Biomedical subjects

K Westerterp

Publications and source records attributed to K Westerterp.

11 recordsLinked to original sources

PubMed2005

Validity of reported energy expenditure and reported intake of energy, protein, sodium and potassium in rheumatoid arthritis patients in a dietary intervention study.

OBJECTIVES: The aim of the study was to validate a diet history interview (DHI) method and a 3-day activity registration (AR) with biological markers. SUBJECTS AND STUDY DESIGN: The reported dietary intake of 33 rheumatoid arthritis patients (17 patients on a Mediterranean-type diet and 16 patients on a control diet) participating in a dietary intervention study was assessed using the DHI method. The total energy expenditure (TEE), estimated by a 3-day AR, was used to validate the energy intake (EI). For nine subjects the activity registration was also validated by means of the doubly labelled water (DLW) method. The excretion of nitrogen, sodium and potassium in 24-h urine samples was used to validate the intake of protein, sodium and potassium. RESULTS: There was no significant difference between the EI and the TEE estimated by the activity registration or between the intake of protein, sodium and potassium and their respective biological markers. However, in general, the AR underestimated the TEE compared to the DLW method. No significant differences were found between the subjects in the Mediterranean diet group and the control diet group regarding the relationship between the reported intakes and the biological markers. CONCLUSION: The DHI could capture the dietary intake fairly well, and the dietary assessment was not biased by the dietary intervention. The AR showed a bias towards underestimation when compared to the DLW method. This illustrates the importance of valid biological markers.

Arthritis, Rheumatoid↗

PubMed2001

Physical activity assessed by activity monitor and doubly labeled water in children.

PURPOSE: To validate the Computer Science and Application's (CSA) activity monitor for assessment of the total amount of physical activity during two school-weeks in 9-yr-old children and to develop equations to predict total energy expenditure (TEE) and activity energy expenditure (AEE) from activity counts and anthropometric variables. METHODS: A total of 26 children (15 boys and 11 girls, mean age 9.1 +/- 0.3 yr) were monitored for 14 consecutive days. TEE was simultaneously measured by the doubly labeled water method. Averaged activity counts (counts.min(-1)) were compared with data on: 1) TEE, 2) AEE = TEE minus basal metabolic rate (BMR; estimated from predictive equations), and 3) daily physical activity level (PAL = TEE/BMR). RESULTS: Physical activity determined by activity counts was significantly related to the data on energy expenditures: TEE (r = 0.39; P < 0.05), AEE (r = 0.54; P < 0.01), and PAL (r = 0.58; P < 0.01). Multiple stepwise regression analysis showed that TEE was significantly influenced by gender, body composition (body weight or fat free mass), and activity counts (R(2) = 0.54--0.60). AEE was significantly influenced by activity counts and gender (R(2) = 0.45). There were no significant differences between activity counts and PAL in discriminating among activity levels with "low" (PAL < 1.56), "moderate" (1.57 < or = PAL > or = 1.81), and "high" (PAL > 1.81) intensity. CONCLUSION: Activity counts from the CSA activity monitor seems to be a useful measure of the total amount of physical activity in 9-yr-old children. Activity counts contributed significantly to the explained variation in TEE and was the best predictor of AEE.

Activities of Daily Living↗

PubMed2000

Field evaluation of the Computer Science and Application's Inc. Activity monitor during running and skating training in adolescent athletes.

This study investigated the validity of the CSA activity monitor for assessment of the total amount of physical activity in adolescent athletes. Activity data were compared to data on daily energy expenditure and its derivatives measured by the doubly labeled water method. Seven athletes (speed skaters) with a mean age of 18.2+/-1.1 y were monitored twice (off-season and pre-season) by the activity monitor for eight consecutive days. The primary training during the off-season period was running whereas the pre-season period mainly involved skate training (i.e. inline skating, slideboard training, and skating imitations). Activity counts were significantly correlated to all energy estimates during the off-season period (r=0.93-0.96; P<0.01) whereas not during the pre-season period (r=0.32-0.57). A two-way multivariate analysis of variance showed a significant period effect for activity counts (668+/-163 vs. 548+/-91; P=0.026) whereas not for total daily energy expenditure (15.7+/-2.1 MJ x d(-1) vs. 16.0+/-1.0 MJ x d(-1); P=0.71). The relationship between activity counts and total daily energy expenditure seems to be affected by different training conditions. Therefore these circumstances have to be carefully considered in the interpretation of activity monitor data.

Activities of Daily Living↗

PubMed1998

Assessment of energy expenditure in overweight women.

