Beta-hydroxy-beta-methylbutyrate supplementation in health and disease: a systematic review of randomized trials

ß-Hydroxy-ß-methylbutyrate: A feed supplement influencing performance, bone metabolism, intestinal morphology, and muscle quality of laying hens: a preliminary one-point study

Laying hens, selectively bred for high egg production, often suffer from bone fragility and fractures, impacting their welfare and causing economic losses. Additionally, gut health and muscle quality are crucial for overall health and productivity. This study aimed to evaluate the effects of ß-Hydroxy-ß-methylbutyrate (HMB) supplementation on performance, bone metabolism, intestinal morphology, and muscle quality in laying hens. Forty-eight Bovans Brown hens were divided into a control group and an HMB-supplemented group (0.02% HMB in diet). The study spanned from the 31st to the 60th wk of age. Assessments included bone mechanical testing, serum hormonal analysis, histological analysis of bone and intestine, and muscle quality analysis. The HMB supplementation led to decreased feed intake without affecting body weight or laying rate in laying hens. It caused an increase in both mean daily and total egg weight, indicating improved feed utilization, without influencing the feed intake to egg weight ratio. Enhanced bone formation markers and altered intestinal morphometric parameters were observed, along with improved trabecular bone structure. However, no changes in measured other bone quality indices, including geometric, densitometric, or mechanical properties were observed. Muscle analysis revealed no significant changes in overall meat quality, except for a decrease in cholesterol content and alterations in the fatty acid profile, notably a reduction in total n-3 polyunsaturated and total polyunsaturated fatty acids (PUFA). In conclusion, although not all effects of HMB supplementation were unequivocally beneficial, the positive changes in performance data and trabecular bone microarchitecture support further research into various doses and durations of supplementation. Such studies are necessary to fully understand and optimize the benefits of HMB for enhancing the health and productivity of laying hens.

Muscle-building supplement β-hydroxy β-methylbutyrate stimulates the maturation of oligodendroglial progenitor cells to oligodendrocytes

Oligodendrocytes are the myelinating cells in the CNS and multiple sclerosis (MS) is a demyelinating disorder that is characterized by progressive loss of myelin. Although oligodendroglial progenitor cells (OPCs) should be differentiated into oligodendrocytes, for multiple reasons, OPCs fail to differentiate into oligodendrocytes in MS. Therefore, increasing the maturation of OPCs to oligodendrocytes may be of therapeutic benefit for MS. The β-hydroxy β-methylbutyrate (HMB) is a muscle-building supplement in humans and this study underlines the importance of HMB in stimulating the maturation of OPCs to oligodendrocytes. HMB treatment upregulated the expression of different maturation markers including PLP, MBP, and MOG in cultured OPCs. Double-label immunofluorescence followed by immunoblot analyses confirmed the upregulation of OPC maturation by HMB. While investigating mechanisms, we found that HMB increased the maturation of OPCs isolated from peroxisome proliferator-activated receptor β-/- (PPARβ-/- ) mice, but not PPARα-/- mice. Similarly, GW6471 (an antagonist of PPARα), but not GSK0660 (an antagonist of PPARβ), inhibited HMB-induced maturation of OPCs. GW9662, a specific inhibitor of PPARγ, also could not inhibit HMB-mediated stimulation of OPC maturation. Furthermore, PPARα agonist GW7647, but neither PPARβ agonist GW0742 nor PPARγ agonist GW1929, alone increased the maturation of OPCs. Finally, HMB treatment of OPCs led to the recruitment of PPARα, but neither PPARβ nor PPARγ, to the PLP gene promoter. These results suggest that HMB stimulates the maturation of OPCs via PPARα and that HMB may have therapeutic prospects in remyelination.

