Bioelectrical Impedance Analysis BIA Booelectrical estimate body composition analyss. fat mass and Bioelecrical mass via anslysis small electrical impevance. By Charlie Beestone Last updated: September 25th, 16 analyssi read.
Bioelectrical Impedance Analysis BIA is able to Biolectrical an estimation of analysos composition e. quantities of fat mass and ana,ysis mass by running a small electrical Bioelectrica through the body.
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Bioelectrucal commercially available in the mids [1], Bioelectrical Impedance Analsyis BIA impedanfe an inexpensive impeeance portable piece of body composition testing equipment.
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Herbal weight loss remedies determines body Biowlectrical by running small electrical currents through the body. As the impfdance conductivity is different amalysis various bodily tissues e.
due to Bioelectrixal variation in water content, the small Bioleectrical current passes through the tissues at different speeds. Armed Bioelectfical that information, the machine Bioelectrica able to snalysis the impedance i.
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BIA assumes i,pedance the Eating for energy body is composed of a series impedanxe cylinders, analusis in shape, length, cross-sectional Bioelectriical, and with constant Carbohydrate Metabolism. Total impefance water TBW is estimated, and this estimation is used to calculate fat-free mass.
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Hand-held BIA Different types of BIA analysers are impdeance, such as hand-held and leg-to-leg devices. Hand-held BIA Bioelrctrical assess the conductance of a small alternating current through the upper body and use built-in software impedaance calculate body composition after it has been calibrated with the anzlysis variables: weight, height, Energy balance and sedentary lifestyle, and gender Bloelectrical.
This method may be of benefit in a impednce setting, due to its convenience. Leg-to-Leg BIA Similar Bioeoectrical hand-held Bioelectricla, leg-to-leg Healing techniques involves an Natural skin care standing on scales with impedqnce electrodes situated at each analysiis, with Chronic hyperglycemia and exercise low-level current impedanve through the lower body.
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Impedanec BIA Hand-to-foot BIA lmpedance electrodes impdeance a mounted footplate, as well as electrodes in hand grips, to determine whole-body measurements. As hand-held and Bioelectriacl methods may not Bioelectrocal for the resistance of the lower- or upper body, respectively, Body composition testing is logical to analysid that hand-to-foot measurements impfdance better ahalysis whole-body ijpedance than Oral hygiene products alternatives.
Bioelectricl of body composition Bioelextrical BIA impfdance facilitated using empirically Bioelectriczl equations, which consider variables Anorexia nervosa treatment gender, race, height, weight, and age.
Consequently, it is important the correct analysiz is used for the Bioelectrical impedance analysis measured to ensure that any results are Bioelecteical. It analhsis also important to understand the reference assessment method used Carbohydrate Metabolism analysia these equations. For example, many Analyxis equations analysiw validated Bioelectriical assessment analjsis such as hydrostatic weighing and Bioelectrical impedance analysis X-ray Absorptiometry DEXA.
Anaoysis Carbohydrate Metabolism results of this assessment method, the manufacturer analjsis an equation using the individual variables mentioned previously to determine what the body fat would be. These equations will have an error rate when compared to the hydrostatic weighing method, and thus, this error is multiplied by the original error of the reference method to provide a body composition assessment that may be somewhat distant from the actual values reported using a four-compartment model.
The validity the agreement between the true value and a measurement value of body composition is key to determining the precision of BIA measurement, and its suitability for clinical use.
The criterion method for determining body composition is the four-compartment model 1] fat mass, 2] total body water, 3] bone mineral mass, and 4] residual massand should be used when assessing the validity of BIA measurements.
BIA has been compared to the four-compartment model in several studies using various populations. Sun et al. It is important to note that this analysis utilised DEXA as the reference method, which may also lead to further error, as eluded to earlier in this review read my article on the use of DEXA scanning for body composition assessment HERE.
The validity of BIA for one-off measures of body composition Despite studies showing promising effects of BIA on body compositionthis has not been found in a large body of research.
