Deuterium Oxide Dilution Research Articles

Body composition by dilution of deuterium oxide in Mexican children with lymphoma and solid tumors

Objective Scant information exists about the changes in body composition of children during the first months of chemotherapy. These changes can be determined by using a better method than the body mass index. This study compared the changes of body composition by dilution of deuterium oxide in Mexican children with lymphoma and with solid tumors. Methods Seventeen patients were enrolled and classified as having lymphoma or solid tumor. Body composition was measured by a deuterium dilution technique after the first course of chemotherapy and again after 2 and 6 mo of therapy. Data were compared by means of paired t and Student’s t tests. Simple linear regression was applied to examine the relation between age and changes in fat mass (FM) and fat-free mass (FFM). Results The groups were similar at baseline. Six months after initiation of chemotherapy, weight and height had increased ( P < 0.05) in the lymphoma group, whereas only height had increased in the solid-tumor group; total body water, FM, and FFM increased in the lymphoma group ( P < 0.01) but not in the solid-tumor group. Age did not influence FM or FFM in either group. Conclusion In children with lymphoma whose treatment included corticosteroid use, increase in FM content was demonstrated during the first 6 mo of treatment. In patients with solid tumors, FM content did not change during treatment. With an increase in FM content, one should bear in mind that overweight and obesity may result in cardiovascular disease and development of breast cancer in adult life.

Use of bioelectrical impedance analysis to assess body composition in rural Gambian children

To validate the Tanita BC-418MA Segmental Body Composition Analyser and four-site skinfold measurements for the prediction of total body water (TBW), percentage fat-free mass (%FFM) and percentage body fat (%BF) in a population of rural Gambian children. One hundred and thirty-three healthy Gambian children (65 males and 68 females). FFM estimated by the inbuilt equations supplied with the Tanita system was assessed by comparison with deuterium oxide dilution and novel prediction equations were produced. Deuterium oxide dilution was also used to develop equations for %BF based on four-site skinfolds (biceps, triceps, subscapular and suprailiac). The inbuilt equations underestimated FFM compared to deuterium oxide dilution in all the sex and age categories (P<0.003), with greater accuracy in younger children and in males. The best prediction of %FFM was obtained from the variables height, weight, sex, impedance, age and four skinfold thickness measurements (adjusted R(2)=0.84, root mean square error (MSE)=2.07%). These data suggest that the Tanita instrument may be a reliable field assessment technique in African children, when using population and gender-specific equations to convert impedance measurements into estimates of FFM.

Breast Milk Intake Is Not Reduced More by the Introduction of Energy Dense Complementary Food than by Typical Infant Porridge

The effect of different energy densities of complementary foods on breast milk consumption is not well understood. In this study, we tested the hypothesis that provision of fortified spread (FS), a micronutrient fortified, energy-dense (22 kJ/g), ready-to-use food, to Malawian infants would not decrease their breast milk intake more than a traditional corn + soy blended flour (CSB). Forty-four healthy 6-mo-old infant and mother pairs were enrolled in a prospective, parallel group, investigator-blinded, randomized controlled complementary feeding trial. Infants were randomized to receive 25 g/d of FS, 50 g/d of FS, or 72 g/d of CSB. The primary outcome was the difference in breast milk intake after 1 mo of complementary feeding as measured by the dose-to-mother deuterium oxide dilution technique. Outcomes were compared using repeated measures ANOVA. A total of 41 mother-infant pairs completed the study. At enrollment, 88% of the infants had received corn porridge. At baseline, the infants consumed 129 ± 18 g·kg body wt−1·d−1 (mean ± SD) of breast milk. After 1 mo of complementary feeding with 25 g/d FS, 50 g/d FS, or 72 g/d CSB, their breast milk consumption was 115 ± 18 g·kg body wt−1·d−1, a significant reduction; however, the effects of the complementary foods did not differ from one another (F-value model = 4.33, P = 0.0008 for effect of time and P = 0.69 for effect of type of food). The results suggest that complementary feeding of Malawian infants with FS has the same effect on their breast milk intake as complementary feeding with traditional CSB porridge.

