Doubly labeled water

npj Microgravity

Bedrest shifts fasting and postprandial fuel selection towards carbohydrate use over lipids, potentially affecting astronauts’ performance and health. We investigated whether this change occurs in astronauts after at least 3 months onboard the International Space Station (ISS). We further explored the associations with diet, physical activity (PA), and body composition. Before and during spaceflight, respiratory quotient (RQ), carbohydrate, and fat oxidation were measured by indirect calorimetry before and following a standardized meal in 11 males (age = 45.7 [SD 7.7] years, BMI = 24.3 [2.1] kg m−²). Postprandial substrate use was determined by 0-to-260 min postprandial incremental area under the curve (iAUC) of nutrient oxidation and the difference between maximal postprandial and fasting RQ (ΔRQ). Food quotient (FQ) was calculated from diet logs. Fat (FM) and fat-free mass (FFM) were measured by …

The American Journal of Clinical Nutrition

BackgroundThe association of total energy intake (EI) with all-cause mortality is uncertain, as are the dependencies of this association on age and weight change history.ObjectivesTo identify an EI biomarker suitable for use in epidemiologic association studies, and to study EI associations with total mortality in a Women’s Health Initiative (WHI) cohort of postmenopausal U.S. females (1993-present).DesignEI biomarkers were developed based on doubly-labeled water (DLW) total energy expenditure (TEE) and weight variation during the two-week DLW protocol period using the energy balance method, in an embedded feeding study (n=153). This along with two earlier WHI nutrition biomarker studies having TEE assessments (n=1131 total), with 14.6 years (median) follow-up, constituted a prospective cohort for the study of EI and all-cause mortality.ResultsAn empirical biomarker for log (EI) was developed that had …

British Journal of Nutrition

We aim to understand the effects of hydration changes on athletes’ neuromuscular performance, on body water compartments, fat-free mass hydration and hydration biomarkers and to test the effects of the intervention on the response of acute dehydration in the hydration indexes. The H2OAthletes study (clinicaltrials.gov ID: NCT05380089) is a randomised controlled trial in thirty-eight national/international athletes of both sexes with low total water intake (WI) (i.e. < 35·0 ml/kg/d). In the intervention, participants will be randomly assigned to the control (CG, n 19) or experimental group (EG, n 19). During the 4-day intervention, WI will be maintained in the CG and increased in the EG (i.e. > 45·0 ml/kg/d). Exercise-induced dehydration protocols with thermal stress will be performed before and after the intervention. Neuromuscular performance (knee extension/flexion with electromyography and handgrip), hydration …

Clinical Nutrition

Background & aimsThe multicompartment approach to body composition modeling provides a more precise quantification of body compartments in healthy and clinical populations. We sought to develop and validate a simplified and accessible multicompartment body composition model using 3-dimensional optical (3DO) imaging and bioelectrical impedance analysis (BIA).MethodsSamples of adults and collegiate-aged student-athletes were recruited for model calibration. For the criterion multicompartment model (Wang-5C), participants received measures of scale weight, body volume (BV) via air displacement, total body water (TBW) via deuterium dilution, and bone mineral content (BMC) via dual energy x-ray absorptiometry. The candidate model (3DO-5C) used stepwise linear regression to derive surrogate measures of BV using 3DO, TBW using BIA, and BMC using demographics. Test-retest precision of the …

Clinical Nutrition

BackgroundAthletes vary in hydration status due to ongoing training regimes, diet demands, and extreme exertion. With water being one of the largest body composition compartments, its variation can cause misinterpretation of body composition assessments meant to monitor strength and training progress. In this study, we asked what accessible body composition approach could best quantify body composition in athletes with a variety of hydration levels.MethodsThe Da Kine Study recruited collegiate and intramural athletes to undergo a variety of body composition assessments including air-displacement plethysmography (ADP), deuterium-oxide dilution (D2O), dual-energy X-ray absorptiometry (DXA), underwater-weighing (UWW), 3D-optical (3DO) imaging, and bioelectrical impedance (BIA). Each of these methods generated 2- or 3-compartment body composition estimates of fat mass (FM) and fat-free mass …

