[Activity of some enzymes of the energy metabolism of the striated muscle in relationship to the body composition in subjects of diverse body weight].
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Alcohol Oxidoreductases↗
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Body composition in ballet dancers measured by total body electrical conductivity.
The purpose of this study was to describe the body composition of adolescent and young adult ballet dancers using total body electrical conductivity (TOBEC). We studied 112 female and 33 male dancers. The mean ages were 15.0 +/- 2.0 and 18.7 +/- 3.1 yr for females and males, respectively. The mean percent body fat (PBF) values were 20.1 +/- 3.6% for the females and 14.5 +/- 4.2% for the males. Age and pubertal development were not significantly related to PBF in the females. Age and pubertal status were significantly inversely related to PBF in the males. There was no difference in dance history, percent body fat, and abdominal/hip or waist/hip ratios in eumenorrheic vs amenorrheic dancers. Estimated calorie intake indicated that dancers with menstrual abnormalities had lower calorie intake than those with normal menses. This is the largest group of ballet dancers whose body composition has been studied. Our PBF measurements are higher than in previous reports using hydrodensitometry, which may have underestimated body fat by not accounting for the increased bone density in the lower extremities of dancers. Our data suggest that previous measurements of PBF in dancers are underestimates; these new data challenge our concept of PBF values in dancers.
Adipose Tissue↗
Body composition in sport and exercise: directions for future research.
Body composition has become a major field of interest for many exercise and sport scientists as well as clinicians who specialize in the prevention of and rehabilitation from hypokinetic diseases. This paper discusses the state of the art within selected areas of body composition, identifying significant areas of controversy and proposing specific problems where research should be focused. The areas addressed include the following: the use of body density to estimate relative body fat in selected populations, the use of anthropometric equations to estimate body composition, body composition assessment for profiling and counseling athletes, and alterations in appetite and body composition resulting from acute bouts of exercise and from exercise training.
Animals↗
Relative influences of sex, race, environment, and HIV infection on body composition in adults.
BACKGROUND: The factors that control body composition in disease are uncertain. OBJECTIVE: We planned to compare the relative influences of HIV infection, sex, race, and environment on body composition. METHODS: We analyzed results of body composition studies performed by bioelectrical impedance analysis in 1415 adults from 2 cohorts: white and African American men and women from the United States, and African men and women (279 HIV-infected and 1136 control). The effects of sex and HIV infection on weight, body cell mass, and fat-free mass were analyzed by using both unadjusted and age-, weight-, and height-adjusted data. RESULTS: Control men weighed more and had more body cell mass and fat-free mass than did control women, although control women had more fat. The strongest correlates with body composition were height and weight, followed by sex. HIV infection, age, environment, and race. Control men and women weighed more and had more body cell mass, fat-free mass, and fat than did HIV-infected men. However, differences in body composition between HIV-infected and control groups were strongly influenced by sex. Of the differences in weight between HIV-infected and uninfected subjects, fat-free mass accounted for 51% in men but only 18% in women, in whom the remainder was fat. Sex effects were similar in African and American groups. CONCLUSIONS: Sex has a marked effect on the changes in body composition during HIV infection, with women losing disproportionately more fat than men. Sex-related differences in body composition were narrower in the HIV-infected groups. Race and environment had smaller effects than sex and HIV infection.
Adolescent↗
The effect of beta-hydroxy beta-methylbutyrate on muscular strength and body composition in collegiate football players.
This study assesses the effects of daily beta-hydroxy beta-methylbutyrate (HMB) supplementation on muscular strength (bench press, squats, and power cleans) and body composition (body weight and body fat) among collegiate football players undergoing a strenuous exercise program. Subjects were collegiate football players (n = 35) training under the supervision of certified strength coaches averaging 20 hours of weekly exercise. In the first supplementation period, 16 of the 35 subjects were supplemented with 3 g of HMB per day for 4 weeks; the other 19 received a placebo followed by a 1-week washout period and then a second supplementation period in a randomized double-blind crossover, placebo design. There were no significant changes (p > 0.05) in muscular strength, including bench press, squats, and power cleans, among the subjects. There were also no significant changes (p > 0.05) in body composition, including body fat and body weight. Very little clinical evidence exists for supplementing HMB in athletic populations.
Adipose Tissue↗
Validity of body composition methods across ethnic population groups.
Most in vivo body composition methods rely on assumptions that may vary among different population groups as well as within the same population group. The assumptions are based on in vitro body composition (carcass) analyses. The majority of body composition studies were performed on Caucasians and much of the information on validity methods and assumptions were available only for this ethnic group. It is assumed that these assumptions are also valid for other ethnic groups. However, if apparent differences across ethnic groups in body composition 'constants' and body composition 'rules' are not taken into account, biased information on body composition will be the result. This in turn may lead to misclassification of obesity or underweight at an individual as well as a population level. There is a need for more cross-ethnic population studies on body composition. Those studies should be carried out carefully, with adequate methodology and standardization for the obtained information to be valuable.
