Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Energy”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 127 records · Page 7Linked to original sources
PubMedDate not supplied

Energy-enriched hospital food to improve energy intake in elderly patients.

BACKGROUND: It was hypothesized that energy intake in hospitalized elderly patients could be improved by increasing the density of energy of the food and that the volume of food actually consumed, even with a higher energy content than the normal, would not change with servings of high energy-dense hospital food. METHODS: Thirty-six elderly patients (52 to 96 years) of both sexes, long-term treated at two comparable wards, participated in this study. The patients were given 6 weeks of regular hospital food (RHF, 1670 kcal/d, 7.0 MJ) and 6 weeks of high-energy food (HE, 2520 kcal/d, 10.5 MJ). The volume of food was kept constant. A crossover study design was used. Food intake, energy intake, body weight, and modified functional condition (Norton scale) were measured. RESULTS: Regardless of type of food (RHF or HE) and time of day (lunch or dinner), he food portion size (volume of food) intake was the same, approximately 80% of the portions consumed. HE led to a 40% increase in energy intake (from 25 +/- 1 during RHF to 35 +/- 2 kcal/kg/d, p < .0001), which resulted in a 3.4% increase in body weight (p < .001) after 3 weeks of HE. Only minimal changes in functional condition were found. The cost of HE was substantially lower (-85%) than any other mean available for improvement of energy intake. CONCLUSIONS: A significant increase in energy intake can be achieved by higher energy density in regular hospital food and that HE does not cause a decrease in the volume of the food consumed. These findings suggest that it is the volume of food rather than the energy that limits voluntary energy intake of hospital food in elderly hospitalized patients.

Aged↗
PubMed1982

Partition of energy metabolism and energy cost of growth in the very low-birth-weight infant.

Energy requirements are partitioned between needs for maintenance (including resting metabolism, thermoregulation, and muscular activity) and needs for synthesis and storage of new tissue. The partition of energy utilization was evaluated by 22 metabolic and nutritional balance studies in 13 formula-fed (SMA 20/24), growing, appropriate-for-gestational age, very low-birth-weight infants (mean +/- SE birth weight, 1,155 +/- 39 gm; study weight, 1,271 +/- 60 gm; age at study, 21 +/- 2 days; weight gain, 16.8 +/- 1 gm/kg/day). Continuous open-circuit, indirect calorimetry was performed for periods of 6 +/- 0.25 hours in a thermoneutral environment. Results expressed as mean kilocalories per kilogram per day (+/- SE) were: energy intake, 148.6 (+/- 3.9); stool and urine losses, 18.2 (+/- 1.5); metabolizable energy, 130.4 (+/- 3.5); "basal" metabolic rate, 47.0 (+/- 0.75); energy cost of activity, 4.3 (+/- 0.9); thermic effect of food, 11.3 (+/- 0.65); energy stored in new tissue, 67.8 (+/- 3.0). These results provide a partition of energy utilization in very low-birth-weight infants under thermoneutral conditions. Increased activity and a thermal environment outside the neutral range will augment maintenance energy requirements, thus decreasing the amount of energy available for growth if metabolizable energy intake remains constant. The energy cost of growth (ie, for synthesis of, and storage in, new tissue) was determined as 4.9 kcal/gm of weight gain. To attain the equivalent rate of intrauterine weight gain, a metabolizable energy intake of approximately 60 kcal/kg/day in excess of maintenance requirements of 51.3 kcal/dk/day must be provided.

Anthropometry↗
PubMed1993

Energy storing property of so-called energy-storing prosthetic feet.

The purpose of this study is to evaluate the energy storing and releasing property of 14 different prosthetic feet, in which so-called energy storing prosthetic feet are included. The prostheses were fitted to a young male amputee who walked on a level and slope walkway. Gait-analysis data were obtained by an automatic gait measurement system from which the ankle moment and ankle angular velocity were calculated. From these values, the power and the energy at the ankle joint were calculated. The prosthetic feet were ranked according to the total amount of energy, that is the sum of energy being stored and released. Both of the stored and released energy are important feature of the prosthetic feet. According to these evaluation criteria, we ranked the feet into three groups. The high total energy feet were Flex-Walk,a SAFE II,b and High Functionc. The medium total energy feet were SAFE,b Greissinger,d Seattle,e Copy II,f and Dynamic.d The low total energy feet were Seattle Light,e Fore Joint,g Quantum,h SACH,dSTEN,i and Uniaxial.d As for the subjective feeling, our subject preferred higher energy absorbing feet, in which a somewhat high level of energy was stored but low level of energy was released.

