Body Potassium Content Research Articles

Blood pressure alteration associated with abnormal body electrolyte and water balance in colitis mice.

Previous studies reported that there is an association between abnormal body fluid balance and prognosis in colitis patients. However, it remains to be clarified the effects of colitis on characteristics of body electrolytes or water content, including alternation in blood pressure. In this study, we examined the effects of colon injury on body water balance and blood pressure in the dextran sodium sulfate (DSS)-induced colitis mouse model. We evaluated body electrolytes and water content, blood pressure, and urea-associated water conservation in DSS mice. By 5 days after the treatment, DSS mice exhibited diarrhea but relatively maintained body weight and total body sodium, potassium, and water content by increases in water intake and hepatic ureagenesis. On 7 days after DSS treatment, when colitis becomes severe, DSS mice significantly decreased food and water intake, and body weight but significantly increased relative total body sodium, potassium, and water content per dry mass. Notably, DSS induced more total body dry mass loss relative to water loss. These body electrolytes and water accumulation on day 7 were associated with a reduction in urinary osmole excretion and urine volume accompanied by renal urea accumulation. DSS mice significantly increased blood pressure by day 5 and then decreased on day 7. These findings suggest that body electrolyte and fluid imbalance and alternations in blood pressure in colitis vary with the stage and severity of the condition. Assessment and correction of electrolyte and water content at the tissue level would be important to improve the prognosis of colitis.

URINE SODIUM-TO-POTASSIUM RATIO DOES NOT ACCURATELY REFLECT DIETARY SODIUM-TO-POTASSIUM RATIO

Objective: High sodium intake is associated with an increased risk of cardiovascular disease, whereas a high potassium intake is associated with a reduced risk. Dietary counselling requires accurate estimation of sodium and potassium intake, but 24-hour urine sodium and potassium excretion demonstrated not to reflect actual intake. Urine sodium-to-potassium (Na/K) ratio is a promising alternative as it may be less affected by aldosterone-induced rhythmic changes in total body sodium and potassium content, is less influenced by incomplete urine collections, and incorporates both the effect of sodium and potassium. Our study assesses whether 24-hour urine Na/K ratio is superior in predicting dietary intake compared to 24-hour urine sodium or potassium excretion. Design and method: A post-hoc analysis was performed on data from the long-term sodium balance studies Mars105 and Mars520. Ten healthy participants received a diet with a known sodium and potassium content and collected 24-hour urine samples for 105 or 205 days. We calculated the log fold difference between dietary intake and urine content of sodium, potassium and Na/K ratio. We compared these estimates of accuracy using a mixed-effects model with a random intercept per subject. We analysed whether the accuracy differed among 6, 9 and 12 grams salt intake or was affected by the number of 24-hour urine collections. Results: Urine Na/K ratio underestimated dietary Na/K ratio with a median difference of -0.21 (IQR -0.47 to 0.09). Compared to sodium and potassium assessment, the Na/K ratio was significantly less accurate in predicting intake (Figure 1A). Only for the 6 gram salt phase the Na/K ratio did not perform significantly worse than sodium measurements. Increasing the number of 24-hour urine measurements to three or seven improved accuracy of the Na/K ratio, although it remained inferior to separate assessment of sodium and potassium excretion (Figure 1B). Conclusions: The 24-hour urine Na/K ratio is less accurate than 24-hour urine sodium excretion for estimation of dietary intake in a controlled setting.

Koncept infuzionog rastvora kao leka - infuzioni rastvor je lek

Fluid prescription is the basis of critical care, emergency and hospital department therapy. Fluid management is directed according to daily fluid needs and output, body weight, sodium, potassium and glucose content. The consideration of potential risks of fluid overload presents advanced strategy in practice. Monitoring and recording of intravenous and other fluid management is of utmost importance but it is usually poor. Scientific research in the last fifteen years announces a new era in fluid therapy. At the beginning, volume of fluid was pointed out both in the area of initial critical care presentation and the period after the resuscitation. Then, the scientific data about fluid composition increased attention to potential adverse effects of fluid and electrolyte accumulation. Finally, it becomes apparent that fluid and electrolyte overload may influence patient outcomes. Everything previously mentioned was mainly studied in critical care patients and produced new apprehention of the fluid as the solitary drug. The aim of this mini review was to point out the importance of defining fluid as the drug and to present main definitions in this area in this moment.

