Efficacy of β-hydroxy-β-methylbutyrate supplementation in elderly and clinical populations

A Prospective, Observational Study of the Effect of a High-Calorie, High-Protein Oral Nutritional Supplement with HMB in an Old and Malnourished or at-Risk-of-Malnutrition Population with Hip Fractures: A FracNut Study

BACKGROUND

Hip fractures are prevalent among older people, often leading to reduced mobility, muscle loss, and bone density decline. Malnutrition exacerbates the prognosis post surgery. This study aimed to evaluate the impact of a 12-week regimen of a high-calorie, high-protein oral supplement with β-hydroxy-β-methylbutyrate (HC-HP-HMB-ONS) on nutritional status, daily activities, and compliance in malnourished or at-risk older patients with hip fractures receiving standard care.

SUBJECTS AND METHODS

A total of 270 subjects ≥75 years of age, residing at home or in nursing homes, malnourished or at risk of malnutrition, and post hip fracture surgery, received HC-HP-HMB-ONS for 12 weeks. Various scales and questionnaires assessed outcomes.

RESULTS

During the 12 weeks of follow-up, 82.8% consumed ≥75% of HC-HP-HMB-ONS. By week 12, 62.4% gained or maintained weight (+0.3 kg), 29.2% achieved normal nutritional status (mean MNA score +2.8), and 46.8% improved nutritional status. Biochemical parameters improved significantly. Subjects reported good tolerability (mean score 8.5/10), with 87.1% of healthcare providers concurring.

CONCLUSIONS

The administration of HC-HP-HMB-ONS markedly enhanced nutritional status and biochemical parameters in older hip-fracture patients, with high compliance and tolerability. Both patients and healthcare professionals expressed satisfaction with HC-HP-HMB-ONS.

Combined Exercise Training and Nutritional Interventions or Pharmacological Treatments to Improve Exercise Capacity and Body Composition in Chronic Obstructive Pulmonary Disease: A Narrative Review

Chronic obstructive pulmonary disease (COPD) is a chronic respiratory disease that is associated with significant morbidity, mortality, and healthcare costs. The burden of respiratory symptoms and airflow limitation can translate to reduced physical activity, in turn contributing to poor exercise capacity, muscle dysfunction, and body composition abnormalities. These extrapulmonary features of the disease are targeted during pulmonary rehabilitation, which provides patients with tailored therapies to improve the physical and emotional status. Patients with COPD can be divided into metabolic phenotypes, including cachectic, sarcopenic, normal weight, obese, and sarcopenic with hidden obesity. To date, there have been many studies performed investigating the individual effects of exercise training programs as well as nutritional and pharmacological treatments to improve exercise capacity and body composition in patients with COPD. However, little research is available investigating the combined effect of exercise training with nutritional or pharmacological treatments on these outcomes. Therefore, this review focuses on exploring the potential additional beneficial effects of combinations of exercise training and nutritional or pharmacological treatments to target exercise capacity and body composition in patients with COPD with different metabolic phenotypes.

Does β-Hydroxy-β-Methylbutyrate Have Any Potential to Support the Treatment of Duchenne Muscular Dystrophy in Humans and Animals?

Skeletal muscle is the protein reservoir of our body and an important regulator of glucose and lipid homeostasis. The dystrophin gene is the largest gene and has a key role in skeletal muscle construction and function. Mutations in the dystrophin gene cause Duchenne and Becker muscular dystrophy in humans, mice, dogs, and cats. Duchenne muscular dystrophy (DMD) is an X-linked neuromuscular condition causing progressive muscle weakness and premature death. β-hydroxy β-methylbutyrate (HMB) prevents deleterious muscle responses under pathological conditions, including tumor and chronic steroid therapy-related muscle losses. The use of HMB as a dietary supplement allows for increasing lean weight gain; has a positive immunostimulatory effect; is associated with decreased mortality; and attenuates sarcopenia in elderly animals and individuals. This study aimed to identify some genes, metabolic pathways, and biological processes which are common for DMD and HMB based on existing literature and then discuss the consequences of that interaction.

Nutrition and Exercise Treatment of Sarcopenia in Hip Fracture Patients: Systematic Review

Background

This study aimed to investigate nutritional or rehabilitation intervention protocols for hip fracture patients with sarcopenia and to analyze the effect of these protocols through a systematic review of studies that reported clinical results.

Methods

Studies were selected based on the following criteria: (1) study design: randomized controlled trials or non-randomized comparative studies; (2) study population: patients with hip fracture; (3) intervention: nutritional or rehabilitation; and (4) reporting the clinical outcomes and definition of sarcopenia.

Results

Of the 247 references initially identified from the selected databases, 5 randomized controlled studies and 2 comparative studies were selected for further investigation. The total number of patients was 497. We found 2 specific rehabilitation interventions, one medication intervention using erythropoietin, and 4 nutritional interventions using amino-acid or protein. Among the studies included in this systematic review, 2 studies did not find a clear statistical difference in assessment tools compared to controls after intervention. On the other hand, the rest of the studies positively interpreted the results for intervention. The most frequently used assessment tool for intervention was handgrip strength.

Conclusions

Although mainstream methods of intervention for sarcopenia include nutritional, exercise, and drug interventions, the validity of these interventions in elderly hip fractures has not been clearly proven. In addition, as most studies only reported short-term results, there is no consensus on the optimal long-term treatment.

Revisiting Cancer Cachexia: Pathogenesis, Diagnosis, and Current Treatment Approaches

The objective of this article is to group together various management strategies and to highlight the recent treatment modifications that attempt to target the multimodal etiological factors involved in cancer cachexia. The contemporary role of nursing fraternity in psychosocial and nutritional assessment of cancer patients is briefly discussed. Cachexia is a syndrome of metabolic disturbance, characterized by the inflammation and loss of muscle with or without loss of adipose tissue. In cancer cachexia, a multifaceted condition, patients suffer from loss of body weight that leads to a negative impact on the quality of life and survival of the patients. The main cancers associated with cachexia are that of pancreas, stomach, lung, esophagus, liver, and that of bowel. The changes include increased proteolysis, lipolysis, insulin resistance, high energy expenditure, and reduced intake of food, all leading to impaired response to different treatments. There is no standardized treatment for cancer cachexia that can stabilize or reverse this complex metabolic disorder at present. The mainstay of cancer cachexia therapy remains to be sufficient nutritional supplements with on-going efforts to explore the drugs that target heightened catabolic processes and complex inflammation. There is a need to develop a multimodal treatment approach combining pharmacology, exercise program, and nutritional support to target anorexia and the severe metabolic changes encountered in cancer cachexia.

How to Increase Muscle Mass in Critically Ill Patients: Lessons Learned from Athletes and Bodybuilders

PURPOSE OF REVIEW

Decades of research on nutrition and exercise on athletes and bodybuilders has yielded various strategies to promote anabolism and improve muscle health and growth. We reviewed these interventions in the context of muscle loss in critically ill patients.

