Doubly labelled water–calibration approach attenuates the underestimation of energy intake calculated from self-reported dietary assessment data in Japanese older adults

Objective: Self-reported energy intake (EI) estimation may incur systematic errors that could be attenuated through biomarker calibration. We aimed to confirm whether calibrated EI was comparable to total energy expenditure (TEE) measured using the doubly labelled water (DLW) technique. Design: Cross-sectional study. Setting: General older population from the Kyoto–Kameoka Study, Japan. Participants: This study included sub- and main cohorts of 72 and 8,058 participants aged ≥65 years, respectively. EI was evaluated using a validated FFQ, and calibrated EI was obtained using a previously developed equation based on the DLW method. TEE was considered representative of true EI and also measured using the DLW method. We used a Wilcoxon signed-rank test and correlation analysis to compare the uncalibrated and calibrated EI with TEE. Results: In the sub-cohort, the median TEE, uncalibrated EI, and calibrated EI were 8,559 kJ, 7,088 kJ, and 9,269 kJ, respectively. The uncalibrated EI was significantly lower than the TEE (median difference = −1,847 kJ; interquartile range [IQR]: −2,785 to −1,096), although the calibrated EI was not (median difference = 463 kJ; IQR: −330 to 1,541). The uncalibrated (r = 0.275) and calibrated EI (r = 0.517) significantly correlated with TEE. The reproducibility was higher for calibrated EI (interclass correlation coefficient [ICC] = 0.982) than for uncalibrated EI (ICC = 0.637). Similar findings were observed when stratifying the sample by sex. For medians, uncalibrated EI was lower (˜17%) than calibrated EI in the main cohort. Conclusions: Biomarker calibration may improve the accuracy of self-reported dietary intake estimation.

Validity of Triply Labelled Water Analysis for Energy Expenditure Measurements in Mice

The Doubly Labelled Water (DLW) method is widely used to determine energy expenditure. In this work, we demonstrate the addition of the third stable isotope, 17O, to turn it into Triply Labelled Water (TLW), using the three isotopes measurement of optical spectrometry. We performed TLW (2H, 18O and17O) measurements for the analysis of the CO2 production (rCO2) of mice on different diets for the first time. Triply highly enriched water was injected into mice, and the isotope enrichments of the distilled blood samples of one initial and two finals were measured by an Off-Axis Integrated Cavity Output Spectroscopy instrument. We evaluated the impact of different calculation protocols and the values of evaporative water loss fraction. We found that the dilution space and turnover rates of 17O and 18O were equal for the same mice group, and that values of rCO2 calculated based on 18O-2H, or on 17O-2H agreed very well. This increases the reliability and redundancy of the measurements and it lowers the uncertainty in the calculated rCO2 to 3% when taking the average of two DLW methods. However, the TLW method overestimated the rCO2 compared to the indirect calorimetry measurements that we also performed, much more for the mice on a high-fat diet than for low-fat. We hypothesize an extra loss or exchange mechanism with a high fractionation for 2H to explain this difference.

Impact of walking aids on estimating physical activity using a tri-axial accelerometer in frail older adults

ObjectivesThis study aimed to compare the estimation error of physical activity level (PAL) estimated using a tri-axial accelerometer between an independent walking group and an assisted walking group with walking aids.MethodsSubjects were 6 older adults who could walk independently and 10 older adults requiring walking assistance during gait. Total energy expenditure (TEE) was measured using the doubly labelled water (DLW) method over 2 weeks and PAL was calculated as the measured TEE divided by the basal metabolic rate measured using indirect calorimetry (PALDLW). The participants wore a tri-axial accelerometer (Active style Pro HJA-750C) on the waist simultaneously as the DLW period, and the estimated PAL was derived from it (PALACC).ResultsThe median PAL estimation error in the assisted walking group was −0.30 kcal/day (range: −0.77 to −0.01 kcal/day) and more underestimated than that in the independent walking group (p=0.02). The estimation error of PALACC was significantly correlated with PALDLW (r=−0.80, p<0.01).ConclusionsUsing the accelerometer, PAL was underestimated for older adults who used walking aids but not for those who walked independently under free-living conditions.

