The Study:  Evaluation of multi-frequency bioelectrical impedance analysis for the assessment of body composition in individuals with obesity.              

 

The Facts:

a. The authors wished to compare multi-frequency bioelectrical impedance analysis (MF-BIA) to air displacement plethysmography (ADP) for evaluation of body composition.

b. They had 62 subjects.

c. The average Body Mass Index (BMI) of the subjects was 38.9

d. The authors noted that body composition is important to the health of patients.

e. They indicated that in obese patients it is difficult to accurately track the effects of weight loss because of changes in both hydration and fat free mass.

f. They note that methods to evaluate body composition include MF-BIA, ADP (Air Displacement Pethysmography) and also dual-energy X-ray absorptiometry (DXA) aka Dexa Scans.

g. They note that although DXA has been shown to be  accurate in normal weight subjects it has been shown to underestimate the fat free body mass (FFM) and overestimate the amount of fat in elderly subjects.

h. ADP is similar to underwater weighing but it uses air displacement as opposed to water displacement to measure body volume.  “ADP is fast and easy to operate and comes with preprogrammed multiple population-specific body composition equations.”

i.  However, the authors note that bioelectrical impedance analysis is quick, portable and much less expensive.

j. “During the assessment, [bioelectrical impedance analysis] BIA analyzers introduce a small electrical current into the body and measure the resistance, or impedance, to current flow.

k.  “Multi-frequency bioelectrical impedance analysis measurements were conducted using the InBody 720.”

l.  Since there is a difference in the impedance between fat and muscle, the use of multifrequency BIA allows for more accurate measurement of fat, water and muscle levels than older BIA units that only employ a single frequency.

m. In this study: “Our findings indicate that MF-BIA produces similar body composition values as ADP.”

 Take Home:

The MF-BIA body composition results were found to be comparable to those found with ADP. You vcan now purchase affordable mutifrequency scales which will deliver results very comparable to state of the art equipment.

Reviewer's Comments:

So why did I review this article. Those of us who have used BIA to measure body composition know that it is significantly affected by hydration levels. But those were usually single frequency not multi frequency BIA scales. Also note that the InBody 720 used here is a high end unit which has both hand and foot electrodes as compared to the foot only electrodes of many (most) consumer models. It was encouraging to see that the results were very close to those obtained with ADP.

Like most of you, I am interested in the effects of my own exercise and diet efforts.  I have ordered a consumer grade multifrequency scale and am encouraged by how that seems to be performing as compared to my old single frequency unit. It’s very helpful to be able to discern whether changes in weight are due to changes in fat, muscle or water. It does make a difference. Remember what I always say, “Science is to be lived not learned.” But in reality you still have to learn it first!

 

Reviewer:  Roger Coleman DC 

Editor’s Comments:  Dr. Coleman and I are both working seriously on weight reduction. (Old guy stuff!) I ordered the same “Tanita” brand, multi frequency scale to replace my old, single frequency unit and instantly saw that my readouts were more accurately reflecting what was happening in my weight loss journey. Additionally, I am amazed at how consistent it is. I recently had the experience of visiting my G.P. Of course I got weighed on an old spring type scale when I entered the exam room. I was struck by just how little information was available to my doctor compared to my own home unit. Interested doctors may wish to check out some of the professional grade multi frequency models available. Please note, I have no association with Tanita scales…just a pleased user of their products, but I was happy to see this paper published documenting the accuracy of multi frequency units.  

Editor: Mark R. Payne DC

Reference: PA Sullivan, CD Still, ST Jamieson et. al. Evaluation of multi-frequency bioelectrical impedance analysis for the assessment of body composition in individuals with obesity. Obes Sci Pract. 2018 Dec 26;5(2):141-147.doi:10.1002/osp4.321. eCollection 2019 Apr. 

Link to Abstract: https://pubmed.ncbi.nlm.nih.gov/31019731/

Link to Full Text:  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6469329/pdf/OSP4-5-141.pdf