PURPOSE: To compare field measures of average daily energy expenditure (ADEE) against criterion data by the doubly labeled water method (DLW) in overweight women. METHODS: The subject were 20 overweight (BMI 29.9 +a- 3.0 kg.m-2) premenopausal women. Energy expenditure was measured by DLW and by the factorial method (activity diary, two techniques differing by method to obtain resting energy expenditure, REE), heart-rate monitoring (HR, two techniques differing by the FLEX-point to discriminate sedentary and activity HR), accelerometer, and pedometer. RESULTS: The ADEE(DLW) was 10.26 +a- 1.1 MJ.d-1. The mean bias (ADEE by the alternative minus ADEE(DLW) was smallest for the accelerometer (+ 0.08 +a- 1.63 MJ) and HR-FLEX10 (+ 0.11 +a- 1.67 MJ). The HR-FLEX(0) technique (lower FLEX-point) overestimated ADEE by + 1.18 (+a- 1.97 MJ). However, the random error (SD of bias) was smaller for both factorial techniques (REE measured: -0.48 +2- 0.81 MJ; REE calculated from the WHO equation: -0.22 +2- 0.88 MJ). CONCLUSION: The results show that simple factorial methods may assess ADEE with small random errors in population with a rather narrow range of physical activity. The accelerometer and HR with the higher FLEX-point have comparable results with smaller bias but larger random error compared with the factorial techniques.

Adult↗

PubMed1996

Determination of total body water by a simple and rapid mass spectrometric method.

A rapid and inexpensive method was developed to determine deuterium enrichment in body fluids. This is achieved by converting water into acetylene. To vacutainer tubes a small amount of calcium carbide is added. The tubes are evacuated and 25 microliters of sample are injected through the stopper. The reaction takes place spontaneously at room temperature in a few seconds. Enrichment at mass 27 compared with mass 26 can be determined by continuous flow isotope ratio mass spectrometry without any interference from the carrier gas helium. A series of D2O samples diluted with increasing amounts of H2O is prepared at the time of measurement of the biological samples and the measured ratios are used to calculate the isotope dilution of the unknown. The relative error of the method is 1.6% when a dose of 25 ml kg-1 is administered to the patient. The method was compared with two different methods in use in other laboratories, by a published method The means of the differences were -0.1 and 0.08 1, respectively, with standard deviations of 0.63 and 3.0.

Acetylene↗

PubMed1996

Amenorrhea in ballet dancers in the Netherlands.

The prevalence of amenorrhea was studied among 113 professional and student ballet dancers in the Netherlands (mean age 23.3 yr, SD 4.8). Sixty-one dancers not on oral contraceptives were included in the subsequent analyses. Six cases (prevalence 9.8 percent, 95 percent confidence interval: 2.4-17.2) with secondary amenorrhea (< or = 4 cycles per year; previous menstruation > or = 3 months prior to the study; menarche > or = 1 yr prior to the study) were found. Two dancers had primary amenorrhea (no menarche at the age of > or = 16). There was a negative correlation between the age of menarche and the number of menstrual cycles during the 12 months preceding the study (r = -0.46, P = 0.001). Body composition (four-compartment model), amount of dancing (recorded), resting energy expenditure (ventilated hood), dietary intake (recorded), and indices of eating disorders (Eating Disorders Inventory, EDI) were studied in 15 of the dancers, 5 amenorrheic and 10 eumenorrheic. No significant differences were found between the amenorrheic and eumenorrheic dancers. An explanation for the lower prevalence of amenorrhea in ballet dancers in the Netherlands, compared with U.S. dancers, was not obvious. Relatively low EDI scores (25.8, SD 14.5) in a subsample of 24 dancers could indicate less rigid emphasis on leanness and dieting.

Adult↗

PubMed1996

Energy turnover in a sailing crew during offshore racing around the world.

Energy turnover during offshore sailing was studied in 11 male crew members of one team during the first three legs of the 1993-1994 Whitbread Round The World Race. The effect of racing on the energy balance of the crew members was studied by anthropometric measurements and dietary intake as calculated from food inventories before and after each leg. Energy turnover, calculated from dietary intake and release of endogenous energy as a result of changes in body composition, was higher than expected (about 18-20 MJ.d-1). These findings were confirmed using the doubly labeled water technique in six crew members during the third leg, in which mean energy turnover was found to be 19.3 MJ.d-1. Changes in body weight and composition indicated a negative energy balance during all legs.

Adult↗

PubMed1995

Effect of varying protein intake on energy balance, protein balance and estimated weight gain composition in premature infants.

OBJECTIVE: We studied the effect of varying only protein intake on energy balance, protein balance and estimated weight gain composition in premature infants fed either a formula with a protein content of 2.0 g/100 ml (F2) or a protein content of 1.5 g/100 ml (F1.5). DESIGN: Premature infants were randomly allocated to receive F1.5 or F2. Weight gain composition was estimated from protein and energy balances. Energy expenditure was measured with doubly labelled water. PATIENTS: F1.5, n = 8; gestational age 32 +/- 3 weeks, birth weight 1716 +/- 560 g. F2, n = 8; gestational age 32 +/- 3 weeks, birth weight 1544 +/- 488 g. RESULTS: Infants fed F2 showed a significantly higher protein accretion (P = 0.003) and weight gain (P = 0.011) when compared to the infants fed F1.5. There were no differences in the energy balance. The estimated weight gain composition was different between both groups. CONCLUSION: The F2 fed infants had an estimated weight gain composition comparable to the reported intrauterine values, while the F1.5 fed infants showed a weight gain composition more comparable to the reported values of the full term infant. The impact of nutrient composition in premature infant formulas on body composition and growth is discussed.

