Human resting energy expenditure in relation to dietary potassium

This study investigates the putative effect of potassium on energy expenditure. Eight young adult men were submitted to two different normocaloric mixed diets in a randomized order, containing either 163 +/- 9 or 69 +/- 2 mmol potassium/d. On the fifth day of each diet, after an overnight fast, resting metabolic rate (RMR) was measured over a 1-h period. After these measurements, either a potassium load (50 mmol) or a placebo were given to subjects submitted to the low- or the high-potassium diet, respectively. RMR was then measured again for 3 h and the last hour was kept for further analysis. Results showed that acute and chronic variations in potassium intake do not induce significant changes in RMR, and chronic but not acute changes in serum potassium concentration were significantly correlated with changes in energy expenditure (r = 0.74, P less than 0.05) by mechanisms that remain to be elucidated.     

Racial differences in energy expenditure and aerobic fitness in premenopausal women

BACKGROUND: Aerobic fitness, or maximal oxygen uptake (f1.gif" BORDER="0">O(2)max), and energy expenditure (EE) may be lower in African Americans than in whites. OBJECTIVE: The objective of this study was to compare sleeping EE (SEE), resting EE (REE), free-living total EE (TEE), and f1.gif" BORDER="0">O(2)max in African American and white women after adjustment for body composition and free-living activity-related energy expenditure (AEE). DESIGN: Eighteen African American and 17 white premenopausal women were matched for weight, percentage body fat, and age. SEE and REE were measured in a room calorimeter and f1.gif" BORDER="0">O(2)max was measured on a treadmill. Fat-free mass (FFM) and fat mass (FM) (4-compartment model), AEE (doubly labeled water and SEE), and regional lean tissue (dual-energy X-ray absorptiometry) were used as adjustment variables in SEE, REE, TEE, and f1.gif" BORDER="0">O(2)max comparisons. RESULTS: The African American women had significantly more limb lean tissue and significantly less trunk lean tissue than did the white women. The African American women also had significantly lower SEE (6.9%), REE (7.5%), TEE (9.6%), and f1.gif" BORDER="0">O(2)max (13.4%) than did the white women. Racial differences persisted after adjustment for f1.gif" BORDER="0">O(2)max, AEE, FFM, and limb lean tissue but disappeared after adjustment for trunk lean tissue. The f1.gif" BORDER="0">O(2)max difference was independent of all body-composition variables and of AEE. CONCLUSIONS: African American women had lower aerobic fitness than did white women, independent of differences in lean tissue or AEE. Diminished racial differences in SEE, REE, and TEE after adjustment for trunk lean tissue suggest that low EE in African American women is mediated by low volumes of metabolically active organ mass.     

Sex differences in resting energy expenditure and their relation to insulin resistance in children (EarlyBird 13)

BACKGROUND: Insulin resistance is believed to be the process underlying type 2 diabetes and premature cardiovascular disease. We have established that a relation between body mass and insulin resistance calculated by homeostasis model assessment (HOMA-IR) exists by 5 y of age in contemporary UK children. Resting energy expenditure (REE) is variable among individuals and is one of many factors controlling body mass. OBJECTIVE: The objective was to investigate the relations between REE, body mass, and HOMA-IR in young children. DESIGN: EarlyBird is a nonintervention prospective cohort study of 307 healthy 5-y-olds that asks the question: Which children develop insulin resistance and why? REE by indirect calorimetry and HOMA-IR were measured in addition to total body mass, fat-free mass (FFM) by bioimpedance, body mass index (BMI; in kg/m(2)), and skinfold thickness when the mean age of the cohort was 5.9 +/- 0.2 y. RESULTS: Whereas the BMI of the boys was lower than that of the girls (x +/- SD: boys, 15.9 +/- 1.9; girls, 16.5 +/- 1.9; P = 0.03), their REE was higher by 6% (x +/- SD: 4724 +/- 615 compared with 4469 +/- 531 kJ/d; P = 0.002). This difference persisted after adjustment for FFM and other anthropometric variables (P = 0.04). In boys, there was a weak, although significant, inverse correlation between REE and HOMA-IR, independent of fat mass and FFM (boys: r = -0.21, P = 0.03; girls: r = 0.12, P = 0.34). CONCLUSION: There is a sex difference in REE at 6 y of age that cannot be explained by body composition. The difference appears to be intrinsic, and its contribution to sex differences in adiposity and HOMA-IR in children merits further exploration.     

