Lean Soft Tissue Mass Research Articles

Supplementation with Bovine Milk or Soy Beverages Recovers Bone Mineralization in Young Growing Rats Fed an Insufficient Diet, in Contrast to an Almond Beverage

ABSTRACTBackgroundNondairy beverages, produced from soy, rice, oat, almond, or coconut, are increasingly being used as alternatives to dairy milk, with the perception that they are healthier and/or more sustainable products than dairy products.ObjectiveThe aim of this study was to compare the effects of supplementing either bovine milk, soy, or almond-based beverages to young, growing rats fed an intact-protein diet or a diet that had protein substituted with amino acids (AA-diet).MethodsThree-week-old male Sprague-Dawley rats were randomly assigned to 5 groups (n = 10/group) and fed ad libitum for 4 wk. Two control groups were fed either standard AIN-93G food [20% casein (CN) protein] or AIN-93G with amino acids (AAs) equivalent to CN protein, and water to drink. Three treatment groups were fed AIN-93G AA and supplemented with either bovine ultra-heat treatment (UHT) milk or soy or almond UHT beverages. Rat weight gain and food intakes were recorded. During week 4, body composition was assessed using DEXA to determine lean soft tissue, fat, and bone mass. At trial end, bone biomechanical properties and blood plasma mineral concentrations were measured.ResultsAt the end of the trial, animals supplemented with almond beverage were lightest (P > 0.05), with higher plasma calcium concentrations (P > 0.05) and lower bone mineral content (BMC) and bone density (P > 0.05) than animals supplemented with milk or soy beverage. Soy-supplemented animals had similar BMC and bone density compared with milk-supplemented animals, although the soy group gained most weight (P > 0.05) and had the highest fat:lean ratio (P > 0.05) compared with other groups.ConclusionsIn the model tested, supplementing rats with bovine UHT milk and soy UHT beverage provided favorable bone health outcomes. Conversely, almond UHT beverage was not an effective supplement and could be detrimental to bone mineralization and strength outcomes.

Sex differences in lower-limb arterial stiffness following acute aerobic exercise

Summary Objectives This study was to investigate sex differences in central and peripheral arterial stiffness after exercise in young adults. Methods Sixty-one young adults (32 males, 29 females; age 18–35 years) performed an acute bout of aerobic exercise at 70% of heart rate reserve. The carotid-femoral, carotid-radial, and femoral-ankle pulse wave velocity, and carotid and femoral artery diameters, were measured before exercise and 30- and 60-min after exercise using applanation tonometry (Millar Instruments, Houston, TX, USA) and SphygmoCor (AtCor Medical, Sydney, Australia). Results The sex-by-time interactions were not significant for the carotid-femoral and carotid-radial pulse wave velocity, but were significant for the femoral-ankle pulse wave velocity (P = 0.03). There were also significant sex-by-time interactions for the relative diameter changes in the femoral artery (P = 0.043), but not in the carotid artery. The change in femoral-ankle pulse wave velocity from pre-exercise to 60-min post-exercise was significantly positively correlated with leg lean soft tissue mass in males (P = 0.01, R = 0.45), but not in females. Conclusion Our study shows that the effect of acute aerobic exercise on lower-limb arterial stiffness varies between the sexes, with greater reductions in arterial stiffness in young males than in females.

Elevated serum creatine kinase in the early stage of sporadic amyotrophic lateral sclerosis.

To assess the changes of muscle-related biomarkers at the early stage of amyotrophic lateral sclerosis, and to confirm these findings in an experimental animal model. Thirty-nine subjects with sporadic amyotrophic lateral sclerosis and 20 healthy controls were enrolled and longitudinally evaluated. We evaluated serum creatine kinase and creatinine levels and appendicular lean soft-tissue mass using dual X-ray absorptiometry. The levels of biomarkers at early ALS stages were estimated using linear mixed models with unstructured correlation and random intercepts. We also analyzed the longitudinal changes of serum creatine kinase and creatinine, together with the mRNA levels of acetylcholine receptor subunit γ (Chrng) and muscle-associated receptor tyrosine kinase, markers of denervation, in the gastrocnemius muscle of superoxide dismutase 1 (SOD1)G93A transgenic mice, an animal model of amyotrophic lateral sclerosis. The estimated levels of creatine kinase were higher in subjects with amyotrophic lateral sclerosis at the early stage than in healthy controls, although the estimated appendicular lean soft-tissue mass and creatinine levels were equivalent between both groups, suggesting that the elevation of creatine kinase precedes both muscular atrophy and subjective motor symptoms in sporadic amyotrophic lateral sclerosis. In SOD1G93A mice, the serum levels of creatine kinase were elevated at 9weeks of age (peri-onset) when Chrng started to be up-regulated, and were then down-regulated at 15weeks of age, consistent with the clinical data from patients with sporadic amyotrophic lateral sclerosis. Creatine kinase elevation precedes muscular atrophy and reflects muscle denervation at the early stage.

