boys 65.5 ± 6.0%, girls 66.6 ± 6.5%), low body fat (boys 16.1 ± 2.4%, girls 16.5 ± 2.9%) and higher ECM/BCM coefficients (boys 1.0 ± 0.13, girls 1.02 ± 0.11). The authors draws, attention to the importance of monitoring other body composition parameters. The percentage of fat-free mass (FFM) and the share of segmental distribution of body fat and muscle mass on individual parts of the human body.


2001 ◽  
Vol 281 (1) ◽  
pp. E1-E7 ◽  
Author(s):  
Zimian Wang ◽  
F. Xavier Pi-Sunyer ◽  
Donald P. Kotler ◽  
Jack Wang ◽  
Richard N. Pierson ◽  
...  

Potassium is an essential element of living organisms that is found almost exclusively in the intracellular fluid compartment. The assumed constant ratio of total body potassium (TBK) to fat-free mass (FFM) is a cornerstone of the TBK method of estimating total body fat. Although the TBK-to-FFM (TBK/FFM) ratio has been assumed constant, a large range of individual and group values is recognized. The purpose of the present study was to undertake a comprehensive analysis of biological factors that cause variation in the TBK/FFM ratio. A theoretical TBK/FFM model was developed on the cellular body composition level. This physiological model includes six factors that combine to produce the observed TBK/FFM ratio. The ratio magnitude and range, as well as the differences in the TBK/FFM ratio between men and women and variation with growth, were examined with the proposed model. The ratio of extracellular water to intracellular water ( E/I) is the major factor leading to between-individual variation in the TBK/FFM ratio. The present study provides a conceptual framework for examining the separate TBK/FFM determinants and suggests important limitations of the TBK/FFM method used in estimating total body fat in humans and other mammals.


1976 ◽  
Vol 41 (2) ◽  
pp. 223-229 ◽  
Author(s):  
J. Womersley ◽  
J. V. Durnin ◽  
K. Boddy ◽  
M. Mahaffy

Body fat and the fat-free mass (FFM) were estimated in 36 men and 43 women deliberately chosen to represent a variety of physical types; these were 1) young sedentary, 2) “muscular,” 3) younger obese, 4) older obese, and 5) older nonobese individuals of both sexes. The body fat and the FFM were estimated from measurements of body density (by total immersion in water, measurement being made of the residual volume of air present in the lungs at immersion) and from measurements of total body potassium (using a whole-body monitor to assess the natural 40K isotope present in the body). The muscular men and women and the younger obese men and women had a considerably greater FFM and thus had greater quantities of potassium than the corresponding sedentary groups. There were significantly different estimates of the FFM calculated from density and from total body K in three groups, the sedentary young men, the muscular, and the younger obese women. The density and the potassium content of the FFM appear to decline with obesity and aging. Muscular development is associated with a decrease in the density but an increase in the potassium content of the FFM.


PEDIATRICS ◽  
1961 ◽  
Vol 28 (6) ◽  
pp. 861-869
Author(s):  
Donald B. Cheek ◽  
T. G. Maddison ◽  
M. Malinek ◽  
J. H. Coldbeck

The present study extends previous observation on the extracellular volume and total body chloride of infants in the neonatal period. It is shown that the decrease in the corrected bromide space is most rapid in postnatal life during the first 2 weeks when 40 ml/kg are lost. By the end of the second week, body weight approaches birth weight. Hence by that time there is a gain of 40 gm/kg, and mainly of protein and cell water. Growth processes are in full progress. The values obtained by other workers for the chloride space of muscle in premature, full-term and 6-month-old infants do not vary considerably from the corrected bromide space for the whole body at these age periods. Nine infants born around the thirty-sixth week of gestation, and of diabetic mothers, were investigated concerning composition and distribution of water and electrolytes, mainly on the third day of postnatal life. It was found that total water was reduced on a weight basis by 37 ml/kg, and this reduction can be explained on the basis of increased body fat, as demonstrated by other workers. The corrected bromide space (on the basis of weight, not age) was reduced by 50 ml/kg of weight, and it was considered that part of this reduction was not due to body fat increase. As much as 40 ml of water/kg of lean body weight probably shifts from the extracellular to the intracellular phase. There is a reduction of extracellular sodium and chloride in infants born of diabetic mothers. This finding was supported by muscle analysis of one infant who died of the respiratory distress syndrome. No change was found in the plasma osmotic pressure or in the concentrations of sodium and chlorides in plasma. The urea content of plasma was elevated, due perhaps to the reduction in extracellular volume.


