May Bioelectrical Impedance Analysis Method Be Used in Alternative to the Dual-Energy X-Ray Absorptiometry in the Assessment of Fat Mass and Fat-Free Mass in Patients with Obesity? Pros, Cons, and Perspectives

Adding Branched-Chain Amino Acids and Vitamin D to Whey Protein Is More Effective than Protein Alone in Preserving Fat Free Mass and Muscle Strength in the First Month after Sleeve Gastrectomy

OBJECTIVES

Sleeve gastrectomy (SG) is one of the most commonly performed weight loss (WL) bariatric procedures. The main goal of WL is reducing total body weight (TBW) and fat mass (FM). However, TBW loss is systematically accompanied by a decline in fat-free mass (FFM), predominantly in the first post-surgical month, despite protein supplementation. Branched-chain amino acids (BCAAs) and vitamin D seem to attenuate loss of FFM and, thus, reduce the decline in muscle strength (MS). However, data on the role of an integrated supplementation with whey protein plus BCAAs plus vitamin D (P+BCAAs+Vit.D) vs. protein alone on total weight loss (TWL), fat mass (FM), fat-free mass (FFM), and (MS) in the first month after SG are lacking. Therefore, the present study aims to evaluate the impact of P+BCAAs+Vit.D vs. protein alone supplementation on TWL, FM, FFM, and MS in the first month after SG.

MATERIALS AND METHODS

Before SG and at 1 month afterward, we prospectively measured and compared TBW, FM, FFM, and MS in 57 patients who received either a supplementation with P+BCAAs+Vit.D (n = 31) or protein alone (n = 26). The impact of P+BCAAs+Vit.D and protein alone supplementation on clinical status was also evaluated.

RESULTS

Despite non-significant variation in TBW, FM decreased more significantly (18.5% vs. 13.2%, p = 0.023) with the P+BCAA+Vit.D supplementation compared to protein alone. Furthermore, the P+BCAA+Vit.D group showed a significantly lower decrease in FFM (4.1% vs. 11.4%, p < 0.001) and MS (3.8% vs. 18.5%, p < 0.001) compared to the protein alone group. No significant alterations in clinical status were seen in either group.

CONCLUSION

P+BCAA+Vit.D supplementation is more effective than protein alone in determining FM loss and is associated with a lower decrease in FFM and MS, without interfering with clinical status in patients 1 month after SG.

Association of visceral fat area or BMI with arterial stiffness in ideal cardiovascular health metrics among T2DM patients

BACKGROUND

"Obesity paradox" occurs in type 2 diabetes mellitus (T2DM) patients when body mass index (BMI) is applied to define obesity. We examined the association of visceral fat area (VFA) as an obesity measurement with arterial stiffness in seven ideal cardiovascular health metrics (ICVHMs).

METHODS

A total of 29 048 patients were included in the analysis from June 2017 to April 2021 in 10 sites of National Metabolic Management Centers. ICVHMs were modified from the recommendations of the American Heart Association. Brachial-ankle pulse wave velocity (BaPWV) ≥ 1400 cm/s was employed to evaluate increased arterial stiffness. Multivariate regression models were used to compare the different effects of BMI and VFA on arterial stiffness.

RESULTS

Lower VFA was more strongly associated with low BaPWV than lower BMI when other ICVHMs were included (adjusted odds ratio [OR], 0.85 [95% confidence interval [CI], 0.80-0.90] vs OR 1.08 [95% CI, 1.00-1.17]). Multivariable-adjusted ORs for arterial stiffness were highest in patients with the VAT area VFA in the range of 150-200 cm2 (adjusted OR, 1.26 [95% CI 1.12-1.41]). Compared with participants with VAT VFA < 100 cm2 , among participants with higher VAT VFA, the OR for arterial stiffness decreased gradually from 1.89 (95% CI, 1.73-2.07) in patients who had ≤1 ICVHM to 0.39 (95% CI, 0.25-0.62) in patients who had ≥5 ICVHMs.

CONCLUSION

In patients with T2DM, using VAT for anthropometric measures of obesity, VFA was more relevant to cardiovascular risk than BMI in the seven ICVHMs. For anthropometric measures of obesity in the ICVHMs to describe cardiovascular risk VFA would be more optimal than BMI.