Nutritional Supplementation and Exercise as Essential Allies in the Treatment of Chronic Heart Failure: The Metabolic and Molecular Bases

Chronic heart failure (CHF) is one of principal health problems in industrialized countries. Despite therapeutical improvement, based on drugs and exercise training, it is still characterized by elevated mortality and morbidity. Data show that protein energy malnutrition, clinically evident primarily with sarcopenia, is present in more than 50% of CHF patients and is an independent factor of CHF prognosis. Several pathophysiological mechanisms, primarily due to the increase in blood hypercatabolic molecules, have been proposed to explain this phenomenon. Nutritional supplementation with proteins, amino acids, vitamins and antioxidants have all been used to treat malnutrition. However, the success and efficacy of these procedures are often contradictory and not conclusive. Interestingly, data on exercise training show that exercise reduces mortality and increases functional capacity, although it also increases the catabolic state with energy expenditure and nitrogen-providing substrate needs. Therefore, this paper discusses the molecular mechanisms of specific nutritional supplementation and exercise training that may improve anabolic pathways. In our opinion, the relationship between exercise and the mTOR complex subunit as Deptor and/or related signaling proteins, such as AMPK or sestrin, is pivotal. Consequently, concomitantly with traditional medical therapies, we have proposed a combination of personalized and integrated nutritional supplementation, as well as exercise to treat malnutrition, and anthropometric and functional CHF-related disorders.

Inflammaging and Frailty in Immune-Mediated Rheumatic Diseases: How to Address and Score the Issue

Frailty is a new concept in rheumatology that can help identify people more likely to have less favorable outcomes. Sarcopenia and inflammaging can be regarded as the biological foundations of physical frailty. Frailty is becoming more widely accepted as an indicator of ageing and is linked to an increased risk of negative outcomes such as falls, injuries, and mortality. Frailty identifies a group of older adults that seem poorer and more fragile than their age-matched counterparts, despite sharing similar comorbidities, demography, sex, and age. Several studies suggest that inflammation affects immune-mediated pathways, multimorbidity, and frailty by inhibiting growth factors, increasing catabolism, and by disrupting homeostatic signaling. Frailty is more common in the community-dwelling population as people get older, ranging from 7 to 10% in those over 65 years up to 40% in those who are octogenarians. Different parameters have been validated to identify frailty. These primarily relate to two conceptual models: Fried's physical frailty phenotype and Rockwood's cumulative deficit method. Immune-mediated rheumatic diseases (IMRDs), such as rheumatoid arthritis, spondyloarthritis, systemic lupus erythematosus, systemic sclerosis, and vasculitis, are leading causes of frailty in developing countries. The aim of this review was to quantitatively synthesize published literature on the prevalence of frailty in IMRDs and to summarize current evidence on the relevance and applicability of the most widely used frailty screening tools.

Nutritional Strategies to Manage Malnutrition and Sarcopenia following Liver Transplantation: A Narrative Review

Persisting or newly developed malnutrition and sarcopenia after liver transplant (LT) are correlated with adverse health outcomes. This narrative review aims to examine the literature regarding nutrition strategies to manage malnutrition and sarcopenia after LT. The secondary aims are to provide an overview of the effect of nutrition strategies on the incidence of infections, hospital length of stay (LOS), acute cellular rejection (ACR), and mortality after LT. Four databases were searched. A total of 25 studies, mostly of mid-high quality, were included. Six studies found a beneficial effect on nutritional parameters using branched-chain amino acids (BCAA), immunomodulating diet (IMD), or enteral nutrition (EN) whereas two studies using beta-hydroxy-beta-methylbutyrate (HMB) found a beneficial effect on muscle mass and function. Fourteen studies using pre- or pro-biotics, IMD, and EN were effective in lowering infection and six studies using IMD, BCAA or HMB reported reduced hospital LOS. Finally, four studies using HMB and vitamin D were effective in reducing ACR and one study reported reduced mortality using vitamin D after LT. In conclusion, nutritional intervention after LT has different beneficial effects on malnutrition, sarcopenia, and other advert outcomes. Additional large and well-constructed RCTs using validated tools to assess nutritional status and sarcopenia are warranted to ensure more robust conclusions.

