The Body Composition Assessment - Report Example

Name: Instructor's name: The course: 23rd November, 2009 The Research Protocol for Assessment of Body composition (Fat Mass and Fat Free Mass) Among Obese Women of 21-35 Years of Age 1.0 Background Information Body composition assessment has proved to be of importance in physiological and metabolic studies. Fat for example has been found to have effects on mobility, morbidity and has effects on medical treatment (Johansson et al, p. 323). Assessment of the amount of fat an individual has is therefore very important since it will help in the management /control of its effects such as the ones mentioned above. Obesity for example is caused by excess accumulation of body fat and body fat is contributed to by the amount of calories that one takes. If this can be controlled, then obesity can be controlled as well (Heyward p. 231). One way of reducing or controlling obesity is through weight loss programs. The aim of a weight loss program is to achieve fitness and fitness is only achieved by doing the right kind of exercises and taking the right diet (Heidrich p. 6). People with obesity have an imbalance in their body composition. They have more of fat than other body compositions. Weight loss programs are designed to create a balance between the caloric expenditure and caloric intake of people. The obese people’s caloric intake and expenditure have to be determined in order to design a program that will help them reduce weight (Heyward p. 231). Body weight is reduced by one’s diet and exercises which increase the caloric expenditure of a person hence weight loss. A deficit of 35000 kcal for example is required for the loss of 0.45 kg of fat. In order to determine if a certain amount of Kcal have been lost, an assessment method have to be used. In case of obese people, concentration is on the loss of fat since these are in excess. Achievement of the program’s aim therefore means determination of the amount of fat lost during the program considering the amount of weight that needs to be lost. There are five methods that can be used to assess the changes in fat mass and fat free mass. These are: dual energy X-ray absorptiometry (DEXA), under water weighing (UWW), computed tomography (CT), magnetic resonance imaging (MRI) and bio-electric impedance analysis (BIA) (Gropper et al p. 284-287). In this paper, the aim is to describe a protocol that can be used for the assessment of body fat and fat free mass among obese women. Analysis of information about the above methods will be done and only two appropriate assessment methods selected. Aims: To find out the appropriate methods for assessing body fat mass and fat free mass To describe a protocol with two methods of fat mass and fat free mass assessment in obese women of 21-35 years of age under a weight loss program that utilizes diet control and exercise as methods of loosing weight. Objectives Research about the available methods for assessing fat mass and fat free mass Evaluate the methods based on available information about their accuracy, advantages and disadvantages considering the subjects Select the appropriate methods Method The subjects involved in this study are obese women of 21-35 years of age. Information about body composition assessment methods was collected from articles and reports on previous studies and books containing information about the five body composition assessment methods. An evaluation of the already researched on assessment methods was done and two assessment methods selected. Analysis of the methods considered accuracy, reliability in relation to the subjects. Two Selected Methods a) Magnetic Resonance Imaging MRI utilizes the radio waves transmitted by an activated atomic nuclei from the body to measure fat distribution, body fat, muscle size, organ size and body water contents. The emitted signal is recorded and used to develop a computerized image. This method is considered safe and noninvasive but is expensive (Gropper et al p. 286). It has no health risks as compared to X- ray and computed tomography scans (EMD 2009). b) Dual Energy X-ray Absorptiometry (DEXA) This is an imaging technique under absorptiometry that involves scanning of a portion of or the whole body using a photon beam. The dual energy X-ray absorptiometry utilizes gadolinium as the radio nuclide source and scans subjects using two different energy levels. This enables the estimated measurement of fat mass and fat free mass (Gropper et al p. 285-286; DNFS Videos). The photon source is placed beneath a table where the subject lies and a detector above. These pass over the subject and measurements taken. The attenuation of the X-ray beams is calculated by use of a computer and calculation is based on specific restriction on the fat and the fat free masses (Gropper et al p.286). This method is very efficient and has high reproducible results. It is convenient when compared to UWW. Previously before it was used for the measurement of fat mass, DEXA was developed for the determination of bone mineral density but later modified to determine body composition. This makes it more convenient than UWW which is affected by bone mineral density (BMD) (Johansson et al, p. 323). According to Johansson and other researchers, UWW is dependent on the assumption that body density is constant and that the body is divided into two parts which are; the adipose tissue and the lean body mass (p. 323). Adipose tissue is assumed to have a constant density of 0.9g/cm3 while lean body mass is assumed have a constant density of 1.1g/cm3 (Johansson et al, p. 323). The method does not take into account the possibility of lean mass density differences. Johansson and others noted that BMD varies with age and bone has the highest density compared to other body tissues. This explains why UWW method of assessment may not be accurate in measuring body composition. UWW is also affected by the air contents in the lungs as well as the gastrointestinal tract gas content (Johansson et al, p. 323). Johansson and the others’ research was a study comparing DEXA and UWW. It found out that BMD affects fat measurement in the body while UWW is used. Inaccurate results were obtained from subjects with low body fat. When the subject had low bone mass, the fat content was overestimated while high bone mass produced low fat content