Profiling Determinants of Resting Energy Expenditure in Colorectal Cancer

Background: Understanding resting energy expenditure (REE) is important for determining energy requirements; REE might be altered in individuals with cancer. The objective of this study was to characterize determinants of REE in patients with stages II–IV colorectal cancer (CRC).Methods: REE was measured via indirect calorimetry in patients with newly diagnosed CRC. Computerized tomography images from medical records ascertained skeletal muscle and total adipose tissue cross-sectional areas, which were then transformed to lean soft tissue (LST) and fat mass (FM) values (in kg). Linear regression assessed determinants of REE.Results: 86 patients were included (n = 55, 64.0% male; 60 ± 12 years old; median body mass index: 27.6, interquartile range: 24.3–31.2 kg/m2), with most (n = 40) having stage III disease. Age, sex, and weight were significant predictors of REE [R2 = 0.829, standard error of the estimate (SEE): 128 kcal/day, P < 0.001]. Replacing weight with LST and FM yielded a similar model, with age, sex, LST, and FM predictive of REE (R2 = 0.820, SEE: 129 kcal/day, p < 0.001).Conclusion: Age, sex, weight, LST, and FM were the main contributors to REE. Further investigation of REE changes over time and its relationship to total energy expenditure, dietary intake, and clinical outcomes should be explored.

The Relationship between Bone Mineral Accrual and Changes of Body Composition in Competitive Girl Runners

Low bone density is a complication of a long-term strict weight control during adolescence in women. PURPOSE: To assess whether decrease in percent body fat (%BF) is associated with an impaired bone mineral accrual in girl runners. METHODS: Consecutive 22 freshmen girl runners (15y/o, 158cm, 45kg) during 7 years in competitive high school teams were evaluated over 2 years of training. DXA was performed at the preparatory phase (baseline) and repeated after 23 ± 2 months (follow-up). The runners were divided into 2 groups; negative (DEC, n=11) or positive (GAIN, n=11) changes of %BF (Δ%BF) during the period. The effect of the period and the group on the changes in bone mineral content (BMC) and density (BMD) of total body less head and z-score were analyzed by 2-way repeated measures ANOVA. As for lean soft tissue mass (LSM) and fat mass (FM), paired t-test was used to compare between baseline and follow-up. Bivariate correlation analysis was used to examine the relationship between bone mineral accrual (ΔBMC and ΔBMD) and Δ%BF as well as the changes of FM (ΔFM) and LSM (ΔLSM). Written informed consent was obtained from the runners and their parents. P<0.05 was considered as statistically significant. RESULTS: %BF changed from 17.4 to 14.3 (DEC) and 15.0 to 18.4 % (GAIN). The period had significant effects on BMC, BMD, and z-score without interactions. Contrast showed significant increases in those variables, while the group of Δ%BF had no significant effect, indicating the values of DEC and GAIN were similarly increased; 1.57 to 1.64 and 1.66 to 1.77 kg, 0.98 to 1.00 and 1.00 to 1.03 g/cm2, and -0.25 to -0.20 and 0.04 to 0.22, respectively. The DEC runners gained LSM (34.2 to 36.1 kg) and reduced FM (7.7 to 6.4 kg) significantly, while the GAIN runners significantly increased FM (6.9 to 9.0 kg) without LSM change (36.6 to 37.0 kg). Neither Δ%BF nor ΔFM, but ΔLSM was significantly correlated with ΔBMC (r=0.45) and ΔBMD (r=0.55). CONCLUSIONS: Bone mineral was equally accrued among the runners of which %BF increased or decreased, where the accretion was associated with LSM gain. Competitive distance runners would develop leanness by not only losing FM but also gaining LSM (i.e., skeletal muscle) along with long-term exercise training. This would ameliorate an impairment of bone mineral acquisition by strict weight control.