RECENT FINDINGS

For critically ill patients, ensuring optimum protein intake is important, potentially using a whey-containing source and supplemented with vitamin D and leucine. Agents like hydroxyl β-methylbutyrate and creatine can be used to promote muscle synthesis. Polyunsaturated fatty acids stimulate muscle production as well as have anti-inflammatory properties that may be useful in critical illness. Adjuncts like oxandralone promote anabolism. Resistance training has shown mixed results in the ICU setting but needs to be explored further with specific outcomes. Critically ill patients suffer from severe proteolysis during hospitalization as well as persistent inflammation, immunosuppression, and catabolism syndrome after discharge. High protein supplementation, ergogenic aids, anti-inflammatories, and anabolic adjuncts have shown potential in alleviating muscle loss and should be used in intensive care units to optimize patient recovery.

A multimodal approach to cancer-related cachexia: from theory to practice

Introduction: Cachexia represents a relevant issue in oncological care, which is still lacking effective therapies. Although the incidence of cancer cachexia varies across cancer types, it is responsible for approximately a quarter of cancer-related deaths. The pathophysiology of this syndrome is multifactorial, including weight loss, muscle atrophy and impairment of the pro-/anti-inflammatory balance.Areas covered: Diagnostic criteria and optimal endpoints for cachexia-dedicated trials are still debated, slowing the identification of interventions counteracting cachexia sequaele. The multifaceted features of this syndrome support the rationale for personalized therapy. A multimodal approach is likely to offer the best option to address key cachexia-related issues. Pharmacologic agents, physical exercise, nutritional and psycho-social interventions may have a synergistic effect, and improve quality of life.Expert opinion: A personalized multimodal intervention could be the best strategy to effectively manage cancer cachexia. To offer such a comprehensive approach, a specialized staff, including health professionals with different expertise, is necessary. Each specialist plays a specific role inside the multimodal intervention, with the aim of delivering the best cancer care and access to the most effective therapeutic options for each patient.

Higher Branched-Chain Amino Acid Intake Is Associated with Handgrip Strength among Korean Older Adults

Sarcopenia is a disease of old age characterized by decreased muscle mass and strength. Branched-chain amino acids (BCAAs) promote muscle mass synthesis and increase muscle strength. We aimed to develop a dietary amino acid database and to examine the association between BCAA intake and handgrip strength in Korean older adults. Data from the Korea National Health and Nutrition Examination Survey 2014–2018 were used. Overall, 4852 participants aged ≥65 years were included in the study. Demographic, lifestyle, and health data were obtained through interviews and questionnaires. The 24-h recall method was used to assess dietary intake. An amino acid database was established using the 9th revision of the Korean Standard Food Composition Table. The mean handgrip strength was estimated from triplicate measurements obtained using the dominant hand. Multivariable linear regression analysis was performed to assess the association between BCAA intake and handgrip strength. Grains greatly contributed to amino acid intake; however, a significant negative association was observed between handgrip strength and increased BCAA intake through grains. In the fully adjusted model, leucine intake and handgrip strength showed a positive association. Thus, consuming BCAAs (especially leucine) via a variety of food sources can help maintain muscle health in older people.

Oral Nutritional Supplement with β-hydroxy-β-methylbutyrate (HMB) Improves Nutrition, Physical Performance and Ameliorates Intramuscular Adiposity in Pre-Frail Older Adults: A Randomized Controlled Trial

OBJECTIVES

Supplementation of high protein oral nutrition shakes supplemented with β-hydroxy-β-methylbutyrate (HP-HMB) has been shown to improve muscle mass, muscle strength, and physical performance in older adults, but the roles of HP-HMB supplementation on the intramuscular adiposity remained unknown. This 12-week randomized controlled trial evaluated the changes of muscle mass, muscle strength, physical performance and intramuscular adiposity among community-dwelling pre-frail older persons.

METHODS

This was an open-label, parallel group, randomized controlled trail that enrolled 70 community-dwelling pre-frail older persons without active or uncontrolled conditions, disability or dementia. The intervention group was provided with two services of HP HMB (Ensure® Plus Advance containing 3g HMB) per day for 12 weeks, and the control group was provided with professional nutritional counselling for sufficient protein intake. All participants received functional assessments, laboratory tests and magnetic resonance imaging (MRI) of the dominant leg before and after study. Intramuscular adipose tissue (IMAT) and the mid-thigh cross-sectional area (CSA) of muscle were obtained by MRI, and the IMAT-to-CSA ratio was calculated to evaluate intramuscular adiposity.

RESULTS

Overall, 62 participants (mean age: 71.1±3.8 years, 69.4% female) completed the study (HP-HMB group: 29, control group: 33) and comparisons of baseline characteristics between groups were not statistically different. For the primary outcome, HP-HMB group showed significant improvements in the CSA of mid-thigh muscle (mean increase of CSA: 149.1±272.3 for HMB group vs -22.9±309.1 mm2 for control group, P=0.045). The improvement of MNA-SF was borderline (0.28±0.75 vs. -0.15±0.94, P=0.064), but serum levels of Vit D were significantly increased in the HMB group (3.83±8.18 vs. -1.30±4.81 ng/mL, P=0.002). Moreover, the body weight and BMI were significantly increased in the HMB group (1.10±1.18 vs. 0.24±1.13 kg, P=0.005; 0.56±0.68 vs. 0.22±0.47 kg/m2, P=0.019). In particular, the IMAT-to-CSA ratio was reduced in the HMB group (-0.38±1.21 vs. -0.02±2.56 %, P=0.06). Using the generalized estimating equation, we found that SPPB score in chair rise test was significantly improved (β=0.71, 95% C.I.0.09-1.33, P=0.026).

CONCLUSIONS

The 12-week supplementation with high protein oral nutrition shake supplemented with 3g HMB per day significantly increased muscle mass, as well as nutritional status and physical performance, and ameliorated the intramuscular adiposity of pre-frail older persons. Further study is needed to explore the long-term benefits of HP-HMB supplementation on muscle and metabolic health for older adults.

Cancer cachexia and skeletal muscle atrophy in clinical studies: what do we really know?

Research investigators have shown a growing interest in investigating alterations underlying skeletal muscle wasting in patients with cancer. However, skeletal muscle dysfunctions associated with cancer cachexia have mainly been studied in preclinical models. In the present review, we summarize the results of clinical studies in which skeletal muscle biopsies were collected from cachectic vs. non-cachectic cancer patients. Most of these studies suggest the presence of significant physiological alterations in skeletal muscle from cachectic cancer patients. We suggest a hypothesis, which connects structural and metabolic parameters that may, at least in part, be responsible for the skeletal muscle atrophy characteristic of cancer cachexia. Finally, we discuss the importance of a better standardization of the diagnostic criteria for cancer cachexia, as well as the requirement for additional clinical studies to improve the robustness of these conclusions.