1990 ◽  
Vol 78 (4) ◽  
pp. 377-381 ◽  
Author(s):  
T. H. J. Goodship ◽  
P. C. Butler ◽  
D. Rodham ◽  
B. Clayton ◽  
P. D. Home ◽  
...  

1. Total-body potassium and fat-free mass have been measured in 31 insulin-dependent diabetic patients and 31 age- and sex-matched normal volunteers. 2. Body mass index was significantly higher in the insulin-dependent diabetic patients (24.7 ± .5 vs 23.3 ± 0.4 kg/m2; P = 0.05). 3. Total-body potassium, uncorrected and corrected for weight and for fat-free mass, was not significantly different in the two groups (3281 ± 141 mmol, 47.3 ± 1.3 mmol/kg body weight, 60.9 ± 1.0 mmol/kg fat-free mass, and 3315 ± 143 mmol, 48.6 ± 1.0 mmol/kg body weight, 60.4 ± 0.8 mmol/kg fat-free mass, respectively, in diabetic patients and non-diabetic subjects). There was no relationship between blood glucose control, as assessed by glycated haemoglobin concentrations, and total-body potassium. 4. These results suggest, by contrast with previous reports, that in insulin-dependent diabetic patients, showing varying degrees of glycaemic control (glycated haemoglobin range 6.1–15.3%, mean 9.0%) that: (a) there is no significant abnormality of body potassium homoeostasis, and (b) there is no relation between total-body potassium and glycaemic control.


2001 ◽  
Vol 21 (3_suppl) ◽  
pp. 163-167 ◽  
Author(s):  
Graham Woodrow ◽  
Brian Oldroyd ◽  
Antony Wright ◽  
W. Andrew Coward ◽  
John H. Turney ◽  
...  

♦ Objectives To assess the validity of measuring total body potassium (TBK) to estimate fat-free mass (FFM) and body cell mass (BCM) in patients on peritoneal dialysis (PD). ♦ Methods We studied 29 patients on PD (14 men, 15 women) and 30 controls (15 men, 15 women). We calculated TBK by using a whole-body counter to measure 1.46 MeV gamma-ray emissions from naturally occurring 40K. We measured total body water (TBW) by deuterium oxide dilution, and extracellular water (ECW) from bromide dilution. These measurements allowed us to estimate intracellular water (ICW), fat-free mass dilution (FFMDilution), and body cell mass dilution (BCMDilution). ♦ Results The FFMTBK in male PD patients (55.7 ± 7.0 kg) did not differ from that in male controls (57.0 ± 10.9 kg). The FFMTBK in female PD patients (38.4 ± 6.8 kg) was less than that in female controls (44.7 ± 4.5, p < 0.01). The FFMDilution did not differ from the FFMTBK. Correlation of FFMTBK and FFMDilution was r = 0.90, p < 0.0001 for all subjects; r = 0.90, p < 0.0001 for PD patients; and r = 0.90, p < 0.0001 for controls. Bland–Altman comparison of FFMDilution with FFMTBK in individuals showed bias 0.6 kg, range –8.5 kg to 9.7 kg for the whole group; bias 1.4 kg, range –7.9 kg to 10.7 kg for PD patients; and bias –0.2 kg, range –9.0 kg to 8.6 kg for controls. The BCMTBK in male PD patients (30.1 ± 4.5 kg) did not differ from that in male controls (31.9 ± 6.2 kg). The BCMTBK in female PD patients (19.0 ± 4.4 kg) was less than that in female controls (23.1 ± 2.9 kg, p < 0.01). The BCMDilution results did not differ from those for the BCMTBK. Correlation of BCMTBK and BCMDilution was r = 0.90, p < 0.0001 for all subjects; r = 0.87, p < 0.0001 for PD patients; and r = 0.93, p < 0.0001 for controls. Bland–Altman comparison of BCMDilution with BCMTBK in individuals showed bias 0.1 kg, range –5.9 kg to 6.1 kg for the whole group; bias 0.0 kg, range –6.9 kg to 6.9 kg for PD patients; and bias 0.1 kg, range –5.0 kg to 5.2 kg for controls. The [K+]ICW did not differ between PD patients and controls (148.0 ± 25.1 mmol/L vs 148.1 ± 14.3 mmol/L, p = nonsignificant). ♦ Conclusions Total body potassium is a valid, noninvasive technique for measuring FFM and BCM in PD patients. In our PD patient group, depletion of FFM and BCM as compared with controls was identified in the women but not in the men.


