Adult Lean Body Mass Research Articles

The Role of Protein Intake and its Timing on Body Composition and Muscle Function in Healthy Adults: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Increased protein intake has been suggested to improve gains in muscle mass and strength in adults. Furthermore, the timing of protein intake has been discussed as a margin of opportunity for improved prevention measures. This systematic review investigated the effect of protein supplementation on body composition and muscle function (strength and synthesis) in healthy adults, with an emphasis on the timing of protein intake. Randomized controlled trials were identified using PubMed, Web of Science, CINAHL, and Embase, up to March 2019. For meta-analyses, data on lean body mass (LBM), handgrip strength, and leg press strength were pooled by age group (mean age 18-55 or >55 y) and timing of protein intake. The quality of evidence was assessed using the Grading of Recommendations, Assessment, Development and Evaluations approach. Data from 65 studies with 2907 participants (1514 men and 1380 women, 13 unknown sex) were included in the review. Twenty-six, 8, and 24 studies were used for meta-analysis on LBM, handgrip strength, and leg press strength, respectively. The protein supplementation was effective in improving (mean difference; 95% CI) LBM in adults (0.62kg; 0.36, 0.88) and older adults (0.46kg; 0.23, 0.70), but not handgrip strength (older adults: 0.26kg; -0.51, 1.04) and leg press strength (adults: 5.80kg; -0.33, 11.93; older adults: 1.97kg; -2.78, 6.72). Sensitivity analyses removing studies without exercise training had no impact on the outcomes. Data regarding muscle synthesis were scarce and inconclusive. Subgroup analyses showed no beneficial effect of a specific timing of protein intake on LBM, handgrip strength, and leg press strength. Overall, the results support the positive impact of protein supplementation on LBM of adults and older adults, independently of intake timing. Effects on muscle strength and synthesis are less clear and need further investigation. This systematic review was registered on PROSPERO as CRD42019126742.

Use of Novel High-Protein Functional Food Products as Part of a Calorie-Restricted Diet to Reduce Insulin Resistance and Increase Lean Body Mass in Adults: A Randomized Controlled Trial.

Significant reductions in insulin resistance (IR) can be achieved by either calorie restriction or by the increase of lean mass. However, calorie restriction usually results in significant loss of lean mass. A 6-week randomized controlled feeding trial was conducted to determine if a calorie-restricted, high-protein diet (~125 g protein/day consumed evenly throughout the day) using novel functional foods would be more successful for reducing IR in comparison to a conventional diet (~80 g protein/day) with a similar level of calorie restriction. Healthy adults (age 20–75 years; body mass index, 20–42 kg/m2) with raised triglyceride/high-density lipoprotein ratios were randomly assigned to the control group (CON: test foods prepared using gluten-free commercial pasta and cereal) or to the high-protein group (HPR: test foods prepared using novel high-protein pasta and cereal both rich in wheat gluten). Mean weight loss did not differ between groups (−2.7 ± 2.6 and −3.2 ± 3.0 kg for CON (n = 11) and HPR (n = 10) respectively, p = 0.801); however, the 6-week change in fat-free mass (FFM) differed significantly between groups (−0.5 ± 1.5 and +1.5 ± 3.8 kg for CON and HPR respectively, p = 0.008). IR improved in HPR vs. CON participants (homeostasis model assessment-estimated insulin resistance [HOMAIR] change: −1.7 ± 1.4 and −0.7 ± 0.7 respectively; p = 0.020). The change in HOMA-IR was related to the change in FFM among participants (r = −0.511, p = 0.021). Thus, a high-protein diet using novel functional foods combined with modest calorie restriction was 140% more effective for reducing HOMA-IR in healthy adults compared to a lower protein, standard diet with an equal level of calorie restriction.

The Validation of Multi-Frequency Bioimpedance Analyzers for the Assessment of Segmental Lean Body Mass in Adults.

The Validation of Multi-Frequency Bioimpedance Analyzers for the Assessment of Segmental Lean Body Mass in Adults.