Associations between uncoupling protein 2, body composition, and resting energy expenditure in lean and obese African American, white, and Asian children

BACKGROUND: Little is known about genes that affect childhood body weight. OBJECTIVE: The objective of this study was to examine the association between alleles of the mitochondrial uncoupling protein 2 (UCP2) gene and obesity because UCP2 may influence energy expenditure. DESIGN: We related UCP2 genotype to body composition and resting energy expenditure in 105 children aged 6-10 y. Overweight children and nonoverweight children of overweight parents were genotyped for a 45-base pair deletion/insertion (del/ins) in 3'-untranslated region of exon 8 and for an exon 4 C to T transition. RESULTS: Eighty-nine children were genotyped for the exon 8 allele: 50 children had del/del, 33 had del/ins, and 6 had ins/ins. Mean (+/-SD) body mass index (BMI; in kg/m(2)) was greater for children with del/ins (24.1 +/- 5.9) than for children with del/del (20.4 +/- 4.8; P < 0.001). BMI of ins/ins children (23.7 +/- 7.8) was not significantly different from that of del/ins children. A greater BMI in del/ins children was independent of race and sex. Body composition was also different according to UCP2 genotype. All body circumferences and skinfold thicknesses examined were significantly greater in del/ins than in del/del children. Body fat mass as determined by dual-energy X-ray absorptiometry was also greater in del/ins than in del/del children (P < 0.005). For 104 children genotyped at exon 4, no significant differences in BMI or body composition were found among the 3 exon 4 genotypes. Neither resting energy expenditure nor respiratory quotient were different according to UCP2 exon 4 or exon 8 genotype. CONCLUSIONS: The exon 8 ins/del polymorphism of UCP2 appears to be associated with childhood-onset obesity. The UCP2/UCP3 genetic locus may play a role in childhood body weight.     

Body-composition differences between African American and white women: relation to resting energy requirements

BACKGROUND: Body composition differs between African American (AA) and white women, and the resting metabolic rate (RMR) is likely to be lower in AA women than in white women. OBJECTIVE: We tested 2 hypotheses: that AA women have a greater proportion of low-metabolic-rate skeletal muscle (SM) and bone than do white women and that between-race musculoskeletal differences are a function of body weight. DESIGN: Hypothesis 1 was tested by comparing SM, bone, adipose tissue, and high-metabolic-rate residual mass across 22 pairs of matched AA and white women. Magnetic resonance imaging and dual-energy X-ray absorptiometry were used to partition weight into 4 components, and RMR was both calculated from tissue-organ mass and measured. Hypothesis 2 was evaluated by measuring SM, bone, fat, and residual mass in 521 AA and white women with the use of dual-energy X-ray absorptiometry alone. RESULTS: Hypothesis 1: AA women had greater SM ( +/- SD group difference: 1.52 +/- 2.48 kg; P < 0.01) and musculoskeletal mass (1.72 +/- 2.66 kg; P < 0.01) than did white women. RMR calculated from body composition and measured RMR did not differ; RMR estimated by both approaches tended to be lower (approximately 160 kJ/d) in AA women than in white women. Hypothesis 2: SM was significantly correlated with weight, height, age, and race x weight interaction; greater SM in the AA women was a function of body weight. CONCLUSIONS: Lower RMRs in AA women than in white women are related to corresponding differences in the proportions of heat-producing tissues and organs, and these race-related body-composition differences increase as a function of body weight.     

Whole-body protein turnover and resting energy expenditure in obese, prepubertal children

BACKGROUND: Obesity is becoming more frequent in children; understanding the extent to which this condition affects not only carbohydrate and lipid metabolism but also protein metabolism is of paramount importance. OBJECTIVE: We evaluated the kinetics of protein metabolism in obese, prepubertal children in the static phase of obesity. DESIGN: In this cross-sectional study, 9 obese children (x +/- SE: 44+/-4 kg, 30.9+/-1.5% body fat) were compared with 8 lean (28+/-2 kg ,16.8+/-1.2% body fat), age-matched (8.5+/-0.2 y) control children. Whole-body nitrogen flux, protein synthesis, and protein breakdown were calculated postprandially over 9 h from 15N abundance in urinary ammonia by using a single oral dose of [15N]glycine; resting energy expenditure (REE) was assessed by indirect calorimetry (canopy) and body composition by multiple skinfold-thickness measurements. RESULTS: Absolute rates of protein synthesis and breakdown were significantly greater in obese children than in control children (x +/- SE: 208+/-24 compared with 137+/-14 g/d, P < 0.05, and 149+/-20 compared with 89+/-13 g/d, P < 0.05, respectively). When these variables were adjusted for fat-free mass by analysis of covariance, however, the differences between groups disappeared. There was a significant relation between protein synthesis and fat-free mass (r = 0.83, P < 0.001) as well as between protein synthesis and REE (r = 0.79, P < 0.005). CONCLUSIONS: Obesity in prepubertal children is associated with an absolute increase in whole-body protein turnover that is consistent with an absolute increase in fat-free mass, both of which contribute to explaining the greater absolute REE in obese children than in control children.     

