胰岛素强化治疗对胃癌围手术期营养代谢的影响：随机对照研究

目的:探讨胃癌围手术期能量及营养物质的代谢特点,研究强化胰岛素治疗对围手术营养代谢的影响.方法:选取胃中、下部癌病理诊断明确并且外科病房ICU住院时间不少于24h的患者64例,取得知情同意后随机分到强化胰岛素治疗(IIT)血糖控制在4.4～6.1 mmol/L.和传统治疗(CIT)组血糖控制在10mmol/L以下;应用CCM营养代谢监测系统测定围手术期静息能量消耗(REE),呼吸商(RQ),每公斤体重静息能量消耗(REE/kg)和脂肪氧化比率,应用多频人体生物电阻抗分析仪测定围手术期人体组分的变化及应用稳态模式评估法计算胰岛素抵抗指数(HOMA-IR).结果:64例病人入选,每组32例,手术创伤引起术后第1、3天REE水平增加约22%和12%,呼吸商降低至0.759和0.791,REE/kg增加28 kcal/kg和26 kcal/kg,脂肪氧化比率增加至78%和65%,Ln-HOMA-IR明显增加(P<0.05);IIT治疗能降低术后第1、3天Ln-HOMA-IR和REE/kg水平;术后人体指标如细胞内液、脂肪组织、蛋白组织、肌肉组织、瘦体组织和体质量较术前水平明显降低(P<0.05);IIT能明显减少脂肪组织、蛋白组织和细胞内液的消耗量(P=0.009,t=0.026).结论:IIT能够有效降低胃癌围手术期胰岛素抵抗程度、降低静息能量消耗的水平和减少脂肪及蛋白质的消耗.     

New specific equation to estimate resting energy expenditure in severely obese patients

Calculating the estimated resting energy expenditure (REE) in severely obese patients is useful, but there is controversy concerning the effectiveness of available prediction equations (PE) using body weight (BW). We evaluated the efficacy of REE equations against indirect calorimetry (IC) in severely obese subjects and aimed to develop a new equation based on body composition compartments. One hundred and twenty severely obese patients had their REE measured (MREE) by IC and compared to the most commonly used PE (Harris-Benedict (HB), Ireton-Jones, Owen, and Mifflin St. Jeor). In a random sample (n = 60), a new REE equation based on fat-free mass (FFM) was developed and validated. All PE studied failed to estimate REE in severe obesity (low concordance correlation coefficient (CCC) and limits of agreement of nearly 50% of the sample ±10% of MREE). The HB equation using actual BW exhibited good results for all samples when compared to IC (2,117 ± 518 kcal/day by HB vs. 2,139 ± 423 kcal/day by MREE, P > 0.01); these results were blunted when patients were separated by gender (2,771 vs. 2,586 kcal/day, P < 0.001 in males and 1,825 vs. 1,939 kcal/day, P < 0.001 in females). A new resting energy expenditure equation prediction was developed using FFM, Horie-Waitzberg, & Gonzalez, expressed as 560.43 + (5.39 × BW) + (14.14 × FFM). The new resting energy expenditure equation prediction, which uses FFM and BW, demonstrates higher accuracy, precision, CCC, and limits of agreement than the standard PE in patients when compared to MREE (2,129 ± 45 kcal/day vs. 2,139 ± 423 kcal/day, respectively, P = 0.1).The new equation developed to estimate REE, which takes into account both FFM and BW, provides better results than currently available equations.     