The Association of Early Life Supplemental Nutrition With Lean Body Mass and Grip Strength in Adulthood: Evidence From APCAPS

In the present study, we examined the associations of early nutrition with adult lean body mass (LBM) and muscle strength in a birth cohort that was established to assess the long-term impact of a nutrition program. Participants (n = 1,446, 32% female) were born near Hyderabad, India, in 29 villages from 1987 to 1990, during which time only intervention villages (n = 15) had a government program that offered balanced protein-calorie supplementation to pregnant women and children. Participants’ LBM and appendicular skeletal muscle mass were measured using dual energy x-ray absorptiometry; grip strength and information on lifestyle indicators, including diet and physical activity level, were also obtained. Ages (mean = 20.3 years) and body mass indexes (weight (kg)/height (m)2; mean = 19.5) of participants in 2 groups were similar. Current dietary energy intake was higher in the intervention group. Unadjusted LBM and grip strength were similar in 2 groups. After adjustment for potential confounders, the intervention group had lower LBM (β = −0.75; P = 0.03), appendicular skeletal muscle mass, and grip strength than did controls, but these differences were small in magnitude (<0.1 standard deviation). Multivariable regression analyses showed that current socioeconomic position, energy intake, and physical activity level had a positive association with adult LBM and muscle strength. This study could not detect a “programming” effect of early nutrition supplementation on adult LBM and muscle strength.

Burn-injured adults with long term functional impairments demonstrate the same response to resistance training as uninjured controls

ObjectiveThe catabolic response associated with major burn injuries results in loss of lean body mass (LBM) and prolonged muscle weakness. Exercise training improves LBM and muscle strength in burn-injured children in the acute post injury phase, yet it is unknown whether adults will experience the same benefits when exercise training is implemented at least two years post injury. ProceduresNine burn-injured participants (%TBSA=42±18.38; time since injury=6.56±3.68 years) and 9 matched controls participated in a 12-week interval training and resistance exercise programme. Muscle strength was assessed via isokinetic dynamometry and LBM was determined via dual energy X-ray absorptiometry. Both measures were administered prior to and following the exercise programme. ResultsThere was no significant difference in LBM or strength between the two groups at baseline. Following the exercise programme, both groups displayed significant improvements in LBM and in hip, shoulder and elbow muscle strength. There was no significant difference in muscle strength or LBM, between the groups, following the exercise training. ConclusionA combined exercise training programme was able to improve muscle strength and lean body mass in adults with burn injury. There was no difference between the two groups in their response to the exercise programme, therefore general exercise prescription principles may be applied directly to the burns population.

Developmental Origins of Physical Fitness: The Helsinki Birth Cohort Study

BackgroundCardiorespiratory fitness (CRF) is a major factor influencing health and disease outcomes including all-cause mortality and cardiovascular disease. Importantly CRF is also modifiable and could therefore have a major public health impact. Early life exposures play a major role in chronic disease development. Our aim was to explore the potential prenatal and childhood origins of CRF in later life.Methods/Principal FindingsThis sub-study of the HBCS (Helsinki Birth Cohort Study) includes 606 men and women who underwent a thorough clinical examination and participated in the UKK 2-km walk test, which has been validated against a maximal exercise stress test as a measure of CRF in population studies. Data on body size at birth and growth during infancy and childhood were obtained from hospital, child welfare and school health records. Body size at birth was not associated with adult CRF. A 1 cm increase in height at 2 and 7 years was associated with 0.21 ml/kg/min (95% CI 0.02 to 0.40) and 0.16 ml/kg/min (95% CI 0.03 to 0.28) higher VO2max, respectively. Adjustment for adult lean body mass strengthened these findings. Weight at 2 and 7 years and height at 11 years became positively associated with CRF after adult lean body mass adjustment. However, a 1 kg/m2 higher BMI at 11 years was associated with −0.57 ml/kg/min (95% CI −0.91 to −0.24) lower adult VO2max, and remained so after adjustment for adult lean body mass.Conclusion/SignificanceWe did not observe any significant associations between body size at birth and CRF in later life. However, childhood growth was associated with CRF in adulthood. These findings suggest, importantly from a public point of view, that early growth may play a role in predicting adult CRF.