Adipose Tissue↗
Endocrine control of body composition in infancy, childhood, and puberty.
Body composition exhibits marked variations across the early human lifetime. The precise physiological mechanisms that drive such developmental adaptations are difficult to establish. This clinical challenge reflects an array of potentially confounding factors, such as marked intersubject differences in tissue compartments; the incremental nature of longitudinal intrasubject variations in body composition; technical limitations in quantitating the unobserved mass of mineral, fat, water, and muscle ad seriatim; and the multifold contributions of genetic, dietary, environmental, hormonal, nutritional, and behavioral signals to physical and sexual maturation. From an endocrine perspective (reviewed here), gonadal sex steroids and GH/IGF-I constitute prime determinants of evolving body composition. The present critical review examines hormonal regulation of body composition in infancy, childhood, and puberty.
Adipose Tissue↗
Body composition evaluation in peritoneal dialysis patients using anthropometric formulas estimating body water.
In adult patients on peritoneal dialysis (PD), estimates of body water (V), fat-free mass (FFM), and body fat (BF) can be obtained by using anthropometric formulas for estimating V. Estimates of V, FFM, and BF can also be obtained by using reference (standard) methods in which V is evaluated by a standard dilution method. To test whether the estimates obtained by the various methods agree, we analyzed published studies that measured V by a standard method in adult PD patients. We then calculated V, FFM, and BF by the Watson, Hume, Sahlgrenska, Chumlea, Lee, and Chertow formulas for the "average subject" in the published studies. We compared the standard and the anthropometric estimates using the limits-of-agreement method of Bland and Altman. Our analysis included six studies involving a total of 262 patients (89 women, 173 men). The six studies measured V by a reference method and allowed calculation of anthropometric V, FFM, and BF for the average patient. We calculated these values: VStandard, 36.8 +/- 4.7 L; VSahlgrenska, 36.9 +/- 4.3 L [p = nonsignificant (NS); Bland-Altman limits of agreement: -3.1 L to 3.3 L]; FFMStandard 50.9 +/- 5.2 kg; FFMSahlgrenska, 50.6 +/- 4.3 kg (Bland-Altman limits of agreement: -5.4 kg to 4.8 kg); BFStandard, 20.3 +/- 3.0 kg; BFSahlgrenska, 20.6 +/- 2.3 kg (Bland-Altman limits of agreement: -4.8 kg to 5.4 kg). Results obtained using the Watson, Hume, Chumlea, and Lee formulas also agreed with the standard estimates. The Chertow formula produced results that systematically overestimated the standard V and FFM values and that underestimated the standard BF. The Watson, Hume, Sahlgrenska, Chumlea, and Lee anthropometric formulas used to calculate V provide estimates of body composition that approximate those obtained using standard methods in PD patients with average body composition. Anthropometric estimates may cause large systematic errors in PD patients whose body composition varies from the average, particularly obese or overhydrated patients.
Anthropometry↗
Determining the rate of body heat storage by incorporating body composition.
The rate of body heat storage (S) is often used as an index of thermal stress. The traditional approach for determining S assumes that the specific heat (Cp) of all body tissues may be averaged to 0.83 kcal X kg-1 X degrees C-1, irrespective of the actual proportion of different tissues in the body. The present theoretical analysis primarily partitions the body into N compartments. However, this analytical approach involves the difficulty of making an exact evaluation of the mass and temperature of multiple compartments. Therefore, by adopting a two-compartment (core and shell) model, the specific heat capacities, mass fractions, and changes in the temperatures of the two compartments are combined, and S is defined as a function of adiposity (= mass fraction of peripheral tissues). Evaluation of a newly developed equation showed close agreement with observations during a series of cold-water immersion trials, and indicated that the new approach seems to adequately predict S as related to body composition.
Adult↗
Validation of expedient methods for measuring body composition in Indian adults.
The body composition of 99 men and 89 women from south India was estimated using hydrodensitometry, bioelectrical impedance and skinfold thickness. Comparisons of the hydrodensitometry (reference method) and skinfold methods showed that there were no significant differences between the methods, for estimates of fat free mass (FFM) and per cent fat. The mean difference between the estimates FFM (bias), from skinfold measurement and hydrodensitometry was small for both groups (+0.16 +/- 1.09 kg in men and +0.67 +/- 0.9 kg in women). The same trend was observed in per cent fat estimates (-0.37 +/- 2.04 in men and -1.49 +/- 2.28 in women), showing that the skinfold method can be used as an accurate and expedient method to determine body composition. The bioelectrical impedance method obtained a significantly lower FFM and higher body fat than the reference (hydrodensitometry) method. This could have been due to the use of an inappropriate equation derived from Western population studies. Hence, a new predictive equation, for the measurement of FFM by the bioelectrical impedance method was derived for this population, using the variables of height2/impedance and FFM measured by underwater weighing. The new equation for the bioelectrical impedance method then gave values of body composition which compared well (0.26 +/- 2.32 kg) in men and (0.36 +/- 2.49 kg) in women with the hydrodensitometry method.