Adult↗
PubMedDate not supplied

[The effect of energy density and viscosity of porridges on the energy intake of infants].

It has been known for at least 25 years that high energy density and low viscosity are desirable attributes of complementary foods. However, the effects of increasing energy density and reducing viscosity of gruels on infant energy intake have only been studied in the last 10 years. Works published between 1986 and 1992 were carried out with infants randomly selected in urban slums or rural areas in India and Tanzania. When gruels are given in a single meal, all of them showed higher energy intake with both high energy-dense and low viscosity gruels. But these studies do not give information about the effects of these gruels on daily energy intake from gruels and on total daily energy intake when they are given with feeding frequencies corresponding to traditional weaning practices. Works published since 1992 were conducted among infants suffering from or recovering from acute diarrhoea or severe malnutrition. A positive effect of increasing energy density of gruels was observed not only on energy intake from gruels but also on total energy intake. On the other hand, effectiveness of reducing viscosity was not clearly demonstrated. Further studies are required, particularly to identify the conditions for which high energy dense gruels prepared from bulk-reduced starchy staples are able to significantly improve infant energy intake.

Diarrhea, Infantile↗
PubMed1996

Average activation energies of low-energy fragmentation processes of protonated peptides determined by a new approach.

An attempt was made to estimate the average activation energies of low-energy fragmentation processes of protonated oligopeptides by combining RRKM theory and the results of electrospray ionization/surface induced dissociation (ESI/SID). The average internal energy was assumed to be deposited by three processes: thermal energy gained in the heated capillary of the electrospray source, energy gain in the capillary-skimmer region of the electrospray source, and energy deposition by collision with the surface. The latter fraction was calculated based on the position of the ESI/SID fragmentation of efficiency curves and the ratio of kinetic to internal energy conversion in SID. Using the average internal energy estimated from the experimental results, the average activation energies were evaluated by applying RRKM theory. The application of this approach for protonated leucine enkephalin resulted in an average activation energy of 36 +/- 5 kcal/mol for the lowest energy decompositions. The approach has also been applied to several other peptides in the mass range of 200-1200 Da, yielding average activation energies in the range of 35-47 kcal/mol.

Amino Acid Sequence↗
PubMed1996

High-energy electron irradiation of proteins and nucleic acids: collisional stopping power and average energy loss.

Inactivation of proteins due to the direct action of ionizing radiation and the electron energy loss spectra of organic materials indicate that an average of 60-66 eV of energy is lost from high energy electrons in each inelastic collision with target molecules. The average energy loss per inelastic collision with high energy electrons in solid, carbon-based materials, proteins and nucleic acids is calculated from mass collisional stopping powers and empirical total inelastic cross-sections. Bragg's Additivity Law is used for the calculation of the mean excitation energy of molecules. For simple organic compounds, the calculated average energy loss is close to that obtained by direct observation of the energy loss suffered by electrons as they pass through thin films of organic material. The density effect correction for the rate of energy loss, important in the more complex case of proteins irradiated with 10 MeV electrons, is determined using the comparable mass collisional stopping power of water and proteins. In this manner, a value is obtained for the average energy per inelastic collision of high energy electrons with proteins, which is similar to the average energy per inactivating event of proteins. Analogous calculations for nucleic acids are also presented.

Electrons↗
PubMed1995

Simulating the folding of small proteins by use of the local minimum energy and the free solvation energy yields native-like structures.