Dietary Amino Acids and Immunonutrition Supplementation in Cancer-Induced Skeletal Muscle Mass Depletion: A Mini-Review

Cancer patients display systemic inflammation, which leads to an increase in protein catabolism, thus promoting the release of free amino acids to further support metabolism and remodelling of muscle proteins. Inflammation associated with tumor growth leads to malnutrition, a factor that increases the risk of developing cachexia. With cancer-induced cachexia, nutritional interventions have gained traction as a preventative method to manage this condition. Currently, cancer consensus recommendations suggest a protein intake above 1.0 g/kg.day-1 up to 2.0 g/k.day-1 for cancer patients, although an ideal amount for some amino acids in isolation has yet to be determined. Due to controversy in the literature regarding the benefits of the biochemical mechanisms of various muscle mass supplements, such as L-leucine (including whey protein and BCAA), β-hydroxy-beta-methyl butyrate (HMβ), arginine, glutamine and creatine, several studies have carefully examined their effects. L-leucine and its derivatives appear to regulate protein synthesis by direct or indirect activation of the mTORC1 pool of kinases, further promoting muscle protein balance. Arginine and glutamine may act by reducing inflammation and infection progression, thus promoting improvements in food intake. Creatine exerts anabolic activity, acting as an immediate energy substrate to support muscle contraction further increasing lean mass, mainly due to greater water uptake by the muscle. In this narrative review, we highlighted the main findings regarding protein consumption and amino acids to mitigate cancer-induced skeletal muscle depletion.

Nutritional interventions for reducing the signs and symptoms of exercise-induced muscle damage and accelerate recovery in athletes: current knowledge, practical application and future perspectives

PURPOSE

This review provides an overview of the current knowledge of the nutritional strategies to treat the signs and symptoms related to EIMD. These strategies have been organized into the following sections based upon the quality and quantity of the scientific support available: (1) interventions with a good level of evidence; (2) interventions with some evidence and require more research; and (3) potential nutritional interventions with little to-no-evidence to support efficacy.

METHOD

Pubmed, EMBASE, Scopus and Web of Science were used. The search terms 'EIMD' and 'exercise-induced muscle damage' were individually concatenated with 'supplementation', 'athletes', 'recovery', 'adaptation', 'nutritional strategies', hormesis'.

RESULT

Supplementation with tart cherries, beetroot, pomegranate, creatine monohydrate and vitamin D appear to provide a prophylactic effect in reducing EIMD. β-hydroxy β-methylbutyrate, and the ingestion of protein, BCAA and milk could represent promising strategies to manage EIMD. Other nutritional interventions were identified but offered limited effect in the treatment of EIMD; however, inconsistencies in the dose and frequency of interventions might account for the lack of consensus regarding their efficacy.

CONCLUSION

There are clearly varying levels of evidence and practitioners should be mindful to refer to this evidence-base when prescribing to clients and athletes. One concern is the potential for these interventions to interfere with the exercise-recovery-adaptation continuum. Whilst there is no evidence that these interventions will blunt adaptation, it seems pragmatic to use a periodised approach to administering these strategies until data are in place to provide and evidence base on any interference effect on adaptation.

Cancer Cachexia: Definition, Staging, and Emerging Treatments

Cachexia is a multifactorial disease characterized by weight loss via skeletal muscle and adipose tissue loss, an imbalance in metabolic regulation, and reduced food intake. It is caused by factors of catabolism produced by tumors in the systemic circulation as well as physiological factors such as the imbalanced inflammatory activation, proteolysis, autophagy, and lipolysis that may occur with gastric, pancreatic, esophageal, lung cancer, liver, and bowel cancer. Cancer cachexia not only negatively affects the quality of life of patients with cancer but also reduces the effectiveness of anti-cancer chemotherapy and increases its toxicity, leading to increased cancer-related mortality and expenditure of medical resources. Currently, there are no effective medical interventions to completely reverse cachexia and no approved drugs. Adequate nutritional support is the main method of cachexia treatment, while drugs that target the inhibition of catabolism, cell damage, and excessive activation of inflammation are under study. This article reviews recent advances in the diagnosis, staging, and evaluation of cancer cachexia.

Surface analysis of etched enamel modified during the prenatal period

Structural changes in the enamel surface subjected to induced demineralization and assessment of the influence of prenatal administration of β-hydroxy β-methylbutyrate (HMB) on enamel resistance were investigated. The examination was conducted on five sets of teeth from one-day-old spiny mice (Acomys cahirinus), one from the control and four from the experimental groups. Surface structure, molecular arrangement and crystalline organization of offspring's enamel both before and after etching were studied. Obtained results revealed that the physical and molecular arrangements of enamel were altered after the prenatal supplementation, and significantly affected its final structure and resistance against acid action. The enamel of incisors from the offspring which mothers were supplemented with HMB in a high dose (0.2 g/kg_bw) and in the late period of gestation (26th-39th day) showed the highest endurance against acid treatment demonstrating only vestigial changes in their surface structure after acid action. Comparing to the remaining experimental groups, it was characterized by a reduced roughness and fractal dimension, significantly lower degree of demineralization and simultaneous lack of notable differences in the Raman spectra before and after acid etching. The results suggest that an increased enamel resiliency was the effect of a relatively high degree of mineralization and higher organization of the surface.

[Sarcopenia and frailty in older patients with rheumatism]

Sarcopenia is an age-related generalized loss of muscle mass and muscle strength resulting in low physical performance, which can be observed in up to 50% of >80-year-old individuals. The consequences are manifold and sarcopenia is closely linked to frailty. Important risk factors are genetics/epigenetics, immobilization, malnutrition and anorexia, hormone deficiencies, chronic inflammation and raised levels of inhibitory factors of tissue regeneration. Thus, functional assessment of muscle strength and physical performance are central components of diagnosing sarcopenia, beyond the mere quantification of muscle mass. Currently, many interventional strategies are being tested, including exercise regimens, nutrition programs, hormone replacement and pharmacological strategies involving anabolic principles. According to the current data, training programs and medications have a high potential.

[Nutritional problematic related to frailty and sarcopenia in older]

INTRODUCTION

Introduction: frailty and sarcopenia are prevalent conditions in older adults which diagnosis and treatment often overlap. Objective: to analyze the nutritional problematic related to frailty and sarcopenia in older adults. Methods: a literature review, about particularities of frailty and sarcopenia, diagnosis and nutritional treatment, has been carried out. Results: frailty is a geriatric syndrome that can be identified by at least three of the following criteria: weight loss, exhaustion, reduced physical activity, increased walk time, low grip strength. Sarcopenia is a muscular disease characterized by low muscle mass and reduced muscle strength as the main determinant. Both conditions can benefit from adequate protein intake (1-1.5 g/kg/day) and regular physical activity. Conclusion: identification, prevention, monitoring and nutritional treatment of frailty and sarcopenia in older adults is important because of its high prevalence. The main goal is to maintain the muscular integrity and minimize muscle loss in older adults. A healthy aging includes regular physical activity and the fulfillment of the protein requirements of this population.

Efficacy of Nutritional Interventions as Stand-Alone or Synergistic Treatments with Exercise for the Management of Sarcopenia

Sarcopenia is an age-related and accelerated process characterized by a progressive loss of muscle mass and strength/function. It is a multifactorial process associated with several adverse outcomes including falls, frailty, functional decline, hospitalization, and mortality. Hence, sarcopenia represents a major public health problem and has become the focus of intense research. Unfortunately, no pharmacological treatments are yet available to prevent or treat this age-related condition. At present, the only strategies for the management of sarcopenia are mainly based on nutritional and physical exercise interventions. The purpose of this review is, thus, to provide an overview on the role of proteins and other key nutrients, alone or in combination with physical exercise, on muscle parameters.

