Bio-Electrical Impedance Analysis: A Valid Assessment Tool for Diagnosis of Low Appendicular Lean Mass in Older Adults?

Background: The diagnosis of sarcopenia is essential for early treatment of sarcopenia in older adults, for which assessment of appendicular lean mass (ALM) is needed. Multi-frequency bio-electrical impedance analysis (MF-BIA) may be a valid assessment tool to assess ALM in older adults, but the evidences are limited. Therefore, we validated the BIA to diagnose low ALM in older adults. Methods: ALM was assessed by a standing-posture 8 electrode MF-BIA (Tanita MC-780) in 202 community-dwelling older adults (age ≥ 55 years), and compared with dual-energy X-ray absorptiometry (DXA) (Hologic Inc., Marlborough, MA, United States; DXA). The validity for assessing the absolute values of ALM was evaluated by: (1) bias (mean difference), (2) percentage of accurate predictions (within 5% of DXA values), (3) the mean absolute error (MAE), and (4) limits of agreement (Bland-Altman analysis). The lowest quintile of ALM by DXA was used as proxy for low ALM (< 22.8 kg for men, < 16.1 kg for women). Sensitivity and specificity of diagnosing low ALM by BIA were assessed. Results: The mean age of the subjects was 72.1 ± 6.4 years, with a BMI of 25.4 ± 3.6 kg/m2, and 71% were women. BIA slightly underestimated ALM compared to DXA with a mean bias of -0.6 ± 1.2 kg. The percentage of accurate predictions was 54% with a MAE of 1.1 kg, and limits of agreement were -3.0 to + 1.8 kg. The sensitivity for ALM was 80%, indicating that 80% of subjects who were diagnosed as low ALM according to DXA were also diagnosed low ALM by BIA. The specificity was 90%, indicating that 90% of subjects who were diagnosed as normal ALM by DXA were also diagnosed as normal ALM by the BIA. Conclusion: This comparison showed a poor validity of MF-BIA to assess the absolute values of ALM, but a reasonable sensitivity and specificity to recognize the community-dwelling older adults with the lowest muscle mass.

Calculation of protein requirements; a comparison of calculations based on bodyweight and fat free mass.

BACKGROUND & AIMS: In dietary practice, it is common to estimate protein requirements on actual bodyweight, but corrected bodyweight (in cases with BMI <20 kg/m2 and BMI ≥30 kg/m2) and fat free mass (FFM) are also used. Large differences on individual level are noticed in protein requirements using these different approaches. To continue this discussion, the answer is sought in a large population to the following question: Will choosing actual bodyweight, corrected bodyweight or FFM to calculate protein requirements result in clinically relevant differences? METHODS: This retrospective database study, used data from healthy persons ≥55 years of age and in- and outpatients ≥18 years of age. FFM was measured by air displacement plethysmography technology or bioelectrical impedance analysis. Protein requirements were calculated as 1) 1.2 g (g) per kilogram (kg) actual bodyweight or 2) corrected bodyweight or 3) 1.5 g per kg FFM. To compare these three approaches, the approach in which protein requirement is based on FFM, was used as reference method. Bland-Altman plots with limits of agreement were used to determine differences, analyses were performed for both populations separately and stratified by BMI category and gender. RESULTS: In total 2291 subjects were included. In the population with relatively healthy persons (n = 506, ≥55 years of age) mean weight is 86.5 ± 18.2 kg, FFM is 51 ± 12 kg and in the population with adult in- and outpatients (n = 1785, ≥18 years of age) mean weight is 72.5 ± 18.4 kg, FFM is 51 ± 11 kg. Clinically relevant differences were found in protein requirement between actual bodyweight and FFM in most of the participants with overweight, obesity or severe obesity (78-100%). Using corrected bodyweight, an overestimation in 48-92% of the participants with underweight, healthy weight and overweight is found. Only in the Amsterdam UMC population, protein requirement is underestimated when using the approach of corrected bodyweight in participants with severe obesity. CONCLUSION: The three approaches in estimation of protein requirement show large differences. In the majority of the population protein requirement based on FFM is lower compared to actual or corrected bodyweight. Correction of bodyweight reduces the differences, but remain unacceptably large. It is yet unknown which method is the best for estimation of protein requirement. Since differences vary by gender due to differences in body composition, it seems more accurate to estimate protein requirement based on FFM. Therefore, we would like to advocate for more frequent measurement of FFM to determine protein requirements, especially when a deviating body composition is to be expected, for instance in elderly and persons with overweight, obesity or severe obesity.

Dietary protein intake is not associated with 5-y change in mid-thigh muscle cross-sectional area by computed tomography in older adults: the Health, Aging, and Body Composition (Health ABC) Study.