ASSESSMENT OF BODY POTASSIUM LEVEL BY GENDER AND AGE IN KOREAN ADULT GROUP.

Most internal radiation dose resulting from natural radionuclides is due to radon and radioactive potassium. Total body potassium (TBK) in human body may vary by ethnic group, gender and age. The objective of this study was to measure TBK and body potassium concentration in Korean subjects. Body potassium concentrations of the subjects were measured with a whole-body counter for 283 adult males and 181 adult females. Average TBK value and body potassium level were 111.2 g and 1.5 g kg-1 for males, while for females they were 71.7 g and 1.4 g kg-1. TBK increased with increasing body weight. Body potassium level per body weight was inversely proportional to age in both genders. The annual effective doses due to 40K in the human body of Korean population were calculated to be 0.15 and 0.13 mSv for males and females, respectively.

Potassium channels in renal proximal tubule

Potassium channels are a diverse family of membrane proteins which are present within all cells of the body. They contain two subunits α, which determine the structure of the channel, and β, which can modify the properties of the channel. Those transmembrane proteins take part in K+ movement across cell membranes, via a highly selective pore. The kidneys have crucial role in maintaining total body potassium content, by matching its intake and excretion. K+ absorption in the proximal tubule is primarily passive and proportional to Na+ and water, so that changes in fluid and potassium transport are closely coupled. Proximal tubular K+ channels are crucial for the maintenance of a hyperpolarized membrane voltage. In leaky epithelia, such as the proximal tubule, the hyperpolarization of the basolateral membrane also results in the hyperpolarization of the apical membrane, due to increase in the K+ conductance of that barrier. They are also involved in regulating cell volume and in recycling potassium across the basolateral membrane. K+ channels of the KCNK and KCNJ gene families have been discovered in the basolateral membrane cell of various species. One of the primary functions of basolateral K+ channels is to recycle K+ across the basolateral membrane for proper function of the Na+-K+-ATPase. Activation by extracellular alkalinization has been associated with a role of TASK-2 in kidney proximal tubule bicarbonate reabsorption. In renal proximal tubules, luminal K+ channels play an important role for restoring the driving force of Na+-coupled transport systems (amino acids, glucose), which depolarize the luminal membrane. Some of these luminal K+ channels are activated directly by the transport-associated depolarization; others are regulated by mediators, second messenger pathways and cell volume.

Physiology and pathophysiology of potassium homeostasis.

Total body potassium content and proper distribution of potassium across the cell membrane is of critical importance for normal cellular function. Potassium homeostasis is maintained by several different methods. In the kidney, total body potassium content is achieved by alterations in renal excretion of potassium in response to variations in intake. Insulin and beta-adrenergic tone play critical roles in maintaining the internal distribution of potassium under normal conditions. Despite homeostatic pathways designed to maintain potassium levels within the normal range, disorders of altered potassium homeostasis are common. The clinical approach to designing effective treatments relies on understanding the pathophysiology and regulatory influences which govern the internal distribution and external balance of potassium. Here we provide an overview of the key regulatory aspects of normal potassium physiology. This review is designed to provide an overview of potassium homeostasis as well as provide references of seminal papers to guide the reader into a more in depth discussion of the importance of potassium balance. This review is designed to be a resource for educators and well-informed clinicians who are teaching trainees about the importance of potassium balance.

Body Potassium Content and Radiation Dose from 40K for the Urals Population (Russia).