Assuming that the protein primary sequence contains all information required to fold a protein into its native tertiary structure, we propose a new computational approach to protein folding by distributing the total energy of the macromolecular system along the torsional axes. We further derive a new semiempirical equation to calculate the total energy of a macromolecular system including its free energy of solvation. The energy of solvation makes an important contribution to the stability of biological structures. The segregation of hydrophilic and hydrophobic domains is essential for the formation of micelles, lipid bilayers, and biological membranes, and it is also important for protein folding. The free energy of solvation consists of two components: one derived from interactions between the atoms of the protein, and the second resulting from interactions between the protein and the solvent. The latter component is expressed as a function of the fractional area of protein atoms accessible to the solvent. The protein-folding procedure described in this article consists of two successive steps: a theoretical transition from an ideal alpha helix to an ideal beta sheet is first imposed on the protein conformation, in order to calculate an initial secondary structure. The most stable secondary structure is built from a combination of the lowest energy structures calculated for each amino acid during this transition. An angular molecular dynamics step is then applied to this secondary structure. In this computational step, the total energy of the system consisting of the sum of the torsional energy, the van der Waals energy, the electrostatic energy, and the solvation energy is minimized. This process yields 3-D structures of minimal total energy that are considered to be the most probable native-like structures for the protein. This method therefore requires no prior hypothesis about either the secondary or the tertiary structure of the protein and restricts the input of data to its sequence. The validity of the results is tested by comparing the crystalline and computed structures of four proteins, i.e., the avian and bovine pancreatic polypeptide (36 residues each), uteroglobin (70 residues), and the calcium-binding protein (75 residues); the C alpha-C alpha maps show significant homologies and the position of secondary structure domains; that of the alpha helices is particularly close.

Animals↗
PubMed2006

Energy transfer between polyatomic molecules II: Energy transfer quantities and probability density functions in benzene, toluene, p-xylene, and azulene collisions.

Collisional energy transfer, CET, is of major importance in chemical, photochemical, and photophysical processes in the gas phase. In Paper I of this series (J. Phys. Chem. B 2005, 109, 8310) we have reported on the mechanism and quantities of CET between an excited benzene and cold benzene and Ar bath. In the present work, we report on CET between excited toluene, p-xylene, and azulene with cold benzene and Ar and on CET of excited benzene with cold toluene, p-xylene, and azulene. We compare our results with those of Paper I and report average vibrational, rotational, and translational energy quantities, , transferred in a single collision. We discuss the effect of internal rotation on CET and the identity of the gateway modes in CET and the relative role of vibrational, rotational, and translational energies in the CET process, all that as a function of temperature and excitation energy. Energy transfer probability density functions, P(E,E'), for the various systems are reported and the shape of the curves for various systems and initial conditions is discussed. The major findings for polyatomic-polyatomic collisions are: CET takes place mainly via vibration-to-vibration energy transfer assisted by overall rotations. Internal free rotors in the excited molecule hinder energy exchange while in the bath molecule they do not. Energy transfer at low temperatures and high temperatures is more efficient than that at intermediate temperatures. Low-frequency modes are the gateway modes for energy transfer. Vibrational temperatures affect energy transfer. The CET probability density function, P(E,E'), is convex at low temperatures and can be concave at high temperatures. A mechanism that explains the high values of and the convex shape of P(E,E') is that in addition to short impulsive collisions there are chattering collisions where energy is transferred in a sequence of short encounters during the lifetime of the collision complex. This also leads to the observed supercollision tail at the down wing of P(E,E'). Polyatomic-Ar collisions show mechanistic similarities to polyatomic-polyatomic collisions, but there are also many dissimilarities: internal rotations do not inhibit energy transfer, P(E,E') is concave at all temperatures, and there is no contribution of chattering collisions.

Journal Article↗
PubMed2006

Oxyntomodulin increases energy expenditure in addition to decreasing energy intake in overweight and obese humans: a randomised controlled trial.