Respiration uncoupling and metabolism in the control of energy expenditure

Metabolic energy expenditure negatively regulates energy balance. Metabolic and catabolic pathways contribute to energy expenditure. Catabolic pathways split C-containing molecules into small molecules and generate reduced coenzymes and ATP. For a given amount of substrate, any increase in energy expenditure requires either increased ATP hydrolysis or decreased ATP synthesis. In skeletal muscles substrate utilisation is coupled to ATP production, whereas ATP hydrolysis is activated during physical exercise and increases energy expenditure. In brown adipose tissue activation of cells during exposure to cold increases substrate utilisation in such a way that glucose and fatty acid oxidation detach from the orthodox coupling to ATP synthesis and result in thermogenesis. The unique mechanism of uncoupling respiration that occurs in brown adipocyte mitochondria represents an attractive strategy for promoting energy expenditure and decreasing the fat content of the body. Moreover, ectopic expression of brown fat uncoupling protein (UCP) 1 in mouse skeletal muscle and induction of UCP1 in mouse or human white adipocytes promote fatty acid oxidation and resistance to obesity. In normal conditions UCP2 and UCP3 do not seem to contribute substantially to energy expenditure. Whether the induction of UCP1, the induction of other UCP or chemical mild uncoupling represent promising strategies for attenuating nutrient efficiency and counteracting obesity should be considered.     

Relationship between blood adipocytokines and resting energy expenditure in young and elderly women

It has been demonstrated in a previous study that resting energy expenditure (REE) is associated with adiponectin levels in the blood. However, body composition was not taken into consideration in that study. The purpose of the present study was to again investigate the relationship between blood adipocytokines and REE, adjusted by body composition, in both young and elderly women. REE and blood adipocytokines were measured in 115 young (age: 22.3+/-2.1 y, BMI: 21.3+/-1.9 kg/m(2)) and 71 elderly (63.4+/-6.5 y, 22.9+/- 2.3 kg/m(2)) women. Dual energy X-ray absorptiometry was used to measure percent body fat. Fat mass and fat free mass (FFM) were calculated. REE (kcal/d and kcal/kg BW/d) was lower in elderly women than in young women, but no significant difference was observed in REE, expressed as kcal/kg FFM/d, between the two groups. Although elderly women had a higher percent body fat and higher serum leptin concentrations than young women, plasma adiponectin concentrations did not differ between young and elderly women. In elderly women, REE (kcal/d) was significantly and inversely correlated with plasma adiponectin concentration (r=-0.386, p<0.001), but REE expressed per kilogram of BW or FFM was not significantly correlated. Furthermore, no significant correlation was observed between REE (kcal/d) and concentrations of plasma adiponectin or serum leptin, after adjusting for potential confounders such as body composition and hormones, in either age group. These results suggest that adipocytokines do not influence REE in adult women.     

Intra- and interindividual variability of resting energy expenditure in healthy male subjects -- biological and methodological variability of resting energy expenditure

The objective of the present study was to investigate the contribution of intra-individual variance of resting energy expenditure (REE) to interindividual variance in REE. REE was measured longitudinally in a sample of twenty-three healthy men using indirect calorimetry. Over a period of 2 months, two consecutive measurements were done in the whole group. In subgroups of seventeen and eleven subjects, three and four consecutive measurements were performed over a period of 6 months. Data analysis followed a standard protocol considering the last 15 min of each measurement period and alternatively an optimised protocol with strict inclusion criteria. Intra-individual variance in REE and body composition measurements (CV(intra)) as well as interindividual variance (CV(inter)) were calculated and compared with each other as well as with REE prediction from a population-specific formula. Mean CV(intra) for measured REE and fat-free mass (FFM) ranged from 5.0 to 5.6 % and from 1.3 to 1.6 %, respectively. CV(intra) did not change with the number of repeated measurements or the type of protocol (standard v. optimised protocol). CV(inter) for REE and REE adjusted for FFM (REE(adj)) ranged from 12.1 to 16.1 % and from 10.4 to 13.6 %, respectively. We calculated total error to be 8 %. Variance in body composition (CV(intra) FFM) explains 19 % of the variability in REE(adj), whereas the remaining 81 % is explained by the variability of the metabolic rate (CV(intra) REE). We conclude that CV(intra) of REE measurements was neither influenced by type of protocol for data analysis nor by the number of repeated measurements. About 20 % of the variance in REE(adj) is explained by variance in body composition.     