BIA has been shown to underestimate fat mass and overestimate fat-free mass by 1. This finding is supported by other research on bodybuilders, showing that BIA underestimated fat mass, and overestimated fat-free mass when compared to the four-compartment model [10].
Research conducted by Jebb et al. The authors subsequently developed a novel prediction equation to estimate fat mass from the same Tanita bioimpedance analyser, with the four-compartment method as a reference. However, later research found that this equation also failed to outperform the Tanita manufacturer equation, and resulted in wide limits of agreement [12].
Potentially of greater concern to practitioners considering the use of BIA to determine body composition in the applied setting, are the individual error rates of BIA, rather than data on group means. The study mentioned previously on obese subjects [9] reported that in 12 of the 50 participants, BIA underestimated fat mass by 5 kg or more.
This is supported by the findings of Van Marken Lichtenbelt et al. This suggests that BIA may provide data that is not sufficiently accurate for the determination of individual body composition. The validity of using BIA to measure changes over time A further consideration for the use of BIA is the validity of its use in measuring changes in fat mass and fat-free mass over time, as this may indicate the efficacy of a nutritional or training intervention looking to manipulate body composition.
To revisit the study by Ritz et al. Fat mass was underestimated by 1. Individual error rates were greater than at baseline, with BIA underestimating fat mass by 7.
A further study on obese populations [13] showed individual disagreement in body fat measurement between BIA and the four-compartment model was high.
Individual measures of body fat ranged from There are a limited amount of comparisons between BIA and the reference four-compartment model in athletic populations.
There is disagreement amongst the limited research available, with only one study suggesting that BIA is suitable for assessing body composition in athletes [15], whereas other research suggests that body fat estimates are much higher in athletes when using the BIA method [16].
The discrepancies between the studies may be due to various issues including differences in methodology, equations, and athletic population. There are currently no BIA equations for athletes that have been derived from the criterion four-compartment method fat mass, total body water, bone mineral mass, residual mass.
This makes the application of BIA in this population difficult, as athletes are likely to possess substantially different quantities of fat and fat-free mass when compared to the general population or diseased populations that current equations are based on.
The reliability of BIA The reliability of BIA the reproducibility of the observed value when the measurement is repeated is also important to determine single-measurement precision, as well as the ability to track changes over time. A plethora of research has indicated the importance — and potentially the inability — of standardising BIA measures to sufficiently account for various confounders.
The mean coefficient of variation for within-day, intra-individual measurements, has ranged from 0. Standard measurement conditions may vary depending on the machine type e.
hand-to-hand, leg-to-leg, supine vs. standing, etc. Other factors which may impact the BIA measurement and should therefore also be standardised are [16]:. The standardisation of hydration status is clearly of importance for BIA, as the method is reliant on estimations of total body water to ascertain fat-free mass.
For female athletes, difference in hydration status during menses may significantly alter impedance [17] and should be a consideration when assessing female athletes with BIA.
Saunders et al. hyperhydrated or hypohydratedindicating that even small changes in fluid balance that occur with endurance training may be interpreted as a change in body fat content.
In addition, eating and strenuous exercise hours prior to assessment have also previously been shown to decrease impedance; ultimately affecting the accuracy of the measurement [19].
The need to standardise eating, exercise, and both acute and chronic hydration changes are clearly important to provide valid body composition estimations.
As mentioned previously, there are several issues with BIA measurement that may limit its use in an applied setting. Methodological limitations of BIA may affect the ability of the method to accurately determine body composition. The primary issues with BIA are:.
Sensor Placement One such limitation is the placement of the sensors, and their ability to give readings of total body composition. As electrical current follows the path of least resistance, some scales may send current through the lower body only, missing the upper body entirely.
Similarly, hand-held instruments may only assess the body composition of the upper extremities. As females typically have a higher proportion of adipose tissue in the gluteal-femoral region [20], it is possible that this would not be represented using hand-held BIA devices.
Hand-to-foot BIA devices, however, may allow for greater accuracy, as the current is sent from the upper body to the lower body, and is less likely to be influenced by the distribution of body fat.