Scaling of adult human bone and skeletal muscle mass to height in the US population.

The scaling of structural components to body size is well studied in mammals, although comparable human observations in a large and diverse sample are lacking. The current study aimed to fill this gap by examining the scaling relationships between total body (TB) and regional bone and skeletal muscle (SM) mass with body size, as defined by stature, in a nationally representative sample of the US population. Subjects were 17,126 non-Hispanic (NH) white, NH black, and Mexican American men and women, aged ≥18 years, evaluated in the National Health and Nutrition Examination Survey who had TB and regional bone mineral (BMin) and lean soft tissue (LST) mass measured by dual-energy X-ray absorptiometry. BMin and appendicular LST served as surrogate bone and SM mass measures, respectively. The allometric model, BMin or LST = α(height)β , in a logarithmic form was used to generate scaling exponents. The findings were similar across all gender and race groups: body mass scaled to height with powers of ~2.0 (mean β ± SE, 1.94 ± 0.08-2.29 ± 0.09) while TB and appendicular BMin and appendicular LST scaled to height with consistently larger powers than those for body mass (eg, all P < .05 in NH white men and women); the largest BMin and LST scaling powers to height were observed in the lower extremities. Bone and SM mass, notably those of the lower extremities, increase as proportions of body mass with greater adult height. Metabolic and biomechanical implications emerge from these observations, the first of their kind in a representative adult US population sample.

Phase angle is associated with the physical fitness of HIV-infected children and adolescents.

The objective of this study was to identify the association of phase angle with physical fitness in children and adolescents infected with HIV. Sixty-four children and adolescents infected with HIV (8-15years old) were tested for vertical transmission. The electrical bioimpedance was used to obtain the phase angle. Body fat (BF) and lean soft tissue mass (LSTM) were measured by x-ray absorptiometry, and the manual grip strength was evaluated by dynamometry. The peak oxygen consumption (VO2 peak) was measured by respiratory change in a submaximal incremental test. Moderate-vigorous physical activity (MVP) and sedentary behavior were measured using accelerometers and were used as covariates. Multiple linear regression was used. The linear correlation analyses demonstrated that the phase angle was inversely proportional to relative BF (r=-0.26), but was not associated with absolute body fat (r=-0.02). The phase angle was directly associated with LSTM (r=0.57), handgrip strength, and (r=0.43) peak VO2 (r=0.55). The phase angle was not associated with absolute BF (β=-0.017, P=0.413) and relative (β=-0.014, P=0.175). The phase angle presented a direct association with LSTM (β=0.041, P=0.019) and peak VO2 (β=0.005; P=0.019), regardless of age, sex, sexual maturation, MVPA, sedentary behavior, antiretroviral drugs, and viral load. No association was found between phase angle and handgrip strength (β=0.153; P=0.199). It was concluded that phase angle was associated with LSTM and the aerobic fitness in HIV-infected children and adolescents.

Pre-training Skeletal Muscle Fiber Size and Predominant Fiber Type Best Predict Hypertrophic Responses to 6 Weeks of Resistance Training in Previously Trained Young Men.