Dietary protein intake among adults in the United States and its relationship to select body composition measures

Higher protein intakes may help maintain lean body mass in adults. The purpose of this research was to examine the relationship between dietary protein and body composition measures among adults in the US, with a focus on older adults, using data from NHANES. Dietary data were from two 24‐hour recalls. Body composition data were from DXA measurements from NHANES 2003–04. SAS and SUDAAN software were used for data management and regression analyses. All analyses were performed separately by age group (19–50, 51–70, and 71+) and gender. Covariables were age, height, total energy intake, physical activity (average intensity from physical activity monitor), total body fat mass (g), race/ethnicity, and education level. Results indicate that protein intake (expressed either as g/day or % of energy) was positively associated with total lean mass (excluding bone) in males 19–50 and 51–70 (P &lt; 0.01) and with trunk lean mass in males of all age groups. The percent of protein contributed by animal foods was positively associated with total and trunk lean mass in males 19–50 (P &lt; 0.01). These associations were not significant in females. Findings suggest that protein intake is a modifiable factor associated with lean body mass in this nationally representative analysis of men. Supported by grants from the CSU Agricultural Research Initiative, National Cattlemen's Beef Association, and the Dairy Council of California.

Age‐dependent capacity to accelerate protein synthesis dictates the extent of compensatory growth in skeletal muscle following undernutrition

In both humans and animals, impaired growth during early life compromises adult lean body mass and muscle strength despite skeletal muscle's large regenerative capacity. To identify the significance of developmental age on skeletal muscle's capacity for catch‐up growth following an episode of undernutrition, mice were suckled on control dams fed a 20% protein diet or from birth to 11 (early malnutrition, EM) or 11 to 22 (late malnutrition, LM) days of age on dams fed a low‐protein (8%) diet. They were refed by cross‐fostering (EM) to control dams or weaning (LM) to a control (20% protein) diet. Hindlimb muscle mass and fractional protein synthesis rates (FSR) were measured on days 0, 2, 7 and 21 of refeeding (n=7–9 per age per treatment). On day 0, EM and LM muscles weighed 76% and 84% of age‐matched control values, respectively (P&lt;0.001). After 21 d of refeeding, muscles weighed 94% (EM; NS) and 88% (LM; P&lt;0.001) of control values. FSR were significantly higher in EM than control muscles 2 and 7 d after refeeding (P&lt;0.01), whereas in LM pups, values were similar to controls at all ages. The increase in FSR in EM pups upon refeeding was attributable to increased ribosomal abundance. The data suggest that skeletal muscle's ability to effect catch‐up growth is dictated by a developmental stage‐dependent capacity for ribosome biogenesis. Funded by NIH AR46308 and USDA/ARS/CSREES 6250‐51000‐033

Body mass index during childhood and adult body composition in men and women aged 56–70 y

BackgroundThe relation between the change in body mass index (BMI) through childhood and body composition in adult life is important because body composition is known to affect adult health. ObjectiveThe objective was to examine how the change in BMI throughout childhood is related to adult lean and fat mass. DesignWe examined how the change in BMI in childhood was related to adult body composition in 885 men and 1032 women born during 1934–1944, whose weights and heights during childhood were recorded serially. Adult lean and fat mass were measured by bioelectrical impedance with an 8-polar tactile electrode system. ResultsIn these 56–70-y-old men and women, adult lean body mass index (lean mass/height2; in kg/m2) was positively associated with BMI at birth (0.24 and 0.20 higher for each 1-SD increase in BMI at birth, respectively) and with more rapid gain in BMI from birth to 1 y (0.17 and 0.22), 1–2 y (0.21 and 0.20), 2–7 y (0.44 and 0.46), and 7–11 y (0.32 and 0.26) of age. Fat mass index (fat mass/height2) was positively associated with more rapid increases in BMI between 2 and 11 y of age. ConclusionsRapid gain in BMI before the age of 2 y increased adult lean body mass without excess fat accumulation, whereas rapid gain in BMI in later childhood, despite the concurrent rise in lean mass, resulted in relatively larger increases in fat mass.