BACKGROUND: Oxyntomodulin has recently been found to decrease body-weight in obese humans and may be a potential anti-obesity therapy. OBJECTIVE: To determine whether oxyntomodulin alters energy expenditure, in addition to reducing energy intake, in 'free-living' overweight and obese volunteers. DESIGN: Randomized double-blind controlled cross-over trial. SETTING: Community and hospital-based. PARTICIPANTS: Fifteen healthy overweight and obese men and women (age: 23-49 years, BMI: 25.1-39.0 kg/m(2)). All volunteers completed the study protocol. INTERVENTIONS: Four-day subcutaneous self-administration of pre-prandial oxyntomodulin, three times daily. Participants were advised to maintain their normal dietary and exercise regimen. MEASUREMENTS: (1) Energy expenditure, measured by indirect calorimetry and combined heart rate and movement monitoring; (2) energy intake, measured during a study meal. RESULTS: Oxyntomodulin administration reduced energy intake at the study meal by 128+/-29 kcal (P=0.0006) or 17.3+/-5.5% (P=0.0071), with no change in meal palatability. Oxyntomodulin did not alter resting energy expenditure; but increased activity-related energy expenditure by 143+/-109 kcal/day or 26.2+/-9.9% (P=0.0221); total energy expenditure by 9.4+/-4.8% (P=0.0454) and physical activity level by 9.5+/-4.6% (P=0.0495). A reduction in body weight of 0.5+/-0.2% was observed during the oxyntomodulin administration period (P=0.0232). CONCLUSION: Oxyntomodulin increases energy expenditure while reducing energy intake resulting in negative energy balance. This data supports the role of oxyntomodulin as a potential anti-obesity therapy.

Adult↗
PubMed1984

Human energy metabolism below, near and above energy equilibrium.

Complete 24 h energy and nitrogen balances were measured for fifteen subjects at three levels of energy intake and for two other subjects at two levels of intake. At each level, the fifteen subjects ate diets consisting of fifteen to twenty separate foods for 7 or 8 d. Faeces and urine were collected for the final 4 d. Respiratory gas exchange was measured during the final 72 h while the subjects stayed in an 11 m3 open-circuit respiration chamber, and simulated office or light household work. The energy balance of the other two subjects was determined initially in a similar way when they consumed a diet which was sufficient for energy equilibrium. Subsequently, the measurements were repeated twice at the same high level of metabolizable energy (ME) intake after 4 and 18 d on that diet. Neither energy nor N digestibilities were significantly affected by intake level or subject. Due to relatively small urinary energy losses the ME content of the gross energy increased slightly at the higher intake. Respiratory quotient increased with intake level from 0.78 to 0.87. The efficiencies of utilization of ME were approximately 1.0 for maintenance (from the low to the intermediate intake level) and decreased to about 0.9 for maintenance and energy deposition (from the intermediate to the high intake level). Estimates of daily ME requirements at energy equilibrium were 149 (SD 13) kJ ME/kg body-weight, 432 (SD 33) kJ ME/kg body-weight 0.75 and 204 (SD 22) kJ/kg lean body mass. The former two values were negatively correlated with percentage body fat although not significantly so. ME utilization and heat production of the other two subjects were nearly equal after 6 and 20 d on a diet supplying 1.5-1.7 times the ME needed for energy equilibrium.

Adolescent↗
PubMed1994

Effective energy: a concept of energy utilization applied across species.

An energy system is described in which, in both single-stomached and ruminant animals, the heat increment of feeding is considered to be linearly related to five measurable quantities. For both kinds of animals three of the quantities, with their heat increments in parentheses, are urinary N (wu; kJ/g), faecal organic matter (wd; kJ/g) and positive protein retention (wp; kJ/g). In ruminants the other two, with their heat increments in parentheses, are CH4 energy (wm; kJ/kJ) and positive lipid retention (w1; kJ/g); in single-stomached animals they are positive lipid retention from feed lipid (wII; kJ/g), and positive lipid retention not from feed lipid (wI; kJ/g). Data from suitable experiments on steers, pigs and chickens were used to test the system and to estimate wu 29.2, wd 3.80, wp 36.5, wm 0.616, wI 16.4 and wII 4.4. The values for wu, wd, wm and (wI - wII) allow an energy scale, called effective energy, to be defined for both single-stomached animals and ruminants. On this energy scale the values of wp and wI, together with the heats of combustion of protein and lipid of 23.8 and 39.6 kJ/g respectively, allow the energy requirement to be expressed as (MH + 50PR + 56LR) for both kinds of animal, where PR and LR are the rates of positive protein and lipid retention (g/d), and MH is the maintenance heat production (kJ/d) which can be estimated as 0.96 of the fasting heat production. The effective energy (EE) yielded to a ruminant animal by a feed ingredient can be estimated as EE (MJ/kg organic matter) = 1.15ME - 3.84 - 4.67DCP, where ME is the metabolizable energy value (MJ/kg organic matter) and DCP is the digested crude protein content (kg/kg organic matter) with both measured at maintenance. Alternatively, EE can be estimated as EE (MJ/kg) = GE (d - 0.228) - 4.67DCP, where GE is the gross energy (MJ/kg) and d is the energy digestibility (MJ/MJ) also measured at maintenance. The EE yielded to a single-stomached animal can be estimated as EE (kJ/g) = 1.17ME - 4.2CP - 2.44, where ME (kJ/g) is measured at, or corrected to, zero N-retention and CP (g/g) is the crude protein (N x 6.25) content of the feed ingredient. The system is simpler for ruminants, and more accurate for both kinds of animal, than those now in use. As effective energy values can be tabulated for ingredients, and are additive to the extent that ME values are additive, they can be used to formulate diets using linear programming.