Dietary β-Hydroxy-β-Methylbutyrate Supplementation Affects Growth Performance, Digestion, TOR Pathway, and Muscle Quality in Kuruma Shrimp (Marsupenaeus japonicas) Fed a Low Protein Diet

An 8-week feeding trial was performed to evaluate the effects of dietary β-hydroxy-β-methylbutyrate (HMB) supplementation on growth performance and muscle quality of kuruma shrimp (Marsupenaeus japonicas) (initial weight: 2.00 ± 0.01 g) fed a low protein diet. The positive control diet (HP) with 490 g/kg protein and negative control diet (LP) with 440 g/kg protein were formulated. Based on the LP, 0.25, 0.5, 1, 2 and 4 g/kg β-hydroxy-β-methylbutyrate calcium were supplemented to design the other five diets named as HMB0.25, HMB0.5, HMB1, HMB2 and HMB4, respectively. Results showed that compared with the shrimp fed LP, the HP, HMB1 and HMB2 groups had significantly higher weight gain and specific growth rate, while significantly lower feed conversion ratio (p < 0.05). Meanwhile, intestinal trypsin activity was significantly elevated in the above three groups than that of the LP group. Higher dietary protein level and HMB inclusion upregulated the expressions of target of rapamycin, ribosomal protein S6 kinase, phosphatidylinositol 3-kinase, and serine/threonine-protein kinase in shrimp muscle, accompanied by the increases in most muscle free amino acids contents. Supplementation of 2 g/kg HMB in a low protein diet improved muscle hardness and water holding capacity of shrimp. Total collagen content in shrimp muscle increased with increasing dietary HMB inclusion. Additionally, dietary inclusion of 2 g/kg HMB significantly elevated myofiber density and sarcomere length, while reduced myofiber diameter. In conclusion, supplementation of 1-2 g/kg HMB in a low protein diet improved the growth performance and muscle quality of kuruma shrimp, which may be ascribed to the increased trypsin activity and activated TOR pathway, as well as elevated muscle collagen content and changed myofiber morphology caused by dietary HMB.

Effects of β-hydroxy-β-methylbutyrate supplementation on recovery from exercise-induced muscle damage: a mini-review

PURPOSE

Several studies have reported that β-hydroxy-β-methylbutyrate (HMB) has beneficial effects on exercise-induced muscle damage (EIMD). Here, we examine the effects and mechanisms of HMB supplementation on exercise-induced muscle damage EIMD and provide guidelines for the application of supplementary HMB.

METHODS

For this review, we performed web searches using PubMed, Web of Science, and Wiley Online Library. Keywords used were 'HMB,' 'HMB and EIMD,' 'HMB and recovery,' 'HMB and resistance exercise,' and 'HMB and eccentric muscle contraction.'

RESULTS

Several previous studies have shown that HMB supplementation can reduce EIMD and promote recovery. In particular, reductions were detected in certain markers of muscle membrane damage, including creatine kinase and lactate dehydrogenase. There may be multiple mechanisms in which HMB supplementation reduces EIMD, including reducing muscle-damage-induced inflammation and oxidative stress and promoting cellular cholesterol synthesis by increasing the production of β-hydroxy-β-methylglutaryl-Co-A, a product of HMB metabolism. In general, the suggested daily intake of HMB is 3 g. In addition, the timing and duration of HMB intake can be classified as chronic [≥ 2 weeks, in which a total of 3 g is consumed daily (3 × 1 g taken at breakfast, lunch, and dinner)] or acute (taken 30-60 min before exercise). The timing of intake during exercise may vary depending upon whether the formulation is calcium HMB (60-120 min before exercise) or the free-acid form of HMB (30-60 min before exercise). Notably, the co-administration of HMB and creatine does not appear to be effective in reducing EIMD.

CONCLUSION

HMB supplementation can be considered as an effective nutritional strategy to minimize EIMD.