Effects of β-hydroxy-β-methylbutyrate (HMB) supplementation in addition to multicomponent exercise in adults older than 70 years living in nursing homes, a cluster randomized placebo-controlled trial: the HEAL study protocol

Background

Evidence supports the fact that multicomponent exercise and HMB supplementation are, separately, effective in improving older adult’s health and palliate functional metabolic diseases in older people. However, the true effect of HMB supplementation combined with a tailored exercise program in frail older adults is still unknown. Thus, the aim of the HEAL (HMB + Exercise = Adults Living longer) study is to assess the effects of the combination of a daily multicomponent exercise and resistance training (VIVIFRAIL program) intervention in addition to HMB supplementation on older adults’ health.

Methods/design

A 24-week cluster randomized, double-blind, placebo-controlled study will be conducted on 104 adults ≥70 years. Nursing homes will be randomized to either of four groups: Ex-HMB (exercise intervention with HMB), Ex-Plac (exercise intervention with placebo), NoEx-HMB (no exercise intervention with HMB), and Controls (No exercise and no HMB). Intervention groups which include exercise will complete the individualized multicomponent (strength, balance and cardiovascular exercises) training program VIVIFRAIL. Intervention groups which include HMB supplementation will receive a 3 g/daily dose of free acid HMB in powder form. The primary outcome measure is the functional capacity. Secondary outcome measures are muscle strength and power, frailty and fall risk, body composition, biochemical analyses and cardiometabolic risk factor, disability and comorbidity, cognitive function and depression.

Discussion

The findings of the HEAL study will help professionals from public health systems to identify cost-effective and innovative actions to improve older people’s health and quality of life, and endorse exercise practice in older adults and people living in nursing homes.

Trial registration

NCT03827499; Date of registration: 01/02/2019.

β-Hydroxy-β-Methylbutyrate Free Acid Attenuates Oxidative Stress Induced by a Single Bout of Plyometric Exercise

PURPOSE

The purpose of this study was to examine the effect of β-hydroxy-β methylbutyrate free acid (HMB-FA) ingestion on oxidative stress and leukocyte responses to plyometric exercise.

METHODS

In a randomized double-blind placebo-controlled design, physically active males were assigned to the HMB-FA (n = 8) or placebo (n = 8) groups that consumed either 1 g of HMB-FA or placebo 30 min prior to performing an acute plyometric exercise protocol (15 sets of 10 repetitions of maximal-effort vertical jumps). Blood was obtained pre-(T1), post-(T2), and 1-h post-(T3) exercise to determine changes in serum levels of 8-hydroxy-2-deoxyguanosine (8-OHdG), malondialdehyde (MDA), protein carbonyl (PC), and white blood cells (WBC).

RESULTS

The exercise protocol significantly elevated 8-OHdG (HMB-FA, T2 9.5 and T3 12.6%; placebo, T2 18.2 and T3 36.5%), MDA (HMB-FA, T2 11.6 and T3 25.2%; placebo, T2 11.8 and T3 41%) and PC (HMB-FA, T2 6.9 and T3 25%; placebo, T2 23.4 and T3 55.3%) at post- and 1-h post-exercise, respectively. However, at 1-h post-exercise, greater increases in oxidative stress markers (8-OHdG 36.5 vs. 12.6%; MDA 41 vs. 25.1% and PC 55.3 vs. 25%) were observed in the placebo group compared to the HMB-FA group (p < 0.05). In addition, the WBC level was greater for the placebo group in comparison to the HMB-FA group at post-exercise.

CONCLUSION

HMB-FA attenuated oxidative stress and leukocyte responses to plyometric exercise compared with placebo.

Effects of resistance training and/or beta-hydroxy-beta-methylbutyrate supplementation on muscle mass, muscle strength and physical performance in older women with reduced muscle mass: protocol for a randomised, double-blind, placebo-controlled trial

INTRODUCTION

Resistance training (RT) and nutritional supplementation seem to have beneficial effects on muscle properties and physical performance in older adults. However, the reported effects of specific RT programmes and supplementation prescriptions vary among studies. The present study aims to examine the acute and residual effects of RT and/or beta-hydroxy-beta-methylbutyrate (HMB) supplementation on muscle mass, muscle strength and physical performance in older women with reduced muscle mass.

METHODS AND ANALYSIS

This is a randomised, double-blind, placebo-controlled trial. Older women fitting the eligibility criteria were recruited in February 2018 from a population-based sample identified via screening conducted in October 2017. In March 2018, 156 participants were randomly allocated to undergo one of four interventions (RT + HMB, RT + placebo, education + HMB and education + placebo) for 12 weeks. Supervised RT consisted of body weight, elastic band, ankle weight and machine-based exercises two times per week at the Tokyo Metropolitan Institute of Gerontology (TMIG). Each participant ingested HMB (1200 mg) or placebo supplements once daily. Sessions of education not associated with sarcopenia treatment were conducted every 2 weeks. Post-intervention follow-up will be conducted for 12 weeks, until September 2018. The study includes assessments conducted in March (baseline), June (post-intervention) and September 2018 (follow-up). The primary outcome is the longitudinal change in muscle mass. Secondary outcomes include the longitudinal changes in muscle strength, physical performance, muscle thickness, muscle quality, blood counts, blood biochemistry, calf circumference, skin viscoelasticity, habitual dietary intake, habitual physical activity levels, functional capacity and health-related quality of life. Intention-to-treat analyses will be conducted.

ETHICS AND DISSEMINATION

The study protocol was approved by the Ethics Committee of the TMIG, Japan. The study is being conducted according to the principles of the Declaration of Helsinki. The findings will be presented at international academic congresses and published in peer-reviewed international journals.

TRIAL REGISTRATION NUMBER

UMIN000028560; Post-results.

Beta-hydroxy-beta-methylbutyrate and sarcopenia: from biological plausibility to clinical evidence

PURPOSE OF REVIEW

Given the role of leucine as a major regulator of muscle protein turnover, the consumption of protein sources enhanced with this essential amino acid, or its metabolite beta-hydroxy-beta-methylbutyrate (HMB), is assumed to give the greatest benefit in terms of maintenance of muscle mass and function during aging. The aim of this review is to discuss recent literature about HMB metabolism, its pharmacokinetics compared with the metabolite leucine, effectiveness of HMB to improve outcomes in older adults, and novel approaches for HMB use.

RECENT FINDINGS

Overall, this review article highlights the potential relationship between HMB dietary supplementation and parameters related to maintenance of muscle mass and strength in older people. However, there are limitations in the studies conducted so far, including low number of participants per study group, heterogeneity of study designs, methodologies, and outcomes. The combination of HMB with other amino acids or supplements limits the ability to determine the direct impact of HMB alone.

SUMMARY

It is proposed that HMB may be utilized to protect or rebuild muscle mass in older people with reduced lean body mass.

