Impact of nutrition on muscle mass, strength, and performance in older adults

Muscle strength plays an important role in determining risk for falls, which result in fractures and other injuries. While bone loss has long been recognized as an inevitable consequence of aging, sarcopenia—the gradual loss of skeletal muscle mass and strength that occurs with advancing age—has recently received increased attention. A review of the literature was undertaken to identify nutritional factors that contribute to loss of muscle mass. The role of protein, acid–base balance, vitamin D/calcium, and other minor nutrients like B vitamins was reviewed. Muscle wasting is a multifactorial process involving intrinsic and extrinsic alterations. A loss of fast twitch fibers, glycation of proteins, and insulin resistance may play an important role in the loss of muscle strength and development of sarcopenia. Protein intake plays an integral part in muscle health and an intake of 1.0–1.2 g/kg of body weight per day is probably optimal for older adults. There is a moderate inverse relationship between vitamin D status and muscle strength. Chronic ingestion of acid-producing diets appears to have a negative impact on muscle performance, and decreases in vitamin B₁₂ and folic acid intake may also impair muscle function through their action on homocysteine. An adequate nutritional intake and an optimal dietary acid–base balance are important elements of any strategy to preserve muscle mass and strength during aging.     

Morbidity of Focal Therapy in the Treatment of Localized Prostate Cancer

Background

Focal therapy (FT) for prostate cancer (PCa) seems to be part of a natural evolution in the quest to improve the management of early organ-confined disease.

Objective

To assess the morbidity of the initial experience of FT in a tertiary referral center for PCa management.

Design, setting, and participants

From 2009 to 2011, a total of 1213 patients with clinically localized PCa were treated at our institution. Of these patients, 547 were considered to have indolent disease according to the D’Amico criteria for low-risk disease plus unilateral disease with a maximum of three positive biopsies. A total of 106 patients underwent FT using high-intensity focused ultrasonography (HIFU), brachytherapy, cryotherapy, or vascular-targeted photodynamic therapy (VTP).

Outcome measurements and statistical analysis

Complications were prospectively recorded and graded according to the Clavien-Dindo scale. Data were prospectively collected and retrospectively analyzed.

Results and limitations

This study included 106 patients, median age 66.5 yr (interquartile range [IQR]): 61–73), who had a prostate hemiablation; 50 patients (47%) had cryotherapy, 23 patients (22%) had VTP, 21 patients (20%) received HIFU, and 12 patients (11%) had brachytherapy. The median prostate-specific antigen (PSA) level was 6.1 ng/ml (IQR: 5–8.1), all the patients had a biopsy Gleason score of 6, and the median prostate weight was 43 g (IQR: 33–55). The median International Prostate Symptom Score was 6 (IQR: 3–10), and the median International Index of Erectile Function score was 20 (IQR: 15–23). After treatment, the median PSA at 3, 6, and 12 mo was 3.1 2.9, and 2.7 ng/ml (IQR: 2–5.1, 1.1–4.7, and 1–4.4), respectively. Thirteen percent of the patients experienced treatment-related complications. There were 11 minor medical complications (10 grade 1 complications and 1 grade 2 complication), 2 grade 3 complications, and no grade 4 or higher complications.

Conclusions

FT for a highly selected population with PCa is feasible and had an acceptable morbidity with <2% major complications.     

Changes in nutrient intake and inflammation following an anti-inflammatory diet in spinal cord injury

Objective: The objective of the current study was to describe the observed changes in nutrient intakes following a 3-month anti-inflammatory diet, and to explore potential relationships between the change in nutrients and the change in various inflammatory mediators.

Design: A secondary analysis of a prior randomized controlled clinical trial.

Setting: Individuals with SCI within the Niagara region.

Participants: Twenty individuals with various levels and severities of SCI.

Intervention: Three-month anti-inflammatory diet.

Outcome Measures: The change in nutrient intake and corresponding changes to various inflammatory mediators.

Results: The treatment group demonstrated a significant reduction in fat intake (P?=?0.02), a significant increase in protein intake (P?=?0.02), and no change in carbohydrates (P?=?0.23) or energy intake (P?=?0.10). The treatment group showed a significant increase in some nutrients with established anti-inflammatory properties including vitamins A, C, and E, and omega-3 fatty acids (P?<?0.01). Significant reductions in proinflammatory nutrients were observed including trans fatty acids (P?=?0.05), caffeine (P?<?0.01), and sodium (P?=?0.02). The treatment group also showed significant reductions in the proinflammatory mediators interferon-y (P?=?0.01), interleukin-1β (P?<?0.01), and interleukin-6 (P?<?0.05). Further, several proinflammatory mediators were negatively correlated with anti-inflammatory nutrients, including vitamin A, carotenoids, omega-3 fatty acids, and zinc.