Long-term whole-body monitoring of radionuclides in residents of the Urals Region has been performed at the Urals Research Center for Radiation Medicine (URCRM, Chelyabinsk). Quantification of 40K was achieved by measuring the 40K photopeak with four phoswich detectors in whole body counter SICH-9.1M. The current study presents the results of 40K measurements in 3,651 women and 1,961 t-test; U-test men aged 11–90; measurements were performed in 2006–2014. The residents belonged to two ethnic groups, Turkic (Tatar, Bashkir) and Slavs (mainly Russian). The levels of 40K-body contents depend upon gender, age, and body mass. Significant ethnic-differences were not found in 40K-body contents and 40K concentrations in terms of Bq per kg of body weight (in groups homogenous by age and gender). Both 40K-body contents and concentrations were significantly higher in men than in women in all age-groups; the difference was about 25%. The measured 40K-body content in men of 20–50 years was about 4200 Bq (134 g of K) and about 3000 Bq (95 g of K) in women. By the age of 80 these values decreased to 3200 Bq (102 g of K) in men and 2500 Bq (80 g of K) in women. Annual dose rates were maximal in the age group of 20–30 years– 0.16 mGy/y for men and 0.13 mGy/y for women. Further, the dose-rates decreased with age and in the groups of 60–80 years were 0.13 mGy/y for men and 0.10 mGy/y for women. Within groups homogeneous by age and gender, individual dose rates are described by a normal statistical distribution. The coefficient of variation ranges from 9 to 14%, and on the average is 12.5%. Doses from naturally occurring 40K accumulated over 70 years were found to be 9.9 mGy for men and 8.3 mGy for women; over 90 years - 12.5 and 10.4 mGy.

Sweat Potassium Decreases with Increased Sweating in Perimenopausal Women

Objective: To investigate the relationship between rate of sweat production and sweat potassium concentration in premenopausal (PreM), perimenopausal (PeriM) and postmenopausal (PostM) women after a moderate exercise. Study Design: This is a cross-sectional study conducted in May 2012 at the Department of Physiology, University of Benin, Nigeria. Methods: Thirty healthy female volunteers comprising of PreM (aged: 22.5±0.8 yrs, n = 10), PeriM (aged: 46.5±1.1 yrs, n = 10), and PostM (aged: 52.2±0.9 yrs, n=10) participated in the study. Sweat was obtained with a sweat suction apparatus from a 120 cm circular area marked on the skin of the face and neck after a 15 min walk on a calibrated treadmill at a speed of 4.2 km/h at 27°C and a relative humidity of 85-95%, followed by measurement of sweat volume (SV) and [K]. Sweat rate (SR) was determined by dividing the volume of sweat produced by the duration of exercise. Thirst perception (TP) was self-rated using the Visual Analogue Scale (VAS). Original Research Article Amabebe et al.; BJMMR, 14(2): 1-10, 2016; Article no.BJMMR.23890 2 Results: The PeriM women demonstrated higher SR (ml/min) (P = .01) and SV (ml) (P = .0006) compared to women in the other groups: SR (PeriM = 0.12±0.01; PreM = 0.07±0.02; PostM = 0.06±0.01), and SV (PeriM = 1.7±0.2; PostM = 0.9±0.1). However, they had lower sweat [K] (mmol/l) (P = .04), compared to their PostM counterparts (PeriM = 19.98±1.5; PostM = 24.90±1.8). Furthermore, sweat [K] was inversely associated with SR (r = -0.4, P = .02). Also, change in TP (cm) was highest (P = .001) in the PeriM women (PeriM = 2.5±0.2; PreM = 2.1±0.3; PostM = 0.99±0.2). Conclusion: Although excessive sweating can lead to depletion of the body's potassium concentration, the sweat potassium concentration decreases with increased sweating especially in perimenopausal women. This requires further investigation, as it could be an adaptive mechanism inhibiting excessive potassium loss.