胰岛素强化治疗对胃癌围手术期营养代谢的影响：随机对照研究

目的：探讨胃癌围手术期能量及营养物质的代谢特点,研究强化胰岛素治疗对围手术营养代谢的影响。方法：选取胃中、下部癌病理诊断明确并且外科病房ICU住院时间不少于24h的患者64例,取得知情同意后随机分到强化胰岛素治疗（IIT）组血糖控制在4.4~6.1mmol/L,和传统治疗（CIT）组血糖控制在10mmol/L以下;应用CCM营养代谢监测系统测定围手术期静息能量消耗（REE）,呼吸商（RQ）,每公斤体重静息能量消耗（REE/kg）和脂肪氧化比率,应用多频人体生物电阻抗分析仪测定围手术期人体组分的变化及应用稳态模式评估法计算胰岛素抵抗指数（HOMA-IR）。结果：64例病人入选,每组32例,手术创伤引起术后第1、3天REE水平增加约22%和12%,呼吸商降低至0.759和0.791,REE/kg增加28kcal/kg和26kcal/kg,脂肪氧化比率增加至78%和65%,Ln-HOMA-IR明显增加（P〈0.05）;IIT治疗能降低术后第1、3天Ln-HOMA-IR和REE/kg水平;术后人体指标如细胞内液、脂肪组织、蛋白组织、肌肉组织、瘦体组织和体质量较术前水平明显降低（P〈0.05）;IIT能明显减少脂肪组织、蛋白组织和细胞内液的消耗量（P=0.009,t=0.026）。结论：IIT能够有效降低胃癌围手术期胰岛素抵抗程度、降低静息能量消耗的水平和减少脂肪及蛋白质的消耗。     

Correlations of pedometer readings with energy expenditure in workers during free-living daily activities

In a total of 23 subjects consisting of 10 clerical and 13 assembly workers in a factory, the pedometer readings during a day of free-living activity were analyzed for the relation with energy expenditure as determined by the simultaneously recorded 24-hour heart rate. The 24-hour energy expenditures in the clerical and assembly workers were 9515 kJ (2274 kcal) and 9698 kJ (2318 kcal) respectively. The whole day readings of the pedometer for all the subjects moderately correlated (r = 0.438, p less than 0.05) with the net energy cost (NEC) as determined by subtracting the sleeping metabolic cost from the energy expenditure (clerical workers: r = 0.781, p less than 0.01; assembly workers: r = 0.188, p less than 0.05). The correlation analysis of the pedometer readings with the NEC in three activity phases in a day (work, commuting and staying at home), showed that the extent of the relationship differed by job types and activity phases. The best correlation was obtained during commuting in both of the job types (clerical workers: r = 0.843, p less than 0.01; assembly workers: r = 0.743, p less than 0.01). During work, a quite strong correlation (r = 0.889, p less than 0.01) was obtained with the clerical workers but not with the assembly workers. No significant correlations were found in the data while the subjects were at home. The capacity of the pedometer to detect the impacts of body movements, and the characteristics of activity, are responsible for the differences in correlation.(ABSTRACT TRUNCATED AT 250 WORDS)     

Energy Intake and Physical Activity in Pima Indians: Comparison with Energy Expenditure Measured by Doubly-Labeled Water

To test the validity of survey techniques for measuring diet and activity patterns of Pima Indians, sequential 24-hour recalls, a food frequency ques tionnaire (FFQ), and an activity questionnaire were compared to free-living energy expenditure. Total energy expenditure (TEE) measured by doubly labeled water was 13.27 ± 2.95 MJ/d for the 12 males (mean±SD: 35 ± 14 yr; 97 ± 35 kg; 32 + 9% body fat) and 11.67 ± 1.85 MJ/d for the 9 females (31 ± 13 yr; 106 ± 32 kg; 49 ± 6% body fat). Energy intake assessed by 24-hour recall was 13.59 ± 7.81 MJ/d for men and 9.29 ± 2.77 MJ/d for women, compared to 12.84 ± 2.85 and 9.40 ± 2.61 MJ/d for men and women, respectively, by FFQ. Both dietary methods indicated significant underreporting by women when compared to TEE. Energy intake assessed by FFQ was significantly correlated with TEE (r=0.48, p=0.03). This was true with 24-hour recall energy intake only when data from two extremely large alcohol consumers were eliminated (r=0.64, p=0.03, N=19). Although a low level of activity was apparent, the activity questionnaire produced significant correlations with measurements of energy expenditure and therefore represents an important tool for examining the relationship between physical activity and diseases.     