BACKGROUND: A higher protein intake is suggested to preserve muscle mass during aging and may therefore reduce the risk of sarcopenia. OBJECTIVES: We explored whether the amount and type (animal or vegetable) of protein intake were associated with 5-y change in mid-thigh muscle cross-sectional area (CSA) in older adults (n = 1561). METHODS: Protein intake was assessed at year 2 by a Block food-frequency questionnaire in participants (aged 70-79 y) of the Health, Aging, and Body Composition (Health ABC) Study, a prospective cohort study. At year 1 and year 6 mid-thigh muscle CSA in square centimeters was measured by computed tomography. Multiple linear regression analysis was used to examine the association between energy-adjusted protein residuals in grams per day (total, animal, and vegetable protein) and muscle CSA at year 6, adjusted for muscle CSA at year 1 and potential confounders including prevalent health conditions, physical activity, and 5-y change in fat mass. RESULTS: Mean (95% CI) protein intake was 0.90 (0.88, 0.92) g · kg-1 · d-1 and mean (95% CI) 5-y change in muscle CSA was -9.8 (-10.6, -8.9) cm2. No association was observed between energy-adjusted total (ß = -0.00; 95% CI: -0.06, 0.06 cm2; P = 0.982), animal (ß = -0.00; 95% CI: -0.06, 0.05 cm2; P = 0.923), or plant (ß = +0.07; 95% CI: -0.06, 0.21 cm2; P = 0.276) protein intake and muscle CSA at year 6, adjusted for baseline mid-thigh muscle CSA and potential confounders. CONCLUSIONS: This study suggests that a higher total, animal, or vegetable protein intake is not associated with 5-y change in mid-thigh muscle CSA in older adults. This conclusion contradicts some, but not all, previous research. This trial was registered at www.trialregister.nl as NTR6930.

Exercise and Nutrition Strategies to Counteract Sarcopenic Obesity.

As the population is aging rapidly, there is a strong increase in the number of individuals with chronic disease and physical limitations. The decrease in skeletal muscle mass and function (sarcopenia) and the increase in fat mass (obesity) are important contributors to the development of physical limitations, which aggravates the chronic diseases prognosis. The combination of the two conditions, which is referred to as sarcopenic obesity, amplifies the risk for these negative health outcomes, which demonstrates the importance of preventing or counteracting sarcopenic obesity. One of the main challenges is the preservation of the skeletal muscle mass and function, while simultaneously reducing the fat mass in this population. Exercise and nutrition are two key components in the development, as well as the prevention and treatment of sarcopenic obesity. The main aim of this narrative review is to summarize the different, both separate and combined, exercise and nutrition strategies so as to prevent and/or counteract sarcopenic obesity. This review therefore provides a current update of the various exercise and nutritional strategies to improve the contrasting body composition changes and physical functioning in sarcopenic obese individuals.

Reduction in energy expenditure during weight loss is higher than predicted based on fat free mass and fat mass in older adults.

BACKGROUND & AIM: The aim of this study was to describe a decrease in resting energy expenditure during weight loss that is larger than expected based on changes in body composition, called adaptive thermogenesis (AT), in overweight and obese older adults. METHODS: Multiple studies were combined to assess AT in younger and older subjects. Body composition and resting energy expenditure (REE) were measured before and after weight loss. Baseline values were used to predict fat free mass and fat mass adjusted REE after weight loss. AT was defined as the difference between predicted and measured REE after weight loss. The median age of 55 y was used as a cutoff to compare older with younger subjects. The relation between AT and age was investigated using linear regression analysis. RESULTS: In this study 254 (M = 88, F = 166) overweight and obese subjects were included (BMI: 31.7 ± 4.4 kg/m2, age: 51 ± 14 y). The AT was only significant for older subjects (64 ± 185 kcal/d, 95% CI [32, 96]), but not for younger subjects (19 ± 152 kcal/d, 95% CI [-9, 46]). The size of the AT was significantly higher for older compared to younger adults (ß = 47, p = 0.048), independent of gender and type and duration of the weight loss program. CONCLUSIONS: We conclude that adaptive thermogenesis is present only in older subjects, which might have implications for weight management in older adults. A reduced energy intake is advised to counteract the adaptive thermogenesis.

Effect of a high protein diet and/or resistance exercise on the preservation of fat free mass during weight loss in overweight and obese older adults: a randomized controlled trial.