Amino Acids in Cancer and Cachexia: An Integrated View

Rapid tumor growth requires elevated biosynthetic activity, supported by metabolic rewiring occurring both intrinsically in cancer cells and extrinsically in the cancer host. The Warburg effect is one such example, burning glucose to produce a continuous flux of biomass substrates in cancer cells at the cost of energy wasting metabolic cycles in the host to maintain stable glycemia. Amino acid (AA) metabolism is profoundly altered in cancer cells, which use AAs for energy production and for supporting cell proliferation. The peculiarities in cancer AA metabolism allow the identification of specific vulnerabilities as targets of anti-cancer treatments. In the current review, specific approaches targeting AAs in terms of either deprivation or supplementation are discussed. Although based on opposed strategies, both show, in vitro and in vivo, positive effects. Any AA-targeted intervention will inevitably impact the cancer host, who frequently already has cachexia. Cancer cachexia is a wasting syndrome, also due to malnutrition, that compromises the effectiveness of anti-cancer drugs and eventually causes the patient's death. AA deprivation may exacerbate malnutrition and cachexia, while AA supplementation may improve the nutritional status, counteract cachexia, and predispose the patient to a more effective anti-cancer treatment. Here is provided an attempt to describe the AA-based therapeutic approaches that integrate currently distant points of view on cancer-centered and host-centered research, providing a glimpse of several potential investigations that approach cachexia as a unique cancer disease.

An umbrella review of systematic reviews of β-hydroxy-β-methyl butyrate supplementation in ageing and clinical practice

The compound β-hydroxy-β-methyl butyrate (HMB) is proposed to increase or mitigate the loss of skeletal muscle and improve muscle function. We undertook a review of systematic reviews of HMB supplementation to promote gains or mitigate muscle loss in ageing and clinical populations. Following PRISMA guidelines, we searched for systematic reviews reporting the effect of HMB in our target populations. Dual-energy X-ray absorptiometry (DXA) measured lean soft-tissue mass (LSTM) was accepted as a proxy for muscle. We identified 15 systematic reviews that met our inclusion criteria, which were independently evaluated. The methodological quality of the reviews was assessed using A Measurement Tool to Assess Systematic Reviews (AMSTAR), and standardized effectiveness statements were generated. Five of 15 studies found some evidence that HMB augmented LSTM; the remaining 10 studies reported some evidence favouring no difference (6/10 studies) or insufficient evidence to determine an effect (4/10 studies). Of the 12 studies that evaluated strength, 4/12 found some evidence, 5/12 found some evidence of no effect with one article finding some evidence in favour of patients in peri-hospitalized and no evidence for those that are community-dwelling, 4/12 had insufficient evidence to determine an effect, and 1/12 had insufficient evidence. No]study reported a positive effect of HMB on physical function; however, 2/10 studies found some evidence favouring no effect, and 7/10 studies reported insufficient evidence to determine an effect. The effectiveness of HMB supplementation in augmenting LSTM was heterogeneous, with most reviews finding no effect or inconclusive evidence to determine an effect. Most reviews concluded that HMB supplementation did not affect strength outcome measures or studies were inconclusive. The current evidence is insufficient to assess the impact of HMB supplementation on functional outcome measures. Our analysis shows minor, inconsistent support for HMB as part of an oral nutritional supplement or as a stand-alone supplement (or combined with other amino acids) to increase or promote retention of LSTM, improve strength, and no evidence that it improves physical function in older persons or clinical populations.

Efficacy of Oral Nutritional Supplements in Patients Undergoing Surgical Intervention for Hip Fracture

Introduction: Malnutrition is considered a risk factor among geriatric individuals with hip fracture, affecting functional healing and recovery, increasing healthcare spending, and associated with high mortality. In this study, we sought to evaluate the clinical efficacy of oral nutritional supplements in geriatric patients undergoing surgery for hip fracture. Material and Methods: We retrospectively analyzed data of 1625 consecutive patients who underwent fixation or arthroplasty for hip fracture in a tertiary medical center between 2017 and 2020. Patients who had no available albumin or body mass index levels were excluded. The study group is of patients who received an advanced formula in the form of an oral nutritional supplement (ONS), and the control group of patients that received no ONS. Peri- and postoperative complications, readmissions, short-term mortality, and albumin levels were compared between the 2 groups. Results: The final cohort included 1123 patients, 298 in the study group and 825 controls, with a follow-up of at least 1-year. Provision of the advanced enriched formula was not associated with 30-day, 90-day, or 1-year mortality (P = .62, P = .52, and P = .72, respectively) or any perioperative complications, such as 30-day or 90-day readmission (P = .37 and P = .1, respectively), revision surgery of any cause (P = .35), and postoperative infection rates (P = .73). Albumin levels on admission and the minimum albumin levels during hospitalization were similar between the groups, but they were significantly higher in the study group before discharge (33.42 g/L vs. 32.79 g/L, P = .01). Discussion: The use of an ONS was not associated with reduced perioperative complications or mortality, although it did affect nutritional status, as indicated by increased albumin levels, a known marker of nutritional status. Conclusions. While current findings do not support ONS use to minimize major postoperative complication after hip fracture surgery, further long-term study is warranted to evaluate subjective and functional outcomes associated with improved nutritional status.

