Energy expenditure/basal metabolic rate ratios in normal and marginally undernourished Colombian children 6-16 years of age

Measurements of basal (BMR) and resting (RMR) metabolic rates, maintenance (MEE) and total daily energy expenditures (TDEE) have been made in Colombian children 6-16 years of age classified as nutritionally normal (boys, n = 129; girls, n = 72) and marginally undernourished (boys, n = 171; girls, n = 74). TDEE/BMR ratios were calculated for comparison with those suggested by FAO/WHO/UNU (1985) and to provide data for children less than 10 years of age. TDEE was measured in free-living, individually calibrated subjects by the heart-rate method. TDEE/BMR increased significantly with age in boys from 1.60 to 1.84 in control subjects and 1.46 to 1.92 in undernourished boys. There was no significant increase with age in the girls. There were no statistically significant differences between nutritional groups but girls had significantly lower values than boys. There was a greater rate of increase in TDEE than BMR with age and girls spent more time in light activities and less in high level activities than boys.     

Patterns of daily energy expenditure in normal and marginally undernourished school-aged Colombian children

Using minute-by-minute heart rate recording, the pattern of energy expenditure (EE), total daily energy expenditure (TDEE) and energy expenditure in activity (EAC) were measured in 132 boys and 110 girls 6-8, 10-12 and 14-16 years of age during ordinary school days. The children were living under economically deprived conditions in Colombia; 70 boys and 59 girls were classified as having marginal malnutrition of sufficient degree to retard growth and sexual maturation. EE, TDEE and EAC increased with age, were in general less in undernourished than control subjects and less in girls than in boys. The age and nutritional group effects were ascribable to differences in lean body mass (LBM). However, the reduced activity in girls was greater than could be accounted for by differences in LBM and are probably the result of cultural pressures. Thus, at the levels of normal activity encountered during school days, the reduced energy expenditure found in undernourished children can be accounted for by differences in body size.     

Basal metabolic rate in children with a solid tumour

OBJECTIVE: To study the level of and changes in basal metabolic rate (BMR) in children with a solid tumour at diagnosis and during treatment in order to provide a more accurate estimate of energy requirements for nutritional support. DESIGN: An observational study. SETTING: Tertiary care at the Centre for Paediatric Oncology, University Hospital Nijmegen. SUBJECTS: Thirteen patients were recruited from a population of patients visiting the University Hospital Nijmegen for treatment. All patients asked to participate took part in and completed the study. INTERVENTION: BMR was measured by indirect calorimetry, under stringent, standardised conditions, for 20 min and on three different occasions in all patients. Continuous breath gas analysis using a mouthpiece was performed. Weight, height and skinfold measurements were performed before each measurement. MAIN OUTCOME MEASURES: BMR was expressed as percentage of the estimated reference value, according to the Schofield formulas based on age, weight and sex, and in kJ (kcal) per kg of fat-free mass. RESULTS: At diagnosis, the BMR was higher than the estimated reference BMR in all patients and 44% of the patients were considered hypermetabolic. Mean BMR (as percentage of reference) was significantly increased (11.6% (s.d. 6.7%); P=0.001), but decreased during treatment in 12 of the 13 patients (mean decrease 12.7% (s.d. 3.9%); P<0.0001). Furthermore, a significant negative correlation (P=-0.67; P=0.01) was found between the change in BMR and tumour response. CONCLUSIONS: These data suggest that the BMR of children with a solid tumour is increased at diagnosis and possibly during the first phase of oncologic treatment. This may be important when determining energy requirements for nutritional support.     

Basal metabolic rate in monozygotic and dizygotic twins

The basal metabolic rate (BMR) was determined in 14 pairs of monozygotic (MZ; 11 females, 3 males) and 12 pairs of dizygotic (DZ; 10 females, 2 males) twins, with mean ages of 22.7 and 26 years. Zygosity was confirmed using DNA fingerprinting. When BMR was expressed as kJ/d, kJ/kg/d and kJ/kg FFM/d significant intra-class correlation coefficients were observed in the MZ twins of 0.82, 0.79 and 0.85, respectively. The DZ twins showed much lower intra-class correlations coefficients of 0.1, 0.07 and -0.04. Although the results of the study suggest a likely genetic component to the variation in BMR, they should be interpreted with caution as heritability estimates vary with the method of calculation. These will be critically discussed in the paper.     