Correlation between lean skin water and lean body water during acute dehydration

To determine the relationship between total body water (TBW) and local water content measured in the skin (SW) this study assessed 8 piglets in a dehydration model. Total body water was assessed by deuterium oxide (D2O) dilution throughout the experiments, and by whole body carcass analysis at the end of each experiment. Additionally extracellular water and plasma volume were assessed using bromide dilution and Evan’s blue, respectively. Skin water was assessed by tissue biopsies, taken at 60 min intervals throughout the experiment. Lean body water (LBW) and lean skin water (LSW) were assessed by extracting the fat from the carcass and biopsy samples. A correlation does exist between TBW and SW with r2=0.558 (P<0.05), however, the strongest correlation occurred between LBW and LSW with r2=0.844 (P<0.05) and a standard error of prediction of 0.87%. These data demonstrate that LSW gives an accurate and precise estimate of LBW, and could therefore be used to determine the hydration index in appropriate research settings.

Milk intake and carbon dioxide production of piglets determined with the doubly labelled water technique

The present study was undertaken to study different methodological aspects of quantifying CO2 production and milk intake of suckling piglets using the doubly labelled water (DLW) technique. In total, 37 piglets were enriched intraperitoneally with DLW to study equilibration time of 18O (n = 3), to validate the estimation of milk intake and CO2 production (n = 10) of piglets fed milk replacer and to quantify milk intake and CO2 production of piglets nursed ordinarily by sows (n = 24). Enrichment of 18O in expired air was analysed without any sample preparation, whereas enrichment of 18O in serum was analysed after a minimum step of sample preparation, which included pipetting of the sample, blowing gaseous CO2 into the vial for 3 s and equilibrating for 24 h. The 18O enrichment of CO2 in expired air was constant within 30–40 min of intraperitoneal injection, suggesting that DLW was equilibrated within the body water by that time. For piglets fed milk replacer, the estimation of the daily CO2 production by the DLW method (64.0 ± 2.7 l CO2/day) was in agreement with that obtained by respiration trials (64.7 ± 1.8 l CO2/day). Furthermore, the intake of milk replacer (891 ± 63 g/day) determined by deuterium oxide (D2O) dilution was similar in magnitude to that found by weighing the milk disappearance (910 ± 58 g/day). The milk intake of piglets fed milk replacer was comparable with that of sucking piglets, but sucking piglets had a remarkably higher CO2 production than artificially reared piglets, which likely was caused by a higher intake of milk solids and a higher activity level. For sucking piglets, the daily CO2 production increased curvilinearly with increasing live weight (LW) in kg: piglet CO2 production (l/day) = 25.75 × LW − 1.01 × LW2. In conclusion, 18O equilibrates fast within the body water pool when administered intraperitoneally, and the accuracy of assessing milk intake and rate of CO2 production using the DLW technique is promising. Assessment of excess enrichment of 18O in serum proved to be robust. Finally, the CO2 production of piglets fed milk replacer differs considerably from that of sucking piglets.

Influence of methods used in body composition analysis on the prediction of resting energy expenditure

There are considerable differences in published prediction algorithms for resting energy expenditure (REE) based on fat-free mass (FFM). The aim of the study was to investigate the influence of the methodology of body composition analysis on the prediction of REE from FFM. In a cross-sectional design measurements of REE and body composition were performed. The study population consisted of 50 men (age 37.1+/-15.1 years, body mass index (BMI) 25.9+/-4.1 kg/m2) and 54 women (age 35.3+/-15.4 years, BMI 25.5+/-4.4 kg/m2). REE was measured by indirect calorimetry and predicted by either FFM or body weight. Measurement of FFM was performed by methods based on a 2-compartment (2C)-model: skinfold (SF)-measurement, bioelectrical impedance analysis (BIA), Dual X-ray absorptiometry (DXA), air displacement plethysmography (ADP) and deuterium oxide dilution (D2O). A 4-compartment (4C)-model was used as a reference. When compared with the 4C-model, REE prediction from FFM obtained from the 2C methods were not significantly different. Intercepts of the regression equations of REE prediction by FFM differed from 1231 (FFM(ADP)) to 1645 kJ/24 h (FFM(SF)) and the slopes ranged between 100.3 kJ (FFM(SF)) and 108.1 kJ/FFM (kg) (FFM(ADP)). In a normal range of FFM, REE predicted from FFM by different methods showed only small differences. The variance in REE explained by FFM varied from 69% (FFM(BIA)) to 75% (FFM(DXA)) and was only 46% for body weight. Differences in slopes and intercepts of the regression lines between REE and FFM depended on the methods used for body composition analysis. However, the differences in prediction of REE are small and do not explain the large differences in the results obtained from published FFM-based REE prediction equations and therefore imply a population- and/or investigator specificity of algorithms for REE prediction.