Influence of ascorbic acid on the thermic effect of feeding in overweight and obese adult humans

The thermic effect of feeding (TEF: increase in energy expenditure following acute energy intake) is an important physiological determinant of total daily energy expenditure and thus energy balance. Approximately 40% of TEF is believed to be mediated by sympathoadrenal activation and consequent beta-adrenergic receptor stimulation of metabolism. In sedentary adults, acute administration of ascorbic acid, a potent antioxidant, augments the thermogenic response to beta-adrenergic stimulation. We hypothesized that acute ascorbic acid administration augments TEF in sedentary overweight and obese adults. Energy expenditure was determined (ventilated hood technique) before and 4 h after consumption of a liquid-mixed meal (caloric equivalent 40% of resting energy expenditure (REE)) in 11 sedentary, overweight/obese adults (5 men, 6 women; age: 24 +/- 2 years; BMI: 28.5 +/- 1.0 kg/m(2) (mean +/- s.e.)) on two separate, randomly ordered occasions: during continuous intravenous administration of saline (placebo control) and/or ascorbic acid (0.05 g/kg fat-free mass). Acute ascorbic acid administration prevented the increase in plasma concentration of oxidized low-density lipoprotein in the postprandial state (P = 0.04), but did not influence REE (1,668 +/- 107 kcal/day vs.1,684 +/- 84 kcal/day; P = 0.91) or the area under the TEF response curve (33.4 +/- 2.4 kcal vs. 30.5 +/- 3.6 kcal; P = 0.52) (control vs. ascorbic acid, respectively). Furthermore, acute ascorbic acid administration had no effect on respiratory exchange ratio, heart rate, or arterial blood pressure in the pre- and postabsorptive states (all P > 0.64). These data imply that the attenuated TEF commonly observed with sedentary lifestyle and obesity is not modulated by ascorbic acid-sensitive oxidative stress.     

Improved insulin action following short-term exercise training: role of energy and carbohydrate balance.

Short-term exercise training improves insulin action, but the impact of replacing the energy expended during exercise to prevent energy deficit is unclear. The purpose of this study was to establish the role of an energy deficit in mediating improved insulin action after short-term exercise training. Two groups of previously sedentary, overweight/obese subjects performed 6 consecutive days of moderate-intensity walking to expend approximately 500 kcal/day. In one group, energy and carbohydrate expended during exercise was replaced [balance group (BAL), n = 8] and in the other group, energy was not replaced [deficit group (DEF), n = 8]. Insulin action (blood glucose uptake during glucose infusion) and selected lipids and adipokines were measured pre- and posttraining. Training increased estimated daily energy expenditure by approximately 500 kcal/day (DEF = 469 +/- 45, BAL = 521 +/- 48), generating an energy deficit in DEF (-481 +/- 24 kcal/day) but not BAL (+8 +/- 20 kcal/day). Insulin action increased 40% in DEF (P = 0.032) but not BAL (-8.4%, P = 0.107). Hepatic glucose production was suppressed during glucose infusion in DEF (30.2 +/- 9.5%, P = 0.037) but not BAL (-10.0 +/- 7.4%, P = 0.417). Fasting leptin concentrations declined in DEF but not BAL. Six days of exercise training without energy replacement significantly increased insulin action. Restoring energy balance by refeeding the energy and carbohydrate expended during exercise resulted in no change in insulin action. These findings suggest that changes in short-term energy and/or carbohydrate balance play a key role in mediating the beneficial effects of exercise on whole body and hepatic insulin action.     

Effects of experimental weight perturbation on skeletal muscle work efficiency in human subjects

Maintenance of reduced or elevated body weight results in respective decreases or increases in energy expended in physical activity, defined as 24-h energy expenditure excluding resting energy expenditure and the thermic effect of feeding, beyond those attributable to weight change. We examined skeletal muscle work efficiency by graded cycle ergometry and, in some subjects, rates of gastrocnemius muscle ATP flux during exercise by magnetic resonance spectroscopy (MRS), in 30 subjects (15 males, 15 females) at initial weight and 10% below initial weight and in 8 subjects (7 males, 1 female) at initial weight and 10% above initial weight to determine whether changes in skeletal muscle work efficiency at altered body weight were correlated with changes in the energy expended in physical activity. At reduced weight, muscle work efficiency was increased in both cycle ergometry [mean (SD) change = +26.5 (26.7)%, P < 0.001] and MRS [ATP flux change = -15.2 (23.2)%, P = 0.044] studies. Weight gain resulted in decreased muscle work efficiency by ergometry [mean (SD) change = -17.8 (20.5)%, P = 0.043]. Changes in muscle efficiency at altered body weight accounted for 35% of the change in daily energy expended in physical activity.     