Changes in Lean Tissue Mass, Fat Mass, Biological Parameters and Resting Energy Expenditure over 24 Months Following Sleeve Gastrectomy

Sleeve gastrectomy (SG) induces weight loss but its effects on body composition (BC) are less well known. The aims of this longitudinal study were to analyse the BC changes from the acute phase up to weight stabilization following SG. Variations in the biological parameters related to glucose, lipids, inflammation, and resting energy expenditure (REE) were concomitantly analysed. Fat mass (FM), lean tissue mass (LTM), and visceral adipose tissue (VAT) were determined by dual-energy X-ray absorptiometry in 83 obese patients (75.9% women) before SG and 1, 12 and 24 months later. After 1 month, LTM and FM losses were comparable, whereas at 12 months the loss of FM exceeded that of LTM. Over this period, VAT also decreased significantly, biological parameters became normalized, and REE was reduced. For most of the BC, biological and metabolic parameters, no substantial variation was demonstrated beyond 12 months. In summary, SG induced a modification in BC changes during the first 12 months following SG. Although the significant LTM loss was not associated with an increase in sarcopenia prevalence, the preservation of LTM might have limited the reduction in REE, which is a longer-term weight-regain criterion.

Influence of the type of electrodes in the assessment of body composition by bioelectrical impedance analysis in the supine position

BACKGROUND & AIMS

The main source of error in body composition assessment of bedridden patients by bioelectrical impedance analysis (BIA) is the electrode inadequacy and placement. As electrocardiogram (ECG) electrodes are often used for BIA measurements, this study aimed to compare three of them with a reference BIA electrode.

METHODS

BIA was performed sequentially on 24 healthy subjects in the supine position, using 3 different ECG electrodes (3M® Red Dot® 2330; Ambu® BlueSensor 2300; Ambu® BlueSensor SU-00-C) and the reference electrode (Bianostic AT®) for the BIA device (Nutriguard-M®, Data Input, Germany). Resistance (R), reactance (Xc), phase angle (PhA), appendicular skeletal muscle index (ASMI), fat-free mass index (FFMI) and fat mass percentage (FM%) obtained with the different electrodes were compared using Bland-Altman plots, repeated measures one-way ANOVA and paired t-test. Patient characteristics potentially involved in BIA measurement differences were assessed using linear regression analysis.

RESULTS

The study population consisted of 9 men and 15 women, 33% and 47% of whom were overweight, respectively. The measured R was within the physiological range for all men (428-561 Ω) and women (472-678 Ω), regardless of the type of electrodes used. Compared to the reference electrode, the 3M® Red Dot® 2330 and Ambu® BlueSensor SU-00-C electrodes gave significantly different Xc and PhA values, but only the Ambu® BlueSensor SU-00-C gave significantly different ASMI, FFMI and FM% at 50 kHz, with biases of -0.2 kg/m², -0.3 kg/m² and +1.4%, respectively. The higher the current frequency, the lower was the Xc and PhA measured by the Ambu® BlueSensor SU-00-C compared to the reference electrode. These measurement differences seemed mainly due to the too small gel area of the Ambu® BlueSensor SU-00-C (154 mm²) compared to the reference electrode (1311 mm²).

CONCLUSIONS

The use of electrodes with small gel area affects BIA measurement in the supine position, especially when PhA is used as an indicator of the nutritional status. Therefore, it is essential to specify the type of electrodes and carry out comparative tests before changing consumables for body composition assessment, to ensure BIA measurement reliability in clinical and research settings.

Body Composition Changes Following Sleeve Gastrectomy Vs. One-Anastomosis Gastric Bypass: Tehran Obesity Treatment Study (TOTS)

PURPOSE

This study aimed to evaluate body composition changes and the determinants of fat-free mass loss (FFML) up to 3 years after sleeve gastrectomy (SG) and one-anastomosis gastric bypass (OAGB).

MATERIALS AND METHODS

A prospective study was conducted on 3864 patients with severe obesity who underwent either SG (2746, 76.1% women, mean age: 39.2 ± 11.6 years, and BMI: 44.3 ± 5.6 kg/m2) or OAGB (1118, 82.2% women, age: 39.9 ± 10.7 years, BMI: 45.6 ± 6.3 kg/m2). Body composition parameters were measured by bioelectrical impedance analysis preoperatively and 1, 3, 6, 9, 12, 18, 24, and 36 months after surgery. Changes in body composition were assessed using the propensity matched generalized estimated equation (GEE) method. The determinants of fat-free mass loss/weight loss (FFML/WL%) were defined using a mixed-model GEE analysis.

RESULTS

Means of FM, FFM, and FFML/WL% decreased significantly in both study groups (Ptrend < 0.001). Changes in BMI, EWL%, FM, and FFML/WL% were different between the two groups (Pbetween < 0.05). The results showed a better FFM preservation and a greater FM loss over time in the OAGB group compared to the SG group (Pinteraction < 0.05). FFML during the first 3 months was greater in the SG compared to the OAGB group (P < 0.001). SG surgery, higher preoperative BMI, and female gender were associated with greater FFML/WL%.