Metabolic consequences of body size and body composition in hemodialysis patients

Small body mass index is associated with increased mortality in chronic hemodialysis patients. The reasons for this observation are unclear but may be related to body composition. This study aimed to investigate the body composition in chronic hemodialysis patients. The difference between body mass and the sum of muscle, bone, subcutaneous, and visceral adipose tissue masses, measured by whole body magnetic resonance imaging, was defined as the high metabolic rate compartment representing the visceral mass. Protein catabolic rate was calculated from urea kinetics. Forty chronic hemodialysis patients (mean age 54.7 years; 87.5% African Americans; 45% females) were studied. High metabolic rate compartment expressed in percent of body weight was inversely related to body weight (r=-0.475; P=0.002) and body mass index (r=-0.530; P<0.001). In a multiple linear regression model, protein catabolic rate was significantly correlated only with high metabolic rate compartment (r=0.616; P<0.001). Assuming that protein catabolic rate in addition to protein intake reflects urea and uremic toxin generation, it follows that high metabolic rate compartment is the major compartment involved in their generation. Consequently, uremic toxin production rate may be relatively higher in patients with low body weight and low body mass index as compared to their heavier counterparts. The poorer survival observed in smaller dialysis patients may be related to these relative differences.

A novel method to determine lean body water using localized skin biopsies: correlation between lean skin water and lean body water in an overhydration model

To determine the relationship between total body water (TBW) fraction and local water content measured in the skin (SW) this study assessed eight anesthetized piglets in an overhydration model. TBW was assessed by deuterium oxide dilution and body mass measurements taken throughout the experiments, and by whole body carcass analysis at the end of each experiment. Additionally, extracellular water and plasma volume were assessed using bromide dilution and Evan's blue dilution, respectively. SW was assessed by tissue biopsies taken at 60-min intervals throughout the experiment. Lean body water (LBW) fraction and lean skin water (LSW) fraction were assessed by extracting the fat from the carcass and biopsy samples. A correlation does exist between TBW fraction and SW fraction with r2=0.58 (P<0.05); however, the strongest correlation occurred between the LBW fraction and LSW fraction with r2=0.87 (P<0.05) and an SE of prediction of 0.77%. These data demonstrate that LSW gives an accurate and precise estimate of LBW and could therefore be used to determine the hydration index in appropriate research settings.

A novel method to determine lean body water using localized skin biopsies: correlation between lean skin water and lean body water in an over‐hydration model

To determine the relationship between total body water (TBW) and local water content measured in the skin (SW) this study assessed 8 piglets in an over-hydration model. Total body water was assessed by deuterium oxide (D2O) dilution throughout the experiments, and by whole body carcass analysis at the end of each experiment. Additionally extracellular water and plasma volume were assessed using bromide dilution and Evan's blue, respectively. Skin water was assessed by tissue biopsies, taken at 60 min intervals throughout the experiment. Lean body water (LBW) and lean skin water (LSW) were assessed by extracting the fat from the carcass and biopsy samples. A correlation does exist between TBW and SW with r2=0.585 (P<0.05), however, the strongest correlation occurred between LBW and LSW with r2=0.8653 (P<0.05) and a standard error of prediction of 0.77%. These data demonstrate that LSW gives and accurate and precise estimate of LBW, and could therefore be used to determine the hydration index in appropriate research settings.