Thirty-day β-hydroxy-βmethylbutyrate supplementation with a controlled diet does not alter the morphological and morphometric characteristics of the rat diaphragm muscle

ABSTRACT Objective To evaluate the β-hydroxy-βmethylbutyrate supplementation influence on the morphological and morphometric characteristics of the diaphragm muscle of rats and verify whether there are sex differences. Methods Experimental study with 48 Wistar rats (24 of each sex) divided into 3 groups: Control Group: in which a daily diet with saline solution was offered; Experimental Group: the same amount of food from the Control group consumed in the previous day and 0.3g/kg of β-hydroxy-βmethylbutyrate; Ad libitum Experimental Group: ad libitum feeding with the same dose of the supplement. The analysis consisted of histomorphometry and classification in diaphragm muscle fiber area bands. The procedures occurred 30 days after the start of the experiment. Data were analyzed using the one-way ANOVA and Tukey tests (p<0.05). Results There was no increase in the cross-sectional area of the diaphragm muscle fibers with the supplementation protocol employed and a similar histological pattern in both sexes. No significant changes were observed in muscle fiber size ranges in the supplemented groups, suggesting that there was no hypertrophy of muscle fibers. Conclusion This study suggests that β-hydroxy-βmethylbutyrate supplementation does not cause changes in the morphological and morphometric characteristics of the diaphragm muscle, regardless of sex.

The Effects of Beta-Hydroxy-Beta-Methylbutyrate-Free Acid Supplementation and Resistance Training on Oxidative Stress Markers: A Randomized, Double-Blind, Placebo-Controlled Study

The aim of this study was to investigate the effects of 6-week beta-hydroxy-beta methylbutyrate-free acid (HMB-FA) supplementation on oxidative stress and biochemical variables in responses to resistance training. Sixteen healthy young males participated in this study and were randomly assigned to a HMB-FA supplementation group (n = 8) or a placebo supplementation group (n = 8). The resistance training program was applied for 6 weeks with two sessions per week. Blood samples were collected before and after training, and 8-hydroxy-2-deoxyguanosine (8-OHdG), malondialdehyde (MDA), protein carbonyl (PC), and biochemical variables, such as alanine transaminase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), and the numbers of total white blood cells (WBC), neutrophils, lymphocytes, and monocytes were analyzed. Following intervention, both the HMB-FA and placebo supplementation groups showed significant decreases in MDA (effect size [ES]; &minus;0.39, &minus;0.33) and PC (ES; &minus;1.37, &minus;1.41), respectively. However, 8-OHdG did not change after 6 weeks of training in any of the groups. In addition, both groups showed similar training effects on biochemical variables after 6 weeks of intervention. It was concluded that HMB-FA supplementation during resistance training did not add further adaptive changes related to oxidative stress markers.

Prevalence of sarcopenia and associated factors in institutionalised older adult patients

BACKGROUND & AIMS

Sarcopenia is a syndrome characterised by a progressive and generalised loss of skeletal muscle mass and strength with a risk of adverse outcomes such as physical disability, poor quality of life and death. The main aim of the present study was to establish the prevalence of sarcopenia using EWGSOP-defined criteria in institutionalised older adult patients in long-term care institutions. A secondary purpose was to identify the risk factors that develop Sarcopenia in this population.

METHODS

A Multicentre cross-sectional study was conducted in 334 institutionalised older adult patients, where the prevalence of sarcopenia and its relation with certain risk factors were measured. Physical performance was measured by gait speed, muscle strength measured by a handheld dynamometer and skeletal muscle mass measured using bioimpedance analysis. Different variables were collected: body mass index (BMI), diseases documented in the clinical record, the numbers of falls, the level of activity and functional ability.

RESULTS

Two hundred eighty five individuals were included. According the EWGSOP algorithm and the cut-off points proposed by Masanes et al. for the Spanish population, 118 (41.4%) participants presented sarcopenia, of which 32 patients (27%) suffered from moderate sarcopenia, 78 patients (66%) were identified as severe sarcopenia patients and only 8 (7%) were classified as sarcopenic obesity. More female residents (96 females (81.4%) vs. 22 males (18.6%), p < 0.0001) tended to be sarcopenic. Patients diagnosed with sarcopenia tended to be more functionally impaired and had a more unfavourable BMI than those who were not sarcopenic (Barthel score 40.93 vs, 49.22, p = 0.0034 and BMI 23.57 vs, 27.61, p < 0.0001). Results from regression analysis indicated that those older than 85 years old (OR 2.495, 95% CI 1.401-4.441), the female gender, (OR 3.215, 95%CI 1.635-6.324) and whose BMI was lower than 22 (OR 5.973, 95% CI 2.932-12.165) appeared to be associated with sarcopenia, whereas the Barthel Index and other factors were not.

CONCLUSION

The present study suggests that sarcopenia is highly prevalent in patients living in long-term care institutions, especially in female patients. Our findings support that the muscle mass was negatively associated with poor nutritional status and poor capacity to develop basic activities of daily living that indicates high dependency of these patients and high necessity of care.

Cancer cachexia: Diagnosis, assessment, and treatment

Cancer cachexia is a multi-factorial syndrome, which negatively affects quality of life, responsiveness to chemotherapy, and survival in advanced cancer patients. Our understanding of cachexia has grown greatly in recent years and the roles of many tumor-derived and host-derived compounds have been elucidated as mediators of cancer cachexia. However, cancer cachexia remains an unmet medical need and attempts towards a standard treatment guideline have been unsuccessful. This review covers the diagnosis, assessment, and treatment of cancer cachexia; the elements impeding the formulation of a standard management guideline; and future directions of research for the improvement and standardization of current treatment procedures.

Oral Supplementation with Beta-Hydroxy-Beta-Methylbutyrate, Arginine, and Glutamine Improves Lean Body Mass in Healthy Older Adults

Oral intake of beta-hydroxy-beta-methylbutyrate (HMB), arginine, and glutamine may ameliorate muscle loss by stimulating protein synthesis and decreasing protein degradation while simultaneously decreasing inflammation. Previous studies provide evidence for improvement in body composition with dietary supplementation of these ingredients among patients with muscle-wasting diseases. The objectives of this study were to examine the effects of this amino acid mixture on lean body mass, muscle volume, and physical function among healthy older adults. Thirty-one community-dwelling men and women, aged 65-89 years, were randomized to either two oral doses of the amino acid supplement (totaling 3 g HMB, 14 g arginine, 14 g glutamine) or placebo daily for six months. At baseline and month six, lean body mass was measured by air displacement plethysmography, dual-energy X-ray absorptiometry (DXA), and four-compartment model. Muscle volume of quadriceps was quantified by magnetic resonance imaging (MRI), and participants performed a battery of tests to assess physical function. As compared to the placebo group, the treatment group exhibited improvement in a timed stair climb (p =.016) as well as significant increases in lean body mass by all methods of assessment (p <.05). Regional analysis by DXA revealed increased arm lean mass in the supplement group only (p =.035). However, no change was observed in MRI-derived quadriceps volume. Dietary supplementation with HMB, arginine, and glutamine improved total body lean mass among a small sample of healthy older adults. Further research is indicated to elucidate mechanisms of action and to determine whether supplementation may benefit frail elders. Registered under ClinicalTrials.gov identifier no. NCT01057082.

