Dietary Reference Intake (DRI): Estimated Energy Requirement (EER) Revision of 2002 Dietary Reference Intakes (DRI) for Energy in Preschoolage

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1 Revision of Dietary Reference Intakes (DRI) for Energy in Preschoolage Children Nancy F. Butte, PhD Children s Nutrition Research Center Baylor College of Medicine Dietary Reference Intake (DRI): Estimated Energy Requirement (EER) EERs aim to balance total energy expenditure (TEE) at a level of physical activity consistent with health and to support growth rates in children compatible with a healthy body size and composition IOM DRI committee decided to base energy requirements on TEE measured using doubly labeled water (DLW) Estimated Energy Requirement (EER): Total Energy Expenditure(TEE) Doubly-labeled water (DLW) is stable isotope method which measures free-living total energy expenditure (TEE) In weight-stable adults, TEE is a reliable indicator of energy intake and thus EER EER = TEE In children, an allowance is made for energy deposition during growth EER = TEE + energy deposition Derivation of EER: Total Energy Expenditure Approach IOM DRI committee compiled a normative DLW database of healthy, free living, and normal weight individuals Obtain raw data from published DLW studies Define inclusion and exclusion criteria Develop separate predictive equations for TEE: infants and toddlers children 3 y old adults EER for four Physical Activity Levels (PAL) PAL = TEE/ BMR 1

2 IOM DLW Normative Database Inclusion criteria Healthy, free-living individuals Healthy BMI ranges - yrs: weight-height percentiles between 3rd and 97th 3- yrs: BMI percentiles between 5th and 85th > yrs: BMI Representative of broad spectrum of age, gender, weight, height and physical activity (PA) levels DLW database is appropriate for the determination of TEE and EER at different life stages in relation to gender, weight, height, and PA. IOM Normative DLW Database TEE By Age TEE (kcal/d) Age (y) Female Male IOM Normative DLW Database Age (y) n BMI TEE PAL Males 3-8* Females 3-8* * 3 y/o n= 4 y/o n=3 5 y/o n=1 IOM Development of TEE Prediction Equations Non-linear regression procedure, with least squares loss function Relative contribution of weight and height kept constant within each sex PAL included as 4-level ordinal data, allowing modification of the contribution of weight and height to TEE depending on activity level

3 Prediction Equations of TEE General Models Ages 3 - y: TEE = A + B x Age + PA x (D x Weight + E x Height) A : Constant term B : Age coefficient PA: Physical activity coefficient D: Weight coefficient E: Height coefficient Physical Activity Categories Category PAL Range Energy Equivalence Sedentary Basal energy expenditure, thermic effect of feeding, minimal PA for independent living Low active Walking.5-3 miles/d Walking 5-7 miles/d Very active Walking 1-1 miles/d EER for Children 3- y EER = TEE + Energy deposition (+ kcal/d) Boys: EER (kcal/d) = 88-6 x Age + PA (7 WT + 93 HT) + E deposition (PA=1, 1.13, 1.6, 1.4) Girls: EER (kcal/d) = x Age + PA (1 WT HT) + E deposition (PA=1, 1.16, 1.31, 1.56) Li l Cal Study Novel approaches to assess energy expenditure and physical activity in preschool-age children To measure TEE by DLW method To compare measured against predicted TEE by DRI equations To develop new TEE prediction equations for sedentary, low-active, active and very active PAL categories To provide descriptors of PAL categories to classify and implement new TEE prediction equations in preschool-age children Butte NF et al. Am J Clin Nutr 14;1:

4 Li l Cal Study Design CNRC Room Respiration Calorimeters Preschool children, ages h Protocol for measurement of energy expenditure (EE) and physical activity (PA) Room calorimetry Actiheart and Actigraph GT3X 7-day Measurement of free-living TEE and PA Doubly labeled water method Actiheart and Actigraph GT3X Li l Cal: Heart Rate and Accelerometers ACTIHEART Subject Description Boys Girls Total n Age (y) 4.5 ± ± ±.9 Weight (kg) 17.4 ± ± ±.6 Height (m) 1.6 ± ± ±.8 BMI 15.3 ± ± ±.8 Weight-for-age percentile 48 ± 6 48 ± 4 48 ± 5 Height-for-age percentile 54 ± 9 56 ± 7 55 ± 8 BMI-for-age percentile 4 ± 45 ± 3 44 ± DXA FM (%WT) 3.7 ± ± ± 5.3 ACTIGRAPH 4

5 Room Respiration Calorimetry: Energy Expenditure and HR How much energy do preschoolers really expend? In the room calorimeter Heart Rate (bpm) HR_AH ENERGY Energy (kcal/min) 6 9:54 1:54 11:54 1:54 13:54 14:54 15:54 Time of Day (4 hr clock) Measured Sleeping Metabolic Rate Predicted Basal Metabolic Rate Metabolic Equivalents for BMR Energy Expenditure (kcal/kg/d) Measured Sleeping Metabolic Rate Predicted BMR (Schofield Equation) Age Group (y) VO (ml-o /kg/min) EE (kcal/kg/h) Adult Age (y) 5

6 Physical Activity Ratio PAR = EE/BMR Sleep TV time Play Dance/Aerobics Run in place How much energy do preschoolers really expend? Free-living environment Age (years) Doubly Labeled Water Method Doubly Labeled Water DLW is stable isotope method for the measurement of total energy expenditure. TEE encompasses BMR, TEF, thermoregulation, physical activity and synthetic cost of growth. DLW method entails oral administration of O and H to estimate VCO. Gas isotope ratio mass spectrometry analysis (GIRMS) Accuracy: 3-9% SD (Schoeller 1991) H labels water pool HHO k H = r HO H O r CO = k H -k O O labels water and bicarbonate pool H O CO O k O =r CO + r HO VO = VCO /RQ TEE = VO VCO 6