Estimation of total body water from foot‐to‐foot bioelectrical impedance analysis in patients with cancer cachexia – agreement between three prediction methods and deuterium oxide dilution

Bioelectrical impedance analysis (BIA) is a useful bedside measure to estimate total body water (TBW). The aim of this study was to determine the agreement between three equations for the prediction of TBW using BIA against the criterion method, deuterium oxide dilution, in patients with cancer cachexia. Eighteen measurements of TBW using foot-to-foot BIA in seven outpatients with cancer cachexia (five male and two female, age 56.4 +/- 6.7 years) at an Australian hospital. Three prediction formulae were used to estimate TBW - TBW(ca-radiotherapy) developed in patients with cancer undergoing radiotherapy, TBW(ca-underweight) and TBW(ca-normal weight) developed in underweight and normal weight patients with cachexia. TBW was measured using the deuterium oxide dilution technique as the gold standard. Mean measured TBW was 39.5 +/- 6.0 L. There was no significant difference in measured TBW and estimates from prediction equations TBW(ca-underweight) and TBW(ca-radiotherapy). There was a significant difference in measured TBW and TBW(ca-normal weight). All prediction equations overestimated TBW in comparison with measured TBW. The smallest bias was observed with TBW(ca-underweight) (0.38 L). The limits of agreement are wide (>7.4 L) for each of the prediction equations compared with measured TBW. At a group level, TBW(ca-underweight) is the best predictor of measured TBW in patients with cancer cachexia. For an individual however, the limits of agreement are wide for all prediction equations and are unsuitable for use. Practitioners need to be aware of the limitations of using TBW prediction equations for individuals.

Body fat measurement in Indian men: comparison of three methods based on a two-compartment model

Obesity is a major risk factor for diabetes and related disorders. The current classification of obesity is based on body mass index (BMI, kg/m(2)), which is a surrogate for the total body fat. Since the relationship between BMI and body fat varies in different populations, an independent validation of the BMI-body fat relationship in the population of interest is desirable. (1) To study the validity of field methods of measuring body fat (multiple skinfolds and bioimpedance) against a criterion method (deuterium dilution) and (2) To compare the prevalence of obesity (WHO 2000 criteria for BMI) with adiposity (body fat >25%) in middle-aged Indian men in rural and urban Pune. Community-based multistage stratified random sampling of middle-aged men from rural and urban Pune for study of body composition and cardiovascular risk. A third of these men, selected to represent wide BMI distribution, were studied for body fat measurements by specific methods. A total of 141 healthy men, approximately similar number from rural, urban slums and middle class from Pune. They were 39.3 (+/-6.2) y old and had a BMI of 21.9 (+/-3.7) kg/m(2). Anthropometry (height, weight and multiple skinfold thicknesses) by trained observers using standardised technique to calculate body fat by Durnin and Womersley's equation. Total body water and body fat by bioelectrical impedance analysis (BIA) and deuterium oxide dilution (D(2)O). Mean total body fat was 14.3 kg (23.0%) by anthropometry, 16.5 kg (26.0%) by BIA and 15.3 kg (24.6%) by D(2)O method. Although there was a good correlation between fat estimation by three methods (r= approximately 0.9, P<0.001 all), compared to D(2)O method anthropometry underestimated body fat by 1.0 kg and BIA overestimated fat by 1.2 kg (P<0.001 both). Using the standard cut-point of 25% body fat for 'adiposity' 29.5% rural, 46.0% slum and 75.0% middle class men were adipose. These proportions were considerably higher than the number of men who were 'preobese' (BMI> or =25-29.9 kg/m(2), 9.0% rural, 22.0% urban slums and 27.0% urban middle class) and 'obese' (BMI >30 kg/m(2), 4.0% urban slums, none in rural and urban middle class). We recommend that future studies assessing risk for chronic diseases in Indians should measure adiposity by anthropometry (multiple skinfolds) or BIA (calibrated for Indians) rather than relying only on BMI cut-points.