Wasting and body composition of adults with pulmonary tuberculosis in relation to HIV-1 coinfection, socioeconomic status, and severity of tuberculosis

To examine the impact of HIV coinfection, socioeconomic status (SES) and severity of tuberculosis (TB) on the body composition and anthropometric status of adults with pulmonary TB. Cross-sectional study. Five TB clinics in Dar es Salaam, Tanzania. A total of 2231 adult men and women diagnosed with pulmonary TB, prior to the initiation of anti-TB therapy. We compared the distribution of anthropometric characteristics including body mass index (BMI), mid-upper arm circumference (MUAC), triceps skin-fold (TSF), and arm muscle circumference (AMC) by HIV status, SES characteristics, and indicators of TB severity (bacillary density in sputum and Karnofsky performance score). Similar comparisons were carried out with body composition variables from bioelectrical impedance analysis and albumin concentrations, in a subsample of 731 subjects. In multivariate analysis, HIV infection was significantly associated with lower MUAC and AMC in both men and women, but not with BMI or TSF. Compared to HIV-uninfected women, those who were HIV infected had lower body cell mass (BCM) (adjusted difference = -0.85 kg, P = 0.04), intracellular water (-0.68 l, P = 0.04), and phase angle (-0.52, P = 0.02). Albumin concentrations were significantly lower in both men and women infected with HIV. Among HIV-infected men, CD4 cell counts <200/mm(3) were related to lower intracellular water, BCM, fat-free mass and phase angle. Independent of HIV infection, BMI and MUAC were positively related to SES indicators and the Karnofsky performance score; and inversely related to bacillary density. HIV infection is associated with indicators of low lean body mass in adults with TB; socioeconomic factors and TB severity are important correlates of wasting, independent of HIV. The National Institute of Allergy and Infectious Diseases (UO1 AI 45441-01).

Serum insulin-like growth factor (IGF)-I and IGF-binding protein-1 in elderly people: relationships with cardiovascular risk factors, body composition, size at birth, and childhood growth.

The IGF system is important in regulation of fetal and childhood growth. In later life, IGF-I and IGF-binding protein-1 (IGFBP-1) have been implicated in the pathogenesis of arteriosclerosis. They are, thus, potential candidates in explaining the link between early growth and adult cardiovascular disease. We measured fasting serum IGF-I and IGFBP-1 concentrations in 394 men and women from a cohort of 7086 individuals, born between 1924 and 1933 in Helsinki, Finland, whose weight and height were recorded at birth and from 7 to 15 yr of age. They also underwent clinical examination, including measurement of body fat using bioimpedance, blood pressure, glucose tolerance, and plasma insulin and fibrinogen concentrations. Serum IGF-I was positively correlated with fasting glucose (r = 0.10, P = 0.06) and fibrinogen (r = 0.19, P = 0.0001) concentrations and blood pressure (systolic and diastolic r = 0.10, P </= 0.05) and inversely with percentage body fat (r = -0.13, P = 0.01) and waist circumference (r = -0.11, P = 0.03). IGFBP-1 was inversely correlated with adult body mass index (BMI) (r = -0.46, P < 0.0001), fasting glucose and insulin concentrations, and blood pressure. There were correlations between the adult level of IGFBP-1 and birth weight (r = 0.11, P = 0.03) and ponderal index (weight/length(3)) at birth (r = 0.13, P = 0.01), but IGF-I was not related to birth measurements. There were interactive effects between childhood height or BMI and adult BMI on IGF-I and IGFBP-1 in adulthood. Tall height and high BMI at 7 yr were associated with low IGF-I (P = 0.03 for height and P = 0.003 for BMI) and high IGFBP-1 (P = 0.02 and P = 0.06) in adulthood but only in those subjects whose current BMI was below median. On further analysis these interactive effects were particularly strong for height in childhood and adult lean BMI (lean body mass/height(2)). Among men and women of below-average lean BMI, tall height at 7 yr was associated with low adult IGF-I (P = 0.007) and high IGFBP-1 (P = 0.0004) concentrations [interaction (7-yr height x adult lean BMI); P = 0.008 for IGF-I and 0.001 for IGFBP-1]. There is no evidence that reduced fetal growth programs IGF-I concentrations in old age. An association between small size at birth and low IGFBP-1 concentrations may in part reflect fetal programming effects on insulin resistance. Given the anabolic effects of the GH-IGF-I axis, subjects with tall height in childhood but low adult lean body mass may be at risk of late-life GH-IGF-I axis dysfunction. Prospective studies should address whether this group is susceptible to type 2 diabetes, coronary heart disease, and osteoporosis.