in the body (Johansson et al, p. 326). DEXA proved very convenient in measuring the body composition since it produced the same results as a high precision scale instrument used to measure total body weight. UWW was also found to be inconvenient because it required submergence in water for along time which is not comfortable and not fit for the young and the old (Johansson et al, p. 326) MRI and DEXA are the most appropriate methods. In some two studies, DXA was compared with MRI. The studies revealed overestimated values when DXA was used compared to MRI. In one of the studies, the difference only occurred in some parts of the body as compared to MRI. This was a study involving HIV+ patients and men and women. The difference only occurred in the leg fat of HIV+ and control patients and in the trunk fat of men and women (Scherzer et al, p. 1095). In yet another similar study, MRI was compared to DEXA. The aim of the study was to show the importance of MRI irrespective of the easy availability and low cost of DEXA. It was found that DEXA significantly overestimated both regional and total body fat mass compared to MRI irrespective of its manufacturer (Lukaski, p. 875). In another study comparing MRI, UWW, DEXA and CT, all the methods were found to have their own assumptions and limitations making it difficult to make one a reference method (Tothill et al, p. 459). UWW depends on the constant densities of lean tissue and fat assumption, DEXA different brands produce different results for the same subjects when measuring bone mineral density which shows poor calibration and MRI and CT scans fat determination methods depend on accuracy of outlining the adipose tissue margins, which according to Tothill and other researchers, has no validation (p. 458). Bioelectrical Impedance Analysis/Bio-Electrical Impedance Analysis (BIA) measures the fat and fat free mass through the measurement of electrical conductivity. According to the information in the New Fitness, BIA is affected by hydration and when one is dehydrated, the amount of fat tissue can be overestimated. This means that the correct amount of fat eliminated from an obese patient’s body is not determined (2009). So many factors affect hydration and these include; taking too much caffeine, a woman’s menstrual cycle, exercising before measuring, illness, diuretics, eating before measurement, taking too much alcohol and certain drugs. Women of 21-35 have their menstrual cycles at different times of the month and so this method does not produce consistent measurements of their body fat and fat free mass. Additionally, a weight and loss program has exercise as part of its intervention and exercise affects hydration which in turn affects measurement of fat mass and fat free mass by BIA. The results produced may therefore not be reliable (New Fitness 2009). BIA is also affected by electrical imbalance (Gropper et al p. 287). BIA also requires the derivation of population-specific BIA-equations because of the prediction formula to derive body composition. In a study involving elderly people, BIA produceddifferent numerical estimates of body fat because of BIA dependence on prediction formula (Mazariegos et al, 174) Computed Tomography (CT)’s equipment is expensive and there are very high risks of developing cancerous diseases due to long exposure to ionizing radiation (Gropper et al p. 286). 6.0 Conclusion The appropriate protocol to use in the assessment of fat mass and fat free mass is dependent on age, gender, subject’s health status, effectiveness and the health risks of using it. The cost of the equipment also affects which method to use in a weight loss program but this is not given much priority as the first five. Under Water Weighing for example, is not appropriate for the young and the old. In the above protocol, DEXA and MRI have been found to be the appropriate methods of assessment. Their selection has been given based on an analysis that has eliminated the other methods due to their disadvantages in relation to the subjects and reliability. 7.0 Works Cited Department of Nutrition and Food Sciences (DNFS) Videos: Methods of Body Composition Analysis Tutorials. Encyclopedia of Mental Disorders (EMD). Magnetic Resonance Imaging, 2009. Retrieved on 23rd Nov, 2009 from: http://www.minddisorders.com/Kau-Nu/Magnetic-resonance-imaging.html Gropper, Sareen S., Smith, Jack L. and Groff, James L. Advanced Nutrition and Human Metabolism. 5th Ed. Kentucky, Cengage Learning, 2008. Heidrich, Ruth E. Senior Fitness: the Diet and Exercise Program for Maximum Health and Longevity. New York, Lantern Books, 2005. Heyward, Vivian H. Advanced Fitness Assessment and Exercise Prescription. 5th Ed. Illinois, US. Human Kinetics, 2006. Johansson Anna G, Forsiund Anders, Anders S, Mailmin Hans, Hambraeus Letf and Ljung Sverker, Determination of Body Composition-a Comparison of Dual Energy X-ray Absorptiometry and Hydrodensitometry. American Journal of Clinical Nutrition. 57:323-6, 1993. Lukaski, Henry C. In Search of a Practical Tool to Assess Regional Body Composition. American Journal of Clinical Nutrition. 2008; 88, 875– 6. Mazariegos, Manolo, Valdez Carlos, Kraaij Sophia, Van Setten Conny, Liurink, Cornelien, Breuer Katharina, Haskell Marjorie, Mendoza Ivan, Solomon Noel W. and Deurenberg Paul, A Comparison of Body Fat Estimates Using Anthropometry and Bioelectrical Impedance Analysis with Distinct Prediction Equations in Elderly Persons in the Republic of Guatemala. Nutrition. Elsevier Science Inc. 12:168-175, 1996.---pdf 8 New Fitness. Body Fat Measuring - Know where you stand with your weight, 2009. Retrieved on 23rd Nov, 2009 from: http://www.new-fitness.com/body_fat_measuring.html Scherzer Rebecca, Wei Shen, Bacchetti Peter, Kotler Donald, Lewis Cora E, Shlipak Michael G, Punyanitya Mark, Heymsfield Steven B and Grunfeld Carl. Comparison of Dual-energy X-ray Absorptiometry and Magnetic Resonance Imaging–Measured Adipose Tissue Depots in HIV-Infected and Control Subjects. American Journal of Clinical Nutrition. 2008; 88:1088 –96. Tothill P., Han T. S., Avenell A., McNeill G. and Reid D. M., Comparisons Between Fat Measurements by Dual-energy X-ray Absorptiometry, Magnetic Resonance Imaging and Underwater Weighing. Research Report. Department of Medical Physics, Western General Hospital, U.K. and Aberdeen Royal Infirmary, U.K. Read More