Animal Nutritional Physiological Phenomena↗
PubMed1994

Effect of dietary energy restriction on retention of protein, fat and energy in broiler chickens.

1. Broiler chickens were fed 60-100% of recommended energy intakes to study the effects of energy restriction on protein and fat retention. 2. At an energy retention of 179 kJ/kg W0.75 d, only protein was retained. At higher energy intakes, each increment in retention had a rather constant composition: about 85% energy in fat and 15% in protein. At lower energy intakes body fat was mobilised whereas protein was deposited. 3. The efficiencies of energy retention in protein and fat were estimated to be 0.66 and 0.86 respectively. 4. The rather constant composition of additional retained energy after additional energy supply provides an explanation for a linear relationship between energy intake and energy retention.

Aging↗
PubMed1984

Estimation of energy expenditure and maintenance energy requirements of college-age men and women.

Data from two nationwide dietary surveys have led to the suggestion that human energy requirements have been overestimated. A 5-wk energy balance study was conducted to estimate the energy expenditure and maintenance energy requirements of 12 college-age men and women, 20 to 29 yr of age, by the factorial method and by measurement of energy intake and changes in body energy content (intake/balance technique). Mean daily energy expenditure estimated by the intake/balance technique and the factorial method, respectively, was 3081 and 3040 kcal (r = 0.90) for the male subjects and 2183 and 2283 kcal (r = 0.53) for the female subjects. Although differences between the intake/balance and factorial estimations of energy expenditure tended to be greater for individuals than groups and for females than males, the factorial method as performed in this study provided accurate estimations of energy expenditure. In addition, the estimated energy requirements of the college-age subjects in this study provide evidence to support the Recommended Dietary Allowances for energy for this age group.

Adult↗
PubMed1995

Interaction of acute changes in exercise energy expenditure and energy intake on resting metabolic rate.

The effects on resting metabolic rate (RMR) of energy intake and exercise energy expenditure were examined in eight trained men under four conditions: 1) high energy flux (HF), 90 min of exercise at 75% VO2max on 3 d while in energy balance; 2) low energy flux (LF), no exercise for 3 d while in energy balance; 3) negative energy balance (NEB), exercise on 3 d while consuming low-flux meals; and 4) positive energy balance (PEB), no exercise for 2 d while consuming high-flux meals. Eight untrained men were studied in LF. There were effects of exercise energy expenditure and energy intake on RMR, and an exercise x diet interaction (P < 0.05). RMR was greater in trained than in untrained subjects only when trained subjects were in HF. These data indicate that RMR is influenced by exercise, energy intake, and their interaction and suggest that higher RMR in trained vs untrained individuals results from acute effects of HF rather than from a chronic adaptation to exercise training.

Adolescent↗
PubMed1998

Energy density of foods affects energy intake in normal-weight women.