Short-term progressive resistance training increases strength and lean body mass in adults infected with human immunodeficiency virus

To assess the efficacy of progressive resistance training (PRT) in increasing strength and lean body mass (LBM) in HIV-infected adults. Twenty-five adults with HIV infection were trained using a highly intensive PRT regimen for 8 weeks, followed by an additional 8 weeks of observation under ad libitum physical activity conditions. Twenty-four of the 25 patients completed the first phase of the study. They had significant increases in strength on all four exercises tested (P < 0.0001), and an increase in LBM of 1.75 +/- 1.94 kg (mean +/- SD, P < 0.0002), with a concomitant decline in fat of 0.92 +/- 2.22 kg (P < 0.05), and no significant change in weight or bone mineral content. Twenty-one of the patients returned for follow-up 8 weeks after completing the PRT. Compared with their baseline values, their mean lean mass remained 1.40 +/- 1.8 kg higher (P < 0.003). Among those who continued to train to some extent, lean mass increased by a mean of 1.1 +/- 1.6 kg (n = 9, P < 0.05 versus end of PRT), whereas those who did no further training showed an increase in lean mass of 0.28 +/- 1.4 kg (n = 12, P = NS versus end of PRT). The difference between the two groups was not, however, significant (P = 0.25). Among six patients with AIDS wasting, the increase in LBM was larger than among non-wasted patients (2.8 versus 1.4 kg, P < 0.06), and there was an increase in both weight (+3.9 versus -0.2 kg, P < 0.002) and fat mass (+ 0.95 versus -1.5 kg, P < 0.002) at 8 weeks, which persisted at 16 weeks (weight: +4.0 versus -1.6 kg, P < 0.0002; fat: +1.6 versus -1.9 kg, P < 0.01). This preliminary study suggests that short-term, high intensity PRT can significantly increase LBM and strength in HIV infection, and may be used as an alternative or adjunct to pharmacological anabolic treatments in this disease.

Fattening and fatty acid synthetase in juvenile richardson's ground squirrels

1. 1. Intraperitoneal white adipose tissue (WAT) first appeared in juvenile squirrels when they were 10–12 weeks old and had achieved about two thirds of adult lean body mass. 2. 2. Rate of fat deposition at age 12–16 weeks was about 6.5 g per week, similar to the rate in adults during their respective periods of prehibernatory fattening when expressed as fat deposited per 100 g of lean body mass. 3. 3. Upon emergence from the natal burrow there was little fatty acid synthetase (FAS) activity and most of that was in liver. At 14 weeks of age nearly all FAS activity was in WAT, suggesting WAT was the primary tissue of fatty acid synthesis. 4. 4. At a given age, there were no differences between sexes in FAS activity of liver, WAT, or brown adipose tissue (BAT).

Adult lean body mass declines with age: Some longitudinal observations

Lean body mass, as estimated from 40K counting, declines progressively during adult life. The rate of decline tends to speed up in later years, and is somewhat greater in the male. By age 65–70 the average male has 12 Kg. less LBM than at age 25; the female has 5 Kg. less. Longitudinal observations show that this trend is for the most part biological, not secular in origin. The magnitude of the decline is such, and the sex difference in LBM great enough to suggest that age and sex should both be taken into account in such matters as drug dosage and nutritional requirements.

Measures of body fat and related factors in normal adults—I: Introduction and methodology

A valid clinically applicable anthropometric method to estimate body fat and lean body mass in adults would aid in the epidemiological study of diseases associatedwith overweight. Such a method has been developed from anthropometric measurements of 2053 healthy Caucasian men and women and Negro men between the ages of 25 and 44 years and from laboratory determinations of body density and total body water for 8 per cent of all subjects. This is the subject of the following report [45]. Successful employment of this method depends upon exact duplication of the measurement techniques. The anthropometric measurements have been detailed for reproducibility by interested clinicians. Methods used to study additional parameters associated with body composition are given: diet, physical activity and somatotype. Potassium-40 and cesium-137 techniques have been described. Subsequent papers will present results and interrelationships of the several studied factors.