BACKGROUND: Intentional weight loss in obese older adults is a risk factor for accelerated muscle mass loss. We investigated whether a high protein diet and/or resistance exercise preserves fat free mass (FFM) during weight loss in overweight and obese older adults. METHODS: We included 100 overweight and obese adults (55-80 year) in a randomized controlled trial (RCT) with a 2 × 2 factorial design and intention-to-treat analysis. During a 10-week weight loss program all subjects followed a hypocaloric diet. Subjects were randomly allocated to either a high protein (1.3 g/kg body weight) or normal protein diet (0.8 g/kg), with or without a resistance exercise program 3 times/week. FFM was assessed by air displacement plethysmography. RESULTS: At baseline, mean (±SD) BMI was 32 ± 4 kg/m2. During intervention, protein intake was 1.13 ± 0.35 g/kg in the high protein groups vs. 0.98 ± 0.29 in the normal protein groups, which reflects a 16.3 ± 5.2 g/d higher protein intake in the high protein groups. Both high protein diet and exercise did not significantly affect change in body weight, FFM and fat mass (FM). No significant protein*exercise interaction effect was observed for FFM. However, within-group analysis showed that high protein in combination with exercise significantly increased FFM (+0.6 ± 1.3 kg, p = 0.011). CONCLUSION: A high protein diet, though lower than targeted, did not significantly affect changes in FFM during modest weight loss in older overweight and obese adults. There was no significant interaction between the high protein diet and resistance exercise for change in FFM. However, only the group with the combined intervention of high protein diet and resistance exercise significantly increased in FFM. TRIAL REGISTRATION: Dutch Trial Register, number NTR4556, date 05-01-2014.

A high whey protein-, leucine-, and vitamin D-enriched supplement preserves muscle mass during intentional weight loss in obese older adults: a double-blind randomized controlled trial.

BACKGROUND: Intentional weight loss in obese older adults is a risk factor for muscle loss and sarcopenia. OBJECTIVE: The objective was to examine the effect of a high whey protein-, leucine-, and vitamin D-enriched supplement on muscle mass preservation during intentional weight loss in obese older adults. DESIGN: We included 80 obese older adults in a double-blind randomized controlled trial. During a 13-wk weight loss program, all subjects followed a hypocaloric diet (-600 kcal/d) and performed resistance training 3×/wk. Subjects were randomly allocated to a high whey protein-, leucine-, and vitamin D-enriched supplement including a mix of other macro- and micronutrients (150 kcal, 21 g protein; 10×/wk, intervention group) or an isocaloric control. The primary outcome was change in appendicular muscle mass. The secondary outcomes were body composition, handgrip strength, and physical performance. Data were analyzed by using ANCOVA and mixed linear models with sex and baseline value as covariates. RESULTS: At baseline, mean ± SD age was 63 ± 5.6 y, and body mass index (in kg/m(2)) was 33 ± 4.4. During the trial, protein intake was 1.11 ± 0.28 g · kg body weight(-1) · d(-1) in the intervention group compared with 0.85 ± 0.24 g · kg body weight(-1) · d(-1) in the control group (P < 0.001). Both intervention and control groups decreased in body weight (-3.4 ± 3.6 kg and -2.8 ± 2.8 kg; both P < 0.001) and fat mass (-3.2 ± 3.1 kg and -2.5 ± 2.4 kg; both P < 0.001), with no differences between groups. The 13-wk change in appendicular muscle mass, however, was different in the intervention and control groups [+0.4 ± 1.2 kg and -0.5 ± 2.1 kg, respectively; ß = 0.95 kg (95% CI: 0.09, 1.81); P = 0.03]. Muscle strength and function improved over time without significant differences between groups. CONCLUSION: A high whey protein-, leucine-, and vitamin D-enriched supplement compared with isocaloric control preserves appendicular muscle mass in obese older adults during a hypocaloric diet and resistance exercise program and might therefore reduce the risk of sarcopenia. This trial was registered at the Dutch Trial Register (http://www.trialregister.nl) as NTR2751.

Application of a [13CO2] breath test to study short-term amino acid catabolism during the postprandial phase of a meal.

A [13CO2] breath test was applied as a non-invasive method to study the catabolism of ingested amino acids shortly after a meal. This test requires the ingestion of a [1-13C]-labelled amino acid and the analysis of expired air for [13C] enrichment and CO2. The recovery of label as [13CO2] reflects the catabolism of the [1-13C]-labelled substrate. Such a non-steady state approach provides information that is complementary to the information obtained by steady-state methods using a primed continuous infusion of tracer amino acids during the fed state. In a model study with twenty adult male rats, two groups of animals were fed twice a day with one of two semi-synthetic iso-energetic diets. One diet contained egg white protein (EW) as the sole amino acid source. The second diet contained a mixture of free amino acids with a pattern similar to that of the EW diet. On day 5 of the dietary treatment, L-[1-13C]leucine, either bound in EW protein or in free form, was ingested as part of the morning meal. The expired air was sampled at 30 min intervals for 5 h. The rate of recovery ranged from 0% to 6% of the dose/h. Up to 120 min after the onset of the meal, the recovery values for the free amino acid diet were higher than those for the EW diet. Differences in recovery reflect differences in postprandial utilisation. The differences in label recovery were mainly determined by the [13C] enrichment of the expired air. As a consequence, CO2 measurements are not mandatory when CO2 production is comparable.