2003 ◽  
Vol 284 (2) ◽  
pp. E416-E423 ◽  
Author(s):  
Ingrid Larsson ◽  
Anna Karin Lindroos ◽  
Markku Peltonen ◽  
Lars Sjöström

Total body potassium (TBK) is located mainly intracellularly and constitutes an index of fat-free mass (FFM). The aim was to examine whether TBK and the TBK-to-FFM ratio (TBK/FFM) can be estimated from sex, age, weight, and height. A primary study group (164 males, 205 females) and a validation group (161 and 206), aged 37–61 yr, were randomly selected from the general population. TBK was determined by whole body counting, and FFM was obtained by dual-energy X-ray absorptiometry (DEXA; FFMDEXA). The primary study group was used to construct sex-specific equations predicting TBK and TBK/FFM from age, weight, and height. The equations were used to estimate TBK and TBK/FFM in the validation group. The estimates were compared with measured values. TBK in different age ranges was predicted, with errors ranging from 5.0 to 6.8%; errors for TBK/FFM ranged from 2.7 to 4.8%, respectively. By adding FFMDEXA as a fourth predictor, the error of the TBK prediction decreased by approximately two percentage units. In conclusion, TBK and TBK/FFM can be meaningfully estimated from sex, age, weight, and height.


1997 ◽  
Vol 272 (1) ◽  
pp. R78-R83 ◽  
Author(s):  
P. J. Hope ◽  
G. A. Wittert ◽  
M. Horowitz ◽  
J. E. Morley

Little is known about feeding regulation in marsupials. Sminthopsis crassicaudata is a small nocturnal marsupial, whose tail contains approximately 25% total body fat. We have characterized the effect of gender, photoperiod, food deprivation, and tail removal (lipectomy) on food intake in S. crassicaudata. Males and females maintained in captivity on long-day (LD, 16:8-h light-dark cycle) and short-day (SD, 9:15-h light-dark cycle) light regimens were studied. Feeding patterns under LD and SD photoperiods were initially measured under conditions of ad libitum food supply and then in groups of animals exposed to 24- and 36-h periods of food deprivation. Feeding occurred predominantly in the dark. Females maintained on SD photoperiods for 5 wk ate less (P < 0.005) than females on LD or males on either SD or LD, but this reduction in food intake was not associated with a decrease either in body weight or tail width. After both 24- and 36-h fasts, total food intake in the subsequent 24 h increased (P < 0.001) up to 100% in all groups, with no gender or photoperiod effect. SD females, however, ate less (P < 0.05) than LD females in the first 6 h after refeeding. Tail width decreased (P < 0.05) in all groups of animals after the 36-h fast but only in LD animals after the 24-h fast (P < 0.05). Body weight decreased similarly in all groups of animals after fasting. The effect of tail removal was studied in LD males. The procedure, which was well tolerated, resulted in an initial decrease in body weight (P < 0.005), which recovered within 3 wk. On day 45 in the animals whose tails were removed, body fat was approximately 30% greater than body fat of controls (P < 0.02). No significant increase in food intake occurred after tail removal. These data demonstrate in Sminthopsis crassicaudata 1) a photoperiod and gender-dependent effect on food intake, 2) the ability to regulate the amount and distribution of total body fat, and 3) a dissociation between the regulation of food intake and changes in body fat stores, which suggest alterations in energy expenditure.


1981 ◽  
Vol 96 (1) ◽  
pp. 213-220 ◽  
Author(s):  
D. A. Little ◽  
R. W. McLean

SUMMARYFollowing the measurement of tritiated water (TOH) spaces, 31 cattle were slaughtered and chemically analysed in this study. They included several breeds, both females and castrate males, and were of varied nutritional history. Their body-fat content ranged from 4 to 21% of fasted live weight.Total body water (including the water in the gut contents) was reliably estimated from TOH space, measured after allowing an overnight 16 h waterless fast for TOH equilibration. Following this regime, residual D.M. in the gut contents amounted to 1·75% of fasted live weight. The relationships of body fat to body weight, and body fat to body water when both were expressed as percentages of body weight, were too variable to be used in any predictive fashion. Equations were derived, using fasted live weight, allowing the accurate estimation in vivo of the quantities of the chemical components in the whole body (i.e. total body minus D.M. in gut contents).It was demonstrated that the sum of total body water and total body fat constituted virtually 80% of total body tissues, and that total body protein closely approximated 80% of the fat-free dry matter, in cattle varying widely in body condition. These relationships constitute the physiological basis of the equations presented.Comparable principles appear to apply to sheep, and a range of other mammalian species.


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