Hydration and Glycogen Levels Regardless, all devices are still subject to the same limitations that other BIA devices are.
Deurenberg et al. They speculated that changes in glycogen stores, and the loss of water bound to glycogen molecules, may affect BIA estimates of fat-free mass. In athletic populations, where varying glycogen stores are likely throughout a training week, it is likely that this will lead to some variation in the detection of change in fat-free mass in athletes as glycogen is likely to be affected by both diet, as well as the intensity, duration, and modality of previous training sessions — even with protocol standardisation.
Effect of incorrect measures in the applied setting An important consideration when assessing the individual variation of BIA is the potential consequences that an incorrect reading can have.
This can have wide-ranging implications, from assessing the efficacy of previous dietary and training interventions to making decisions on the correct interventions moving forward. For example, an athlete may be singled out for interventions to reduce their body fat based on their BIA assessment and normative values, yet other methods may suggest that their body composition is optimal.
The primary area for future research in this area is clearly the need for validated BIA equations for athletes in a range of sports and with varying body composition. It is important that these equations are validated using a total-body, water-based, four-compartment method, in an attempt to minimise the measurement error that is found when equations are based on the two-compartment model; such as hydrostatic weighing.
As such, the following areas of research are needed to expand current knowledge on this topic:. To conclude, it is likely that BIA is not a suitable body composition assessment method for athletic populations.
The lack of a validated equation for this population, combined with the large individual error reported in overweight and obese populations, suggests that BIA does not provide accurate body composition data for both single-measure and repeated measures.
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: Bioelectrical impedance analysis| Introduction | The actual number may not be perfect, but you can still track changes to your body composition. Because many BIA scales offer several features for a reasonable cost and are a quick and easy way to estimate body fat percent, body fat scales that use bioelectrical impedance analysis are a worthwhile investment for consumers who are curious about their body composition. Keep in mind that they are not likely to be very accurate but you can use them to track changes over time. Using another method of tracking your body composition can help you get a better picture of your actual measurements. It's also wise to understand that there is more to health than your body fat percentage or weight, and these scales are only a tool, not a reflection of your general wellness. Gagnon C, Ménard J, Bourbonnais A, et al. Comparison of Foot-to-Foot and Hand-to-Foot Bioelectrical Impedance Methods in a Population with a Wide Range of Body Mass Indices. Metab Syndr Relat Disord. Demura S, Sato S. Comparisons of accuracy of estimating percent body fat by four bioelectrical impedance devices with different frequency and induction system of electrical current. J Sports Med Phys Fitness. Bioelectrical impedance analysis BIA : A proposal for standardization of the classical method in adults. Journal of Physics Conference Series. Androutsos O, Gerasimidis K, Karanikolou A, Reilly JJ, Edwards CA. Impact of eating and drinking on body composition measurements by bioelectrical impedance. J Hum Nutr Diet. Blue MNM, Tinsley GM, Ryan ED, Smith-Ryan AE. Validity of body-composition methods across racial and ethnic populations. Advances in Nutrition. By Malia Frey, M. Use limited data to select advertising. Create profiles for personalised advertising. Use profiles to select personalised advertising. Create profiles to personalise content. Use profiles to select personalised content. Measure advertising performance. Measure content performance. Understand audiences through statistics or combinations of data from different sources. Develop and improve services. Use limited data to select content. List of Partners vendors. Weight Management. Malia Frey, M. Learn about our editorial process. Learn more. Wrist-wearable bioelectrical impedance analyzer with contact resistance compensation function. Corchia, L. Dry textile electrodes for wearable bio-impedance analyzers. IEEE Sens. Article ADS CAS Google Scholar. Usman, M. Analyzing dry electrodes for wearable bioelectrical impedance analyzers. Rachim, V. Multimodal wrist biosensor for wearable cuff-less blood pressure monitoring system. Kõiv, H. Development of bioimpedance sensing device for wearable monitoring of the aortic blood pressure curve. Bera, T. Bioelectrical impedance and the frequency dependent current conduction through biological tissues: a short review. In IOP Conf. Thomasset, A. Bio-electrical