Estimation of resting energy expenditure by anthropometry

The role of anthropometry in estimating resting energy expenditure (REE) has been assessed in 142 clinically stable patients. Ninety eight patients had cancer (54 weight stable, 44 weight losing) and 44 patients had nonmalignant illness (27 weight stable, 17 weight losing). Mid-arm muscle circumference (MAMC) measurements correlated significantly with REE measured by indirect calorimetry in each of the groups studied. Weight loss significantly affected this correlation whereas cancer did not. The correlation in weight stable patients was poorer than that in weight losing patients, possibly reflecting inaccuracy of anthropometric measurements due to subcutaneous adipose tissue. Significant correlations were also observed between mid-arm circumference (MAC) and REE, and between MAMC and whole body oxygen consumption.REE can be estimated from MAMC measurements in weight stable and weight losing patients with benign or malignant disease. This simple method may be of value in estimating REE where indirect calorimetry facilities are unavailable.     

Dietary intake of energy and nutrients in relation to resting energy expenditure and anthropometric parameters of Czech pregnant women

Purpose

The aim of this study was to evaluate the dietary intake of energy and nutrients (DIEN) of Czech pregnant women and to assess relationships with body size variables during pregnancy.

Methods

One hundred and fifty-two randomly recruited healthy pregnant Czech women, who were normoglycemic, euthyroid, nonsmokers, not anemic, and not users of chronic medications or abusers of alcohol or drugs from countryside and city with different education, were recruited for the study. Anthropometric parameters were measured and resting energy expenditure obtained by indirect calorimetry after 12 h of fasting during four phases of pregnancy. DIEN was evaluated from self-reported dietary intake records over 7 days.

Results

Positive correlations were demonstrated between measured resting energy expenditure and intake of energy, substrates and some minerals and vitamins, and negative correlations between DIEN and anthropometric parameters. Lower dietary intake of energy and differences between dietary intake of nutrients and recommended daily allowances during pregnancy of Czech women were documented.

Conclusions

The difference between pregnancy body weight and ideal body weight was shown to be a determinant of DIEN. From recent knowledge on prevention of various pathological states, the supplementation or modification of nutritional intake of food with folate, iron, vitamin D, zinc, iodine and fiber for Czech pregnant women is recommended.     

胰腺癌病人静息能量消耗增加与血浆细胞因子关系的研究

目的:通过检测胰腺癌病人的静息能量消耗(REE)和血浆细胞因子,探讨两者间的关系。方法:用间接能量测定法检测34例诊断为胰腺癌的病人(试验组)和同期30例腹股沟疝病人(对照组)的REE,测定血浆细胞因子(TNF-α、IL-6、IL-1),将REE和细胞因子做相关性分析。结果:试验组病人REE非常显著地高于对照组,为(1 449.03±315.47)kcal vs(1 344.67±128.52)kcal,P<0.01;呼吸商(RQ)非常显著地低于对照组,为(0.81±0.06)vs(0.88±0.08),P<0.01;细胞因子TNF-α和IL-6非常显著地高于对照组(P<0.01),而IL-1两组无显著性差异。胰腺癌病人血浆TNF-α与REE有非常显著的正相关性(P<0.01);IL-6与REE有显著相关性(P<0.05)。结论:胰腺癌病人REE显著增加,血浆细胞因子TNF-α和IL-6显著升高。胰腺癌病人REE的升高可能与细胞因子TNF-α和IL-6的升高有一定的相关性。     

Positive association between resting energy expenditure and weight gain in a lean adult population

BACKGROUND: Weight gain in adulthood is common, from modest gains in developing countries to substantial increases in Western societies. Evidence of the importance of energy expenditure in adult weight change has been limited to studies conducted in Pima Indians, in whom resting energy expenditure (REE) was found to be inversely associated with weight gain. OBJECTIVE: The aim was to determine whether REE was predictive of weight change in lean Nigerian adults. DESIGN: Weight was measured in 744 adults on 2-4 occasions over 5.5 y. REE was measured in the second follow-up examination. Sex-specific, mixed-effects models with REE, fat-free mass, and age as fixed effects were used to test the association between REE and weight change. RESULTS: Adults aged >19 y (n = 352 men and 392 women) were included in these analyses. At baseline, the mean (+/-SD) age was 45.9 +/- 16.1 y for the whole population; the mean weight was 61.4 +/- 10.7 and 58.1 +/- 12.1 kg and body mass index (in kg/m(2)) was 21.4 +/- 3.2 and 23.1 +/- 4.0 for men and women, respectively. Over a mean 5.5 y of follow-up, the age-adjusted weight gain was 0.42 kg/y for the men and 0.59 kg/y for the women. In mixed-effects models, REE was positively associated with weight gain in both men and women (P < 0.001). No significant association was observed in participants who lost weight. CONCLUSIONS: In contrast with observations in overweight Pima Indians, REE adjusted for body size and composition was positively associated with weight gain in lean Nigerian adults. This suggests either that the potential for differential regulation of body weight in lean compared with overweight populations exists or that the increased REE in this population was the result, rather than cause, of weight gain.     