Limited evidence exists regarding differentially expressed biomarkers between previously-trained low versus high hypertrophic responders in response to resistance training. Herein, 30 college-aged males (training age 5 ± 3 years; mean ± SD) partook in 6 weeks of high-volume resistance training. Body composition, right leg vastus lateralis (VL) biopsies, and blood were obtained prior to training (PRE) and at the 3-week (W3) and 6-week time points (W6). The 10 lowest (LOW) and 10 highest (HIGH) hypertrophic responders were clustered based upon a composite hypertrophy score of PRE-to-W6 changes in right leg VL mean muscle fiber cross-sectional area (fCSA), VL thickness assessed via ultrasound, upper right leg lean soft tissue mass assessed via dual x-ray absorptiometry (DXA), and mid-thigh circumference. Two-way ANOVAs were used to compare biomarker differences between the LOW and HIGH clusters over time, and stepwise linear regression was performed to elucidate biomarkers that explained significant variation in the composite hypertrophy score from PRE to W3, W3 to W6, and PRE to W6 in all 30 participants. PRE-to-W6 HIGH and LOW responders exhibited a composite hypertrophy change of +10.7 ± 3.2 and -2.1 ± 1.6%, respectively (p < 0.001). Compared to HIGH responders, LOW responders exhibited greater PRE type II fCSA (+18%, p = 0.022). Time effects (p < 0.05) existed for total RNA/mg muscle (W6 > W3 > PRE), phospho (p)-4EBP1 (PRE > W3&W6), pan-mTOR (PRE > W3 < W6), p-mTOR (PRE > W3 < W6), pan-AMPKα (PRE > W3 < W6), pan-p70s6k (PRE > W3), muscle ubiquitin-labeled proteins (PRE > W6), mechano growth factor mRNA (W6 > W3&PRE), 45S rRNA (PRE > W6), and muscle citrate synthase activity (PRE > W3&W6). No interactions existed for the aforementioned biomarkers and/or other assayed targets (muscle 20S proteasome activity, serum total testosterone, muscle androgen receptor protein levels, muscle glycogen, or serum creatine kinase). Regression analysis indicated PRE type II fiber percentage (R2 = 0.152, β = 0.390, p = 0.033) and PRE type II fCSA (R2 = 0.207, β = -0.455, p = 0.019) best predicted the PRE-to-W6 change in the composite hypertrophy score. While our sample size is limited, these data suggest: (a) HIGH responders may exhibit more growth potential given that they possessed lower PRE type II fCSA values and (b) possessing a greater type II fiber percentage as a trained individual may be advantageous for hypertrophy in response to resistance training.

Fluid distribution and cell integrity indicators evaluated by bioelectrical impedance in university athletes: comparison between team sports and individual sports

Objective: To compare indicators of fluid distribution and cellular integrity in university athletes through a cross-sectional study of 167 university athletes (18–35 years) who competed in team sports and individual sports. Approach: Bioimpedance was used to estimate total body water (TBW), intracellular water (ICW), extracellular water (ECW), ECW/ICW ratio, impedance (Z), reactance (Xc), resistance (R), phase angle, body cell mass (BCM) and ECW/BCM ratio at a frequency of 50 kHz. X-ray absorptiometry was used to determine lean soft tissue mass and body fat. As covariables, sex, age, time of practice and type of modality were obtained by questionnaire. Main results: Individual male athletes presented higher values of ECW/ICW ratio (means difference MD = 0.006, p = 0.020) and ECW/BCM ratio (MD = 0.006, p = 0.017) than team sports male athletes. Values of Z (MD = 24.988, p = 0.009), Xc (MD = 3.327, p = 0.008) and R (MD = 24.755, p = 0.09) were higher in male athletes practicing team sports than individual sports. Female team sports athletes presented higher values of Z (MD = 32.029, p = 0.015) and R (MD = 31.987, p = 0.015) than individual female athletes. It was concluded that ECW/ICW and ECW/BCM ratios were higher in male athletes who practiced individual sports. For the Z, R, and Xc values, the athletes in team sports presented higher values. The female athletes who practiced team sports presented higher values of Z and R than did individual female athletes. Significance: ECW/ICW and ECW/BCM ratios were higher in male athletes who practiced individual sports. For the Z, R, and Xc values, the athletes in team sports presented higher values. The female athletes who practiced team sports presented higher values of Z and R than did individual female athletes.

Exclusion of Trunk Region Reduces Biological Error but Increases Technical Error of DXA Lean Soft Tissue Estimates From Nonfasted Assessments