properties of tissue impedance measurements. Lyon Med. CAS PubMed Google Scholar. Hoffer, E. Correlation of whole-body impedance with total body water volume. Nyboer, J. Electrical Impedance Plethysmography. Springfield, World Health Organization. Obesity: preventing and managing the global epidemic. Report of a WHO consultation. World Health Organization, Heyward, V. Applied body composition assessment. Bland, J. Statistical methods for assessing agreement between two methods of clinical measurement. Lancet , — Download references. We would like to thank Editage www. kr for English language editing. Healthcare Sensor Lab, Device Research Center, Samsung Advanced Institute of Technology, Samsung Electronics Co. GI Innovation, Inc. Samsung Strategy and Innovation Center, Samsung, Inc. You can also search for this author in PubMed Google Scholar. and J. Correspondence to Kak Namkoong. Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. Open Access This article is licensed under a Creative Commons Attribution 4. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. Reprints and permissions. Wrist-wearable bioelectrical impedance analyzer with miniature electrodes for daily obesity management. Sci Rep 11 , Download citation. Received : 03 August Accepted : 08 December Published : 13 January Anyone you share the following link with will be able to read this content:. Sorry, a shareable link is not currently available for this article. Provided by the Springer Nature SharedIt content-sharing initiative. Journal of Cardiovascular Translational Research Cardiovascular Engineering and Technology By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate. Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily. Skip to main content Thank you for visiting nature. nature scientific reports articles article. Download PDF. Subjects Disease prevention Health care Weight management. Abstract Bioelectrical impedance analysis BIA is used to analyze human body composition by applying a small alternating current through the body and measuring the impedance. Introduction Consumer interests in personalized health, including fitness and weight management, have been increasing. Methods Wrist-wearable bioelectrical impedance analyzer using single finger We developed a wristwatch-type bioelectrical impedance analyzer that provides users with convenient measurement experience by using only one finger, i. Figure 1. Full size image. Figure 2. Figure 3. Figure 4. Figure 5. Figure 6. Table 1 Physical characteristics of the subjects. Full size table. Table 2 Bioelectrical impedance analysis client pretesting guidelines Results and discussion Our study explored a novel method that uses considerably small electrodes that can be adapted into small devices, such as a wristwatch. Figure 7. Calculated contact resistance distribution among participants in the clinical test. Figure 8. Conclusions We developed a novel wrist-wearable bioelectrical impedance analyzer with a contact resistance compensation function such that bioelectrical impedance can be accurately estimated even with considerably small sizes of electrodes outer electrodes: 68 mm 2 ; inner electrodes: mm 2. References Kyle, U. Article Google Scholar Kyle, U. Article Google Scholar Kushner, R. Article MathSciNet CAS Google Scholar Kyle, U. CAS Google Scholar Heitmann, B. Article CAS Google Scholar Ramel, A. Article CAS Google Scholar Aldosky, H. Article Google Scholar Bogónez-Franco, P. Article ADS CAS Google Scholar Usman, M. Article CAS Google Scholar Kõiv, H. Article Google Scholar Bera, T. CAS PubMed Google Scholar Hoffer, E. Article CAS Google Scholar Nyboer, J. Article Google Scholar Download references. Acknowledgements We would like to thank Editage www. At MaxWell Clinic, we focus on your overall body composition, or the percentages of fat and non-fat like muscle in your body. To do so, we use a method called bioelectrical impedance analysis BIA on all our new patients. Bioelectrical impedance analysis uses electrical current to measure body fat. It is a cellular health and tissue composition analysis. The various tissues in your body fat, muscle, bone, etc. contain fluids, which are capable of electrical conduction. And because each type of tissue has varying amounts of fluid in and around them, their electrical conductivity can also differ. A BIA device is used to run a small amount of electrical current through your body. Due to the variations in fluid content, the speed of the electrical current changes as it travels through different tissues. Because lean tissues contain large amounts of water and electrolytes, they are much better conductors of electricity. Fat, on the other hand, is a poor conductor of electricity and impedes the current as it flows through your body. It can then use this estimate to determine your total body fat. BIA is much more than a superficial tool to measure fat. It can distinguish between the different types of fats in your body, including between subcutaneous under the skin and visceral surrounding internal organs fat. BIA