Russell Rising

Comparison of Several Equations and Derivation of a New Equation for Calculating Basal Metabolic Rate in Obese Children

OBJECTIVES To compare basal metabolic rate (BMR) calculated by the Harris-Benedict, Ravussin, Cunningham, World Health Organization (WHO) and Schofield equations to BMR determined in an obese pediatric population. The second objective is to derive a new equation, based on measured BMR in obese children, for calculating BMR in obese pediatric patients. METHODS The study included 110 (50 male/60 female) healthy obese subjects (BMI > 28) (11.7 +/- 2.8 years, 73 +/- 27 kg, 152 +/- 14 cm and 38 +/- 6% fat) who had preprandial BMR determined by indirect calorimetry. These results were compared to BMR calculated with the five above mentioned equations. Fat-free mass was determined by bioelectrical impedance and body composition was calculated using the appropriate equation. The age groups analyzed were as follows: males 3 to 10 and 11 to 18 years old; females 3 to 10 and 11 to 18 years old. A new equation was derived by stepwise multiple regression analysis using 100 randomly selected subjects from our test group and tested using the remaining 10 subjects. RESULTS Basal metabolic rate calculated by the Ravussin and Cunningham equations in all subgroups was lower (p < 0.05) than measured BMR. Basal metabolic rate calculated by the Harris-Benedict equation was lower (p < 0.05) than measured BMR in male populations ages 3 to 10, 11 to 18, and in the entire cohort. Measured BMR was overestimated by the Harris-Benedict equation (p < 0.05) in females 11 to 18 years old; by the WHO equation (p < 0.05) in both male and females 3 to 10 years old and by the Schofield equation (p < 0.05) in males 11 to 18 years old. In comparison to measured BMR, the WHO equation appeared to be the most accurate for estimating BMR in males and females 11 to 18 years old. However, BMR calculating using our new equation in the 10 test subjects was similar to measured BMR. CONCLUSIONS The WHO equation was the most accurate of the prediction equations studied. However, our new prediction equation may be more appropriate for calculating BMR in an obese pediatric population.

Relationship between maternal obesity and infant feeding-interactions

BackgroundThere are no data regarding the relationship between maternal adiposity and interaction and feeding of infants and possible contribution to childhood obesity. In this study we determined the relationship between maternal body weight and composition and infant feeding patterns and maternal-infant interaction during 24-hour metabolic rate measurements in the Enhanced Metabolic Testing Activity Chamber (EMTAC).MethodsThe amount of time four obese (BMI = 33.5 ± 5.3 kg/m2) and three normal weight (BMI = 23.1 ± 0.6 kg/m2) biological mothers, spent feeding and interacting with their infants, along with what they ingested, was recorded during 24-hour metabolic rate measurements in the EMTAC. The seven infants were 4.9 ± 0.7 months, 69 ± 3 cm, 7.5 ± 0.8 kg, 26 ± 3 % fat and 29 ± 25 percentile for weight for length. Energy and macronutrient intake (kcal/kg) were assessed. Maternal body composition was determined by air displacement plethysmorgraphy and that of the infants by skin-fold thicknesses. Pearson correlations and independent t-tests were utilized for statistical analysis (p < 0.05).ResultsInfants born to obese biological mothers consumed more energy (87.6 ± 18.9 vs. 68.1 ± 17.3) and energy as carbohydrate (25 ± 6 vs.16 ± 3; p < 0.05) than their normal weight counterparts. Most of the increased intake was due to complementary feedings. Twenty-four hour infant energy intake increased with both greater maternal body weight (r = 0.73;p < 0.06) and percent body fat. Furthermore, obese biological mothers spent less total time interacting (570 ± 13 vs. 381 ± 30 minutes) and feeding (298 ± 32 vs.176 ± 22 minutes) (p < 0.05) their infants than their normal weight counterparts. Twenty-four hour interaction time negatively correlated with both maternal body weight (r = -0.98; p < 0.01) and percent body fat (r = -0.92; p < 0.01). Moreover, infants of obese mothers slept more (783 ± 38 vs. 682 ± 32 minutes; p < 0.05) than their normal weight counterparts. However, there were no differences in total 24-hour energy expenditure, resting and sleeping metabolic rates (kcal/kg) for infants born to obese and normal weight biological mothers.ConclusionGreater maternal body weight and percent body fat were associated with greater infant energy intakes. These infants were fed less frequently and consumed more carbohydrates in a shorter period of time as compared to infants from normal weight biological mothers. These variations in feeding patterns may predispose certain infants to obesity.

Lower energy expenditures in infants from obese biological mothers.