7 Doubly Labeled Water Dosages (oral).86 g H O /kg body weight at 99.9 atom% H 1.38 g H O /kg body weight at 1 atom% O Sampling urine Collection period - 7 d Gas isotope ratio mass spectrometry analysis (GIRMS) Conversion H O to H zinc reduction method H O-CO exchange method Isotopic abundance Doubly labeled Water Boys Girls Total n H dilution space (N H : kg) 1.6 ± 1.7 a 9.9 ± ± 1.6 O dilution space (N O: kg) 1. ± ± ± 1.6 H/ O dilution spaces (N H /N O ) 1.4 ± ± ±.1 H turnover rate (k H: d -1 ) -.13 ± ± ±.3 O turnover rate (k O: d -1 ) -.17 ± ± ±.3 H ln DOB vs. days (r) ± ± ±.5 O ln DOB vs. days (r) ± ± ±.4 Doubly labeled Water TEE by DLW in IOM Database and Li l Cal Study Boys Girls Total DRI Normative DLW Database Preschool-aged Children n VCO (mol d) 9.43 ± ± ± 1.35 BMR (kcal d -1 ) 893 ± ± ± 66 TEE (kcal d -1 ) 1197 ± ± ± 171 TEE (kcal kg -1 d -1 ) 69.4 ± ± ± 7.6 PAL 1.34 ± ± ±.14 Total Energy Expenditure (kcal/d) A B Age (y) Weight (kg) 7

8 Total Energy Expenditure (kcal/d) Measured TEE vs. IOM DRI Equations Predicted by DRI equations Very active Low active Sedentary 15 1 Measured by DLW in this study Weight (kg) Physical Activity Levels Energy cost of physical activities, expressed as multiples of BMR, increase from early childhood to adulthood, but the impact of these age-related changes on daily PAL was not appreciated DRIs same PAL categories were used for children and adults Due to decrease in BMR from 47 to 7 kcal/kg/d, PAL values in normative DLW database increase between the ages of 3-8, 9-13 and 14- y: 1.39 to 1.56 to 1.8 in boys 1.48 to 1.6 to 1.69 in girls Physical Activity Categories Category IOM PAL Preschooler PAL Sedentary Low active Very active >1.5 Revised Nonlinear Regression Models for Prediction of TEE for Boys Coefficient SE t P-value Boys, ages 3-5 y Constant (b ) a a a Weight coefficient (b ) Height coefficient (b 3 ) R squared.963 Absolute mean error (kcal/d). ± 36.8 Mean percent error.1 ± 3.% RMSE (kcal/d)

9 Revised Nonlinear Regression Models for Prediction of TEE for Girls Coefficient SE t P-value Girls, ages 3-5 y Constant (b ) a a a Weight coefficient (b ) Height coefficient (b 3 ) R squared.94 Absolute mean error (kcal/d). ± 34. Mean percent error.1 ± 3.% RMSE (kcal/d) 33.9 Revised EER for Children 3-5 y EER = TEE + Energy deposition (+ kcal/d) Boys: EER (kcal/d) = PA x (16 x WT x HT) + E deposition (PA=1, 1., 1.37, 1.64) Girls: EER (kcal/d) = 35 + PA x (11.6 x WT x HT) + E deposition (PA=1, 1.5, 1.46, 1.6) Bland-Altman Plot Predicted and Measured TEE Revised EER for Preschool-age Children Differences between predicted and measured TEE (kcal/d) Age (y) Weight (kg) Height (m) Sedentary DRI Revised DRI Low Very Sedentary Low Very Girls ,6 1,3 1,375 1, ,64 1, ,113 1,9 1,455 1, ,19 1,131 1, ,169 1,359 1,537 1, ,8 1, 1,37 Boys ,14 1,34 1,465 1, ,38 1,135 1, ,195 1,37 1,546 1, ,15 1,11 1, ,55 1,446 1,638 1,874 1,4 1,177 1,93 1, Mean of predicted and measured TEE (kcal/d) 9

10 Revised EER for Preschool-age Boys Revised EER for Preschool-age Girls Estimated Energy Requirement (EER) (kcal/d) DRI Very Rev. DRI Very DRI Rev. DRI DRI Low Rev. DRI Low DRI Sedentary Rev DRI Sedentary Estimated Energy Requirement (EER) (kcal/d) DRI Very Rev. DRI Very DRI Rev. DRI DRI Low Rev. DRI Low DRI Sedentary Rev DRI Sedentary Age (y) Age (y) Descriptors of PAL Categories Sedentary PAL Low active PAL PAL Very PAL n TEE (kcal d -1 ) 968 ± ± ± ± 143 TEE (kcal kg -1 d -1 ) 59.6 ± ± ± ± 5.9 PAL 1.13 ± ± ± ±.6 Ancillary Measurements of PAL Actiheart (counts.d -1 ) 9,699 95,7 13,981 1,1 Actigraph X-axis (counts.d -1 ) 448, , 513,5 617,135 Conclusion DRI equations result in overestimation of TEE due to erroneous PAL classification of children Observed PAL increased from infancy to early childhood due to decreasing BMR and developmental maturation of growing children Advocate revised PAL categories in preschool-age children Present new prediction equations for TEE and thus EER based on weight, height and PAL Actigraph (steps.d -1 ) 7,85 8,638 9,51 1,634 1