Implementation of an overnight fast is a pervasive recommendation prior to body composition assessment, but this is not always feasible. Previous research has indicated that for dual-energy X-ray absorptiometry (DXA) scans, the trunk region may be particularly susceptible to biological error induced by food and fluid intake. This analysis explored the potential utility of excluding the trunk region from nonfasted DXA scans. Recreationally active adults were assessed by DXA after an overnight fast and again after consumption of standardized high-carbohydrate and low-carbohydrate diets. The effects of food consumption on total and appendicular lean soft tissue (LST; ALST) and ALST-derived skeletal muscle mass (SMM) were evaluated via analysis of variance, and metrics of reliability were calculated. In both conditions, the constant error of nonfasted assessments was slightly lower when the trunk was excluded (ALST and SMM: 0.7-1.2%; LST: 1.5%). However, in both conditions, the total error, standard error of the estimate, and limits of agreement were higher for ALST and SMM (total error: 2.4-3.0%; standard error of the estimate: 2.2-2.8%; and limits of agreement: 4.5-5.6%) than LST (total error: 2.1%; standard error of the estimate: 1.3-1.4%; and limits of agreement: 2.5-2.8%) when expressed relative to mean values. The added technical error due to demarcation of body regions for ALST and SMM appears to outweigh the removal of biological error due to exclusion of the trunk. Although elimination of the trunk region is theoretically appealing for nonfasted DXA assessments, it is apparently an inferior method compared with utilizing whole-body LST.

Prospective Study on Body Composition, Energy Balance and Biological Factors Changes in Post-menopausal Women with Breast Cancer Receiving Adjuvant Chemotherapy Including Taxanes

In breast cancer patients, weight and fat mass changes observed after chemotherapy have been related to poor prognosis but some recent works using modern chemotherapy failed to find this correlation with weight gain. In this study, the extent of changes in weight and body composition (DEXA, impedance) was characterized until six months after current chemotherapy, in 50 post-menopausal women with breast cancer. The evolution of factors contributing to the energy balance and some biological factors were also described. During chemotherapy, 20% of women lost weight due to both fat (−13.1% ± 10.3) and lean soft tissue mass loss (−3.6% ± 4.6). Twenty percent of women gained weight. No significant fat mass gain was observed in these women but significant water gain was highlighted. Six months later, women who gained weight presented a gain in fat mass (15.4% ± 19.0), especially in the abdominal region. Age and initial BMI were negatively correlated with fat mass in multivariate analyzes (r = 0.486, P = 0.0030). No significant variation of the glucose homeostasis, triglycerides, and HDL-Cholesterol was found six months after chemotherapy. These results do not suggest major adverse metabolic disturbances six months after modern chemotherapy and only a mild fat mass gain was observed in women who gained weight.

DXA-Rectified Appendicular Lean Mass: Development of Ultrasound Prediction Models in Older Adults.

Dual-energy X-ray absorptiometry (DXA)-derived appendicular lean soft tissue mass (aLM) is used to diagnose sarcopenia. However, DXA-derived aLM includes non-skeletal muscle components, such as fat-free component of adipose tissue fat cell. These components, if not accounted for, could falsely inflate the aLM in individuals with a high amount of adipose tissue mass. B-mode ultrasound accurately measures muscle size in older adults. We sought to develop regression-based prediction equations for estimating DXA-rectified appendicular lean tissue mass (i.e. DXA-derived aLM minus appendicular fat-free adipose tissue (aFFAT); abbreviated as aLM minus aFFAT) using B-mode ultrasound. Cross-sectional study. Three hundred and eighty-nine Japanese older adults (aged 60 to 79 years) volunteered in the study. aLM was measured using a DXA, and muscle thickness (MT) was measured using ultrasound at nine sites. An ordinary least-squares multiple linear regression model was used to predict aLM minus aFFAT from sex, age and varying muscle thicknesses multiplied by height. Based on previous studies, we chose to use 4 MT sites at the upper and lower extremities (4-site MT model) and a single site (1-site MT model) at the upper extremity to develop prediction models. The linear prediction models (4 site MT model; R2 = 0.902, adjusted R2 = 0.899, and 1-site MT model; R2 = 0.868, adjusted R2 = 0.866) were found to be stable and accurate for estimating aLM minus aFFAT. Bootstrapping (n=1000) resulted in optimism values of 0.0062 (4-site MT model) and 0.0036 (1-site MT model). The results indicated that ultrasound MT combined with height, age and sex can be used to accurately estimate aLM minus aFFAT in older Japanese adults. Newly developed ultrasound prediction equations to estimate aLM minus aFFAT may be a valuable tool in population-based studies to assess age-related rectified lean tissue mass loss.