Effects of dietary protein content on IGF-I, testosterone, and body composition during 8 days of severe energy deficit and arduous physical activity.

Energy restriction coupled with high energy expenditure from arduous work is associated with an altered insulin-like growth factor-I (IGF-I) system and androgens that are coincident with losses of fat-free mass. The aim of this study was to determine the effects of two levels of dietary protein content and its effects on IGF-I, androgens, and losses of fat-free mass accompanying energy deficit. We hypothesized that higher dietary protein content would attenuate the decline of anabolic hormones and, thus, prevent losses of fat-free mass. Thirty-four men [24 (SD 0.3) yr, 180.1 (SD 1.1) cm, and 83.0 (SD 1.4) kg] participated in an 8-day military exercise characterized by high energy expenditure (16.5 MJ/day), low energy intake (6.5 MJ/day), and sleep deprivation (4 h/24 h) and were randomly divided into two dietary groups: 0.9 and 0.5 g/kg dietary protein intake. IGF-I system analytes, androgens, and body composition were assessed before and on days 4 and 8 of the intervention. Total, free, and nonternary IGF-I and testosterone declined 50%, 64%, 55%, and 45%, respectively, with similar reductions in both groups. There was, however, a diet x time interaction on day 8 for total IGF-I and sex hormone-binding globulin. Decreases in body mass (3.2 kg), fat-free mass (1.2 kg), fat mass (2.0 kg), and percent body fat (1.5%) were similar in both groups (P = 0.01). Dietary protein content of 0.5 and 0.9 g/kg minimally attenuated the decline of IGF-I, the androgenic system, and fat-free mass during 8 days of negative energy balance associated with high energy expenditure and low energy intake.     

Activation of dopamine D2 receptors simultaneously ameliorates various metabolic features of obese women

The metabolic syndrome comprises a cluster of metabolic anomalies including insulin resistance, abdominal obesity, dyslipidemia, and hypertension. Previous studies suggest that impaired dopamine D2 receptor (D2R) signaling is involved in its pathogenesis. We studied the acute effects of bromocriptine (a D2R agonist) on energy metabolism in obese women; body weight and caloric intake remained constant. Eighteen healthy, obese women (BMI 33.2 +/- 0.6 kg/m(2), mean age 37.5 +/- 1.7, range 22-51 yr) were studied twice in the follicular phase of their menstrual cycle in a prospective, single-blind, crossover design. Subjects received both placebo (P; always first occasion) and bromocriptine (B; always second occasion) on separate occasions for 8 days. At each occasion blood glucose and insulin were assessed every 10 min for 24 h, and circadian plasma free fatty acid (FFA) and triglyceride (TG) levels were measured hourly. Fuel oxidation was determined by indirect calorimetry. Body weight and composition were not affected by the drug. Mean 24-h blood glucose (P < 0.01) and insulin (P < 0.01) were significantly reduced by bromocriptine, whereas mean 24 h FFA levels were increased (P < 0.01), suggesting that lipolysis was stimulated. Bromocriptine increased oxygen consumption (P = 0.03) and resting energy expenditure (by 50 kcal/day, P = 0.03). Systolic blood pressure was significantly reduced by bromocriptine. Thus these results imply that short-term bromocriptine treatment ameliorates various components of the metabolic syndrome while it shifts energy balance away from lipogenesis in obese humans.     