Effects of beta-hydroxy-beta-methylbutyrate (HMB) on the expression of ubiquitin ligases, protein synthesis pathways and contractile function in extensor digitorum longus (EDL) of fed and fasting rats

Beta-hydroxy-beta-methylbutyrate (HMB), a leucine metabolite, enhances the gain of skeletal muscle mass by increasing protein synthesis or attenuating protein degradation or both. The aims of this study were to investigate the effect of HMB on molecular factors controlling skeletal muscle protein synthesis and degradation, as well as muscle contractile function, in fed and fasted conditions. Wistar rats were supplied daily with HMB (320 mg/kg body weight diluted in NaCl-0.9%) or vehicle only (control) by gavage for 28 days. After this period, some of the animals were subjected to a 24-h fasting, while others remained in the fed condition. The EDL muscle was then removed, weighed and used to evaluate the genes and proteins involved in protein synthesis (AKT/4E-BP1/S6) and degradation (Fbxo32 and Trim63). A sub-set of rats were used to measure in vivo muscle contractile function. HMB supplementation increased AKT phosphorylation during fasting (three-fold). In the fed condition, no differences were detected in atrogenes expression between control and HMB supplemented group; however, HMB supplementation did attenuate the fasting-induced increase in their expression levels. Fasting animals receiving HMB showed improved sustained tetanic contraction times (one-fold) and an increased muscle to tibia length ratio (1.3-fold), without any cross-sectional area changes. These results suggest that HMB supplementation under fasting conditions increases AKT phosphorylation and attenuates the increased of atrogenes expression, followed by a functional improvement and gain of skeletal muscle weight, suggesting that HMB protects skeletal muscle against the deleterious effects of fasting.

Acute Sarcopenia Secondary to Hospitalisation - An Emerging Condition Affecting Older Adults

There has been increasing interest and research into sarcopenia in community-dwelling older adults since the European Working Group on Sarcopenia in Older People (EWGSOP) agreed a consensus definition in 2010. Sarcopenia has been defined as loss of muscle mass with loss of muscle function (strength or physical performance), with measurements two Standard Deviations (SDs) below the mean of a young reference population. This definition does not necessitate longitudinal measurements, or the absence of acute illness and diagnosis can be made from single measurements. We hypothesise that hospitalisation, due to a combination of acute inflammatory burden and muscle disuse, leads to an acute decline in muscle mass and function and may lead to some individuals meeting criteria for sarcopenia, acutely, based on the EWGSOP definition. This may be partially recoverable or may lead to increased risk of developing sarcopenia long-term. We have denoted the term “acute sarcopenia” to refer to acute loss of muscle mass and function associated with hospitalisation. This review discusses some of the current available research in this context and also identifies some of the knowledge gaps and potential areas for future research.

β-Hydroxy-β-methyl Butyrate Is More Potent Than Leucine in Inhibiting Starvation-Induced Protein Degradation in C2C12 Myotubes

Leucine (Leu) and its metabolites α-ketoisocaproate (KIC) and β-hydroxy-β-methyl butyrate (HMB) are potent regulators of protein turnover. The aim of this study was to compare the inhibitory effects of Leu, KIC, and HMB on protein degradation and to investigate the mechanisms involved. The results showed that the inhibitory effect of HMB (0.38 ± 0.04) was more potent than that of Leu (0.76 ± 0.04) and KIC (0.56 ± 0.04, P < 0.01), and was significantly abolished in the presence of LY294002 (1.48 ± 0.02) and rapamycin (1.96 ± 0.02, P < 0.01). In the presence of insulin, the inhibitory effect of HMB (0.34 ± 0.03) was still more effective than that of Leu (0.60 ± 0.04) and KIC (0.57 ± 0.08, P < 0.05). Interestingly, LY294002 treatment markedly attenuated the effect of HMB, while rapamycin treatment failed to exert the same effect. Thus, HMB appears to be more potent than Leu and KIC in inhibiting protein degradation in the absence or presence of insulin, and this inhibitory effect may be dependent on PI3K/Akt signaling pathway regardless of insulin, and mTOR signaling was only involved in this effect of HMB in the absence of insulin.

Role of Oral Nutritional Supplements Enriched with β-Hydroxy-β-Methylbutyrate in Maintaining Muscle Function and Improving Clinical Outcomes in Various Clinical Settings

Aging and disease-related malnutrition are well associated with loss of muscle mass and function. Muscle mass loss may lead to increased health complications and associated increase in health care costs, especially in hospitalized individuals. High protein oral nutritional supplements enriched with β-hydroxy-β-methylbutyrate (HP-ONS+HMB) have been suggested to provide benefits such as improving body composition, maintaining muscle mass and function and even decreasing mortality rates. The present review aimed to examine current evidence on the effect of HP-ONS+HMB on muscle-related clinical outcomes both in community and peri-hospitalization patients. Overall, current evidence suggests that therapeutic nutrition such as HP-ONS+HMB seems to be a promising tool to mitigate the decline in muscle mass and preserve muscle function, especially during hospital rehabilitation and recovery.

Post-resistance exercise ingestion of milk protein attenuates plasma TNFα and TNFr1 expression on monocyte subpopulations

Attenuating TNFα/TNFr1 signaling in monocytes has been proposed as a means of mitigating inflammation. The purpose of this study was to examine the effects of a milk protein supplement on TNFα and monocyte TNFr1 expression. Ten resistance-trained men (24.7 ± 3.4 years; 90.1 ± 11.3 kg; 176.0 ± 4.9 cm) ingested supplement (SUPP) or placebo (PL) immediately post-exercise in a randomized, cross-over design. Blood samples were obtained at baseline (BL), immediately (IP), 30-min (30P), 1-h (1H), 2-h (2H), and 5-h (5H) post-exercise to assess plasma concentrations of myoglobin; tumor necrosis factor-alpha (TNFα); and expression of tumor necrosis factor receptor 1 (TNFr1) on classical, intermediate, and non-classical monocytes. Magnitude-based inferences were used to provide inferences on the true effects of SUPP compared to PL. Plasma TNFα concentrations were "likely attenuated" (91.6% likelihood effect) from BL to 30P in the SUPP group compared with PL (d = 0.87; mean effect: 2.3 ± 2.4 pg mL^-1). TNFr1 expressions on classical (75.9% likelihood effect) and intermediate (93.0% likelihood effect) monocytes were "likely attenuated" from BL to 2H in the SUPP group compared with PL (d = 0.67; mean effect: 510 ± 670 RFU, and d = 1.05; mean effect: 2500 ± 2300 RFU, respectively). TNFr1 expression on non-classical monocytes was "likely attenuated" (77.6% likelihood effect) from BL to 1H in the SUPP group compared with PL (d = 0.69; mean effect: 330 ± 430 RFU). Ingestion of a milk protein supplement immediately post-exercise appears to attenuate both plasma TNFα concentrations and TNFr1 expression on monocyte subpopulations in resistance-trained men.

Computed tomography measured psoas density predicts outcomes in trauma

BACKGROUND

Age-related loss of muscle mass and function (sarcopenia) is linked to poor outcomes after operation and trauma. Here we evaluate computed tomography measured psoas muscle density and area using quick and simple tools available to the bedside clinician. We hypothesize these measures will predict poor outcomes after blunt traumatic injury.

METHODS

We conducted a retrospective cohort study of patients ages ≥45 years in the Ohio State University Trauma Registry in 2008 that received a computed tomographic scan of the abdomen and/or pelvis with intravenous contrast. Psoas Index and Hounsfield unit average calculation were measured at the L3 level. In the study, 90-day mortality, complication, duration of stay ≥7 days, and dependent discharge were compared with Psoas Index and Hounsfield unit average calculation.