Adult↗
Longitudinal changes in body composition in older men and women: role of body weight change and physical activity.
BACKGROUND: Estimates of body-composition change in older adults are mostly derived from cross-sectional data. OBJECTIVE: We examined the natural longitudinal patterns of change in fat-free mass (FFM) and fat mass (FM) in older adults and explored the effect of physical activity, weight change, and age on these changes. DESIGN: The body composition measured by hydrodensitometry and the level of sports and recreational activity (SRA) of 53 men and 78 women with a mean (+/-SD) initial age of 60.7 +/- 7.8 y were examined on 2 occasions separated by a mean (+/-SD) time of 9.4 +/- 1.4 y. RESULTS: FFM decreased in men (2.0% per decade) but not in women, whereas FM increased similarly in both sexes (7.5% per decade). Levels of SRA decreased more in men than in women over the follow-up period. Baseline age and level of SRA were inversely and independently associated with changes in FM in women only. Neither age nor level of SRA was associated with changes in FFM in men or women. Weight-stable subjects lost FFM. FFM accounted for 19% of body weight in those who gained weight, even in the presence of decreased levels of SRA. Loss of FFM (33% of body weight) was pronounced in those who lost weight, despite median SRA levels >4184 kJ/wk. CONCLUSIONS: On average, FM increased; however, the increase in women was attenuated with advancing age. The decrease in FFM over the follow-up period was small and masked the wide interindividual variation that was dependent on the magnitude of weight change. The contribution of weight stability, modest weight gains, or lifestyle changes that include regular resistance exercise in attenuating lean-tissue loss with age should be explored.
Adipose Tissue↗
Comparative determinations of rat body composition by chemical, near infrared reflectance and total body electrical conductivity analyses.
Rat carcass characteristics were determined by classical chemical analyses, near infrared reflectance (NIR) and total body electrical conductivity (TOBEC), with the aim to establish a rapid, reliable and soft method for numerous body composition predictions. In order to get a wide range in rat carcass protein and fat contents, animals were fed ad libitum with a commercial diet supplemented with various doses of cimaterol, a beta 2-adrenergic agonist having repartitioning effects. Samples analyzed by chemical methods allowed a suitable NIR calibration for protein and fat rat carcass contents. Comparison of chemical and NIR predictions gave equal values for protein and fat determinations. A linear correlation (R = 0.974) could be defined between both parameters. Similarly, the comparison of rat fat content determined with NIR and TOBEC also showed a linear correlation (R = 0.984). These correlations allowed to calculate rat protein content, after TOBEC fat measurements, using the prediction equation established from the linear protein-fat correlation found after NIR analyses. Calculated and NIR measured protein content values had a correlation coefficient of 0.956. It was concluded, that for the experimental conditions and the animal strain used, TOBEC analyses showed the best qualities to meet the fixed goals. TOBEC appeared as a suitable noninvasive method for body composition determinations. Furthermore, the technique enables repeated measurements in living animals for kinetic evaluation studies.
Animals↗
Total body lipid and triglyceride response to energy deficit: relevance to body composition models.
Although the study of human body composition is advancing rapidly, confusion still prevails regarding the molecular-level lipid component. Most molecular-level body composition models are presently based on the overall hypothesis that nontriglyceride lipids constitute an insignificant proportion of total body lipid. A single lipid or "fat" component consisting of triglycerides is thus assumed in most molecular-level body composition models. To test this hypothesis, the present study, carried out in adult rats, was designed to examine two questions: 1) What is the proportion of total lipids as triglycerides? and 2) Is this proportion constant or does it change with negative energy balance and weight loss produced by calorie restriction and increased exercise? Results indicated that with negative energy balance and weight loss there were progressive losses of total body triglyceride and lipid. The proportion of total lipids as triglyceride was 0.83 +/- 0.08 (SD) in control animals, with reductions at 2 and 9 wk of energy restriction [0.82 +/- 0.04 (P = NS vs. control) and 0.70 +/- 0.15 (P = 0.05)] and at 9 wk for energy restriction plus exercise [0.67 +/- 0.09 (P = 0.003)]. Nontriglyceride lipids comprised 2.8% of carcass weight at baseline and decreased to 2.2% by 9 wk of energy restriction and exercise (P = NS). Substantial differences were observed between body composition ratios expressed as percentages of the lipid-free body mass (LFM) and triglyceride-free body mass (TGFM); (e.g., total body water/LFM and TGFM in controls = 72.7 +/- 0.7 and 70.4 +/- 2.2, respectively; P = 0.02). These observations strongly support the existence and importance of nontriglyceride lipids as a body composition component that responds independently from storage triglycerides, with negative energy balance produced by food restriction and exercise.