北京市超重和肥胖成人基础代谢率的研究

目的测定北京市超重和肥胖成人基础代谢率(BMR),分析其与体成分的相关性,寻找适合我国超重肥胖人群基础代谢率的估算公式。方法采用间接测热法测定BMR,双能X线吸收法测定体成分,Pearson相关性分析检验BMR和体成分的关系,并将BMR实测值与常用公式估算值进行比较。结果 85名受试者基础代谢的能量消耗,超重组和肥胖组显著高于体重正常组(P0.001),肥胖组显著高于超重组(P=0.036)。超重组和肥胖组受试对象的基础代谢率与瘦体重相关性最强(r=0.865;r=0.784)。BMI正常和肥胖组受试者的脂肪组织质量与BMR无显著相关性,超重受试者的脂肪组织质量与BMR呈显著负相关(r=-0.484)。HENRY公式和LIU公式的BMR估算值与实测值差异2%,差异无统计学意义。结论超重肥胖人群的BMR要高于体重正常健康者。影响超重肥胖人群BMR的最主要因素是瘦体重,脂肪组织对BMR的影响尚不确定。HENRY公式和LIU公式适合我国超重肥胖人群。     

Basal metabolic rate and energy expenditure of pregnant Nigerian women

The purpose of the present study was to compare basal metabolic rates (BMR) of pregnant Nigerian women from rural and urban areas with values from similar studies in other Third World countries. We also investigated possible changes in BMR during the course of pregnancy. An open-circuit indirect calorimeter was used to measure BMR and energy expenditure (EE) during sedentary activity in forty-one pregnant Nigerian women. The results showed marked variability in BMR among individuals. A correlation analysis between BMR and other biological and physical characteristics revealed bodyweight and gestation as the only variables related to BMR and oxygen consumption. The study revealed no significant difference between BMR and EE of sedentary activity in the subjects. The wide variability may have been due to the nutritional status of the subjects studied, who were drawn largely from the lower socioeconomic groups of Nigerian society. The present study shows that socioeconomic status and nutritional interventions should be taken into account when framing recommendations for maternal nutrition during pregnancy.     

Influence of dietary intervention on artificially increased activity in marginally undernourished Colombian boys

Studies of the pattern of daily energy expenditure (EE), total daily energy expenditure (TDEE) and energy expended in activity (EAC) have been carried out in 14 nutritionally normal and 19 marginally malnourished, free-living boys 10-12 years of age using the minute-by-minute heart rate recording technique. Measurements were made during an ordinary school day and again about 6 months later under conditions of a summer day-camp where the activity levels were artificially increased by encouragement to participate in supervised sports activities and play. The morning and afternoon activities were separated by a dietary intervention in the form of a hot meal providing approximately 3.2 MJ (760 kcal). In the morning sessions of the day-camp the undernourished boys did not keep up with the control group by increasing their EE. However, for about 2 h following the noon meal, they did increase EE to levels comparable to the control group but again reduced their EE later in the afternoon and earlier than the control subjects. The data show an inability of undernourished boys to increase their activity which is positively affected for a short period by dietary intervention.     

Basal metabolic rate of Brazilians living in the Southwestern United States

Estimation of energy requirements relies on adequate values of basal metabolic rate (BMR). Prediction equations recommended for international use have been shown to overestimate BMR in populations living in the tropics. We have previously shown the inadequacy of these equations in samples of Brazilians living in tropical and temperate regions of the country. We sought to investigate whether BMR could adequately be estimated by prediction equations in a sample of Brazilians living in a different setting: the Sonoran desert of the Southwestern USA. BMR was measured under standard conditions in 33 subjects (14 men). Mean bias (estimated-measured) varied from 404.4 to 708.6 kJ day(-1) in women and 566.8 to 1122.8 kJ day(-1) in men, representing 8.5-15 and 8.9-17.6% overestimation, respectively, using the Schofield equations. Bland and Altman analyses showed large, relevant limits of agreement. The results using the recommended equations for the American population (IOM, 2005) were only 2% different from the Schofield equations. The Harris and Benedict equations yielded higher overestimations (15.0 and 16.8% for women and men, respectively) and the Henry and Rees equations also overestimated BMR (8.5 and 8.9%) even though they were developed for populations from the tropics, although to a lesser degree. It is concluded that the equations currently recommended for international use are not appropriate for Brazilians living in the Southwestern USA.     