The Effect of Normalization of Ecw Volume as a Marker of Hydration in Peritoneal Dialysis Patients and Controls

We measured extraceLlular water (ECW) and intracellular water (ICW) volumes in peritoneal dialysis (PD) patients and controls to determine the effect of ICW variation on ECW/ICW ratio and to compare alternative ratios of ECW to height, height2, weight, and body surface area (BSA). We measured body water compartments by deuterium oxide and bromide dilution in 29 PD patients (14 M, 15 F) and 31 controls (15 M, 16 F). ECW was similar in PD patients (17.58 +/- 3.58 L) and controls (17.20 +/- 2.97 L), p = NS. ICW was nonsignificantly lowerin PD patients (17.58 +/- 4.88 L) than in controls (19.71 +/- 5.08 L), p = NS. ECW/ICW was greaterin PD patients (1.06 +/- 0.32) than in controls (0.92 +/- 0.25), p = 0.057, and was inversely correlated with ICW in PD patients (r = -0.733, p < 0.0001) and controls (r = -0.721, p < 0.0001). In contrast, ECW/height, ECW/height2, ECW/weight, and ECW/BSA were similar for the two groups. ECW/ICW is affected by changes in ICW as well as by ECW varying with hydration. ECW/ICW ratio leads to the spurious impression of overhydration in subjects with smaller ICW volumes. ECW/ICW does not reflect hydration alone and other methods of expressing ECW as a measure of hydration need further evaluation.

COMPUTED TOMOGRAPHIC ASSESSMENT OF BODY FAT IN BEAGLES

Obesity is the most common nutritional disorder in small animals. To establish a computed tomographic (CT) method for assessment of visceral and subcutaneous fat content in the dog, CT analysis was performed in normal and obese beagles. Fat area was measured by the level detection method at varied attenuation ranges and compared with body fat content estimated by the deuterium oxide dilution method. Fat area measured at L3 using the attenuation range of -135/-105 Hounsfield unit had the best correlation with body fat content (r = 0.98). Regional fat distribution was almost the same between normal and obese dogs, with more fat accumulation at L1-S1 than T10-T13. Moreover, visceral and subcutaneous fat area could be estimated separately. This CT method may contribute to both the clinical diagnosis and the study of canine obesity, especially for studies in the relationship between body fat distribution and obesity-associated diseases.

Total body water in children with cystic fibrosis using bioelectrical impedance

Background The aim of this study was to assess the ability of commercially available single frequency bioelectrical impedance analysis (BIA) to predict total body water and hence body composition in a cohort of children with cystic fibrosis (CF). Methods In 56 (31 girls, 25 boys) children aged 4 to 18 years, total body water was predicted using BIA and measured using a deuterium oxide dilution technique. Each child provided a urine sample before consuming 0.5 g/kg body weight 10% deuterium oxide. A further urine sample was collected between 4 and 6 h later. Results There was a mean bias between predicted and measured total body water of 1.1 L. The bias was consistent across the range of total body water measured in this study. The relationship between height 2/impedance and measured total body water was TBW=0.35+0.74*height 2/impedance. This equation is similar to other equations found in healthy children. Conclusion We have shown that a commercially available bioelectrical device underestimates measured total body water. We have generated a prediction equation for the population studied, which we believe might enhance the accuracy of the method in children with cystic fibrosis.

Comparison of water turnover rates in young swimmers in training and age-matched non-training individuals.

Total body water (TBW) and water turnover rates (WTR) of 8 competitive swimmers (SW) and 6 age-matched non-training individuals (CON) were determined using deuterium oxide dilution and elimination. During the 7-day study, individuals in the SW group trained 9 times, swimming on average 42.4 km, while the CON group did no regular exercise. Water temperature in the swimming pool was between 26 and 29 degrees C during training sessions. Body mass at the beginning and end of the study period remained essentially the same in the SW (67.8+/- 6.3 kg) and CON (61.1 +/- 8.5 kg) groups. Mean +/- SD TBW of the SW (38.7+/- 5.6 L) was similar to that of the CON (37.5 +/- 8.0 L). Mean WTR was faster in the SW (54 +/- 18 ml x kg x day(- 1) than the CON (28+/- 21 ml x kg x day(-1)). Mean daily urine output was similar in the SW (14 +/- 5 ml x kg x day(-1)) and CON (14+/- 3 ml x kg x day(-1)). Calculated non-renal daily water loss was faster in the SW (41 +/- 21 ml x kg x day(-1)) than the CON (13 +/- 20 ml x kg x day(-1)). This study demonstrates that WTR are faster in young swimmers who exercise strenuously in cool water than in non-training individuals and that the difference was due to the approximately 3-times greater non-renal water losses that the exercising group incurred. This suggests that exercise-induced increases in sweat rates are a major factor in water loss in swimmers training in cool water.

