Phase angle and cellular health: inflammation and oxidative damage.

Phase angle is a composite measure that combines two raw bioelectrical impedance analysis measures: resistance and reactance. Phase angle has been considered an indicator of cellular health, integrity, and hydration. As inflammation and oxidative stress can damage cellular structures, phase angle has potential utility in early detecting inflammatory and oxidative status. Herein, we aimed to critically review the current understanding on the determinants of phase angle and its relationship with markers of inflammation and oxidative stress. We also discussed the potential role of phase angle in detecting chronic inflammation and related adverse outcomes. Several factors have been identified as predictors of phase angle, including age, sex, extracellular to intracellular water ratio, and fat-free mass. In addition to these factors, body mass index (BMI) also seems to influence phase angle. Available data also show that lower phase angle values are correlated (negligible to high correlation coefficients) with higher c-reactive protein, tumour necrosis factor-α, interleukin-6, and interleukin-10 in studies involving the general and aging populations, as well as patients with chronic conditions. Although fewer studies have evaluated the relationship between phase angle and markers of oxidative stress, available data also suggest that phase angle has potential to be used as an indicator (for screening) of oxidative damage. Future studies including diverse populations and bioelectrical impedance devices are required to confirm the validity and accuracy of phase angle as a marker of inflammation and oxidative stress for clinical use.

Time-Restricted Eating in Breast Cancer Survivors: Effects on Body Composition and Nutritional Status.

In this secondary analysis of an 8-wk single-arm feasibility study of weekday time-restricted eating (TRE), we explored the effects of TRE on body composition. Women (n = 22; ≥60 yr) who had completed chemotherapy for early-stage breast cancer and had a body mass index ≥25 kg/m2 were enrolled. Bioelectrical impedance analysis was performed before and after 8 wk of TRE, and nutritional status was evaluated by bioelectrical impedance vector analysis (BIVA). Body weight (p = 0.01) and total fat mass (p = 0.04) decreased with TRE. Phase angle was low (defined as ≤5.6°) in 86% of participants at baseline and did not change. Four participants who initially presented with obesity (>95% ellipse, BIVA) had favorable body composition modifications after TRE. Our study highlighted a less favorable body composition profile, poorer cell integrity and overhydration in these patients. BIVA was a useful method to assess body composition and hydration. A short TRE intervention was associated with decreased estimated fat mass and a favorable change in nutritional status in those with obesity.

An Evaluation of Metabolic, Dietetic, and Nutritional Status Reveals Impaired Nutritional Outcomes in Breast Cancer Patients.

Nutritional status can change in breast cancer patients after treatment. However, the metabolic implications of those alterations are poorly understood. We used a cross-sectional study design to compare body composition, lipids, glucose levels, and adiposity indices in breast cancer patients with a matched control and a healthy group. We recruited women who completed their chemotherapy (BC group) and compared them with a group of women without cancer age and body mass index-paired (MC group) and a group of healthy women (HC group). We estimated body composition by bioelectrical impedance analysis, physical function by handgrip strength, and food consumption by 24-hour food record. A blood sample was collected. We calculated visceral obesity indices (VAI and LAP) and insulin resistance-triglyceride glucose (TyG). Eighty-eight women were included (BC = 36, MC = 36, HC = 16). BC patients demonstrated worse phase angle values, nutritional risk index and lower handgrip strength. Additionally, according to the indices, BC had impairments in lipids, worse glucose levels, and elevated visceral fat adiposity and presented important unhealthy dietary patterns characterized by under-recommended protein consumption and higher caloric intake than the other groups. No differences were observed between both control groups. Further investigations are required to examine the underlying mechanisms and the potential longitudinal changes during surveillance.

Relationship Between Adiposity Indices, Lipodystrophy, and Sarcopenia in HIV-Positive Individuals With and Without Lipodystrophy.

Metabolism disorders, as well as body shape abnormalities, have been associated with the introduction of antiretroviral therapy. The objective of this study was to compare the diagnostic ability of adiposity indices and to discuss criteria for the classification of lipodystrophy and sarcopenia (SP) in HIV-positive individuals. Anthropometric measurements were determined in 268 individuals of both genders, also submitted to the dual-energy X-ray absorptiometry exam. The adiposity indices calculated were body mass index, body mass index adjusted for fat mass (BMIfat), body adiposity index, body adiposity Index for the Fels Longitudinal Study sample, and The Clínica Universidad de Navarra body adiposity estimator. The presence of lipodystrophy was evaluated using the fat mass ratio (FMR). SP was classified using the appendicular lean mass/height2 ratio. The subjects were divided into 3 groups: HIV+LIPO+ (n = 41), HIV+LIPO- (n = 65), and control (C, HIV-negative individuals; n = 162). Among the adiposity indices assessed, BMIfat showed the strongest correlation with total body fat (in percent) for men (r = 0.87, p < 0.001) and women (r = 0.92, p < 0.001). The frequency of SP was 44.8% and 41.7% in HIV+LIPO+, 27.8% and 20.7% in HIV+LIPO- and 63.3% and 45.45% in C, for men and women, respectively. The cutoff point suggested for the diagnosis of lipodystrophy according to the FMR was 1.14. The adiposity indices, particularly the BMIfat, have strong correlation with body fat determined by dual-energy X-ray absorptiometry in HIV-positive patients. The implementation of FMR is recommended for more standardized estimates of the frequency of lipodystrophy.

Phase angle is associated with muscle health and cardiorespiratory fitness in older breast cancer survivors.