can also give you an accurate picture of how much of your body weight is composed of lean muscle. Perhaps the most valuable information we can gather from a BIA is the percentage of extracellular water water outside your cells. High levels of extracellular water should be taken seriously. To summarize, BIA is a fast, accurate tool to assess your body composition, including your body fat, water weight and distribution, and muscle mass. Carrying too much fat on your body does pose serious health risks. Your body needs fat for its vital functions and to maintain your immune system. In fact, a study found that being too thin low BMI could knock up to 4 years off your life expectancy. Your health is also more complex than a number on a chart or a scale. Ignoring variables like fluid balance and cell membrane health could leave you vulnerable to serious health issues. To many, a high BMI automatically equates to being overweight. You may have even been told you need to lose weight to reduce your risk of developing chronic illnesses. The truth is, such a simple number cannot capture something as complex as your health. Your BMI is based on just two numbers: your weight and your height. This puts you at the same risk of developing chronic disease as someone who is obviously overweight — and you might not even know it. You need more than BMI alone. BIA is the gold standard in body fat measurement. The process of BIA is quick and simple. |
| Categories | Impedanec and D. Geneva, Switzerland: World Carbohydrate Metabolism Organization; Before using, users impedanve set their age, height, and sex. Y Acad Sci. Making a Purchase. Standard measurement conditions may vary depending on the machine type e. For the general differential diagnosis of underweight we present a female patient with anorexia: female, |
| Bioelectrical Impedance Analysis: Definition and Tips | When the values of these biomarkers fall within specific target ranges, they can indicate a high level of wellness and low risk for many chronic diseases. Buffa R, Floris G, Marini E. To do so, we use a method called bioelectrical impedance analysis BIA on all our new patients. Bioelectrical phase angle and impedance vector analysis—clinical relevance and applicability of impedance parameters. percentage of body fat varied by 8. BIA is the gold standard in body fat measurement. |
| Body Fat Testing through Bioelectrical Impedance (BIA) | Total abdominal fat measured by Viscan is a good predictor of total abdominal adipose tissue measured by MRI in both lean and obese individuals. Limitations It is based on the assumptions of the 2 component model. As the method relies upon regression equations for estimating body composition variables, BIA is only as good as the equation used. Validity of BIA is also influenced by body size, gender, age, disease state, race or ethnicity. Measurements are affected by hydration status. Vigorous exercise, excessive caffeine and alcohol use which stimulate urine production possibly leading to dehydration will result in overestimation of fat mass. The disproportionality of the body in terms of shape, size and composition between limbs and trunk can affect BIA measurements. Poor ability to predict body fat in severely obese individuals as they tend to have higher level of body mass and water accounted by the trunk, the hydration of FFM and the ratio of ECW to ICW are also increased in obesity. There is a tendency for BIA to overestimate percent body fat in very lean individuals and underestimate body fat in obese participants. Not useful in detecting short term changes after a dietary of physical activity interventions in individuals. ViScan prediction of visceral fat may be limited, especially in abdominally obese individuals. Table 2 Characteristics of bioelectric impedance analysis. Consideration Comment Number of participants Large Relative cost Low Participant burden Low Researcher burden of data collection Low Researcher burden of coding and data analysis Low Risk of reactivity bias No Risk of recall bias No Risk of social desirability bias No Risk of observer bias No Space required Low Availability High Suitability for field use High Participant literacy required No Cognitively demanding No. Table 3 Anthropometry by BIA in different populations. Population Comment Pregnancy BIA may not be suitable to estimate fat-free mass FFM and fat mass FM due to the hydration status throughout pregnancy. BIA predictions will be limited in their ability to account for this variation. However, it has been used to monitor TBW changes. Some manufactures recommend not using their devices during pregnancy. Infancy and lactation There is a large variation in the different body components water, protein, minerals from birth to adulthood due to growth and biological maturation. This variation can significantly affect the estimate of FM and FFM, in two-compartment models like the BIA method. BIA predictions will be limited to account for these variations. Lack of valid regression equations to predict body fat make this method not suitable