BackgroundPrevious studies in adults have found that a lower resting metabolic rate is a predictor of future body weight gain.MethodsTo determine if energy expenditures are reduced in infants born to obese mothers, 21 healthy infants (3.9 ± 1.9 months) born to lean (n = 7, BMI < 25 kg/m2), overweight (n = 7, BMI between 25–30) and obese (n = 7, BMI>30) mothers, respectively, participated in this study. Measurements of infant weight, length and skin-fold thicknesses, and mothers weight and height were obtained. Infant energy expenditure was measured for 4-hours using the Enhanced Metabolic Testing Activity Chamber. Metabolic data were extrapolated to 24-hours and adjusted for differences in age and body composition using linear regression analysis (SPSS, version 13) and expressed as kcal/day. Differences between the three groups were determined by one way ANOVA with the Bonferroni Post Hoc test procedure (p < 0.05).ResultsInfants born to obese mothers had a greater BMI (16.7 ± 1.2) than those from both the overweight (15.3 ± 1.4, p < 0.05) and lean groups (15.1 ± 1.3; p < 0.05). The infants of obese mothers had greater body fat (26.8 ± 2.1) than those from the overweight group (22.4 ± 5.0, p < 0.06). Infant BMI correlated (r = 0.53; p < 0.01) with that of their mothers. Extrapolated 24-h EE (kcal/d) correlated with fat-free mass (r = 0.94; p < 0.01). Infants extrapolated 24-h EE from both obese (472.1 ± 30.7 kcal/d; p < 0.05) and overweight groups (471.8 ± 39.5; p < 0.05) were lower than those of the lean group (532.4 ± 30.7).ConclusionLower extrapolated 24-h energy expenditure was present in infants of overweight and obese biological mothers during the first three to six months of life. Furthermore, these infants showed increased BMI and body fat. If these changes are unchecked future childhood obesity may result.

Daily metabolic rate in healthy infants

BACKGROUND Previous estimates of daily metabolic rate in infants were based on short-term unstandardized measurements of energy expenditure (EE). OBJECTIVE Determine 24-hour metabolic profiles in infants. METHODS Energy expenditure (kcal/min by indirect calorimetry) and physical activity (oscillations in weight/min/kg body weight) were measured in 10 healthy infants (5.0+/-0.8 months, 68+/-3 cm, 7.3+/-0.8 kg) for 24 hours in the Enhanced Metabolic Testing Activity Chamber while allowing parental interaction. Energy intake, 24-hour EE, resting metabolic rate (RMR), and sleeping metabolic rate (SMR) (kcal/kg/day) were determined. In addition, extrapolated 24-hour EE, RMR, and SMR from the first 4 and 6 hours of data were compared with 24-hour measurements. RESULTS Twenty-four-hour energy intake, EE, RMR, and SMR (mean+/-SD) were 78.2+/-17.6, 74.7+/-3.8, 65.1+/-3.5, and 60.3+/-3.9, respectively. EE and physical activity showed a decrease at 11:30 pm and a return to daytime levels by 5:30 am, suggesting a metabolic circadian rhythm. Extrapolated 24-hour EE, RMR, and SMR from the first 4 hours (72.2+/-6.6, 65.9+/-8.7, and 64.9+/-6.4) and 6 hours (74.8+/-6.7, 65.8+/-6.6, and 64.8+/-5.6) were similar to 24-hour measurements. CONCLUSIONS An apparent circadian rhythm in metabolic rate and physical activity was detected by 24-hour measurements. Furthermore, shorter-term measurements of the variables were comparable with 24-hour values.

Energy expenditures & physical activity in rats with chronic suboptimal nutrition

BackgroundSub-optimally nourished rats show reduced growth, biochemical and physiological changes. However, no one has assessed metabolic rate adaptations in rats subjected to chronic suboptimal nutrition (CSN). In this study energy expenditure (EE; kcal/100 g body weight) and physical activity (PA; oscillations in weight/min/kg body weight) were assessed in rats subjected to three levels of CSN.ResultsBody weight gain was diminished (76.7 ± 12.0 and 61.6 ± 11.0 g) in rats fed 70 and 60% of the ad-libitum fed controls which gained more weight (148.5 ± 32.3 g). The rats fed 80% gained weight similarly to controls (136.3 ± 10.5 g). Percent Fat-free body mass was reduced (143.8 ± 8.7 and 142.0 ± 7.6 g) in rats fed 70 and 60% of ad-libitum, but not in those fed 80% (200.8 ± 17.5 g) as compared with controls (201.6 ± 33.4 g). Body fat (g) decreased in rats fed 80% (19.7 ± 5.3), 70% (15.3 ± 3.5) and 60% (9.6 ± 2.7) of ad-libitum in comparison to controls (26.0 ± 6.7). EE and PA were also altered by CSN. The control rats increased their EE and PA during the dark periods by 1.4 ± 0.8 and 1.7 ± 1.1 respectively, as compared with light the period; whereas CSN rats fed 80 and 70% of ad-libitum energy intake had reduced EE and PA during the dark periods as compared with the light period EE(7.5 ± 1.4 and 7.8 ± 0.6 vs. 9.0 ± 1.2 and 9.7 ± 0.8; p < 0.05, respectively), PA(3.1 ± 0.8 and 1.6 ± 0.4 vs. 4.1 ± 0.9 and 2.4 ± 0.4; p < 0.05) and RQ (0.87 ± 0.04 and 0.85 ± 0.5; vs. 0.95 ± 0.03 and 0.91 ± 0.05 p < 0.05). In contrast, both light (7.1 ± 1.4) and dark period (6.2 ± 1.0) EE and PA (3.4 ± 0.9 and 2.5 ± 0.5 respectively) were reduced in rats fed 60% of ad-libitum energy intake.ConclusionCSN rats adapt to mild energy restriction by reducing body fat, EE and PA mainly during the dark period while growth proceeds and lean body mass is preserved. At higher levels of energy restrictions there is decreased growth, body fat and lean mass. Moreover EE and PA are also reduced during both light and dark periods.