The Assessment of Daily Energy Expenditure of Commercial Saturation Divers Using Doubly Labelled Water

Commercial saturation divers are exposed to unique environmental conditions and are required to conduct work activity underwater. Consequently, divers’ physiological status is shown to be perturbed and therefore, appropriate strategies and guidance are required to manage the stress and adaptive response. This study aimed to evaluate the daily energy expenditure (DEE) of commercial saturation divers during a 21-day diving operation in the North Sea. Ten saturation divers were recruited during a diving operation with a living depth of 72 metres seawater (msw) and a maximum working dive depth of 81 msw. Doubly labelled water (DLW) was used to calculate DEE during a 10-day measurement period. Energy intake was also recorded during this period by maintaining a dietary log. The mean DEE calculated was 3030.9 ± 513.0 kcal/day, which was significantly greater than the mean energy intake (1875.3 ± 487.4 kcal; p = 0.005). There was also a strong positive correction correlation between DEE and total time spent performing underwater work (r = 0.7, p = 0.026). The results suggested saturation divers were in a negative energy balance during the measurement period with an intraindividual variability in the energy cost present that may be influenced by time spent underwater.

Schweres Lungenemphysem: Zusammenhänge zwischen klinischen Verläufen nach bronchoskopischer Volumenreduktion und metabolischen Parametern erkennen

<b>Background:</b> Hypermetabolism and muscle wasting frequently occur in patients with severe emphysema. Improving respiratory mechanics by bronchoscopic lung volume reduction (BLVR) might contribute to muscle maintenance by decreasing energy requirements and alleviating eating-related dyspnoea. <b>Objective:</b> The goal was to assess the impact of BLVR on energy balance regulation. <b>Design:</b> Twenty emphysematous subjects participated in a controlled clinical experiment before and 6 months after BLVR. Energy requirements were assessed: basal metabolic rate (BMR) by ventilated hood, total daily energy expenditure (TDEE) by doubly labelled water, whole body fat-free mass (FFM) by deuterium dilution, and physical activity by accelerometry. Oxygen saturation, breathing rate, and heart rate were monitored before, during, and after a standardized meal via pulse oximetry and dyspnoea was rated. <b>Results:</b> Sixteen patients completed follow-up, and among those, 10 patients exceeded the minimal clinically important difference of residual volume (RV) reduction. RV was reduced with median (range) 1,285 mL (–2,430, –540). Before BLVR, 90% of patients was FFM-depleted despite a normal BMI (24.3 ± 4.3 kg/m2). BMR was elevated by 130%. TDEE/BMR was 1.4 ± 0.2 despite a very low median (range) daily step count of 2,188 (739, 7,110). Following BLVR, the components of energy metabolism did not change significantly after intervention compared to before intervention, but BLVR treatment decreased meal-related dyspnoea (4.1 vs. 1.7, <i>p</i> = 0.019). <b>Conclusions:</b> Impaired respiratory mechanics in hyperinflated emphysematous patients did not explain hypermetabolism. <b>Clinical Trial Registry Number:</b> NCT02500004 at www.clinicaltrial.gov.

Validating accelerometry-derived proxies of energy expenditure using the doubly-labelled water method in the smallest penguin species

Understanding energy use is central to understanding an animal's physiological and behavioural ecology. However, directly measuring energy expenditure in free-ranging animals is inherently difficult. The doubly-labelled water (DLW) method is widely used to investigate energy expenditure in a range of taxa. Although reliable, DLW data collection and analysis is both financially costly and time consuming. Dynamic body acceleration (e.g. VeDBA) calculated from animal-borne accelerometers has been used to determine behavioural patterns, and is increasingly being used as a proxy for energy expenditure. Still its performance as a proxy for energy expenditure in free-ranging animals is not well established and requires validation against established methods. In the present study, the relationship between VeDBA and the at-sea metabolic rate calculated from DLW was investigated in little penguins (Eudyptula minor) using three approaches. Both in a simple correlation and activity-specific approaches were shown to be good predictors of at-sea metabolic rate. The third approach using activity-specific energy expenditure values obtained from literature did not accurately calculate the energy expended by individuals. However, all three approaches were significantly strengthened by the addition of mean horizontal travel speed. These results provide validation for the use of accelerometry as a proxy for energy expenditure and show how energy expenditure may be influenced by both individual behaviour and environmental conditions.