The American journal of clinical nutrition

BackgroundThe association of TEE with all-cause mortality is uncertain, as is the dependence of this association on age.ObjectivesTo examine the association between TEE and all-cause mortality, and its age interaction, in a Women’s Health Initiative (WHI) cohort of postmenopausal United States women (1992–present).MethodsA cohort of 1131 WHI participants having DLW TEE assessment of ∼10.0 y (median) following WHI enrollment with ∼13.7 y (median) of subsequent follow-up, was used to study the EE associations with all-cause mortality. To enhance the comparability of TEE and total EI, key analyses excluded participants having >5% weight change between WHI enrollment and DLW assessment. The influence of participant age on mortality associations was examined, as was the ability of concurrent and earlier weight and height measurements to explain the results.ResultsThere were 308 deaths …

BMC geriatrics

BackgroundDysregulated energy metabolism is one hypothesized mechanism underlying frailty. Resting energy expenditure, as reflected by resting metabolic rate (RMR), makes up the largest component of total energy expenditure. Prior work relating RMR to frailty has largely been done in cross section with mixed results. We investigated whether and how RMR related to 1-year frailty change while adjusting for body composition.MethodsN = 116 urban, predominantly African-American older adults were recruited between 2011 and 2019. One-year frailty phenotype (0–5) was regressed on baseline RMR, frailty phenotype, demographics and body composition (DEXA) in an ordinal logistic regression model. Multimorbidity (Charlson comorbidity scale, polypharmacy) and cognitive function (Montreal Cognitive Assessment) were separately added to the model to assess for change to the RMR-frailty relationship. The …

Nature metabolism

Obesity is caused by a prolonged positive energy balance,. Whether reduced energy expenditure stemming from reduced activity levels contributes is debated,. Here we show that in both sexes, total energy expenditure (TEE) adjusted for body composition and age declined since the late 1980s, while adjusted activity energy expenditure increased over time. We use the International Atomic Energy Agency Doubly Labelled Water database on energy expenditure of adults in the United States and Europe (n = 4,799) to explore patterns in total (TEE: n = 4,799), basal (BEE: n = 1,432) and physical activity energy expenditure (n = 1,432) over time. In males, adjusted BEE decreased significantly, but in females this did not reach significance. A larger dataset of basal metabolic rate (equivalent to BEE) measurements of 9,912 adults across 163 studies spanning 100 years replicates the decline in BEE in both …

The Journal of Nutrition

BackgroundAlthough prior evidence indicates that water intake is important for health, the ability to accurately measure community-dwelling intake is limited. Only a few studies have evaluated self-reported water intake against an objective recovery biomarker.ObjectivesThe aim was to compare preformed water intakes (all sources including food) by multiple Automated Self-Administered 24-h recalls (ASA24s), food frequency questionnaires (FFQs), and 4-d food records (4DFRs) against a recovery biomarker, doubly labeled water (DLW), to assess measurement error.MethodsOver 1 y, 1082 women and men (50%), aged 50 to 74 y, were asked to complete 6 ASA24s, 2 FFQs, 2 unweighted 4DFRs, and an administration of DLW (n = 686). Geometric means of water intake by self-report tools were compared with DLW. Attenuation factors and correlation coefficients between self-reported and the recovery biomarker …

Like many, my career in nutrition did not follow a straight path. In high school and later in college, I had always been interested in mathematics. When I had to pick an avatar from among the Sesame Street characters, I choose the Count, although I must admit Cookie Monster was a close second. I was interested in answering questions such as “How much, How many and How fast”? The academic exercises that were of most interest to me were not in my science classes, but were the word problems in my math and calculus classes. They were surprising fun to solve because they were usually revolved around one of those same three questions and they involved a solution based on a combination of logic and math. While they were fun to solve, I did not choose math as a major, but instead pursued chemistry because that too allowed me to ask those same questions and allowed me to spend time in a laboratory …