Effects of Exogenous Recombinant Human Growth Hormone on an Animal Model of Suboptimal Nutrition

BACKGROUND Nutritional dwarfing, a form of suboptimal nutrition, has been identified as a frequent cause of short stature and delayed sexual development in children. Retarded growth is an adaptive response to suboptimal nutrition. OBJECTIVE To assess whether recombinant human growth hormone (rhGH) may promote growth during various levels of suboptimal nutrition. METHODS Using a previously developed rat model of suboptimal nutrition, six groups of rats (six rats/group) were fed a balanced 1:1 carbohydrate:fat ratio diet for 4 weeks. Three of the groups were administered daily injections of rhGH (0.1 mg/100 g BW) subcutaneously in the back while the other three groups were kept as controls and were given similar dosages of normal saline solution (NSS). Restricted rats within each treatment group were pair fed 80 and 60% of the ad-libitum rats intake. Daily intake of the 80 and 60% fed groups were determined based on the intake of the ad-libitum fed groups. Serum IGF-I and insulin were determined after 4 weeks of dietary treatment by radioimmunoassay while IGFBP-3 was determined by an immunoradiometric assay. Body composition was assessed in all rats by carcass analysis. RESULTS After 4 weeks, total weight gain and tail growth were higher (p < 0.05) in the rhGH treated group at 80 and 60% of-libitum energy intake. Serum levels of IGF-I and IGFBP-3 were higher (p < 0.05) in rhGH treated rats fed at 60% of ad-libitum. In comparison to the NSS groups, administration of rhGH in rats fed ad-libitum increased total body water. Energy restriction caused decreased fat percentage (p < 0.05) in both rhGH and NSS groups without differences among treated groups. CONCLUSION These results suggest that the anabolic effects of rhGH may overcome mild to moderate energy restriction.

Carbohydrate Malabsorption May Increase Daily Energy Requirements in Infants

OBJECTIVE Carbohydrate malabsorption in infants has been found to increase nutrient losses. However, the effect of this alteration on daily metabolic rate is unknown. We assessed daily metabolic rates in infants with asymptomatic carbohydrate malabsorption (ACM) after a single fruit juice load. METHODS Sixteen healthy infants with ACM (63.3 +/- 5.6 cm, 7.5 +/- 1.0 kg, 5.6 +/- 0.8 mo, peak breath hydrogen [BH2] = 39.1 +/- 22.4 ppm) and 16 without ACM (64.3 +/- 3.9 cm, 7.8 +/- 1.0 kg, 5.0 +/- 0.8 mo, BH2 = 9.4 +/- 4.7 ppm), after a single fruit juice load, had 24-h energy expenditure (24-h EE; kcal x kg(-1) x d(-1)), resting (RMR; kcal x kg(-1) x d(-1)) and sleeping (SMR; kcal x kg(-1) x d(-1)) metabolic rates extrapolated from 3.5-h assessments in the Enhanced Metabolic Testing Activity Chamber. Furthermore, RMR was calculated with the World Health Organization (WHO), Schofield weight-based and weight- and height-based equations. Carbohydrate absorption was determined by BH2. Differences (P < 0.05) were determined by t test. RESULTS All infants with ACM had greater (P < 0.05) extrapolated 24-h EE (91.2 +/- 24.8 versus 78.0 +/- 6.8) and RMR (71.8 +/- 15.2 versus 59.5 +/- 5.9). This represented an increase of 15-18.5%, respectively, in energy expenditures. Carbohydrate malabsorption was a significant determinant of EE, RMR, and SMR. However, the WHO (53.8 +/- 1.0 versus 54.1 +/- 0.9) and both Schofield equations (54.7 +/- 0.9 versus 54.9 +/- 1.0 and 50.6 +/- 7.5 versus 47.3 +/- 6.7) failed to detect any differences in RMR. There was a 20 percentile reduction in growth performance in infants with carbohydrate malabsorption. CONCLUSIONS Infants with ACM following fruit juice ingestion may have increased daily energy expenditure leading to increased metabolic requirements.