Interactions of lean soft-tissue and chemotherapy toxicities in patients receiving anti-cancer treatments

Use of cross-sectional imaging to identify whole-body lean soft-tissue mass has recently emerged as an attractive prognostic factor for chemotherapy toxicities. Beyond that, there is increasing interest in use of lean soft-tissue mass as a more accurate method for dosing chemotherapy, as compared to body surface area. In this review, we summarize the current evidence that supports interactions between skeletal muscle and chemotherapy, the role of lean soft tissue in predicting chemotherapy toxicities and potential use of an alternate method of chemotherapeutic dosing, all based on quantification of skeletal muscle mass by computed tomography.

Influence of Skeletal Muscle Mass and Spinal Alignment on Surgical Outcomes for Lumbar Spinal Stenosis.

Study Design Retrospective observational study.Purpose We considered the relationship between spinal alignment and skeletal muscle mass on clinical outcomes following a surgery for lumbar spinal stenosis (LSS).Overview of Literature There are no reports of preoperative factors predicting residual low back pain following surgery for LSS.Methods Our target population included 34 women (mean age, 74.4 years) who underwent surgery for LSS. Prior to and 6 months after the surgery, systemic bone mineral density and lean soft tissue mass were measured using dual-energy X-ray absorptiometry. Skeletal muscle mass index (SMI) was calculated as the sum of the arm and leg lean mass in kilograms divided by height in meters squared. The spinal alignment was also measured. Clinical outcomes were evaluated using the Japanese Orthopedic Association scoring system, leg and low back pain Visual Analog Scale, and Roland–Morris Disability Questionnaire (RDQ). Additionally, we examined the bone mineral density, skeletal muscle mass, and spinal alignment before and after the surgery. We used the Spearman correlation coefficient to examine the associations among clinical outcomes, preoperative muscle mass, and spinal alignment.Results Sarcopenia (SMI <5.46) was observed in nine subjects (26.5%). Compared with normal subjects (SMI >6.12), RDQ was significantly higher in subjects with sarcopenia (p =0.04). RDQ was significantly negatively correlated with SMI (r =−0.42, p <0.05). There was a significant positive correlation between postoperative RDQ and pelvic tilt (PT; r =0.41, p <0.05). SMI and PT were significantly negatively correlated (r =−0.39, r <0.05).Conclusions Good postoperative outcomes were negatively correlated with low preoperative appendicular muscle mass, suggesting that postoperative outcomes were inferior in cases of decreased appendicular muscle mass (sarcopenia). Posterior PT due to decreased limb muscle mass may contribute to postoperative back pain, showing that preoperatively reduced limb muscle mass and posterior PT are predictive factors in the persistence of postoperative low back pain.

Lean Soft Tissue Mass Measured Using Dual-Energy X-Ray Absorptiometry Is an Effective Index for Assessing Change in Leg Skeletal Muscle Mass Following Exercise Training

It is difficult to precisely and easily estimate the changes in skeletal muscle mass (SMM) following exercise training. We aimed to assess whether the change in lean soft tissue mass measured using dual-energy X-ray absorptiometry (DXA) reflects the change in SMM measured using magnetic resonance imaging (MRI) following exercise training in both the leg and trunk regions. Anthropometry, DXA, and MRI measurements of the trunk and leg regions were obtained in 10 male college sumo wrestlers before and after exercise training (mean duration between measurements: ~2 yr). Contiguous magnetic resonance images with 1-cm slice thickness and without gap were obtained from the first cervical vertebra to the ankle joints as reference data. Skeletal muscle volume was calculated from the summation of the digitized cross-sectional areas. The volume measurements were converted into mass by using an assumed skeletal muscle density (1.041 g/cm3). Trunk and leg areas, using DXA regional computer-generated lines, were adjusted to coincide with each discrete region by using MRI. Although the change in the DXA-measured lean soft tissue mass in the trunk region was significantly different from that of the MRI-measured SMM (Cohen's d = −1.3145, concordance correlation coefficient = 0.26, p < 0.01), the changes were similar in the leg region (Cohen's d = 0.07, concordance correlation coefficient = 0.87, p = 0.88). The exercise training-induced change in lean soft tissue mass significantly correlated with that in SMM, both in the leg (r = 0.88, p < 0.01) and trunk (r = 0.64, p < 0.05) regions. Bland–Altman analysis did not indicate a bias for the changes in leg lean soft tissue mass and SMM following exercise training. These results suggest that lean soft tissue mass measured using DXA is an effective index for assessing change in leg SMM following exercise training.