Simulated microgravity is known to induce a shift in fasting fuel selection in favor of carbohydrate use and in detriment of lipids, and to reduce metabolic flexibility (MF), ie, the capacity to adjust fuel oxidation to changes in substrate availability and energy demand. Given their potential adverse effects on performance and health, we aimed to determine whether such metabolic alterations occur in astronauts during long-term spaceflights. We further explored the associations with diet, physical activity, and body composition. Before and after at least three months onboard the International Space Station, respiratory quotient (RQ), carbohydrate and fat oxidation were measured by indirect calorimetry before and following a standardized meal in 11 male astronauts (age= 45.7 [SD 7.7] years, BMI= 24.3 [2.1] kg/m²). MF was determined by 0-to-260 min postprandial incremental area under the curve (iAUC) of nutrient oxidation and the difference between maximal postprandial and fasting RQ (ΔRQ). The food quotient (FQ) was calculated from diet logs. Fat (FM) and fat-free mass (FFM) were measured by hydrometry and physical activity by accelerometry and diary logs. Three months in space increased fasting RQ (P= 0.01) and carbohydrate oxidation (P= 0.04), and decreased fasting lipid oxidation (P< 0.01). An increase in FQ (P< 0.001) indicated a shift in diet composition. Spaceflight-induced changes in RQ adjusted on ground RQ were associated with inflight FQ (P< 0.01). No changes were noted in mean postprandial nutrient oxidation or ΔRQ. Individual postprandial lipid oxidation iAUC was negatively associated with changes in FFM and inflight aerobic …

International Journal of Sports Physiology and Performance

Previous studies have used the doubly labeled water method to evaluate the total energy expenditure (TEE) during Ironman, ultramarathon trail runs, and competitive road cycling. However, the technique has not been applied to a 24-hour cross-country mountain-bike event. Purpose : This case study aimed to measure the TEE, cycling metrics, and ad libitum nutrient/fluid intake during a 24-hour cross-country mountain-bike race. Methods : A trained male cyclist (41 y, 74.1 kg, 172.4 cm) received an oral dose of doubly labeled water prior to the 24-hour event for the calculations of TEE and water turnover. Nude body weight and urine samples were collected prerace, during the race, and postrace. Total nutrient intake and total fluid intake in addition to cycling metrics (speed, power output, cadence, and heart rate) were continuously …

To date, nutritional epidemiology has relied heavily on relatively weak methods including simple observational designs and substandard measurements. Despite low internal validity and other sources of bias, claims of causality are made commonly in this literature. Nutritional epidemiology investigations can be improved through greater scientific rigor and adherence to scientific reporting commensurate with research methods used. Some commentators advocate jettisoning nutritional epidemiology entirely, perhaps believing improvements are impossible. Still others support only normative refinements. But neither abolition nor minor tweaks are appropriate. Nutritional epidemiology, in its present state, offers utility, yet also needs marked, reformational renovation. Changing the status quo will require ongoing, unflinching scrutiny of research questions, practices, and reporting—and a willingness to admit that “good …

Frontiers in Pediatrics

BackgroundThe consequences of obesity are ominous, yet healthcare professionals are not adequately preventing or treating obesity in youth with Down syndrome (DS). Total daily energy expenditure (TDEE) is the energy expended in 24 h through physical activity and life-sustaining physiologic processes. An individual's TDEE is essential for determining the daily caloric intake needed to maintain or change body weight. Successful prevention and treatment of obesity in youth with DS is severely compromised by the lack of data on TDEE and information on weight-related behaviors for this high-risk population. This manuscript describes the protocol for the federally funded study that is in process to determine daily energy expenditure in a large cohort of children with DS.MethodsThis observational cross-sectional study will include a national sample of 230 youth with DS, stratified by age (5–11 and 12–18 years of …