Reduced short-term thermic effects of a meal in obese adolescent girls

Post-meal energy expenditure (TEM) was compared for 14 healthy obese (body fat = 45.3%, body mass index, BMI = 35.9 kg m-2) and 9 healthy nonobese (body fat = 20.7%, BMI = 17.8 kg m-2) adolescent girls. The test meal for both groups was a standard 3348.8-kJ, 0.473-1 chocolate milkshake of 15% protein (casein), 40% fat (polyunsaturated/saturated ratio = 0.05; 75 mg cholesterol) and 45% carbohydrate (lactose and sucrose). Glucose, insulin and resting energy expenditure (RMR) were measured at rest prior to meal consumption and 20, 40, 60, 90, and 120 min after the meal. Cumulative net TEM was calculated as the integrated area under the TEM curve with RMR as baseline. Reliability was assessed by retesting 4 subjects, and a placebo effect was tested by administering a flavored energy-free drink. Results indicated high reliability and no placebo effect. The meal resulted in a greater rise in insulin and glucose for the obese compared to the nonobese subjects (P < or = 0.05), and a significant TEM for both groups (P < or = 0.05). The cumulative TEM (W kg-1) was 61.9% greater for the nonobese (P < 0.01) when expressed relative to body mass, and 33.2% greater for the nonobese (P < or = 0.01) when expressed relative to the fat-free body mass. Expressed relative to the meal, the TEM was 25.5% less for the obese (P < 0.01). The data support an energy conservation hypothesis for obese female adolescents.     

Pattern and cost of weight gain in previously obese women

Weight gain is common among postobese individuals, providing an opportunity to address the cost of weight regain on energy expenditure. We investigated the energy cost of weight regain over 1 yr in 28 women [age 39.5 +/- 1.3 (SE) yr; body mass index 24.2 +/- 0.5 kg/m(2)] with recent weight loss (>12 kg). Body composition, total energy expenditure (TEE) using doubly labeled water, resting metabolic rate (RMR), and thermic effect of a meal (TEM) were assessed at 0 and 12 mo. Metabolizable energy intake (MEI) was calculated from TEE and change in body composition. Fourteen women had a weight gain of 13.2 +/- 2.1 kg. Twelve-month cumulative excess MEI, calculated as the intake in excess of TEE at month 0, was 749 +/- 149 MJ. Of this, 462 +/- 83 MJ (62%) were stored as accrued tissue, and 287 +/- 72 MJ (38%) was increased TEE. Expressed per kilogram of body weight gain, the energy cost of weight gain was calculated to be 54.8 +/- 4.6 MJ/kg. Interestingly, weight regain time courses fell into three distinct patterns, possibly requiring varying countermeasures.     

Characterization of the diurnal rhythm of peptide YY and its association with energy balance parameters in normal-weight premenopausal women

PYY may play a role in modulating satiety and energy expenditure; increasing PYY postprandially has been studied largely in single-meal responses. The diurnal rhythm of PYY and its role in energy balance have not been fully characterized. The purpose of our study was to characterize features of the diurnal rhythm of PYY and determine its role in regulating energy balance. This study was a cross-sectional analysis of 11 subjects in whom 24-h repeated blood sampling was conducted at baseline of a larger prospective study. Breakfast (B), lunch (L), dinner (D), and a snack (S) occurred between 0900 and 1900. Total PYY was assayed every hour from 0800 to 1000, every 20 min from 1000 to 2000, and every hour from 2000 to 0800. PYY variables included total AUC, postprandial peaks, and 24-h mean. Energy balance variables included energy intake, RMR, RQ, and NEAT. PYY postprandial peaks were significantly higher than fasting (P < 0.05). Twenty-four-hour peak PYY occurred after L and was significantly higher than all other peaks (P < 0.05). A cubic curve function accounted for most of the variance in PYY (r(2) = 69.9%, P < 0.01). Fasting PYY (0800) correlated with postprandial peaks at B (r = 0.77, P = 0.01), L (r = 0.71, P = 0.01), and D (r = 0.65, P = 0.03). The only significant association between PYY and energy expenditure was that RMR (kcal/24 h) correlated with 24-h mean PYY (r = 0.71, P = 0.013) and total AUC (r = 0.69, P = 0.019). We conclude that PYY displays a meal-driven diurnal rhythm and is correlated to RMR, a major contributor to energy expenditure. Thus, PYY varies in accordance with energy content and RMR, supporting a role for PYY in energy balance modulation.     

Energy expenditure climbing Mt. Everest.