CONCLUSION

In the SG compared to the OAGB group, FFML was greater, especially early after the surgery, emphasizing the need for therapeutic interventions such as regular exercise programs and dietary intake modifications.

Precision and accuracy of bioelectrical impedance analysis devices in supine versus standing position with or without retractable handle in Caucasian subjects

BACKGROUND & AIMS

Bioelectrical impedance analysis (BIA) could be facilitated in subjects who are able to stand by using scales without (BIA_std4) or with a retractable handle (BIA_std8), provided that they are as precise as BIA devices commonly used in the supine position in the hospital setting (BIA_sup). This observational prospective cross-sectional study aimed to compare the precision and accuracy of BIA_std4, BIA_std8 and BIA_sup in a Caucasian population.

METHODS

Fat mass percentage (FM%) was measured in 160 healthy Caucasian subjects (80 men/80 women) aged 20-60 years, with a body mass index (BMI) ≥18.5 and < 30 kg/m², using the HAGRID Body Fat Scales (Huawei Technologies Co., Ltd., China) in BIA_std4 or BIA_std8 mode, and the Nutriguard-M (Data Input GmbH, Germany) as BIA_sup. Intra-unit and inter-unit precisions of each device were evaluated by calculating the coefficients of variation (CV%) of 3 measurements with 3 different units of each device. Inter-device precisions were evaluated with Pearson correlations, Bland-Altman plots, and repeated measures ANOVA followed by post-hoc Bonferroni tests. Accuracy of these BIA devices was estimated in a subgroup of 16 subjects, using comparison with dual-energy X-ray absorptiometry (DXA).

RESULTS

The study population was 40 ± 12 years old, with a body height and weight of 171 ± 10 cm and 72.2 ± 11.5 Kg, respectively. All three devices were very precise with intra-unit CV% of 0.5%, 0.9%, and 0.3% and inter-unit CV% of 0.5%, 1.1%, and 0.4% for BIA_std4, BIA_std8 and BIA_sup, respectively. Inter-device precision was ±2.1% for BIA_std4/BIA_sup, ±1.9% for BIA_std8/BIA_sup, and ±1.3% for BIA_std8/BIA_std4. Bland-Altman plots showed bias ±1.96 SD of 0.3 ± 5.2% for BIA_std4/BIA_sup, -0.4 ± 4.5% for BIA_std8/BIA_sup and -0.6 ± 3.1% for BIA_std8/BIA_std4. Compared to DXA, all three devices tended to underestimate FM% in men with low BMI, while only BIA_std4 and BIA_std8 tended to overestimate FM% in women with high BMI. FM% measurement accuracy was ±2.6% for BIA_sup/DXA, ±3.3% for BIA_std4/DXA, and ±3.4% for BIA_std8/DXA.

CONCLUSIONS

Both BIA_std4 and BIA_std8 show a good intra- and inter-unit precision close to BIA_sup, making them suitable for rapid body composition assessment in non-bedridden subjects. However, all these three devices should not be used interchangeably, because BIA_std4 and BIA_std8 tend to accentuate FM% changes during body composition monitoring compared to BIA_sup and DXA.

TRIAL REGISTRATION

ClinicalTrial.gov no. NCT04504799.

Bioelectrical impedance analysis as an alternative to dual-energy x-ray absorptiometry in the assessment of fat mass and appendicular lean mass in patients with obesity

OBJECTIVE

Obesity is a challenge for bioelectrical impedance analysis (BIA) estimations of skeletal muscle and fat mass (FM), and none of the equations used for appendicular lean mass (ALM) have been developed for people with obesity. By using different equations and proposing a new equation, this study aimed to assess the estimation of FM and ALM using BIA compared with dual-energy x-ray absorptiometry (DXA) as a reference method in a cohort of people with severe obesity.

METHODS

This cross-sectional study compared a multifrequency BIA (TANITA MC-780A) versus DXA for body composition assessment in adult patients with severe obesity (body mass index [BMI] of >35 kg/m²). Comparisons between measured (DXA) and predicted (BIA) data for FM and ALM were performed using the original proprietary equations of the device and the equations proposed by Kyle, Sergi, and Yamada. Bland-Altman plots were drawn to evaluate the agreement between DXA and BIA, calculating bias and limits of agreement (LOA). Reliability was analyzed using intraclass correlation coefficient (ICC). Stepwise multiple regression analysis was used to derive a new equation to predict ALM in patients with obesity and was validated in a subsample of our cohort.