Body Composition↗

PubMed1994

Malabsorption in infants with congenital heart disease under diuretic treatment.

Intestinal absorption and its relationship to increased total body water was studied in seven infants with congenital heart disease receiving regular diuretics due to congestive heart failure. All infants and six age-matched healthy controls were studied for a 3-d period during which time all food intake was recorded, stools were collected, and total body water content (TBW) and extracellular water were measured. All the anthropometric measurements were lower in the infants with congenital heart disease compared with healthy controls. Energy and fat excretion in the stools were significantly increased in the group of patients, but when expressed as a percentage of daily caloric intake or as a percentage of the specific intake (e.g. fat excretion/fat intake x 100), no statistical differences were found. TBW as a percentage of body weight was increased in our patients compared with our controls (84.95 +/- 5.82% versus 68.65 +/- 4.60%; p = 0.01) and so was extracellular water as a percentage of predicted (200.0 +/- 18.6% versus 100.9 +/- 7.2%; p = 0.001). A positive correlation was found between energy and fat excretion as a percentage of the intake and TBW as a percentage of predicted; energy and fat malabsorption did not exceed 8% in the patients with the highest body water content (120% of predicted). It is concluded that malabsorption is not a significant factor in failure to thrive of patients with congenital heart disease who are receiving regular diuretics. Based on the significant negative correlation between excess body water and fat and calorie absorption, however, it is suggested to monitor TBW in patients who fail to gain weight.

Body Water↗

PubMed1992

Total energy expenditure of healthy Swedish women during pregnancy and lactation.

Total energy expenditure (TEE) was estimated in healthy Swedish women by the doubly labeled water method in a longitudinal study during pregnancy and lactation. Measurements were made before pregnancy (A); in gestational weeks 16-18 (B), 30 (C), and 36 (D); as well as 2 (F) and 6 (G) mo after delivery. When the results were interpreted, earlier published data regarding resting metabolic rate (RMR), energy intake, and energy in breast milk were also considered. TEE (MJ/d) and TEE/RMR were 10.5 +/- 2.2 (mean +/- SD) and 1.87 +/- 0.42 (n = 28), 9.6 +/- 2.8 and 1.65 +/- 0.67 (n = 22), 12.5 +/- 3.4 and 1.82 +/- 0.45 (n = 22), 12.2 +/- 4.1 and 1.66 +/- 0.52 (n = 19), 10.6 +/- 2.0 and 1.82 +/- 0.41 (n = 23), and 10.8 +/- 2.7 and 1.79 +/- 0.42 (n = 23) at A, B, C, D, F, and G, respectively. The results indicated that physical activity tended to be decreased during early pregnancy. Taking changes in body energy stores into consideration, it was estimated that subjects recorded 86% and 77% of their energy intakes at A and F respectively.

Adipose Tissue↗

PubMed1992

Gastric emptying, absorption, and carbohydrate oxidation during prolonged exercise.

This study was designed to examine aspects of digestive function that may limit assimilation of water and oxidation of orally ingested carbohydrate (CHO) during exercise. Eight males completed a crossover study in which each cycled on four occasions for 80 min at 70% maximal O2 consumption. Beverage was consumed at 0, 20, 40, and 60 min. Beverages were water, 4.5% glucose (4.5G), 17% glucose (17G), and 17% maltodextrin (17MD). CHO beverages contained 20 meq/l NaCl and were 13C enriched to measure exogenous CHO oxidation. Gastric (beverage) volume was measured at 80 min. Water uptake was estimated by including 2H2O in the beverage and measuring 2H accumulation in blood. Jejunal perfusion tests were conducted at rest with the same subjects and beverages. In 60 min, 1,294 +/- 31 (SE) ml were ingested; at 80 min, volumes emptied with H2O (1,257 +/- 32 ml) and 4.5G (1,223 +/- 32 ml) were greater than with 17G (781 +/- 56 ml) and 17MD (864 +/- 71 ml; P less than 0.05). Total CHO oxidized was similar with all beverages, but there was a greater increase in exogenous CHO oxidation over time with 17G and 17MD than with 4.5G; 54, 19, and 18% of the CHO ingested with 4.5G, 17G, and 17MD, respectively, was oxidized. This represents 57, 32, and 27%, respectively, of the CHO emptied from the stomach. 2H accumulation in the blood was more rapid with H2O and 4.5G than with 17G or 17MD. Net jejunal water absorption was greater from 4.5G than from water. Net water absorption was also observed from 17MD, whereas net secretion was observed with 17G.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