Comparison between measured and predicted resting energy expenditure in mechanically ventilated patients with COPD

The aim of this study was to compare resting energy expenditure (REE) obtained by indirect calorimetry (IC) and Harris-Benedict (H-B) equations, and to examine whether hypocaloric nutrition support could improve protein nutritional status in mechanically ventilated patients with chronic obstructive pulmonary disease (COPD). Thirtythree COPD patients (20 males, 13 females) were recruited and REE was measured by IC. Measured REE (REEm) was compared to predictive REE by H-B equations (REEH-B) and its corrected values. Correlation between REEm and APACHE II score was also analyzed. Patients were randomly divided into hypocaloric energy group (50%-90% of REEm, En-low) and general energy group (90%-130% of REEm, En-gen) for nutrition support. The differences of albumin, prealbumin, transferrin, hemoglobin, and lymphocyte count before and after 7 days nutrition support were observed. Results show that REEH-B and REEH-B×1.2 were significantly lower than REEm (p<0.01). REEm positively correlated with APACHE II score (p<0.05 or p<0.01). After nutrition support, hemoglobin decreased significantly in En-gen group (p<0.05); lymphocyte count in both groups, and transferrin and prealbumin in the En-low group increased significantly (p<0.05 or p<0.01). Our data suggest that 1) these patients' REE were increased; 2) since IC is the best method to determine REE, in the absence of IC, H-B equations (with standard body weight) can be used to calculate REE, but the value should be adjusted by correction coefficients derived from APACHE II; 3) low energy nutrition support during mechanical ventilation in COPD patients might have better effects on improving protein nutritional status than high energy support.     

Predicted and measured resting energy expenditure in healthy young women

Basal energy expenditure (BEE) was either measured by indirect calorimetry or predicted by different formulae in 104 young women: 74 lean and overweight subjects (normal weight, NWt) and 30 obese subjects. The predictive equations were based on weight alone (Owen, FAO-1, Schofield-1) or on weight and height (Harris-Benedict, Mifflin, Kleiber, and again FAO-2 and Schofield-2). With the exception of the Owen equation all the equations over-estimated measured BEE in both study groups. The ratio between measured and predicted value (% MP) varied between 102.3 (Owen) and 87.7 (Kleiber) in the NWt subjects and between 113.2 (Owen) and 89.3 (Schofield-1) in the obese subjects. The range including 95% of the predicted-measured differences (PMdiff) was larger than 1700 kJ/d in the NWt group and 2300 kJ/d in the obese group. In both study groups most of the equations showed a significant relationship between PMdiff and/or % MP with body weight and the magnitude of BEE. In conclusion, these equations are of little help in predicting BEE in a single subject and should be used with caution when assessing energy requirements in populations or groups of subjects.     

Measured and predicted resting energy expenditure in clinically stable patients

Resting energy expenditure (REE), measured by bedside indirect calorimetry, was compared to estimated REE by the Harris-Benedict and Kleiber predictors in 200 clinically stable hospitalized patients (100 males, 100 females) and 72 healthy control subjects (20 males, 52 females).Mean predicted values were not significantly different from measured REE for the male patients and control subjects, but measured REE was significantly overestimated by the Kleiber formula in female patients and controls (p<0.01). In comparison to control subjects, a substantially larger range of individual differences between measured REE and resting energy expenditure as estimated by the Harris-Benedict and Kleiber formulae existed among the male and female patient samples. Measured REE was over or underestimated by greater than 10% via the Harris-Benedict predictors in 40% of the patients but only 20% of the healthy controls. The Kleiber formulae were inappropriate for 46% of the individual patients and 33% of the normal subjects.Since no method exists for identifying the clinically stable patient for whom REE cannot be estimated via these commonly employed predictors, the bedside measurement of resting energy expenditure is the most appropriate method for deriving caloric expenditure and designing subsequent caloric provision regimens for adequate and safe nutritional repletion or maintenance.