Determination of components in traditional Chinese medicines associated with promoting or inhibiting urinary stone formation

ObjectiveTo measure oxalate, calcium, and sodium contents of traditional Chinese medicines (TCMs) that are commonly used to prevent and dissolve urinary stones to exclude the possibility that long-term use of such medicines promotes stone formation. The second objective was to measure citrate, potassium, and magnesium contents in the same medicines to provide possible clues about the mechanisms of prevention and dissolution of urinary stones by TCMs. MethodsTen of the most commonly-used TCMs for preventing and dissolving urinary stones were chosen and subjected to ion chromatography (IC) to measure water-soluble and total oxalate and citrate contents. Inductively coupled plasma atomic emission spectrometry (ICP-AES) was used to measure calcium, potassium, magnesium, and sodium contents in a water extract and in digestion liquid. ResultsAverage contents of water-soluble oxalate, calcium, and sodium in the water extract were 41.92, 84.32, and 22.82 mg/100 g, respectively, far below the normal dietary intake of adults in China. The average contents of citrate and magnesium in water extracts were 268.99 and 66.65 mg/100 g, respectively, below the recommended intake for adults. These ion contents are therefore insufficient to inhibit the formation of urinary stones. The average content of potassium in the water extract was 867.71 mg/100 g, which was relatively abundant, so taking the prescription used in this experimental protocol can increase the body's potassium content to some extent. ConclusionsLong-term use of TCMs would not increase the risk of urinary stone formation. The potassium content in TCMs is high, which is one possible reason for the prevention of urinary stones by TCMs.

Quantifying the dietary potassium requirement of subadult grass carp (Ctenopharyngodon idellus)

A growth trial lasting for 12 weeks was conducted in a semi flow-through system to determine the dietary potassium requirement of juvenile grass carp (Ctenopharyngodon idellus) with an initial body weight of 4.8 g. Seven isonitrogenous and isoenergetic semi-purified diets were compounded with different dietary potassium levels: 1.50, 2.32, 3.28, 5.30, 7.12, 9.45 and 10.44 g kg(-1) diet. The results showed that specific growth rate and feed efficiency of grass carp were significantly (P 0.05). The Na+-K+ ATPase activity value in the gills varied significantly (P 0.05). Body potassium and moisture contents increased and lipid content decreased with dietary potassium content, while ash content in fish body increased first and then decreased as potassium content increased (P < 0.05). Body protein in the 10.44 g kg(-1) group was significantly lowered (P < 0.05). However, calcium, magnesium, phosphorus and sodium contents in dry matter were not affected by dietary potassium level. When the potassium content of water was 1.86-3.10 mg L-1, judging from the polynomial regression analysis for the specific growth rate of fish and the Na+-K+ ATPase activity in the gill, and the broken-line analysis for body potassium content, the optimal dietary potassium content for juvenile grass carp was 4.65, 7.27 and 5.98 g kg(-1) diet respectively. (C) 2014 Elsevier B.V. All rights reserved.

Quantifying the dietary potassium requirement of juvenile grass carp (Ctenopharyngodon idellus)

A growth trial lasting for 12 weeks was conducted in a semi flow-through system to determine the dietary potassium requirement of juvenile grass carp (Ctenopharyngodon idellus) with an initial body weight of 4.8 g. Seven isonitrogenous and isoenergetic semi-purified diets were compounded with different dietary potassium levels: 1.50, 2.32, 3.28, 5.30, 7.12, 9.45 and 10.44 g kg(-1) diet. The results showed that specific growth rate and feed efficiency of grass carp were significantly (P 0.05). The Na+-K+ ATPase activity value in the gills varied significantly (P 0.05). Body potassium and moisture contents increased and lipid content decreased with dietary potassium content, while ash content in fish body increased first and then decreased as potassium content increased (P < 0.05). Body protein in the 10.44 g kg(-1) group was significantly lowered (P < 0.05). However, calcium, magnesium, phosphorus and sodium contents in dry matter were not affected by dietary potassium level. When the potassium content of water was 1.86-3.10 mg L-1, judging from the polynomial regression analysis for the specific growth rate of fish and the Na+-K+ ATPase activity in the gill, and the broken-line analysis for body potassium content, the optimal dietary potassium content for juvenile grass carp was 4.65, 7.27 and 5.98 g kg(-1) diet respectively. (C) 2014 Elsevier B.V. All rights reserved.