This study examined the effect of energy density, independent of fat content and palatability, on food and energy intakes. With use of a within-subjects design, normal-weight women (n = 18) were provided with meals for 2 d during each of three test sessions. During lunch, dinner, and an evening snack, subjects were given free access to a main entree varying in energy density (low, medium, or high). The manipulated main entrees were similar in palatability to their counterparts across conditions. Low-energy compulsory (consumption required) side dishes accompanied each meal. Subjects also consumed a standard, compulsory breakfast. Results showed that subjects consumed a similar amount of food (by weight) across the three conditions of energy density. Thus, significantly more energy was consumed in the condition of high energy density (7532 +/- 363 kJ, or 1800 +/- 86 kcal) than in the medium- (6356 +/- 281 kJ, or 1519 +/- 67 kcal) and low- (5756 +/- 178 kJ, or 1376 +/- 43 kcal) energy-density conditions (P < 0.0001). There were no differences in hunger or fullness before meals, after meals, or over the 2 d across conditions. The results from this study indicate that energy density affects energy intake independent of macronutrient content or palatability, suggesting that the overconsumption of high-fat foods may be due to their high energy density rather than to their fat content.

Adult↗
PubMed2000

Energy expenditure, energy intake, and weight loss in Alzheimer disease.

Alzheimer disease is one of the leading causes of death among older individuals. Unexplained weight loss and cachexia are frequent clinical findings in patients with Alzheimer disease. Thus, it has been postulated that Alzheimer disease may be associated with dysfunction in body weight regulation. This brief review examines the interrelations among energy intake, energy expenditure, and body composition in Alzheimer disease. We explored whether abnormally high daily energy expenditures, low energy intakes, or both contribute to unexplained weight loss and a decline in nutritional status. Specifically, we considered studies that examined energy intake, body composition, and daily energy expenditure and its components. The application of doubly labeled water and indirect calorimetry to understand the etiology of wasting has increased our knowledge regarding the relation among energy expenditure, physical activity levels, and body composition in Alzheimer disease patients. Although the number of studies are limited, results do not support the notion that a hypermetabolic state contributes to unexplained weight loss in Alzheimer disease, even in cachectic patients. Recent findings are presented suggesting an association between abnormally elevated levels of physical activity energy expenditure and elevated appendicular skeletal muscle mass and energy intake in Alzheimer disease patients. Clinical strategies aimed at developing lifestyle and dietary interventions to maintain adequate energy intake, restore energy balance, and maintain skeletal muscle mass should be a future area of investigation in Alzheimer disease research.

Aged↗
PubMed1994

Future directions for energy requirements and food energy values.

The energy values of foods have been expressed in units of metabolizable energy (ME) since Atwater's time. Atwater "specific factors" for protein, fat and carbohydrate of food groups are used to compute energy values for individual foods. Although remarkably successful for many years this system is changing in order to provide the means to predict the energy value of new foods and formulations containing food substitutes, bulking agents, sweeteners, etc. New methods of analysis will allow prediction of energy value of new and unusual foods from chemical analyses. Originally used to determine the needed food supply for whole populations, statements of energy requirements are now needed for diet formulation for individuals. The mean energy requirements of populations are very adequately defined by WHO and the NRC RDA's by establishing ratios of total energy expenditure to basal metabolic rate (BMR). These estimates have been validated by use of the doubly labelled water (DLW) method to measure energy expenditure of free-living subjects over periods of 10-14 days. Substantial improvement in the prediction of energy needs for individuals will require the means to quantify physical effort, resolve effects of body composition on basal metabolic rate, and define the extent of variation in the use of metabolizable energy (ME) in non-steady state situations such as are caused by systematic changes in diet composition, body weight, and patterns of exercise.

Adaptation, Physiological↗
PubMed1999

Modeling of energy balance in early lactation and the effect of energy deficits in early lactation on first detected estrus postpartum in dairy cows.

The general pattern of energy balance in early lactation was modeled. For this purpose, several lactation curves were investigated. The best fitting curve was fit in a random regression model that provided predicted energy balance curves for all lactations. By use of these curves, total energy deficit per lactation, postpartum interval of return to positive energy balance, and nadir of energy balance was determined. In predicted energy balances, nadir of energy balance was present, but variation in postpartum interval to nadir was small. First lactation cows had a smaller energy deficit in early lactation than did older cows. Differences among cows in nadir and total energy deficits in early lactation were large. Both were related to the postpartum interval to first detected estrus with a larger energy deficit and a smaller nadir corresponding to a larger postpartum interval to first detected estrus. From this study, it can be concluded that large energy deficits in early lactation delay first detected estrus.

Animals↗