Predicting body composition from anthropometry and bioimpedance in marginally undernourished adolescents and young adults.

Body-composition prediction equations were developed using data from a sample of 201 female and male Guatemalan ladinos (ie, people of Amerindian-European descent) aged 11-25 y. Fat-free mass (FFM) values were estimated from body density by using the two-component model and age- and sex-specific values for the density of FFM. The root-mean-square error (RMSE) of the best model predicting FFM from a set of simple anthropometric variables was 1.59 kg for females and 1.90 kg for males. The addition of more extensive anthropometry to the set of candidate predictors reduced the RMSE to 1.42 kg for females and 1.88 kg for males. The subsequent addition of a bioelectrical impedance measure (Ht2/R) further reduced the RMSE to 1.32 kg for females and 1.82 kg for males. These results suggest that for a marginally undernourished population with relatively little body fat, simple anthropometrics are as useful as more sophisticated measures for the prediction of body composition.     

Basal metabolic rate of Colombian children 2-16 y of age: ethnicity and nutritional status.

Measurements of basal metabolic rate (BMR) were made in 528 children 2-16 y of age living in underprivileged areas of the city of Cali, Colombia (153 control and 186 undernourished boys, 93 control and 96 undernourished girls). The data are related to BMR calculated from the equations of Schofield and to estimates of the lean body mass (LBM). The ethnic composition of the subjects was 80% mestizo (mixed European and South Amerindian ancestry), 15% black, and 5% white. The data do not show any variations due to race in these subjects. The Schofield equations overestimate the BMR of boys by approximately 6% whereas the estimation of BMR in girls is not significantly different from measured values. More than 65% of the variation in BMR of both nutritionally normal and undernourished boys and girls is explained by variation in body size as estimated by the LBM.     

Basal metabolic rate in anorexia nervosa: relation to body composition and leptin concentrations

BACKGROUND: Leptin is thought to represent a peripheral signal involved in the regulation of energy balance. Its action has been studied in animals and obese subjects. Little is known about leptin's role during negative energy balance. OBJECTIVE: The objective was to evaluate the relation between energy turnover, body composition, and plasma leptin concentrations in anorexia nervosa (AN). DESIGN: Sixteen weight-stable women with AN were compared with 22 control subjects and 14 rehabilitated AN patients (R-AN). Basal metabolic rate (BMR) was measured by indirect calorimetry; fat-free mass (FFM) and fat mass (FM) were calculated according to a 4-compartment model. Plasma leptin was determined by radioimmunoassay. RESULTS: The BMR of AN patients (2.73 +/- 0.37 kJ/min) was significantly lower than that of control subjects (3.45 +/- 0.34 kJ/min) (P < 0.001), even after adjustment for FFM (2.92 +/- 0.33 kJ/min in AN patients and 3.30 +/- 0.26 kJ/min in control subjects; P < 0.004). Plasma leptin concentrations in AN patients were 76% lower than in control subjects, even after body fat was controlled for. In R-AN patients, BMR was not significantly different from that of control subjects and leptin concentrations were generally close to normal. Plasma leptin concentrations correlated significantly with FM (r(2) = 0.53, P < 0.0000) and BMR, even after adjustment for FFM (r(2) = 0.21, P < 0.0003). CONCLUSIONS: BMR and plasma leptin concentrations are depressed in patients with AN; this is not explained by body-composition changes. The relation between leptin and BMR suggests that leptin plays a role in the energy sparing response to exposure to chronic energy deficiency. The return of BMR to normal and the significant increase in leptin concentrations in R-AN patients suggests a full reversibility of this adaptation mechanism.     

Reproducibility of resting metabolic rate measurement in children

The aim of the present study was to determine the reproducibility of measurement of resting metabolic rate (RMR) using a ventilated-hood indirect calorimeter in children using a short protocol suitable for the outpatient setting or home visit. The protocol consisted of an overnight (10-12 h) fast, 5-10 min supine rest, 5-10 min 'settling in' under the ventilated hood, and 12-16 min of measurement. Three measurements of RMR were made in eighteen healthy children (nine boys, nine girls, aged 6-11 years) on alternate days. Reproducibility of RMR was assessed using a reproducibility index and by calculating the CV for intra-individual measurements. The mean CV was 2.6 (SD 1.7)% and the reproducibility index was 95.0%, indicating excellent reliability. The short protocol had higher reproducibility than more stringent protocols described in the literature. The new protocol has a number of practical advantages and should be adequate for most clinical or research purposes.     