Estimation of natural potassium concentration in Romanian males by in vivo gamma-ray spectrometry measurements

At the Whole Body Monitoring Laboratory, from IFIN-HH, Bucharest, Romania, there were performed in vivo gamma-ray spectrometry measurements on 108 Romanian males in order to evaluate the mineral natural potassium content in human body, as total value and concentration. The measurements were performed with a shadow shield whole body counter, tilted chair geometry, based on a shielded NaI(Tl) scintillation detector of 12.5 cm (diameter) × 10 cm (height) crystal size. The results revealed a calculated value of the mean total body potassium (TBK) of 135.03 ± 2.94 g and a value of 1.9 ± 0.022 g of potassium/kg of body weight for the mean body potassium concentration, for the measured males. These values are similar with the values declared for the Reference Man, in ICRP23. Correlations between total body potassium, potassium concentration and age, weight and Body Build Index were investigated and peculiar conclusions were resulted.

A comparative study of body potassium content in males and females at Kalpakkam (India)

A group of 300 subjects of both sexes were measured for total body potassium content using a shadow shield whole-body counting system at Kalpakkam (India). The mean body potassium content for males was 1.7 +/- 0.5 g kg(-1) body weight and 1.5 +/- 0.5 g kg(-1) body weight for females. The body potassium content varies inversely with age as well as with the body weight for both the sexes. However, the total body potassium varies directly with body-build index for both males and females. The mean annual dose due to (40)K for males and females was found to be 149 +/- 44 and 132 +/- 41 uGy, respectively.

Effects of seawater potassium concentration on the dietary potassium requirement of Litopenaeus vannamei

Effects of seawater potassium concentration on the dietary potassium requirement of Litopenaeus vannamei were studied under the condition of artificial seawater at salinity 30‰. Three potassium concentrations in the water were set: 332, 156 and 104 mg l − 1 . And the potassium contents of the casein-gelatin-based experimental diets were 1.09%, 1.53%, 2.49% and 3.46%, respectively. The feeding trial lasted for 56 days. Growth, feeding, nutrient retention and feed conversion efficiency of the shrimp were significantly affected by the potassium concentration in the seawater ( P < 0.05), but the dietary potassium levels showed little effect .The final body weight, specific growth rate, protein efficiency ratio and feed conversion efficiency of shrimp exposed to 104 mg l − 1 water potassium level were, respectively, more than 37%, 26%, 25% and 27.5% lower than of those exposed to higher water potassium levels ( P < 0.05). No significant interaction effects were found between seawater potassium concentration and dietary potassium level. Neither seawater potassium concentrations nor dietary potassium levels influenced the body potassium content. It indicated that L. vannamei may have poor ability of assimilating potassium from dietary sources efficiently at salinity 30‰, and dietary supplementation of potassium had limited effect on improving growth of the shrimp while environmental potassium was sufficient.

Development of a foot-to-foot impedancemeter for measuring body composition during exercise