BACKGROUND & AIM: Phase angle (PhA) obtained from bioelectrical impedance analysis (BIA) is an indicator of cellular integrity and relates to several chronic conditions. The purpose of this secondary analysis was to evaluate the association of PhA with health-related physical fitness, namely, cardiorespiratory fitness, skeletal muscle volume, and myosteatosis (i.e. muscle health) in older breast cancer survivors. METHODS: Twenty-two women ≥60 years with a body mass index (BMI) ≥25 kg/m2 and who completed chemotherapy for early-stage breast cancer were included. BIA, cardiopulmonary exercise tests and magnetic resonance imaging scans were completed before and after eight weeks of time-restricted eating. RESULTS: At baseline, PhA was associated with cardiorespiratory fitness (R2 = 0.54, p < 0.01) and skeletal muscle volume (R2 = 0.83, p < 0.01) and myosteatosis (R2 = 0.25, p = 0.02). Results were similar at follow-up. CONCLUSION: Findings from this pilot study suggest that higher values of PhA are associated with better health-related physical fitness among older breast cancer survivors.

Exploring the potential role of phase angle as a marker of oxidative stress: A narrative review.

Chronic conditions including non-communicable diseases have become increasingly prevalent in the past decade. Proinflammatory cytokines are associated with the development of several pathologies, their prognoses, and their associated mortality. Chronic inflammation is also associated with oxidative stress whereby reactive oxygen species (ROS) induce cellular injury and, thus, by doing so, initiate inflammatory signaling. Phase angle (PhA) is a measurable body composition parameter obtained using bioelectrical impedance analysis (BIA). PhA is considered an indicator of cellular health and integrity and is also related to inflammatory markers and inflammation. Given the association among oxidative stress, cell damage, and inflammation that may in turn be associated with low PhA values, it is expected that PhA could mirror oxidative stress. In this hypothesis-generating, narrative review we summarize the current knowledge regarding the potential relationship between PhA and oxidative stress and their interrelationship in chronic conditions.

Phase angle as a severity indicator for liver diseases.

OBJECTIVE: The aim of this study was to evaluate the applicability of phase angle (PhA) as a severity indicator of chronic liver diseases. METHODS: We examined the medical records of 54 patients-27 with hepatocellular carcinoma (HCC) and 27 with non-alcoholic fatty liver disease (NAFLD). The patients were ≥18 y of age. Clinical data, such as Child-Pugh and Barcelona Clinic Liver Cancer (HCC), aspartate aminotransferase-to-platelet ratio index (APRI) and fibrosis (FIB)-4 (NAFLD), nutritional parameters (body mass index [BMI], handgrip strength [HGS], and bioelectrical impedance [BIA] data) were collected. Nutritional Risk Index (NRI) was calculated. Analysis was performed using Mann-Whitney test and analysis of variance. Simple multiple linear regression for predictions (Child-Pugh in HCC, APRI and FIB-4 in NAFLD). Receiver operating characteristic curve was estimated to search a cutoff for PhA. For survival, we used the Kaplan-Meier estimator. To verify whether PhA affected patients' survival, we used the Mantel-Haenszel. RESULTS: The prevalence of cirrhosis was high in HCC (n = 25) and low in the NAFLD (n = 4). No patient was classified as undernourished based on BMI; however, NRI showed that 74.1% of patients with HCC had nutritional risk. Child-Pugh was positively correlated with the edema index (extracellular water/total body water [ECW/TBW]) and negatively correlated with PhA and HGS. Higher Child-Pugh and BCLC scores were associated with worse NRI. APRI and FIB-4 were positively correlated with weight and BMI. A significant difference between groups was found for the median values of R, ECW/TBW, PhA, HGS, and albumin. There was a trend toward lower survival in patients with HCC, according to the cutoff point of 5.1 degrees for PhA. CONCLUSION: PhA was shown to be an independent prognostic indicator for cirrhosis and may be related to survival in these patients.

Comparison of new adiposity indices for the prediction of body fat in hospitalized patients.

OBJECTIVE: To measure the accuracy of the body mass index (BMI), BMI adjusted for fat mass (BMIfat), body adiposity index (BAI), BAI for the Fels Longitudinal Study sample, Clínica Universidad de Navarra-Body Adiposity Estimator, and fat mass index and to compare the accuracy to that of bioelectrical impedance and dual-energy x-ray absorptiometry (DXA) in a sample of the Brazilian population. METHODS: A cross-sectional study conducted on 240 hospitalized patients, 43 (18%) male and 197 (83%) female. Mean patient ages were 53.0 ± 13.3 y for males and 53.49 ± 14.0 y for females. All subjects underwent anthropometric evaluation, bioelectrical impedance, and DXA, which permitted the calculation of the indices. The level of significance was set at P < 0.05 in the statistical analyses. RESULTS: Mean subject age (y), weight (kg), and height (cm) were 53.0 ± 13.3 and 53.4 ± 14.0; 72.8 ± 14.9 and 67.6 ± 14.0; and 171.0 ± 8.0 and 157.0 ± 7.0 for men and women, respectively. Excess weight was detected in 67.4% and 66% according to the BMI, in 30% and 69.5% according to the BMIfat, and in 51% and 38% according to the BAI for men and women, respectively. Pearson correlation revealed that BMIfat clearly showed a better correlation (r = 0.67) with DXA than the remaining tools. The Clínica Universidad de Navarra-Body Adiposity Estimator was the only body adiposity parameter that was significantly higher in men compared to women. CONCLUSION: The results suggest that BMIfat is the index best related to the prediction of body fat and that the BAI did not exceed the limits of the BMI. Further studies of this type are needed to strengthen the present findings.