RESULTS

In the study, 151 patients met the inclusion criteria. Patients were stratified into interquartile ranges based either on Psoas Index or Hounsfield unit average calculation values. After adjustment with sex-specific cutoffs, the lowest interquartile range of Psoas Index was associated with 90-day mortality (relative risk [RR] 5.95, P < .008), but did not reach significance in other outcomes. The lowest interquartile range of Hounsfield unit average calculation was associated with 90-day mortality (RR 5.95, P < .008), duration of stay ≥ 7 days (RR 1.63, P = .048), complication risk (RR 2.30, P = .002), and dependent discharge 2.14, P = .015).

CONCLUSION

Psoas muscle density is a significant predictor of poor outcomes after traumatic injury. This objective, quick, and readily available measure of sarcopenia can identify patients requiring aggressive nutritional and physical therapy to improve prognosis, prevent recurrent traumatic injury, and aid in discharge planning.

Current Concepts and Unresolved Questions in Dietary Protein Requirements and Supplements in Adults

Protein needs for otherwise healthy individuals older than 19 years are defined by the recommended dietary allowance (RDA) at 0.80 g protein/kg/day. There is no recommendation in the current RDA for subpopulations of older adults or people in various pathological situations. Despite the lack of a separate recommendation, there exists a growing body of evidence that is strongly suggestive of an increased need and/or benefit for protein in older persons. That is, intakes beyond the RDA are, in older persons, associated with benefits. In addition, a number of catabolic states including critical illness also result in a sharp elevation in the needs for protein and amino acids. An underappreciated issue in protein nutrition is the impact of protein quality on clinically relevant outcomes. The introduction of a new protein scoring system—the digestible indispensable amino acid score (DIAAS)—for protein quality has raised a forgotten awareness of protein quality. The DIAAS, which replaces the protein digestibility-corrected amino acid score (PDCAAS), is based on ileal digestibility of protein and a different test protein than PDCAAS and has values greater than 1.0. The aim of this article is a brief review and summary recommendations for protein nutrition and protein requirements in populations who would benefit from more protein than the RDA. The emphasis of the review is on muscle protein turnover, and there is a discussion of the impact of protein quality, particularly as it applies to commercially available protein sources. The evidence for more optimal protein intakes is considered in light of the potential health risks of consumption of protein at levels greater than the RDA.

Effectiveness of nutritional supplementation on sarcopenia and recovery in hip fracture patients. A multi-centre randomized trial

BACKGROUND AND OBJECTIVES

Functional deterioration and reduced mobility in elderly patients with a hip fracture are associated with a loss of both muscle mass and function (sarcopenia). The aim of this study was to assess whether oral nutritional supplementation (ONS) improves muscle mass and nutritional markers (BMI, proteins) in elderly patients with hip fracture.

METHODS

Patients aged 65 years and over with hip fractures admitted to either of two rehabilitation facilities were included. Patients with diabetes, with Barthel index scores <40 prior to the fracture or with pathological fractures were excluded. A random-numbers generator was used to randomly allocate patients to the intervention group (IG) or the control group (CG). Those in the IG received a standard diet plus ONS in the form of two bottles a day of β-hydroxy-β-methylbutyrate (HMB), while those in the CG received a standard diet only. The intervention was not blinded. In order to assess changes in body mass index (BMI), anthropometric parameters were recorded at both admission and discharge. Patients' functional situation was evaluated using the Barthel index (BI) and the Functional Ambulation Categories (FAC) score. Muscle mass was assessed using bioelectrical impedance analysis, which allowed us to calculate appendicular lean mass (aLM). The outcome variable was the difference between aLM upon discharge, minus aLM upon admission (Δ-aLM).

RESULTS

Of the 107 randomised patients (IG n55, CG n52), 49 finished the study in the IG and 43 in the CG. BMI and aLM were stable in IG patients, whilst these parametres decreased in the CG. A significant difference was observed between the two groups (p<0.001, and p=0.020 respectively). The predictive factors for Δ-aLM were ONS (p=0.006), FAC prior to fracture (p<0.001) and BI prior to fracture (p=0.007). The concentration of proteins (p=0.007) and vitamin D (p.001) had increased more in the IG than in the CG.

CONCLUSION

A diet enriched in HMB improves muscle mass, prevents the onset of sarcopenia and is associated with functional improvement in elderly patients with hip fractures. Orally administered nutritional supplements can help to prevent the onset of sarcopenic obesity.

TRIAL REGISTRATION

www.clinicaltrials.gov identifier: NCT01404195, registered 22 July 2011, HYPERPROT-GER Study.

Nutrition, frailty, and sarcopenia

Frailty and sarcopenia are important concepts in the quest to prevent physical dependence, as geriatrics are shifting towards identifications of early stages of disability. Definitions of both sarcopenia and frailty are still developing, and both concepts clearly overlap in their physical aspects. Malnutrition (both undernutrition and obesity) plays a key role in the pathogenesis of frailty and sarcopenia. The quality of the diet along the lifespan has a close relation with the incidence of both entities, and nutritional interventions may be able to reduce the incidence or revert either of them. This brief review explores the role of energy and protein intake and other key nutrients on muscle function. Nutrition may be a key element of multimodal interventions for frailty and sarcopenia. The results of the "Sarcopenia and Physical fRailty IN older people: multi-componenT Treatment strategies" (SPRINTT) trial will offer key insights on the effect of such interventions in frail, sarcopenic older individuals.

Understanding Sarcopenia Development: A Role for Healthy Behaviors

For decades the biomedical community has documented the accelerated loss of muscle mass that occurs with advancing aging, termed sarcopenia. The timely review article ("Attenuation of Adverse Effects of Aging on Skeletal Muscle by Regular Exercise and Nutritional Support") by Arthur Leon presents our current state of knowledge on the biological processes responsible for age-induced loss of muscle mass and function. This loss of skeletal muscle has critical health implications as it can negatively affect morbidity and mortality. A significant theme throughout the review is that a lifelong commitment to regular physical activity and good dietary habits is extremely important to combat age related reductions in muscle mass and function. However, multi-targeted therapeutic approaches, in conjunction with nutrition and exercise, may be beneficial to prevent or treat sarcopenia. Additionally, while significant progress has been made in our understanding of the molecular and biochemical contributors to sarcopenia, further research using well-controlled clinical trials are needed to determine the long-term benefit of exercise and nutrition on aging skeletal muscle.

Efficacy and Safety of Leucine Supplementation in the Elderly

Leucine supplementation has grown in popularity due to the discovery of its anabolic effects on cell signaling and protein synthesis in muscle. The current recommendation is a minimum intake of 55 mg ⋅ kg^-1. d^-1 Leucine acutely stimulates skeletal muscle anabolism and can overcome the anabolic resistance of aging. The value of chronic leucine ingestion for muscle growth is still unclear. Most of the research into leucine consumption has focused on efficacy. To our knowledge, very few studies have sought to determine the maximum safe level of intake. Limited evidence suggests that intakes of ≤1250 mg ⋅ kg^-1. d^-1 do not appear to have any health consequences other than short-term elevated plasma ammonia concentrations. Similarly, no adverse events have been reported for the leucine metabolite β-hydroxy-β-methylbutyrate (HMB), although no studies have tested HMB toxicity in humans. Therefore, future research is needed to evaluate leucine and HMB toxicity in the elderly and in specific health conditions.