Reappraisal of the resting metabolic rate of normal young men

The Harris-Benedict (HB) equation, widely used to estimate the resting metabolic rate (RMR), has been disputed by Owen et al who reported that it overestimates the RMR of men aged less than 50 y by approximately 9%. We measured the RMR of 29 healthy, nonsmoking men aged 18-33 y by direct oxygen consumption with a closed-circuit technique similar to that used by Harris and Benedict (respirometer), as well as by a ventilated-hood technique. RMR determined by the ventilated-hood technique was 5.6% lower than when determined by the respirometer (1643 +/- 148 vs 1721 +/- 145 kcal/d, respectively, means +/- SD; P less than 0.001). RMRs by both these methods were lower than the value of 1813 +/- 164 kcal/d predicted by the HB equation; the 95% confidence intervals (CIs) for RMR were 92.4-98.1% (respirometer) and 88.5-91.1% (ventilated hood) of the value predicted by the HB equation. The 95% CI for RMR determined by ventilated hood was 98.4-103.5% of the value predicted by using a new equation proposed by Owen et al. We conclude that the HB equation overestimates RMR by 9.2% in normal young men. This could be due in part to the inherent discomfort experienced by subjects when the original technique was used.     

Don't forget the undernourished children in our midst

Despite the UK's obesogenic environment, undernourished children still exist and need to be identified so that they can receive the nutritional support they require for healthy growth and development. Undernourished children have an impaired immune system that predisposes them to infection and slower recovery, and depletion of their muscle mass can affect functional capacity. The use of the Screening Tool for the Assessment of Malnutrition in Paediatrics (STAMP), a new tool developed at Manchester Children's Hospitals is discussed. This involves a rapid, simple and validated method for ward nurses to identify children at nutritional risk on admission to hospital. Results have been reliable and reproducible when compared to a full nutritional assessment by a registered paediatric dietitian. At-risk children are referred to a paediatric dietitian or nutritional team for dietetic support. Piloting indicated a need for new weighing and measuring equipment and regular calibration to ensure accurate results. Many hospitals rely on old equipment that is not regularly calibrated. STAMP could be extended to other hospitals in the UK and could be adapted as a tool for measuring and assessing undernourished children in the community. However, nurses using it during the pilot scheme were reluctant to plot growth and BMI centile charts and instead relied on using figures supplied by the tool's ready reckoner which they matched to categories of low, medium or high nutritional risk. It can be argued that height and weight assessment of children is the most non-invasive way of assessing health and well-being in a child and that all health care staff should be competent in this task. Few opportunities appear to exist for training, hence the development of an alternative approach by the Infant and Toddler Forum. This takes the form of a self-learning tool to enable health staff to acquire skills and confidence in measuring and in plotting and interpreting growth and BMI centile charts. This tool can be used as part of continuing professional development for health and child care professionals.     

Basal metabolic rate as a proxy for overnight energy expenditure: the effect of age

Recommendations for daily energy requirements use factorial calculations based on BMR. Expressing total energy requirements as a multiple of BMR is based on the assumption that BMR is equal to overnight metabolic rate (OMR). The objective of the present study was to determine if BMR is an appropriate proxy for OMR in children, young adults and elderly. Data are presented of thirty children (11 (SD 2) years), thirty young adults (25 (SD 5) years) and fifty-nine elderly (61 (SD 5) years). OMR was measured in a respiration chamber while sleep was not hindered and BMR was measured directly afterwards with a ventilated hood system under strictly controlled conditions. The mean ratio of OMR:BMR was 0.92 (SD 0.09) for children, which was significantly different from 1.00 (P<0.001), 1.00 (SD 0.07) for young adults and 1.06 (SD 0.09) for elderly which was also different from 1.00 (P<0.001). For adults, BMR is an appropriate measure of OMR. In children, the use of BMR to estimate OMR would introduce an overestimate and for elderly an underestimate.