Effects of Low-Dose Dairy Protein Plus Micronutrient Supplementation during Resistance Exercise on Muscle Mass and Physical Performance in Older Adults: A Randomized, Controlled Trial.

To investigate whether supplementation with low-dose dairy protein plus micronutrients augments the effects of resistance exercise (RE) on muscle mass and physical performance compared with RE alone among older adults. Randomized controlled trial. Tokyo, Japan. Eighty-two community-dwelling older adults (mean age, 73.5 years) were randomly allocated to an RE plus dairy protein and micronutrient supplementation group or an RE only group (n = 41 each). The RE plus supplementation group participants ingested supplements with dairy protein (10.5 g/day) and micronutrients (8.0 mg zinc, 12 μg vitamin B12, 200 μg folic acid, 200 IU vitamin D, and others/day). Both groups performed the same twice-weekly RE program for 12 weeks. Whole-body, appendicular, and leg lean soft-tissue mass (WBLM, ALM, and LLM, respectively) with dual-energy X-ray absorptiometry, physical performance, biochemical characteristics, nutritional intake, and physical activity were measured before and after the intervention. Data were analyzed by using linear mixed-effects models. The groups exhibited similar significant improvements in maximum gait speed, Timed Up-and-Go, and 5-repetition and 30-s chair stand tests. As compared with RE only, RE plus supplementation significantly increased WBLM (0.63 kg, 95% confidence interval [CI]: 0.31-0.95), ALM (0.37 kg, 95% CI: 0.16-0.58), LLM (0.27 kg, 95% CI: 0.10-0.46), and serum concentrations of 25-hydroxyvitamin D (4.7 ng/mL, 95% CI: 1.6-7.9), vitamin B12 (72.4 pg/mL, 95% CI: 12.9-131.9), and folic acid (12.9 ng/mL, 95% CI: 10.3-15.5) (all P < 0.05 for group-by-time interactions). Changes over time in physical activity and nutritional intake excluding the supplemented nutrients were similar between groups. Low-dose dairy protein plus micronutrient supplementation during RE significantly increased muscle mass in older adults but did not further improve physical performance.

Noninvasive optical imaging of resistance training adaptations in human muscle.

.A quantitative and dynamic analysis of skeletal muscle structure and function can guide training protocols and optimize interventions for rehabilitation and disease. While technologies exist to measure body composition, techniques are still needed for quantitative, long-term functional imaging of muscle at the bedside. We evaluate whether diffuse optical spectroscopic imaging (DOSI) can be used for long-term assessment of resistance training (RT). DOSI measures of tissue composition were obtained from 12 adults before and after 5 weeks of training and compared to lean mass fraction (LMF) from dual-energy X-ray absorptiometry (DXA). Significant correlations were detected between DXA LMF and DOSI-measured oxy-hemo/myoglobin, deoxy-hemo/myoglobin, total-hemo/myoglobin, water, and lipid. RT-induced increases of in oxy-hemo/myoglobin (, ) and total-hemo/myoglobin (, ) from the medial gastrocnemius were detected with DOSI and accompanied by increases in lean soft tissue mass (, ) and increases in 1 rep-max strength (, ). DOSI measures of vascular and/or muscle changes combined with correlations between DOSI and DXA suggest that quantitative diffuse optical methods can be used to evaluate body composition, provide feedback on long-term interventions, and generate new insight into training-induced muscle adaptations.

Fat mass is positively associated with bone mass acquisition in children with small or normal lean mass: A three-year follow-up study.

The independent impact of fat mass (FM) on bone health is difficult to assess, as FM is correlated with lean soft tissue mass (LSTM). In a previous cross-sectional study, FM was suggested to help promote high bone mass acquisition in adolescents with small LSTM. The present prospective cohort study investigated the effects of FM on bone in pubertal children after stratification by height-normalized index of LSTM (LSTMI). The source population was all 5th grade children enrolled in either one of the two public elementary schools in Hamamatsu, Japan. Of these, 545 children who participated in both baseline (at age 11) and follow-up (at age 14) surveys were included in the present analysis. Body composition and whole body areal bone mineral density (aBMD) were measured using dual-energy X-ray absorptiometry. From baseline to follow-up, significant (P<0.05) differences were observed in changes in aBMD among tertiles of change in FM in both sexes after adjusting for confounding factors including LSTMI. After stratification by tertiles of sex-specific LSTMI, adjusted means of changes in aBMD according to tertiles of change in FM within the lowest and second lowest tertiles of LSTMI in both sexes showed a significant increase from the lower tertiles to the highest tertile of change in FM. In the highest tertile of LSTMI, changes in FM showed no significant association with changes in aBMD. These findings suggest that adipose tissue might help promote high bone mass acquisition in pubertal children with small or normal LSTMI.