Foot-to-foot impedancemeters (FFI) are cheaper, simpler and quicker to use than medical type impedancemeters. The purpose of this work was to increase the functions of a prototype FFI derived from a commercially available FFI (Tefal Bodymaster Vision ,Rumilly, France) with performing electronics, in order to obtain extracellular (ECW), total body water (TBW) volumes, body cell mass (BCM) and muscle mass in addition to weight and fat-free mass. A modification of the FFI permitted also to use it with hand and feet reusable electrodes. ECW and TBW measurements with the FFI were achieved by comparison with measurements made using a multifrequency medical impedancemeter Hydra 4200 (Xitron Tech, San Diego) and Dual X ray absorptiometry and appropriate modifications of the bioimpedance spectroscopic (BIS) method (1, 2). For BCM and muscle mass, we used Kotler’s and Wang’s methods respectively to relate them to the total body potassium concentration TBK as BCM = 0.0083 TBK, Muscle mass=0.0093 TBK+0.024 Age-3.21 where TBK is expressed in terms of Xcp, the equivalent reactance at 50 kHz, the subject height H, and his weight W. These methods were applied on a group of 52 children: 12 controls did not practice exercise, 20 jogged intermittently and 20 jogged regularly for three months. Changes in all the physiologic parameters listed above during this period as well as improvement in running speed for the three groups were compared and will be reported. With further development, this FFI prototype, which is easy to

Segment-specific resistivity improves body fluid volume estimates from bioimpedance spectroscopy in hemodialysis patients

Discrepancies in body fluid estimates between segmental bioimpedance spectroscopy (SBIS) and gold-standard methods may be due to the use of a uniform value of tissue resistivity to compute extracellular fluid volume (ECV) and intracellular fluid volume (ICV). Discrepancies may also arise from the exclusion of fluid volumes of hands, feet, neck, and head from measurements due to electrode positions. The aim of this study was to define the specific resistivity of various body segments and to use those values for computation of ECV and ICV along with a correction for unmeasured fluid volumes. Twenty-nine maintenance hemodialysis patients (16 men) underwent body composition analysis including whole body MRI, whole body potassium (40K) content, deuterium, and sodium bromide dilution, and segmental and wrist-to-ankle bioimpedance spectroscopy, all performed on the same day before a hemodialysis. Segment-specific resistivity was determined from segmental fat-free mass (FFM; by MRI), hydration status of FFM (by deuterium and sodium bromide), tissue resistance (by SBIS), and segment length. Segmental FFM was higher and extracellular hydration of FFM was lower in men compared with women. Segment-specific resistivity values for arm, trunk, and leg all differed from the uniform resistivity used in traditional SBIS algorithms. Estimates for whole body ECV, ICV, and total body water from SBIS using segmental instead of uniform resistivity values and after adjustment for unmeasured fluid volumes of the body did not differ significantly from gold-standard measures. The uniform tissue resistivity values used in traditional SBIS algorithms result in underestimation of ECV, ICV, and total body water. Use of segmental resistivity values combined with adjustment for body volumes that are neglected by traditional SBIS technique significantly improves estimations of body fluid volume in hemodialysis patients.

Determination of potassium in the skeletal muscles by whole-body counting.

Changes in muscular function are related to nutritional status, disease and physical activity. To study these relationships, it is desirable to be able to determine the whole body potassium content, which is characteristic to the muscular tissue. This can be achieved by measurements in a whole-body counter, identifying contributions from the upper and lower parts of the body. In a whole-body counter with large plastic scintillators, a special measuring methodology is required. Such a method of measuring (40)K in the leg muscles, extracting the part of the detector signal originating from the lower part of the body, has been developed and tested by independent phantom measurements. The results suggest that it is suited to perform regional measurements of body potassium but validation and implementation into clinical research are still necessary.

Monitoring a Hypothetical Channelopathy in Chronic Fatigue Syndrome

This study was aimed at monitoring of a previously suggested channelopathy in Chronic Fatigue Syndrome, and at searching for possible explanations by means of immune system characteristics. Twenty-seven CFS patients and 20 age and sex matched healthy volunteers were recruited. RNase L-ratio, percent of the norm of whole body potassium content, serum electrolytes (sodium, calcium and potassium), immune cells, blood cell count and erythrocyte sedimentation rate were determined. More than fifty percent of our patients presented with abnormal whole body potassium content. Eight patients had increased, while six had depleted potassium content. Discriminant function analysis revealed that the CFS patients and control subjects could be differentiated on immunophenotyping with the predominant cell differences being the increase in CD19+ CD5+ (mature B-) cells and the decrease in CD3-CD16+ CD56+ (NK) cells in both the percentage and count distributions. The fall in NK-cells was very strongly associated with increases in the RNase L-ratio and falls in serum calcium levels. In addition, four patients with low serum calcium levels showed lower whole body potassium levels. In conclusion, these observations suggest a channelopathy in a subset of CFS patients, probably induced by the deregulated 2-5A RNase L antiviral pathway.