Prenatally administered HMB modifies the enamel surface roughness in spiny mice offspring: An atomic force microscopy study

OBJECTIVE

The aim of this research was to check the effect of the prenatally administered β-hydroxy β-methylbutyrate (HMB) on the development of enamel surface of the spiny mice offspring.

DESIGN

The spiny mice dams were randomly assigned into three groups: control group (not supplemented with HMB) and two experimental groups in which powdered HMB was given at the daily dosage of 0.2g/kg of body weight (group I) and 0.02g/kg of body weight (group II) during the last period of gestation. Newborn pups were euthanized by CO₂ inhalation. The morphology of incisor teeth was analysed using atomic force microscopy (AFM) in semi-contact mode in the height, magnitude and phase domains. Height images became a basis for determination of surface roughness parameters.

RESULTS

Conducted study indicated that maternal HMB administration markedly influences enamel development. Enamel of offspring's teeth in both experimental groups was characterized by significantly smaller values of indices describing surface roughness and profile. HMB supplementation influenced the calculated parameters regardless of the diet type and offspring sex, however higher dose of HMB caused stronger changes in enamel surface's physical properties and could be observed in higher intensity in the male group.

CONCLUSIONS

HMB administration caused reduction in the irregularities of enamel surface, thereby possibly reducing the probability of bacteria adhesion and caries development. These observations may serve to improve nutrition and supplementation of animals and could be a lead for further research.

Cellular and Physiological Effects of Dietary Supplementation with β-Hydroxy-β-Methylbutyrate (HMB) and β-Alanine in Late Middle-Aged Mice

There is growing evidence that severe decline of skeletal muscle mass and function with age may be mitigated by exercise and dietary supplementation with protein and amino acid ingredient technologies. The purposes of this study were to examine the effects of the leucine catabolite, beta-hydroxy-beta-methylbutyrate (HMB), in C₂C₁₂ myoblasts and myotubes, and to investigate the effects of dietary supplementation with HMB, the amino acid β-alanine and the combination thereof, on muscle contractility in a preclinical model of pre-sarcopenia. In C₂C₁₂ myotubes, HMB enhanced sarcoplasmic reticulum (SR) calcium release beyond vehicle control in the presence of all SR agonists tested (KCl, P<0.01; caffeine, P = 0.03; ionomycin, P = 0.03). HMB also improved C₂C₁₂ myoblast viability (25 μM HMB, P = 0.03) and increased proliferation (25 μM HMB, P = 0.04; 125 μM HMB, P<0.01). Furthermore, an ex vivo muscle contractility study was performed on EDL and soleus muscle from 19 month old, male C57BL/6nTac mice. For 8 weeks, mice were fed control AIN-93M diet, diet with HMB, diet with β-alanine, or diet with HMB and β-alanine. In β-alanine fed mice, EDL muscle showed a 7% increase in maximum absolute force compared to the control diet (202 ± 3vs. 188± 5 mN, P = 0.02). At submaximal frequency of stimulation (20 Hz), EDL from mice fed HMB plus β-alanine showed an 11% increase in absolute force (88.6 ± 2.2 vs. 79.8 ± 2.4 mN, P = 0.025) and a 13% increase in specific force (12.2 ± 0.4 vs. 10.8 ± 0.4 N/cm², P = 0.021). Also in EDL muscle, β-alanine increased the rate of force development at all frequencies tested (P<0.025), while HMB reduced the time to reach peak contractile force (TTP), with a significant effect at 80 Hz (P = 0.0156). In soleus muscle, all experimental diets were associated with a decrease in TTP, compared to control diet. Our findings highlight beneficial effects of HMB and β-alanine supplementation on skeletal muscle function in aging mice.

Effects of 6-month supplementation with β-hydroxy-β-methylbutyrate, glutamine and arginine on vascular endothelial function of older adults

BACKGROUND/OBJECTIVES

Vascular endothelial function declines with advancing age, due in part to increased oxidative stress and inflammation, and this age-related vascular dysfunction has been identified as an independent risk factor for cardiovascular diseases. This double-blind, placebo-controlled trial investigated the effects of a dietary supplement containing β-hydroxy-β-methylbutyrate (HMB), glutamine and arginine on endothelial-dependent vasodilation of older adults.

SUBJECTS/METHODS

A total of 31 community-dwelling men and women aged 65-87 years were randomly assigned to two groups. The treatment group received two doses of the supplement daily (totaling 3 g HMB, 14 g glutamine and 14 g arginine) for 6 months, whereas the control group received an isocaloric placebo. At baseline and week 24, vascular endothelial function was measured by flow-mediated dilation of the brachial artery, and fasting blood samples were obtained to measure high-sensitivity C-reactive protein (hsCRP) and tumor necrosis factor-α (TNF-α).

RESULTS

Paired sample t-tests revealed a 27% increase in flow-mediated dilation among the treatment group (P=0.003), whereas no change was observed in the placebo group (P=0.651). Repeated-measures analysis of variance verified a significant time by group interaction (P=0.038). Although no significant changes were observed for hsCRP or TNF-α, a trend was observed for increasing hsCRP among the placebo group only (P=0.059).

CONCLUSIONS

These results suggest that dietary supplementation of HMB, glutamine and arginine may favorably affect vascular endothelial function in older adults. Additional studies are needed to elucidate whether reduced inflammation or other mechanisms may underlie the benefits of supplementation.

Mixture of Arginine, Glutamine, and β-hydroxy-β-methyl Butyrate Enhances the Healing of Ischemic Wounds in Rats

BACKGROUND

This study investigated the effects of an amino acid mixture containing arginine, glutamine, and β-hydroxy-β-methyl butyrate on secondary healing of ischemic wounds in a rat model (N = 18).

METHODS

After the formation of a bipediculated flap on each rat, 2 full-thickness excisional skin wounds (2 × 2 cm) were created on every flap. The rats were then randomized into the control and treatment groups. Every rat received standardized rat food throughout the study. The rats in the treatment group were administered an extra 200 mg/kg of L-arginine, 200 mg/kg of L-glutamine, and 40 mg/kg of β-hydroxy-β-methyl butyrate per day. Wound sizes were measured on days 0, 4, 10, and 14. The rats were sacrificed, and the wounds were excised for biochemical and histologic examination on the 14th day.

RESULTS

As compared with the control group, the treatment group's wound sizes were significantly smaller on days 10 and 14 ( P < .001), as was its inflammatory cell accumulation score ( P = .008). There was no significant difference between the 2 groups in collagen accumulation ( P = .340), granulation tissue maturation ( P = .161), angiogenesis ( P = .387), or reepithelialization ( P = .190) and no significant difference between hydroxyproline concentrations in wounds ( P = .287).

DISCUSSION

This amino acid combination seems to have a positive impact on the secondary healing of experimental ischemic wounds when introduced as a supplement to the standard diet, and the reduction in the inflammatory process appears to play a role in this effect.

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

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.