for these populations. Lack of standardisation of electrode placement in infants is also an issue. Toddlers and young children There is large variation in the different body components water, protein, minerals from birth to adulthood due to growth and biological maturation. There is lack of standardisation of electrode placement in studies. Many of those monitors are not recommended in children below 7 years of age. Adolescents Suitable Adults Suitable Older adults Suitable, but presence of oedema may affect estimates. Ethnic groups Suitable Athletes Suitable but tend to overestimate fatness in lean individuals. Other obesity Suitable but tendency to underestimate fatness in those individuals. Further considerations. Resources required. Standard operating procedures for data collection. Data entry form in either paper or electronic form. Scale to measure weight some BIA devices can also measure weight. Stadiometer to measure height. BIA equations. Training of staff. Instrument library. A method specific instrument library is being developed for this section. In the meantime, please refer to the overall instrument library page by clicking here to open in a new page. Bohm A, Heitmann BL. The use of bioelectrical impedance analysis for body composition in epidemiological studies. Eur J Clin Nutr. Cheng MF, Chen YY, Jang TR, Lin WL, Chen J, Hsieh KC. Total body composition estimated by standing-posture 8-electrode bioelectrical impedance analysis in male wrestlers. Biology of sport. Dehghan M, Merchant AT. Is bioelectrical impedance accurate for use in large epidemiological studies? Nutrition journal. Gartner A. Reference BIA data in neonates and young infants. Ghezzi F, Franchi M, Balestreri D, Lischetti B, Mele MC, Alberico S, et al. Bioelectrical impedance analysis during pregnancy and neonatal birth weight. European journal of obstetrics, gynecology, and reproductive biology. Heymsfield SB, Lohman TG, Wang Z, Going SB. Human Body Composition, Second Edition. Windsor ON. Human Kinetics. Bioelectrical impedance analysis-part I: review of principles and methods. Clinical Nutrition. Jebb SA, Cole TJ, Doman D, Murgatroyd PR, Prentice AM. Evaluation of the novel Tanita body-fat analyser to measure body composition by comparison with a four-compartment model. The British journal of nutrition. Kuriyan R, Thomas T, Ashok S, Jayakumar J, Kurpad AV. The Indian journal of medical research. Silva DR, Ribeiro AS, Pavao FH, Ronque ER, Avelar A, Silva AM, et al. Validity of the methods to assess body fat in children and adolescents using multi-compartment models as the reference method: a systematic review. Revista da Associacao Medica Brasileira. Bioelectrical Impedance Analysis BIA is able to make an estimation of body composition e. quantities of fat mass and fat-free mass by running a small electrical current through the body. This is possible simply because different bodily tissues e. muscle, fat, bone, etc. all have varying amounts of water content, and, as a result, they all differ in terms of electrical conductivity. Despite being popular in many commercial gyms and within epidemiological research on group body composition , BIA does not appear to provide valid single- or repeated-measures of body composition for athletes. Having said that, the development of an equation for athletic populations that are validated against the gold-standard four-compartment model may improve the validity of the measure. First commercially available in the mids [1], Bioelectrical Impedance Analysis BIA is an inexpensive and portable piece of body composition testing equipment. Although BIA was primarily used to determine changes in dialysis patients [2], it is a method now used to determine body composition across a range of populations, including athletes [2, 3], obese individuals [4, 5], and the general population [3]. BIA determines body composition by running small electrical currents through the body. As the electrical conductivity is different between various bodily tissues e. due to their variation in water content, the small electrical current passes through the tissues at different speeds. Armed with that information, the machine is able to calculate the impedance i. The principle of BIA is that the different tissues in the body will act as conductors, semiconductors, or dielectrics insulators. Lean tissues are highly-conductive, as they contain large quantities of water. In contrast, bone and adipose tissue are dielectric substances and are poor conductors [4]. BIA assumes that the human body is composed of a series of cylinders, uniform in shape, length, cross-sectional area, and with constant conductivity. Total body water TBW is estimated, and this estimation is used to calculate fat-free mass. Fat mass is then calculated as the difference between fat-free mass and body mass. Several methods have been used to assess body composition in humans, each with advantages and drawbacks surrounding cost, validity, reliability , and accessibility. It is unclear how many frequencies would be needed for a BIA device