Estimation of colostrum intake in the neonatal pig

AbstractThree trials were performed in order to establish a method of estimation of colostrum intake based on weight gain in newborn pigs. The first trial involved 33 piglets, bottle-fed with sow colostrum and weighed regularly for 25 h. A regression equation relating colostrum intake (CI in g) to birth weight (BWB in kg), weight at CI estimation (BW in kg), age at first suck (tFS in min) and duration of colostrum intake (t in min and with 17 h &lt; t &lt; 25 h) was established with a root mean-square error equal to 33 g. This equation was evaluated with a second data set using 15 further bottle-fed piglets (trial 2). Measured and predicted values were very close (R2 = 0.90). The third trial compared colostrum intake estimated either with the previous equation or with the deuterium oxide dilution method in catheterized sow-reared or bottle-fed piglets (no. = 12 per group). The equation underestimated colostrum intake of those piglets, probably due to prior surgery. However, the feeding method (bottle-feeding v. sow-rearing) had no effect on the relationship between weight gain and colostrum intake. Therefore, the equation established in bottle-fed piglets may be applied to sow-reared piglets.

Energy and protein metabolism in lactating sows fed two levels of dietary fat

The effect of feeding lactating sows with low (LF) or high (HF) dietary fat level (31 vs. 113 g crude fat per kg DM) was studied. Four sows on each diet were subjected to three balance and respiration experiments in weeks 2–4 of lactation. The contribution of piglet heat production (HE) to overall HE of sow and piglets (measured by indirect calorimetry) was measured by the doubly labelled water (DLW) technique in three piglets per litter. The nitrogen balance of the sow decreased with progress of lactation, with no dietary effect. Milk production, estimated by deuterium oxide (D 2O) dilution in DLW enriched piglets, increased ( P<0.001) from 7.69 (week 2) to 10.64 kg/day (week 4). Sow HE was constant throughout lactation (686 kJ/kg 0.75 per day) in spite of increased feed intake and milk production. Oxidation of protein constituted 13% of HE in both groups, while oxidation of carbohydrates and fat constituted 84% and 2% for LF sows and 80% and 7% for HF sows, respectively. The present study suggests that the dietary treatments did not affect milk production, milk fat content or the energy mobilisation of the sow. The maintenance requirement of metabolisable energy (ME) amounted to 482 kJ/kg 0.75 per day. It was concluded that the milk production was limited by the energy supply and that the efficiency for utilisation of dietary ME for milk production increased as lactation progressed.

Abnormalities of Body Composition in Peritoneal Dialysis Patients

Body composition changes occur in peritoneal dialysis (PD) due to abnormalities in nutrition and hydration. We investigated abnormalities of nutrition and hydration in PD patients compared with healthy controls by measurement of total body potassium (TBK) and body water compartments. Cross-sectional comparison study. We measured TBK--an indicator of body cell mass--by whole body counting, total body water (TBW) by deuterium oxide dilution, and extracellular water (ECW) by bromide dilution in 29 PD patients and 32 controls. The absolute mean value of TBK for PD patients was not significantly lower than in controls. The ratios of observed TBK to predicted TBK from prediction formulas were compared. Equations used were those of Boddy, Bruce, Burkinshaw, and Ellis and our own equation derived from a local control database (Leeds). Observed/predicted ratios of TBK were significantly less in PD than in control subjects for all equations. Water volumes did not differ between PD and control groups. Observed/predicted ratios for TBK in PD patients correlated with serum potassium (Boddy r = 0.355, p = 0.06; Bruce r = 0.411, p < 0.05; Burkinshaw r = 0.457, p < 0.01; Leeds r = 0.412, p < or = 0.05; Ellis r = 0.356, p = 0.06) and tended to correlate with serum albumin (Bruce r = 0.343, p = 0.07; Burkinshaw r = 0.421, p < 0.05; Leeds r = 0.357, p = 0.06; Ellis r = 0.310, p = NS). There was no relationship with serum potassium in controls. Serum albumin in PD correlated with TBK (r = 0.445, p < 0.02), TBK/height (r = 0.419, p < 0.05), TBK/weight (r = 0.554, p = 0.002), and TBK/TBW (r = 0.586, p = 0.0001). Extracellular water/intracellular water (ECW/ICW) was inversely related to TBK (r = -0.455, p < 0.02 in PD; r = -0.387, p < 0.05 in controls) and to TBK/height (r = -0.446, p < 0.02 in PD; r = -0.411, p = 0.02 in controls). TBK/weight reduced with age in PD (r = -0.445, p < 0.02), as did TBK/TBW in PD (r = -0.463, p < 0.02). ECW/ICW tended to increase with age in PD (r = 0.351, p = 0.06). Observed/predicted ratio of TBK is reduced in PD patients relative to healthy controls, indicating reduced body cell mass. Serum albumin and potassium reflect TBK indices in PD. Body water volumes did not differ between PD and controls, implying no overall abnormality in hydration in the PD group. However, ECW is relatively increased compared to ICW with decreasing TBK indices, suggesting relative ECW expansion with reduction in body cell mass.