RESULTS

In this study, 115 patients (72.4% women) with severe obesity (mean BMI of 46.1 [5.2] kg/m²) were included (mean age 43.5 [8.6] y). FM_DXA was 61.4 (10.1) kg, FM_BIA was 57.9 (10.3) kg, and ICC was 0.925 (P < 0.001). Bias was -3.4 (4.4) kg (-5.2%), and LOA was -14.0, +7.3 kg. Using the proprietary equations, ALMDXA was 21.8 (4.7) kg and ALMBIA was 29.0 (6.8) kg with an ICC 0.868, bias +7.3 (4.0) kg (+34.1%) and LOA -0.5, +15.1. When applying other equations for ALM, the ICC for Sergi, et al. was 0.880, the ICC for Kyle, et al. was 0.891, and the best ICC estimation for Yamada, et al. was 0.914 (P < 0.001). Bias was +2.8 (2.8), +4.1 (2.9), and +2.7 (2.8) kg, respectively. The best-fitting regression equation to predict ALM_DXA in our population derived from a development cohort (n = 77) was: ALM = 13.861 + (0.259 x H2/Z) - (0.085 x age) - (3.983 x sex [0 = men; 1 = women]). When applied to our validation cohort (n = 38), the ICC was 0.864, and the bias was the lowest compared with the rest of the equations +0.3 (+0.5) kg (+2.7%) LOA -5.4, +6.0 kg.

CONCLUSION

BIA using multifrequency BIA in people with obesity is reliable enough for the estimation of FM, with good correlation and low bias to DXA. Regarding the estimation of ALM, BIA showed a good correlation with DXA, although it overestimated ALM, especially when proprietary equations were used. The use of equations developed using the same device improved the prediction, and our new equation showed a low bias for ALM.

The effect of additional protein on lean body mass preservation in post-bariatric surgery patients: a systematic review

BACKGROUND

As result of bariatric surgery, patients are susceptible to protein deficiency which can result in undesirable lean body mass (LBM) loss. Consumption of high-protein diets or supplements could counteract this, but evidence about the effect is scarce. This paper systematically reviewed the literature to determine the effect of additional protein intake (≥60 g/day) on LBM preservation in post-bariatric patients.

METHODS

An electronic search of PubMed, EMBASE and the Cochrane Library was conducted. Studies were included if patients received a high-protein diet or protein supplements for at least one month, and LBM was assessed. The primary outcome was difference in mean LBM loss between the experimental (protein) and control group. Secondary outcomes were differences in body fat mass, total body water, body mass index and resting metabolic rate.

RESULTS

Two of the five included studies (n = 223) showed that consumption of proteins resulted in significant LBM preservation. Only one study reported a significant difference in the reduction of body fat mass and resting metabolic rate in favour of a high-protein diet, but none of the studies showed a significant difference in total body water loss or body mass index change between the two groups.

CONCLUSIONS

This paper showed inconclusive evidence for LBM preservation due to protein supplementation or a high-protein diet in post-bariatric patients. This outcome might be subjected to certain limitations, including a lack of blinding and a low compliance rate reported in the included studies. More specific and personalized recommendations regarding protein intake may need to be established by high quality research. Studies investigating the quantity (g/day) and quality (whey, casein or soy) of proteins are also needed.

A Randomized, Controlled Trial Comparing the Impact of a Low-Calorie Ketogenic vs a Standard Low-Calorie Diet on Fat-Free Mass in Patients Receiving an Elipse™ Intragastric Balloon Treatment

Background

The Elipse™ intragastric balloon (EIGB) is a new swallowable balloon for weight loss (WL). Preserving metabolically active fat-free mass (FFM) and resting metabolic rate (RMR) during WL are crucial to maximize fat mass (FM) loss. After EIGB placement, a standard low-calorie diet (LCD) is generally prescribed. A low-calorie ketogenic diet (LCKD) has proven to be safe and effective in reducing FM while preserving FFM and RMR.

Objective

To prospectively compare the effects on WL, FM, FFM, and RMR in two groups of patients who were randomized to two different diets: LCKD and a standard LCD after EIGB placement.

Methods

WL, FM, FFM, and RMR were measured before EIGB and at 4 months in 48 patients who received either a LCKD (n = 24) or a standard LCD (n = 24). Compliance in following the prescribed diet was determined with food frequency questionnaires in all patients. The impact of LCKD and LCD on renal function was also evaluated.

Results

The LCKD group showed a significantly lower decrease in FFM and RMR when compared with the LCD group (3.55 vs 14.3%, p < 0.001; 9.79 vs 11.4%, p < 0.001, respectively). FM decreased more significantly with LCKD compared to LCD (41.6 vs 33.1%, p = 0.0606). Compliance in following the prescribed diets, without negative impact on renal function, was found.

Conclusion

Based on our findings, despite the small sample size, we were able to support the hypothesis that LCKD is associated with an increased FM loss while reducing the FFM loss and the RMR, without interfering with renal function after EIGB.