Twenty-four hour metabolic rate measurements utilized as a reference to evaluate several prediction equations for calculating energy requirements in healthy infants

BackgroundTo date, only short-duration metabolic rate measurements of less than four hours have been used to evaluate prediction equations for calculating energy requirements in healthy infants. Therefore, the objective of this analysis was to utilize direct 24-hour metabolic rate measurements from a prior study to evaluate the accuracy of several currently used prediction equations for calculating energy expenditure (EE) in healthy infants.MethodsData from 24-hour EE, resting (RMR) and sleeping (SMR) metabolic rates obtained from 10 healthy infants, served as a reference to evaluate 11 length-weight (LWT) and weight (WT) based prediction equations. Six prediction equations have been previously derived from 50 short-term EE measurements in the Enhanced Metabolic Testing Activity Chamber (EMTAC) for assessing 24-hour EE, (EMTACEE-LWT and EMTACEE-WT), RMR (EMTACRMR-LWT and EMTACRMR-WT) and SMR (EMTACSMR-LWT and EMTACSMR-WT). The last five additional prediction equations for calculating RMR consisted of the World Health Organization (WHO), the Schofield (SCH-LWT and SCH-WT) and the Oxford (OXFORD-LWT and OXFORD-WT). Paired t-tests and the Bland & Altman limit analysis were both applied to evaluate the performance of each equation in comparison to the reference data.Results24-hour EE, RMR and SMR calculated with the EMTACEE-WT, EMTACRMR-WT and both the EMTACSMR-LWT and EMTACSMR-WT prediction equations were similar, p = NS, to that obtained from the reference measurements. However, RMR calculated using the WHO, SCH-LWT, SCH-WT, OXFORD-LWT and OXFORD-WT prediction equations were not comparable to the direct 24-hour metabolic measurements (p < 0.05) obtained in the 10 reference infants. Moreover, the EMTACEE-LWT and EMTACRMR-LWT were also not similar (p < 0.05) to direct 24-hour metabolic measurements.ConclusionsWeight based prediction equations, derived from short-duration EE measurements in the EMTAC, were accurate for calculating EE, RMR and SMR in healthy infants.

Exogenous recombinant human growth hormone effects during suboptimal energy and zinc intake

BackgroundEnergy and Zinc (Zn) deficiencies have been associated with nutritional related growth retardation as well as growth hormone (GH) resistance. In this study, the relationship between suboptimal energy and/or Zn intake and growth in rats and their response to immunoreactive exogenous recombinant human GH (GHi), was determined.ResultsRats treated with GHi and fed ad-libitum energy and Zn (100/100) had increased IGFBP-3 (p < 0.05) as compared with NSS (215 ± 23 vs. 185 ± 17 ng/ml) along with similar body weight gain. Rats treated with GHi and fed suboptimal energy and full Zn (70/100) had significantly increased weight gain (109.0 ± 18.2 vs. 73.8 ± 11.0 g) and serum IGF-I levels (568 ± 90 vs. 420 ± 85 ng/ml), along with decreased total body water (TBW; 61.0 ± 1.6 vs. 65.7 ± 2.1%) as compared to NSS controls. However, body weight gain was reduced (p < 0.05) as compared with rats fed ad-libitum energy. Growth hormone treated rats fed only suboptimal Zn (100/70), had increased weight gain (217.5 ± 13.2 vs. 191.6 ± 17.9 g; p < 0.05) compared to those given NSS. These rats gained weight in similar amounts to those fed full Zn. Rats treated with GHi and fed both suboptimal energy and Zn (70/70) showed similar results to those fed suboptimal energy with appropriate Zn (70/100), along with significant increases in IGFBP-3 levels (322 ± 28 vs. 93 ± 28 ng/ml). All restricted rats had reduced 24-h EE (kcal/100 g BW) and physical activity index (oscillations/min/kg BW) and GHi did not overcome these effects.ConclusionThese results suggest that GHi enhances weight gain in rats with suboptimal energy and Zn intake but does not modify energy expenditure or physical activity index. Suboptimal Zn intake did not exacerbate the reduced growth or decrease in energy expenditure observed with energy restriction.

Exogenous Growth Hormone (GH) Effects During Simultaneous Suboptimal Energy and Zinc Intake 477

Exogenous Growth Hormone (GH) Effects During Simultaneous Suboptimal Energy and Zinc Intake 477