Validation of bioelectrical impedance analysis for estimating limb lean mass in free-living Caucasian elderly people.

BACKGROUND & AIMS: Aging is characterized by a loss of limb lean mass (LLM) that can lead to physical disability and death. Regional bioelectrical impedance analysis (BIA) may be a reliable method for estimating LLM, but no prediction equations are available for elderly Caucasian subjects. The aim of this study was to develop and validate a BIA-based equation for predicting LLM in healthy elderly Caucasians, taking dual X-ray absorptiometry (DXA) as the reference method. METHODS: Using a cross-sectional design, 244 free-living healthy Caucasian subjects (117 men, 179 women) over 60 years of age were enrolled. LLM was measured with DXA (LLMDXA), and the resistance (Rz) and reactance (Xc) of each limb were measured with a regional bioelectrical impedance analyzer. A resistive index (RI) was calculated from stature in meters divided by Rz of each arm. A BIA-based multiple regression equation for predicting the lean mass (LM) of dominant and non-dominant limbs was developed using a double cross-validation technique. RESULTS: Using the sample as a whole, cross-validation resulted in an equation specific for each limb, as follows, where sex equals 1 for males, and 0 for females: LM (kg) = -0.081 + (0.061*RI) + (0.010*body weight) + (0.299*sex) for the dominant arm; LM (kg) = -0.026 + (0.014*RI) + (0.009*body weight) + (0.352*sex) for the non-dominant arm; LM (kg) = -0.462 + (0.027*RI) + (0.047*body weight) + (0.639*sex) + (0.026*Xc) for the dominant leg; and for the non-dominant leg, LM (kg) = -0.522 + (0.029*RI) + (0.045*body weight) + (0.569*sex) + (0.025*Xc). The DXA-measured and BIA-predicted LLM for each limb did not differ significantly. CONCLUSION: Our newly-developed BIA equations seem to provide a valid estimation of LLM in older Caucasian adults.

Taste loss in the elderly: Possible implications for dietary habits.

Aging may coincide with a declining gustatory function that can affect dietary intake and ultimately have negative health consequences. Taste loss is caused by physiological changes and worsened by events often associated with aging, such as polypharmacy and chronic disease. The most pronounced increase in elderly people's detection threshold has been observed for sour and bitter tastes, but their perception of salty, sweet, and umami tastes also seems to decline with age. It has often been suggested that elderly people who lose their sense of taste may eat less food or choose stronger flavors, but the literature has revealed a more complicated picture: taste loss does not appear to make elderly people prefer stronger flavors, but nutrition surveys have pointed to a greater consumption of sweet and salty foods. Real-life eating habits thus seem to be more influenced by other, social and psychological factors. Elderly gustatory function is worth investigating to identify dietary strategies that can prevent the consequences of unhealthy eating habits in the elderly. This paper discusses age-related changes in taste perception, focusing on their consequences on food preferences, and pointing to some strategies for preserving appropriate dietary habits in elderly people.

Effect of Oral Beta-Hydroxy-Beta-Methylbutyrate (HMB) Supplementation on Physical Performance in Healthy Old Women Over 65 Years: An Open Label Randomized Controlled Trial.

UNLABELLED: Although older people are particularly liable to sarcopenia, limited research is available on beta-hydroxy-beta-methylbutyrate (HMB) supplementation in this population, particularly in healthy subjects. In this parallel-group, randomized, controlled, open-label trial, we aimed to evaluate whether an oral supplement containing 1.5 g of calcium HMB for 8 weeks could improve physical performance and muscle strength parameters in a group of community-dwelling healthy older women. Eighty healthy women attending a twice-weekly mild fitness program were divided into two equal groups of 40, and 32 of the treated women and 33 control completed the study. We considered a change in the Short Physical Performance Battery (SPPB) score as the primary outcome and changes in the peak torque (PT) isometric and isokinetic strength of the lower limbs, 6-minute walking test (6MWT), handgrip strength and endurance as secondary outcomes. Body composition was assessed with dual-energy X-ray absorptiometry (DXA) and peripheral quantitative computerized tomography (pQCT). The mean difference between the two groups on pre-post change were finally calculated (delta) for each outcome. After 8 weeks, there were no significant differences between the groups' SPPB, handgrip strength or DXA parameters. The group treated with HMB scored significantly better than the control group for PT isokinetic flexion (delta = 1.56±1.56 Nm; p = 0.03) and extension (delta = 3.32±2.61 Nm; p = 0.03), PT isometric strength (delta = 9.74±3.90 Nm; p = 0.02), 6MWT (delta = 7.67±8.29 m; p = 0.04), handgrip endurance (delta = 21.41±16.28 s; p = 0.02), and muscle density assessed with pQCT. No serious adverse effects were reported in either group. In conclusion, a nutritional supplement containing 1.5 g of calcium HMB for 8 weeks in healthy elderly women had no significant effects on SPPB, but did significantly improve several muscle strength and physical performance parameters. TRIAL REGISTRATION: ClinicalTrials.gov NCT02118181.

Effect of oral magnesium supplementation on physical performance in healthy elderly women involved in a weekly exercise program: a randomized controlled trial.

BACKGROUND: Magnesium deficiency is associated with poor physical performance, but no trials are available on how magnesium supplementation affects elderly people's physical performance. OBJECTIVE: The aim of our study was to investigate whether 12 wk of oral magnesium supplementation can improve physical performance in healthy elderly women. DESIGN: In a parallel-group, randomized controlled trial, 139 healthy women (mean ± SD age: 71.5 ± 5.2 y) attending a mild fitness program were randomly allocated to a treatment group (300 mg Mg/d; n = 62) or a control group (no placebo or intervention; n = 77) by using a computer-generated randomization sequence, and researchers were blinded to their grouping. After assessment at baseline and again after 12 wk, the primary outcome was a change in the Short Physical Performance Battery (SPPB); secondary outcomes were changes in peak torque isometric and isokinetic strength of the lower limbs and handgrip strength. RESULTS: A total of 124 participants allocated to the treatment (n = 53) or control (n = 71) group were considered in the final analysis. At baseline, the SPPB scores did not differ between the 2 groups. After 12 wk, the treated group had a significantly better total SPPB score (Δ = 0.41 ± 0.24 points; P = 0.03), chair stand times (Δ = -1.31 ± 0.33 s; P < 0.0001), and 4-m walking speeds (Δ = 0.14 ± 0.03 m/s; P = 0.006) than did the control group. These findings were more evident in participants with a magnesium dietary intake lower than the Recommended Dietary Allowance. No significant differences emerged for the secondary outcomes investigated, and no serious adverse effects were reported. CONCLUSIONS: Daily magnesium oxide supplementation for 12 wk seems to improve physical performance in healthy elderly women. These findings suggest a role for magnesium supplementation in preventing or delaying the age-related decline in physical performance.