Assessment of body composition in lactating mothers in a rural African community using deuterium oxide

Background and objective. The deuterium oxide (DO) dilution method for measuring body composition was validated against the widely used skinfold (SF) measurement-based equation of Durnin and Womersley. The study involved 10 lactating women living in a rural community in Nandi, Kenya and participating in a cross-sectional study aimed at determining their iron and vitamin A status.Methods. The selection criteria were exclusive breast-feeding, infants between 2 and 4 months of age, maternal parity < 4, birth weight more than 2 500 g and no congenital abnormalities. Maternal and infant anthropometric measurements were taken. DO (approximately 0.1 g 2H2O/kg body water) was given orally to each mother accordingly to the Maastricht protocol (DO) for total body water (TBW) determination. The 2H enrichment of the urine was measured using gas-isotope-ratio mass spectrometry. Blood samples were collected. Serum retinol and ferritin were determined using high- performance liquid chromatography (HPLC) and enzyme-linked immunosorbent assay (ELISA) respectively. Body mass index (BMI) was determined as weight/height (m2). The Bland-Altman pair-wise comparison was used to compare maternal fat-free mass (FFM), body fat (BF) and percentage body fat (% BF) that were determined based on the DO and SF techniques.Results. Maternal mean (± standard deviation (SD)) for parity, age, BMI, haemoglobin (Hb), serum ferritin and serum retinol were 3 (2), 26 (4) years, 23.4 (4), 12.1 (1.8) g/dl, 10.3 (4.0) µg/l and 0.696 (0.300) µmol/l respectively. The FFM, BF and % BF accordingly to the DO and SF methods respectively were 44.0 (4.7) kg v. 42.9 (5.9) kg, 16.7 (8.8) kg v. 17.8 (7.5) kg and 26.2 (8.1)% v. 28.4 (6.4)%. Limits of agreement for underestimation of FFM and % BF were 4.4 kg (SEE 3.4) and 11.6% (SEE 5.8) respectively. Bias in the measurement of FFM and % BF was 1.1 kg (SEE 1.9), and —2.2% (SEE 3.3) respectively.Conclusion. The variability (5.8 - 17.5%) observed in the SF technique may result in lower prediction of % BF. This may be an important factor for community-based nutritional interventions that aim at improving the body composition of vulnerable groups such as pregnant and lactating women or subjectswith severe undernutrition.

Comparison of Various Methods for Estimating Body Fat in Dogs

Obesity is considered one of the most common forms of malnutrition occurring in dogs. Laboratory methods of evaluation of body composition in live dogs have included dual-energy X-ray absorptiometry (DEXA) and deuterium oxide (D(2)O) dilution. Clinical methods of evaluation include assigning a body condition score (BCS) based on visual observation, palpation, and morphometric measurements. This study used these four methods to evaluate 23 healthy, adult, client-owned dogs. Good correlation (coefficient of determination [r(2)]=0.78) was found between measurements of percent body fat (%BF) determined by the D(2)O dilution method and the DEXA scan. Percent body fat can also be estimated using BCS (r(2)=0.92 comparison with DEXA) or by using morphometric measurements with simple calculations (r(2)=0.92 comparison with DEXA).