Conclusion: This study provides evidence that dietary alterations are effective at reducing chronic inflammation in individuals with SCI and provides a preliminary assessment of the related nutrient changes.     

Age-related differences in attentional cost associated with postural dual tasks: Increased recruitment of generic cognitive resources in older adults

Dual-task designs have been used widely to study the degree of automatic and controlled processing involved in postural stability of young and older adults. However, several unexplained discrepancies in the results weaken this literature. To resolve this problem, a careful selection of dual-task studies that met certain methodological criteria are considered with respect to reported interactions of age (young vs. older adults) × task (single vs. dual task) in stable and unstable postural conditions. Our review shows that older adults are able to perform a postural dual task as well as younger adults in stable conditions. However, when the complexity of the postural task is increased by dynamic conditions (surface and surround), performance in postural, concurrent, or both tasks is more affected in older relative to young adults. In light of neuroimaging studies and new conceptual frameworks, these results demonstrate an age-related increase of controlled processing of standing associated with greater intermittent adjustments.     

A comparative study of performance in simple and choice reaction time tasks between obese and healthy-weight children

This study investigated weight status related differences in executive functions and movement execution to determine whether or not childhood obesity is associated with impaired perceptual-motor function. Nineteen obese (OB) children (10 ♂ and 9 ♀, aged 6–12 years) and nineteen gender and age matched healthy-weight (HW) peers performed two computer-based reaction time tasks. For both the simple and four choice reaction time (SRT/CRT) task condition, absolute mean reaction time (RT) and movement time (MT) were determined and expressed as a percentage of total response time (RsT). During the SRT task, OB children were intrinsically slower than their HW peers as reflected by a significantly higher absolute RT, MT and RsT. In the CRT task, however, between-group differences were only present for RT and RsT, whereas absolute MT was comparable among OB and HW participants. As a result, the relative temporal structure of RsT significantly differed between BMI groups, with a greater RT percentage among the OB children. During the CRT condition, OB children probably await final decision-making with regard to the execution of their response movement, which then no longer needs to be adjusted. Our results therefore indicate the use of a more conservative strategy within the OB group, suggesting that childhood obesity is associated with impaired perceptual-motor function. Besides the widely accepted mechanical explanation, a better understanding of the mechanisms underlying OB children's motor incompetence is needed to set up appropriate interventions to tackle this deficit and indirectly address associated health-related problems.     

Inter-individual variability in sensory weighting of a plantar pressure-based, tongue-placed tactile biofeedback for controlling posture

The purpose of the present experiment was to investigate whether the sensory weighting of a plantar pressure-based, tongue-placed tactile biofeedback for controlling posture could be subject to inter-individual variability. To achieve this goal, 60 young healthy adults were asked to stand as immobile as possible with their eyes closed in two conditions of No-biofeedback and Biofeedback. Centre of foot pressure (CoP) displacements were recorded using a force platform. Overall, results showed reduced CoP displacements in the Biofeedback relative to the No-biofeedback condition, evidencing the ability of the central nervous system to efficiently integrate an artificial plantar-based, tongue-placed tactile biofeedback for controlling posture during quiet standing. Results further showed a significant positive correlation between the CoP displacements measured in the No-biofeedback condition and the decrease in the CoP displacements induced by the use of the biofeedback. In other words, the degree of postural stabilization appeared to depend on each subject's balance control capabilities, the biofeedback yielding a greater stabilizing effect in subjects exhibiting the largest CoP displacements when standing in the No-biofeedback condition. On the whole, by evidencing a significant inter-individual variability in sensory weighting of an additional tactile information related to foot sole pressure distribution for controlling posture, the present findings underscore the need and the necessity to address the issue of inter-individual variability in the field of neuroscience.     

Preorthographical constraints on visual word recognition: evidence from a case study of developmental surface dyslexia

We investigated the visual word recognition ability of M.T., a young boy with surface dyslexia, by means of a paradigm that measures performance as a function of the eye fixation position within the word, known as the "viewing-position effect" paradigm. In well-achieving readers, the viewing-position effect is mainly determined by factors affecting letter visibility and by lexical constraints on word recognition. We further quantified M.T.'s sensory limitations on letter visibility by computing visual-span profiles - that is, the number of letters recognizable at a glance. Finally, in an ideal-observer's perspective, M.T.'s performance was compared with a parameter-free model combining M.T.'s letter visibility data with a simple lexical matching rule. The results showed that M.T. did not use the whole visual information available on letter identities to recognize words and that preorthographical factors constrained his word recognition performance. The results can be best accounted for by a reduction of the number of letters processed in parallel.