Accuracy of basal metabolic rate estimated by predictive equations in Japanese with type 2 diabetes.

Estimation of energy demand using basal metabolic rate (BMR) is a rational approach for optimizing glycemic control and weight management in patients with type 2 diabetes mellitus (T2DM). Here, we assessed the accuracy of predictive equations in estimating BMR in Japanese patients with T2DM. BMR was measured indirectly (BMRm) with a portable gas analyzer in the fasting state in 69 Japanese patients with T2DM. BMR was estimated using the Harris-Benedict equation (BMRhb) and Ganpule equation (BMRg). An original predictive equation (BMRdm) was formulated by stepwise multiple regression analysis using subject age, lean soft tissue mass, fat mass and bone mineral content. Mean differences and 95% limits of agreement between measured and three estimated BMRs were evaluated by Bland-Altman plots. In addition, subjects were divided into three BMI groups (normal, BMI <25; overweight, BMI >=25; obese, BMI >=30), and the influence of BMI on the error size between measured and estimated BMRs was assessed. Between BMRm and the three estimated BMRs (BMRhb, BMRg, and BMRdm), there were small systematic errors with large random errors (mean difference±2SD ; -32±365 kcal，26±405 kcal, and -1.6±349 kcal, respectively) and significant proportional errors (r=0.42, 0.44, and 0.30, respectively). BMI subgroup analysis revealed that the obese group showed larger random errors and significant proportional errors compared to the overweight and normal weight groups. Predictive equations provide unacceptably inaccurate estimates of BMR in Japanese patients with T2DM, particularly in obese individuals.

Association of Body Composition with the Performance Level and Running Mileage among Long Distance Runners

PURPOSE: To assess the association between leanness and running performance and training volume among highly trained Japanese long distance runners. METHODS: Body composition was measured by dual energy X-ray absorptiometry in 54 Japanese male long distance runners who belonged to a university track and field team (19.8±1.3 yrs). The training volume was assessed by the average running mileage (km/month) during 5 months prior to the measurement. The runners were routinely divided into 4 categories by the coach of the team according to their performance level and the category of the period was used as the performance level of the runners; team A (n=15), B (n=17), C (n=11), and D (n=11) in the order of the level. Team D included runners who had injuries and restricted their training. Questionnaire survey was performed regarding weight control practices and complaints of fatigue. Written informed consent was obtained from each runner. RESULTS: The mean running mileage of the 54 runners was 606 km/month. Height, body mass, BMI, percent body fat, bone mineral density (BMD), z-score of BMD, and lean soft tissue mass were 172.0±5.2 cm, 57.3±4.4 kg, 19.4±1.0 kg/m2, 6.1±1.3%, 1.175±0.057 g/cm2, -0.524±0.677, and 51.1±4.0 kg, respectively. The mean running mileage was not significantly correlated with any of those variables (p>0.05). The mean running mileage of each category (A, B, C, & D) were 709, 600, 606, and 475 km/month, respectively (p<0.01). Percent body fat were lowest in A (5.7%) and highest in D (6.4%) whereas z-score of BMD were -0.447 and -0.664, respectively. However, ANOVA showed no significant differences in those variables among the categories. Fisher’s exact tests of questionnaire survey revealed significant between-categories differences in percentages of runners attempting weight reduction practices (8.3, 13.3, 53.8, and 38.5%, respectively, p<0.05) and those complained of frequent fatigue (25.0, 53.3, 53.8, and 69.2%, respectively, p<0.05). CONCLUSIONS: The runners had exclusively lean bodies regardless of their performance level and running mileage. The runners with the lowest performance level and the least training volume likely attempted weight reduction practice and complained of fatigue. It was concerned that they might pursue the lower level of percent body fat by restricting energy intake.