Body Composition during the First 2 Years of Life: An Updated Reference

Normative body composition during the first 2 y of life was derived from a prospective study of 76 children. We present 1) fat free mass (FFM) and its components, and fat mass (FM), 2) incremental growth rates partitioned into chemical components, and 3) age-specific and gender-specific constants for converting chemical and physical components into FFM for children during the first 2 y of life. A multicomponent model based on measurements of total body water (TBW), total body potassium (TBK) and bone mineral content (BMC) was used to estimate FFM and FM at 0.5, 3, 6, 9, 12, 18, and 24 mo of age. TBW was determined by deuterium dilution, TBK by whole body counting, and BMC by dual energy x-ray absorptiometry. FFM was higher in boys than girls between 0.5-18 mo of age (p < or = 0.05). Percent FM increased on average from 13 to 31% between 0.5 and 3-6 mo, and then gradually declined. Percent FM was significantly higher in girls than in boys at 6 and 9 mo of age (p < or = 0.02). The components of FFM on a percentage basis changed with age (p = 0.001), but not gender. The protein content of FFM increased gradually with age, while TBW declined (p = 0.001). As a percentage of FFM, osseous mineral increased from 2.0 to 3.4% in boys and from 2.1 to 3.3% in girls between 0.5 and 24 mo (p = 0.001). Density and potassium content of FFM increased gradually with age (p = 0.001). These normative body composition data provide an updated reference upon which to assess normal growth and nutritional status of pediatric populations representative of mixed feeding groups during the first 2 y of life.

Measuring Fat Free Mass and Body Cell Mass in Adolescent Girls with Anorexia Nervosa by Bioelectric Impedance Analysis and Total Body Potassium

An accurate assessment of BCM, the active metabolic component of the body, would provide the dietitian with very useful information for nutritional management of patients. Though BIA, a simple and noninvasive method for estimating body composition, has been shown to be highly correlated with FFM, limited data are available to assess how well BIA estimates BCM in population groups with altered body composition such as patients with anorexia nervosa (AN). The purpose of this study was to determine the level of agreement for FFM and BCM obtained by two body composition measurement techniques, BIA and whole body potassium (40K) counting in patients with AN. Total body potassium (TBK) content was used as the reference method for estimating BCM. In 29 adolescent girls being treated for AN (age 15.4±1.8 y, BMI 16.5±1.8kg/m2), we measured whole body resistance and reactance using BIA at 50kHz and whole body potassium counter on the same day and within the same hour. Mean TBK, and FFM calculated from TBK were 79±12g and 29.7±4.4kg.Estimates of FFM and BCM from BIA were obtained by applying several currently available prediction equations. Estimates of FFM using equations by Davies and Gregory (1991) and Wabitsch et al (1996) were significantly (p<0.0001) correlated with those estimated by TBK (mean 30.0±5.0kg, r=0.67 and mean 31.5±4.2kg, r=0.77, respectively). A good correlation (r=0.75, p<0.000l) was also obtained between measured BCM by TBK (16.S±2.5kg) and predicted BCM from BIA using the equation by Paton et al (1998). The Bland and Altman analysis revealed a small mean difference (−0.1kg of BCM), but large limits of agreement of ±3.9kg. These data suggest that in adolescent girls with AN, BIA may not be a useful clinical tool until equations for estimating BCM are developed for this population.