Nutrition and Body Composition - Essay Example

BODY COMPOSITION ASSESSMENT by Introduction Body composition is descriptively utilised to illustrate the percentages of muscle, water, bone and fat mass in human bodies. Existing research shows that the various forms of prevailing health problems are often associated with the presence of either too much or too little body fat. Thus, human body composition and overall weight present determine the leanness of an individual. The paper will critically evaluate bioelectrical impedance analysis as an effective body composition assessment method. This will be in terms of a comparative analysis of its limitations and strengths in relation to other methods that are also employed. Body Composition Assessment Whole body composition comprises both fat-free body mass (FFM) and total body fat. The former is inclusive of water, bone matter and muscle and the latter pertains to essential fat and storage (stored) fat. Accordingly, Heyward and Stolarczyk (1996) assert that whole-body composition is of interest in terms of sports and exercise, obesity assessment and control of body weight. Of specific importance is the need to consistently ensure that total body fat is maintained at an optimal level (Heyward & Stolarczyk, 1996:4). The total body fat element is critical to optimal human physiological capacity. Thus, too little fatness, as is witnessed in individuals with eating disorders and exercise addiction as well as those with certain diseases, e.g. cystic fibrosis, can eventually result in a serious physiological dysfunction (Heyward & Stolarczyk, 1996:5-6). Through different body density measurements, which utilise established equations and corrections, one is able to calculate the ratio of fat-free mass to fat mass in a human body. This is based upon the ‘much lower density’ of the prevailing fat compartment in terms of their ratio (Heyward & Stolarczyk, 1996:8). However, concerning FFM, the bone matter is denser than the muscle structure. This may lead to the over-estimation of the fat percentage present. This is if there is either relative increase in the body muscle mass (during training) or relative loss of the prevailing bone density as found in individuals suffering from osteoporosis (Heyward & Stolarczyk, 1996:9). A variety of avenues are available through which effective body composition can be measured. This is especially in regard to the ‘approximate’ measurement of body fat percentage present. The most commonly employed method is through use of gun calipers, in measuring the subcutaneous fat thickness at various places on the body. Bioelectrical impedance analysis (BIA), on its part, utilises the body’s prevailing resistance of electrical flow in the measurement of body fat. Ultrasound technology is used in order to measure an individual’s subcutaneous fat thickness, with measurement of body composition being achieved by way of using multiple points. Body Composition Assessment: Bioelectrical Impedance Analysis Bioelectrical impedance analysis (BIA) is one of the commonly utilised avenues through which optimal estimation of body composition, particularly body fat, can be achieved. As Kyle et al. (2004) argue, it pertains to the measurement of existing body fat in relation to the lean body mass of an individual (Kyle et al., 2004:1226). The method has become quite popular since the mid-1980s, traceable to the advent of the first commercially available assessment devices (Kyle et al., 2004:1227). Influential in this regard are the twin aspects of relative low cost incurrence and equipment portability, in comparison with other avenues of analysis. Accordingly, it is quite familiar within the larger consumer market, as an easily accessible and simple avenue for body fat estimation (Kyle, et al., 2004:1228). As Buchholz, Bartok and Schoeller (2004) present, BIA as a non-invasive technique involves placing of two electrodes on an individual’s right hand and foot. Subsequently, an imperceptible low-level electrical current is sent through the body where the current is affected by the water amount present (Buchholz, Bartok & Schoeller, 2006:443). The instrument functions through measurement of how the electric signal is impeded while flowing through various types of bodily tissue structures. On the contrary, the presence of bone matter and fat mass has the effect of slowing down the signal. This avenue of assessment is vital in providing estimates of existing body water from which calculations of body fat are derived by way of utilising selected equations (Buchholz, Bartok & Schoeller, 2004:446/ Dehghan & Merchant, 2008:26). Comparative Analysis of Body Composition Assessment Methods In recent times, the development of segmental BIA has aided in overcoming the prevailing inconsistencies between the human trunk’s body mass and resistance (R). As observed by Kyle et al. (2004), this has increased the overall accuracy and reliability of the testing method. The strength of this method is proven using this technique as a bedside method rapidly increasing based on the aspects of equipment safety and portability. Furthermore, the procedure is itself not only non-invasive but also simple, thereby producing results that are both rapidly obtainable and reproducible (Kyle et al., 2004:1228). A widespread diagnostic tool, ultrasound technology is not only portable, but also relatively inexpensive. It also provides an added strength comparable to the use of BIA (Pollet, 2012:13). BIA further provides an approximate measurement of body mass and fluid, hence providing a decisive assessment tool for the measurement of current health status. In addition, it allows for the timely detection of any imbalance within a human being’s body composition, thereby fostering earlier medical prevention and intervention (Buchholz, Bartok & Schoeller, 2004:444). Use of ultrasound technology, on its part, has the advantage of being able to also directly measure muscle thickness and quantify intramuscular fat. This is through the capturing of muscle their structure and size as well as whichever pathological lesions exist, through real-time tomo-graphic imaging (Pollet, 2012:23). As Buchholz, Bartok and Schoeller (2004) explain, a limitation of the BIA method is that dehydration, the lack of sufficient water level in the body fundamentally influences BIA measurements through increase of the body’s electrical resistance (Buchholz, Bartok & Schoeller, 2004:445). This results in an error, the overestimation of present body fat by an approximate 5kg underestimation of fat-free mass. Another limitation is the use of the method shortly after a meal is consumed resulting in a variation of up to 9.9% between the lowest and highest readings of body fat percentages taken (Buchholz, Bartok & Schoeller, 2004:446). In addition, moderate exercising before testing results in both the underestimation of body fat vis-à-vis the overestimation of fat-free mass because of reduction of impedance. Also, the technique is not sufficiently accurate when recording individual single measurements, as opposed to measuring groups based upon a wide-spread period of time (Dehghan & Merchant, 2008:26). While ultrasound imaging does not use power levels that are too low to cause any pressure effects or adverse heating in human tissue, caution is implored during use. (Pollet, 2012:44). This is informed by the fact that exposure to high quantities of ultrasound exceeding 155 dB may result in harmful heating effects on the human body (Pollet, 2012:44). This is comparable to the BIA technique with optimal levels of current being required towards successful measurement. A notable factor here is that utility of excessive voltage levels may result in the adverse heating or negative pressure effects on both human tissue and water ratio in the body. This may lead to harmful heating effects on the body, which may result in serious internal damage, and even death (Pollet, 2012:47). As an air displacement plethysmograph (ADP) assessment technique, BOD POD utilises whole body densitometry in order approximately determine the fat ratio vis-à-vis body leanness (body composition) (Millard-Stafford et al., 1999:1350). The body volume is also measured through sitting inside the BOD POD, enabling body density to be calculated by dividing the body mass by the body volume (Density = Mass/ Volume). It is only after the overall density has been determined that the relative ratio of lean body mass to body fat is calculated (Millard-Stafford et al., 1999:1351). By utilizing air instead of water as its basis for the measurement of body volume, BOD POD is founded upon the prevailing physical relationship between volume and pressure. Thus, through direct measurement of pressure, the relationship aids in the derivation of various unknown volumes (Millard-Stafford et al., 1999:1352). A strength of and similarity between BOD POD and BIA is in terms of general safety and speed with which results can be calculated. However, the BOD POD is the most safe and accurate of the two techniques. In addition, BOD POD is considered more accurate, fitting up to within 1–2% approximation of body fat for both adults and children, as opposed to BIA that is not considered an optimal reference ‘gold standard’ method (Millard-Stafford et al., 1999:1354). An additional strength of the two methods is based upon the ease of the testing processes in general, where both require compliance with the tool kits/instruments’ test protocols. Accordingly, both require individuals being tested to be relaxed and still in addition to avoiding both coughing and talking during the testing process. In terms of differences and limitations, BOD POD is limited through the utility of very complex equipment, which is not portable and therefore limited in terms of access to a majority of individuals (Millard-Stafford et al., 1999:1355). This is different compared to BIA equipment that is easily portable and safe, therefore useful in various bedside applications. Furthermore, the BIA technique generates results that are not only easily reproducible, but also rapidly obtainable (Kyle, et al., 2004:1230). The BOD POD process, on the other hand, is a more complex procedure requiring the performance of several tests before final and actual body composition results are obtained. Accordingly, there is need to measure the overall volume of air in the lungs in addition to estimating the resulting effects on skin surface area. These are subsequently utilized in making pertinent corrections to existing measurements in order to obtain final approximate results (Millard-Stafford et al., 1999:1353). Other methods compared to BIA Hydrodensitometry is the traditional laboratory method used for body decomposition measurement. This method is time consuming, needs the use of large equipment and also technical skill which is disadvantageous. The skin calliper method (anthropometry) is popular and measures subcutaneous fat directly under the skin. This technique has a +/- 3.5 percent error and is not a viable solution because of effects such as hydration and recent exercise. Near-Infrared interactance is based on light absorption and reflection principles. It has an error of +/- 5 percent and is not reliable. Dual-Energy X-Ray Absorptiometry method is used to measure body bone density and body composition. It can provide site-specific fat distribution. However, it requires large equipment, is costly and only accessible in research and medical settings making it unreliable. The above analysis shows that Bioelectric impedance analysis is popular and reliable to use compared to the other methods. Conclusion It is notable that an optimally balanced ratio of body fat is linked to longevity and good health. On the other hand, the presence of excess body fat in relation to an individual’s lean body mass significantly increases the risk of various health complications. Thus, it is vital to constantly ensure that there is the right balance between the body fat and fat-free mass (FFM). While varying measurement techniques are essential in the proper approximation of existing ratios, some are limited in terms of ease of use and accessibility, i.e. the BOD POD technique. The utility of ultrasound technology on its part is also limited in terms of ease of access and portability as opposed to BIA tools, hence limiting overall applicability in general populations. While BIA is relatively safe and secure, caution is placed upon the proper following of manufacturer instructions. This is in order to not only keep the participant safe (due to the electric charge utilised), but also in order to produce optimal and accurate results to the best estimates. Reference List Buchholz, A C Bartok, C & Schoeller, D A 2004, The validity of bioelectrical impedance models in clinical populations. Nutritional Clinical Practice, 19 (5): 433–46 Dehghan, M & Merchant, A T 2008, Is bioelectrical impedance accurate for use in large epidemiological studies? Nutritional Journal, 7: 26. Heyward, V H & Stolarczyk, L M 1996, Applied body composition assessment. Champaign: Human Kinetics. Kyle, et al. 2004, Bioelectrical impedance analysis – part I: review of principles and methods. Clinical Nutrition, 23 (5): 1226–43. Millard-Stafford, M.L. et al.1999, Evaluation of the BOD POD for assessing body fat in collegiate football players. Medical Science Sports Exercise, 31(9): 1350-56. Pollet, B 2012, Power Ultrasound in Electrochemistry: From Versatile Laboratory Tool to Engineering Solution. John Wiley & Sons. Read More