Weight loss is a well-known phenomenon at high altitude. It is not clear whether the negative energy balance is due to anorexia only or an increased energy expenditure as well. The objective of this study was to gain insight into this matter by measuring simultaneously energy intake, energy expenditure, and body composition during an expedition to Mt. Everest. Subjects were two women and three men between 31 and 42 yr of age. Two subjects were observed during preparation at high altitude, including a 4-day stay in the Alps (4,260 m), and subsequently during four daytime stays in a hypobaric chamber (5,600-7,000 m). Observations at high altitude on Mt. Everest covered a 7- to 10-day interval just before the summit was reached in three subjects and included the summit (8,872 m) in a fourth. Energy intake (EI) was measured with a dietary record, average daily metabolic rate (ADMR) with doubly labeled water, and resting metabolic rate (RMR) with respiratory gas analysis. Body composition was measured before and after the interval from body mass, skinfold thickness, and total body water. Subjects were in negative energy balance (-5.7 +/- 1.9 MJ/day) in both situations, during the preparation in the Alps and on Mt. Everest. The loss of fat mass over the observation intervals was 1.4 +/- 0.7 kg, on average two-thirds of the weight loss (2.2 +/- 1.5 kg), and was significantly correlated with the energy deficit (r = 0.84, P < 0.05). EI on Mt. Everest was 9-13% lower than during the preparation in the Alps.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects on energy expenditure of facial cooling during exercise.

Estimated energy expenditures for men during Arctic manhauling expeditions were 29-33 MJ day-1, higher than those documented for other hard-working groups and exceeding predicted energy costs for such activities. Although physiological effects from generalised cooling were unlikely, cold exposure of the face could have influenced exercise metabolism via autonomic stimulation. This hypothesis was examined by measuring oxygen consumption, energy expenditure, respiratory exchange ratio (R) and cardiovascular changes during rest and exercise, with and without exposure of the face to air at--20 degrees C. Measurements were made in five subjects during 15 min of rest followed by continuous exercise on a cycle ergometer consisting of 15-min periods at 75, 100, 125 and 150 W external work. The cold air caused a profound fall in facial temperatures and small falls in mean skin and rectal temperatures (P less than 0.001). These changes were associated with a small increase in the mean oxygen consumption over all levels of rest and exercise (0.86 l min-1 vs 0.82 l min-1, P less than 0.001) and a corresponding increase in mean energy expenditure (294 W vs 283 W, P less than 0.05). Cold air also caused an increase in mean resting R values (1.00 vs 0.88, P less than 0.01) but a decrease in the mean R value for all levels of exercise (0.85 vs 0.91, P less than 0.05). Pulse rates were unchanged but systolic and diastolic blood pressures were relatively elevated throughout the cold face experiments (P less than 0.001).     

Effects of ambient temperature on adaptive thermogenesis during maintenance of reduced body weight in mice

We showed previously that, at ambient room temperature (22°C), mice maintained at 20% below their initial body weight by calorie restriction expend energy at a rate below that which can be accounted for by the decrease of fat and fat-free mass. Food-restricted rodents may become torpid at subthermoneutral temperatures, a possible confounding factor when using mice as human models in obesity research. We examined the bioenergetic, hormonal, and behavioral responses to maintenance of a 20% body weight reduction in singly housed C57BL/6J +/+ and Lep(ob) mice housed at both 22°C and 30°C. Weight-reduced high-fat-fed diet mice (HFD-WR) showed similar quantitative reductions in energy expenditure-adjusted for body mass and composition-at both 22°C and 30°C: -1.4 kcal/24 h and -1.6 kcal/24 h below predicted, respectively, and neither group entered torpor. In contrast, weight-reduced Lep(ob) mice (OB-WR) housed at 22°C became torpid in the late lights-off period (0200-0500) but did not when housed at 30°C. These studies indicate that mice with an intact leptin axis display similar decreases in "absolute" energy expenditure in response to weight reduction at both 22°C and 30°C ambient temperature. More importantly, the "percent" decrease in total energy expenditure observed in the HFD-WR compared with AL mice is much greater at 30°C (-19%) than at 22°C (-10%). Basal energy expenditure demands are ～45% lower in mice housed at 30°C vs. 22°C, since the mice housed at thermoneutrality do not allocate extra energy for heat production. The higher total energy expenditure of mice housed at 22°C due to these increased thermogenic demands may mask physiologically relevant changes in energy expenditure showing that ambient temperature must be carefully considered when quantifying energy metabolism in both rodents and humans.     