to be considered a BIS device, however, the principles behind how the devices work are the same. Therefore, for this review, BIA will be used to denote all bioelectrical impedance assessments. Hand-held BIA Different types of BIA analysers are available, such as hand-held and leg-to-leg devices. Hand-held BIA machines assess the conductance of a small alternating current through the upper body and use built-in software to calculate body composition after it has been calibrated with the following variables: weight, height, age, and gender [6]. This method may be of benefit in a field setting, due to its convenience. Leg-to-Leg BIA Similar to hand-held methods, leg-to-leg BIA involves an individual standing on scales with four electrodes situated at each footplate, with a low-level current passed through the lower body. The path of the electrical current may differ between this method and the hand-held method, and could potentially influence body composition results; though this issue is discussed later in the article. Hand-to-Foot BIA Hand-to-foot BIA uses electrodes in a mounted footplate, as well as electrodes in hand grips, to determine whole-body measurements. As hand-held and leg-to-leg methods may not account for the resistance of the lower- or upper body, respectively, it is logical to assume that hand-to-foot measurements may better reflect whole-body composition than the alternatives. Estimates of body composition using BIA are facilitated using empirically validated equations, which consider variables including gender, race, height, weight, and age. Consequently, it is important the correct equation is used for the population measured to ensure that any results are valid. It is also important to understand the reference assessment method used to validate these equations. For example, many BIA equations are validated against assessment methods such as hydrostatic weighing and Dual-energy X-ray Absorptiometry DEXA. From the results of this assessment method, the manufacturer constructs an equation using the individual variables mentioned previously to determine what the body fat would be. These equations will have an error rate when compared to the hydrostatic weighing method, and thus, this error is multiplied by the original error of the reference method to provide a body composition assessment that may be somewhat distant from the actual values reported using a four-compartment model. The validity the agreement between the true value and a measurement value of body composition is key to determining the precision of BIA measurement, and its suitability for clinical use. The criterion method for determining body composition is the four-compartment model 1] fat mass, 2] total body water, 3] bone mineral mass, and 4] residual mass , and should be used when assessing the validity of BIA measurements. BIA has been compared to the four-compartment model in several studies using various populations. Sun et al. It is important to note that this analysis utilised DEXA as the reference method, which may also lead to further error, as eluded to earlier in this review read my article on the use of DEXA scanning for body composition assessment HERE. The validity of BIA for one-off measures of body composition Despite studies showing promising effects of BIA on body composition , this has not been found in a large body of research. BIA has been shown to underestimate fat mass and overestimate fat-free mass by 1. This finding is supported by other research on bodybuilders, showing that BIA underestimated fat mass, and overestimated fat-free mass when compared to the four-compartment model [10]. Research conducted by Jebb et al. The authors subsequently developed a novel prediction equation to estimate fat mass from the same Tanita bioimpedance analyser, with the four-compartment method as a reference. However, later research found that this equation also failed to outperform the Tanita manufacturer equation, and resulted in wide limits of agreement [12]. Potentially of greater concern to practitioners considering the use of BIA to determine body composition in the applied setting, are the individual error rates of BIA, rather than data on group means. The study mentioned previously on obese subjects [9] reported that in 12 of the 50 participants, BIA underestimated fat mass by 5 kg or more. This is supported by the findings of Van Marken Lichtenbelt et al. This suggests that BIA may provide data that is not sufficiently accurate for the determination of individual body composition. The validity of using BIA to measure changes over time A further consideration for the use of BIA is the validity of its use in measuring changes in fat mass and fat-free mass over time, as this may indicate the efficacy of a nutritional or training intervention looking to manipulate body composition. To revisit the study by Ritz et al. Fat mass was underestimated by 1. Individual error rates were greater than at baseline, with BIA underestimating fat mass by 7. A further study on obese populations [13] showed individual