Animals↗
Body composition by photon absorptiometry.
Whole-body dual photon measurements of body composition were made in 9 controls, 15 athletes and 5 patients with eating disorders. Measurements of lean body mass, mineral mass and fat mass were accurate. Lean body mass and fat mass were measured with reliabilities of about 0.8 kg while for total body bone mineral mass, the reliability was about 60 g. Women had a smaller lean body mass and a greater fat mass than men. Women with eating disorders had the same body composition as males. Measurements of body composition by dual photon absorptiometry are safe and reliable.
Absorptiometry, Photon↗
Advantage of knee height over height as an index of stature in expression of body composition in adults.
It is not clear how body composition should best be compared between subjects, but it is accepted that simply comparing total mass or percentage fat-free mass (FFM) or fat mass (FM) is not adequate. Indexing body composition to stature seems more appropriate, but the decline in height with age or osteoporosis could confound comparisons of body composition across age or disease groups. Using bioimpedance data from 600 adults in the Framingham Offspring Study, we examined the ability of height and knee height indexes to correctly describe the loss of FFM seen with increasing age between 28 and 75 y. Indexing body composition to height obscured the loss of FFM with age (r = -0.065, P < 0.26 for men; r = -0.050, P < 0.394 for women), whereas indexing body composition to knee height preserved the correct information (r = -0.154, P < 0.007 for men; r = -0.161, P < 0.006 for women). These data suggest that knee height is a reliable surrogate for stature and should be used to adjust body composition measurements when bioimpedance is used to estimate body composition.
Adult↗
Assessing body composition in gastrointestinal disorders.
The assessment of body composition and energy requirements is important for the nutrition of healthy and pathological states such as gastrointestinal disorders, which are known to be associated with abnormalities in body composition among persons with malnutrition and malabsorption. Careful monitoring of body composition is thus recommended for assessing body water compartments, predicting caloric needs and physical performance, and evaluating the development of muscle mass in persons with malabsorption. In the present review we briefly describe the basic body composition models and various techniques used for their assessment and discuss the utility of measuring caloric requirements in persons with gastrointestinal disorders. Assessing body composition may improve the prognosis of malnutrition caused by gastrointestinal disorders and may be useful in monitoring diet treatment.
Body Composition↗
Birmingham Medical Research Expeditionary Society 1977 Expedition: effect of a Himalayan trek on whole body composition, nitrogen and potassium.
The body composition of the 17 members of the BMRES was studied using body weight and fat fold calipers, with measurements of whole body potassium and nitrogen. The full assessment was made just before departure from Birmingham and immediately on return. Daily observations of body weight and fat folds were made during the trek to high altitude. During the ascent all subjects lost body fat but there was little change in lean body mass. After return it was found that there had been further loss of body fat and some loss of lean tissue also. One subject who took methandienone retained potassium but had no increase in body nitrogen. There was no correlation between changes in body composition and acute mountain sickness.
Adult↗
Association of visceral adipose tissue with incident myocardial infarction in older men and women: the Health, Aging and Body Composition Study.
Assessment of body fat distribution, particularly visceral adipose tissue, may be important for accurate risk evaluation for cardiovascular disease in the elderly. This 1997-1998 US study examined the association of incident myocardial infarction (MI) with total adiposity (body mass index and fat mass) and body fat distribution (waist-to-thigh ratio, waist circumference, visceral and subcutaneous adipose tissue) in well-functioning men (n = 1,116) and women (n = 1,387) aged 70-79 years enrolled in the Health, Aging and Body Composition Study. There were 116 MI events (71 in men, 45 in women) during an average follow-up time of 4.6 (standard deviation, 0.9) years. No association was found between incident MI and the adiposity or fat distribution variables for men. For women, visceral adipose tissue was an independent predictor of MI (hazard ratio = 1.67, 95% confidence interval: 1.28, 2.17 per standard-deviation increase; p < 0.001). No association was found between body mass index or total fat mass and MI events in women. The association of visceral adipose tissue with MI in women was independent of high density lipoprotein cholesterol, interleukin-6 concentration, hypertension, and diabetes (hazard ratio = 1.79, 95% confidence interval: 1.24, 2.58 per standard-deviation increase; p < 0.01). The amount of adipose tissue stored in the intraabdominal cavity is an important, independent risk factor for MI in well-functioning, elderly women.
Adipose Tissue↗