medRxiv

Objective To compare multiple body composition analysis methods in athletes with varying states of hydration to the criterion 5-compartment model(5CM) of body composition and assess the relationships of technique-specific estimates of fat and fat-free mass(FM, FFM) to muscle strength. Methods Body composition was assessed in 80(40-female) athletes with a mean age of 21.84.2 years. All athletes underwent laboratory-based methods: air-displacement plethysmography(ADP), deuterium-oxide dilution(D2O), dual-energy X-ray absorptiometry(DXA), underwater-weighing(UWW), and field-based: 3D-optical(3DO) imaging, and three bioelectrical impedance(BIA) devices(S10/SFB7/SOZO). Participants muscular strength was assessed by isokinetic/isometric dynamometry. Accuracy was assessed by Lins concordance correlation coefficient(CCC) and precision by root-mean-square coefficient of variation(RMS-CV%). Results Athletes hydration status(total body water/FFM) was significantly(p<0.05) outside of the normal range in both males(0.63-0.73%) and females(0.58-0.78%). The most accurate techniques(ADP/DXA) showed moderate-substantial agreement(CCC=0.90-0.95) in FM and FFM, whereas all field assessments had poor agreement(CCC<0.90), except 3DO FFM in females(CCC=0.91). All measures of FFM produced excellent <1.0% precision, whereas FM from ADP, DXA, D2O, S10, and UWW had <2.0%. The associations between muscle strength and the various devices FFM estimates differed. However, more accurate body composition compared to the criterion produced a better determination of muscle strength by significant …

Indirect calorimetry is a noninvasive and reliable tool for assessing an individual's energy expenditure and fuel utilization. It indirectly assesses heat production or metabolism of an individual by measuring oxygen consumption and carbon dioxide production. Indirect calorimetry is based on the seminal studies performed by Antoine Lavoisier that identified the chemistry of combustion and demonstrated that the same chemical processes occurred during respiration. Indirect calorimeters range in size from room-sized chambers to hand-held devices. Scientists from multiple disciplines have used it to measure energy expenditure, establish nutrient requirements, measure physical fitness, and evaluate macronutrient utilization during rest and exercise. Clinicians have used indirect calorimetry to optimize the nutritional support in metabolic disorders and to quantify the energy requirements of patients.

Historical Methods: A Journal of Quantitative and Interdisciplinary History

In the United States, recent studies have demonstrated weight gain over Thanksgiving contributing to a significant portion of annual national weight gain. Understanding the social context of how Thanksgiving celebrations were perceived is critical for preventing and reducing excess weight during this time. Energy intake from present-day data was back-calculated from body weight data collected in participants before and after Thanksgiving. Similar calculations were performed in studies that also included Christmas. A Latent Dirichlet Allocation analysis of topics scraped from Twitter under the hashtag #thanksgiving was performed. The top topics and search queries from Google Trends on Thanksgiving 2020 were also identified. Since 1621, the social context of Thanksgiving has evolved from a focus on prayer and celebrated gratitude to a focus on food, football, and retail. What is served on Thanksgiving and its …

Iscience

Lower ambient temperature (Ta) requires greater energy expenditure to sustain body temperature. However, effects of Ta on human energetics may be buffered by environmental modification and behavioral compensation. We used the IAEA DLW database for adults in the USA (n = 3213) to determine the effect of Ta (−10 to +30°C) on TEE, basal (BEE) and activity energy expenditure (AEE) and physical activity level (PAL). There were no significant relationships (p > 0.05) between maximum, minimum and average Ta and TEE, BEE, AEE and PAL. After adjustment for fat-free mass, fat mass and age, statistically significant (p < 0.01) relationships between TEE, BEE and Ta emerged in females but the effect sizes were not biologically meaningful. Temperatures inside buildings are regulated at 18–25°C independent of latitude. Hence, adults in the US modify their environments to keep TEE constant across a wide …

Medicine and science in sports and exercise

PURPOSE:To examine the shape of the relationship between physical activity (PA) and total energy expenditure (TEE) and to explore the role of energy balance status (negative, stable, positive) in influencing this association.METHODS:Cross-sectional. Participants were 584 older adults (50–74 yrs.) participating in the Interactive Diet and Activity Tracking in AARP study. TEE was assessed by doubly labeled water and PA by accelerometer. The relationship between PA and TEE was assessed visually and using non-linear methods (restricted cubic splines). Percent weight change (> 3%) over a six-month period was used as a proxy measurement of energy balance status.RESULTS:TEE generally increased with increasing deciles of PA averaging 2354 (SD= 351) kcal/d in the bottom decile to 2693 (SD= 480) kcal/d in the top decile. Cubic spline models showed an approximate linear association between PA and …