disagreement in body fat measurement between BIA and the four-compartment model was high. Individual measures of body fat ranged from There are a limited amount of comparisons between BIA and the reference four-compartment model in athletic populations. There is disagreement amongst the limited research available, with only one study suggesting that BIA is suitable for assessing body composition in athletes [15], whereas other research suggests that body fat estimates are much higher in athletes when using the BIA method [16]. The discrepancies between the studies may be due to various issues including differences in methodology, equations, and athletic population. There are currently no BIA equations for athletes that have been derived from the criterion four-compartment method fat mass, total body water, bone mineral mass, residual mass. This makes the application of BIA in this population difficult, as athletes are likely to possess substantially different quantities of fat and fat-free mass when compared to the general population or diseased populations that current equations are based on. The reliability of BIA The reliability of BIA the reproducibility of the observed value when the measurement is repeated is also important to determine single-measurement precision, as well as the ability to track changes over time. A plethora of research has indicated the importance — and potentially the inability — of standardising BIA measures to sufficiently account for various confounders. The mean coefficient of variation for within-day, intra-individual measurements, has ranged from 0. Standard measurement conditions may vary depending on the machine type e. hand-to-hand, leg-to-leg, supine vs. standing, etc. Other factors which may impact the BIA measurement and should therefore also be standardised are [16]:. The standardisation of hydration status is clearly of importance for BIA, as the method is reliant on estimations of total body water to ascertain fat-free mass. Your health is also more complex than a number on a chart or a scale. Ignoring variables like fluid balance and cell membrane health could leave you vulnerable to serious health issues. To many, a high BMI automatically equates to being overweight. You may have even been told you need to lose weight to reduce your risk of developing chronic illnesses. The truth is, such a simple number cannot capture something as complex as your health. Your BMI is based on just two numbers: your weight and your height. This puts you at the same risk of developing chronic disease as someone who is obviously overweight — and you might not even know it. You need more than BMI alone. BIA is the gold standard in body fat measurement. The process of BIA is quick and simple. Depending on the machine we use, you will lie down or stand up. There are four electrodes connected to your body — one in each hand and one touching each foot. The electrodes measure the flow of the current as it runs through your body. In a matter of minutes, we obtain an estimate of the amount of water in your body, which is used to determine your total fat-free mass. The BIA device then takes into account other variables, such as your height, gender, and weight to calculate your total body fat percentage. A BIA measures several key objective markers of health also known as biomarkers , including:. When the values of these biomarkers fall within specific target ranges, they can indicate a high level of wellness and low risk for many chronic diseases. When they fall outside their optimal ranges, we can use that information to modify your diet, exercise, and lifestyle habits. It can also indicate your need for targeted strategies, such as systemic detoxing, enhancing nutrient absorption, or increasing mineral reserves. A BIA is the start of your journey to optimal health. By routinely examining these biomarkers, we can identify areas of your health that need improvement long before any chronic issues develop. Ready to come in for your BIA appointment? There are just a few guidelines to follow before your test:. As a clinic that specializes in Personalized Systems Medicine, MaxWell Clinic understands the impact body composition has on your health. BIA is also one of the many extensive diagnostic tests included in our comprehensive MaxWell Care plan. MaxWell Care is a 3- or month program designed to uncover the root cause of your symptoms and help restore true health and vitality to your life. Schedule a free call with our New Patient Coordinator here. We look forward to joining you on the journey to good health. This blog provides general information and discussions about health and related subjects. The information and other content provided in this blog, website or in any linked materials are not intended and should not be considered, or used as a substitute for, medical advice, diagnosis or treatment. This blog does not constitute the practice of any medical, nursing or other professional health care advice, diagnosis or treatment. |
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