Diminished dietary thermogenesis in exercise-trained human subjects

The influence of exercise-training on dietary-induced thermogenesis (DIT) was investigated in humans. The resting metabolic rate was identical in trained and non-trained subjects, but the response to a meal containing 1,636 kcal (6.9 MJ) was markedly lower in trained subjects. Mean dorsal skin temperature, as measured by thermography, was not influenced by training. A significant correlation was observed between postprandial RQ and DIT, which indicates that the reduced energy expenditure noted in trained subjects is related to a greater lipid oxidation. This sparing effect of exercise-training on energy utilization in the form of carbohydrate, is interpreted as adaptive in the sense that energy is preserved for the purpose of producing work.     

Canadian recommendations underestimate energy needs of women over fifty years as determined by doubly-labelled water

Accurate estimations of energy requirements at the population level are crucial because of disease processes associated with energy imbalance. The present objective was to compare energy expenditure with existing Recommended Nutrient Intakes for Canadians (RNIC) and determine whether the RNIC provides a true index of energy requirement in middle-aged and elderly Canadian women. A second objective was to compare energy expenditure and the RNIC to Food and Agriculture Organization, World Health Organization, United Nations University (FAO/WHO/UNU) predictions. Seventy-six women were recruited for the study (67.3 +/- 11.5 y, 63 +/- 11.7 kg, BMI 24.8 +/- 4.4 kg x m(-2)). The two-point doubly-labelled water (DLW) method was used over 13 days to assess energy expenditure while subjects carried out their routine activities. Subjects were stratified to enable age specific requirements for middle-aged and elderly women. At weight maintenance, energy needs were underestimated using the RNIC (7.1 +/- 1.6 MJ x d(-1), 1698 +/- 391 kcal x d(-1)) compared to total energy expenditure (10.0 +/- 3.2 MJ x d(-1), 2395 +/- 746 kcal x d(-1)) as determined by DLW as a whole and for each age group. The RNIC recommendations were lower than the FAO/WHO/UNU estimations even for light activity. Results indicate that mean energy expenditure was 29% greater than the RNIC recommendations created using formulas based on age and weight, whereas the FAO/WHO/ UNU estimations closely approximated energy expenditure based on heavy activity in women 49-79 y and light activity in women over 80 y old. These data suggest a systematic underestimation of Canadian energy recommendations for women.     

The Angiogenic Inhibitor TNP-470 Decreases Caloric Intake and Weight Gain in High-Fat Fed Mice

The angiogenic inhibitor TNP-470 attenuates high-fat diet-induced obesity; however, it is not clear how the compound alters energy balance to prevent weight gain. Five-week-old C57BL/6J mice were fed high-fat diet (45% energy from fat) for 6.5 weeks and treated with TNP-470 (20 mg/kg body weight; n = 7) or vehicle (saline; n = 7). Control mice (n = 8) received standard chow and sham injection. TNP-470 mice initially gained weight, but by day 5 body weight was significantly less than high-fat fed (HFF) mice and not different from that of chow-fed mice, an effect maintained to the end of the study (28.6 ± 0.6 vs. 22.4 ± 0.6 and 22.2 ± 0.5 g). Percent body fat was reduced in TNP-470 compared to HFF mice, but was greater than that of chow mice (34.0 ± 1.5, 23.9 ± 1.5, and 17.0 ± 1.4%, P < 0.05). Food intake in TNP-470-treated mice was less (P < 0.05) than that in HFF mice by day 5 of treatment (2.5 ± 0.1 vs. 2.8 ± 0.1 g/mouse/day) and remained so to the end of the study. Twenty-four hours energy expenditure was greater (P < 0.05) in TNP-470 than HFF or chow mice (7.05 ± 0.07 vs. 6.69 ± 0.08 vs. 6.79 ± 0.09 kcal/kg/h), an effect not explained by a difference in energy expended in locomotion. Despite normalization of body weight, TNP-470 mice exhibited impaired glucose tolerance (area under the curve 30,556 ± 1,918 and 29,290 ± 1,584 vs. 24,421 ± 903 for TNP, HFF, and chow fed, P < 0.05). In summary, the angiogenic inhibitor TNP-470 attenuates weight gain in HFF mice via a reduction in caloric intake and an increase in energy expenditure.