Femoral µCT Analysis, Mechanical Testing and Immunolocalization of Bone Proteins in β-Hydroxy β-Methylbutyrate (HMB) Supplemented Spiny Mouse in a Model of Pregnancy and Lactation-Associated Osteoporosis

A metabolite of leucine, ß-hydroxy-ß-methylbutyrate (HMB), used as a dietary supplement effects muscle tissue gain and bone tissue quality. Since there are no studies on the effects of HMB during pregnancy yet, the aim of the current study was to determine the effects of HMB supplementation during pregnancy on osteoporotic bone quality postpartum and post-lactation using spiny mice (Acomys cahirinus) as the animal models. The six-month-old dams were divided into four groups: pregnant and lactating controls, and pregnant and lactating HMB-treated (during the second trimester of pregnancy) females. The intensity of the immunoreaction of osteocalcin (OC), osteoprotegerin (OPG), bone morphogenetic protein 2 (BMP-2), tissue inhibitor of metalloproteinases 2 (TIMP-2), matrix metalloproteinase 8 and 13 (MMP-8 and MMP-13) and proteins involved in bone turnover, was measured in femoral trabecular and compact bone, as well as in the hyaline and epiphyseal cartilage of the femora. The analysis of the trabecular bone microarchitecture showed that the administration of HMB to pregnant females, by influencing the proteins responsible for bone cell activity and collagen remodeling, can provide protection from bone loss. Based on the results of the current study it can be assumed that HMB administration to pregnant females has a more positive impact on trabecular than compact bone.

Nutrients with anabolic/anticatabolic, antioxidant, and anti-inflammatory properties: Targeting the biological mechanisms of aging to support musculoskeletal health

Old age is associated with declines in bone density and muscle mass and function, which predisposes to mobility disability, falls, and fractures. Poor nutritional status, a risk factor for several age-related pathologies, becomes prevalent in old age and contributes to the structural and functional changes of the musculoskeletal system that increases the risk of osteoporosis, sarcopenia, osteosarcopenia, and physical frailty. The biological mechanisms underpinning these pathologies often overlap and include loss of proteostasis, impaired redox functioning, and chronic low-grade inflammation. Thus, provision of nutrients with anabolic/anticatabolic, antioxidant, and anti-inflammatory properties may be an effective strategy to offset these age-related pathologies. We searched PUBMED for pre-clinical and clinical work examining the effects of nutrients with a combined effect on muscle and bone. This review summarizes recent evidence on the mechanisms of action and potential clinical use of nutrients that concomitantly improve muscle and bone health in older persons.

Pharmacological Treatment of Sarcopenia

Sarcopenia has been acquiring a growing importance in the scientific literature and in doctors' offices. As the population ages, it becomes increasingly essential to know, prevent, and treat this clinical condition. The purpose of the present review is to bring up the current evidence on the diagnosis of this pathology, in a practical way, as well as the main current treatment options.

Anamorelin combined with physical activity, and nutritional counseling for cancer-related fatigue: a preliminary study

PURPOSE

Cancer-related fatigue (CRF) is the most frequent and debilitating symptom in patients with advanced cancer. There are limited effective treatments for CRF. The objective of this prospective longitudinal study was to evaluate the change in CRF at Day 43 after treatment with combination therapy of oral Anamorelin 100 mg daily with physical activity and nutrition counseling.

METHODS

In this study, patients with CRF [≤ 34 Functional Assessment of Chronic Illness Therapy-Fatigue subscales(FACIT-F)] received Anamorelin 100 mg orally daily with standardized physical activity and nutrition counseling for 43 days. Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-F), Anorexia Cachexia(FAACT-ACS), Multidimensional Fatigue Symptom Inventory-Short Form(MFSI-SF), Patient-Reported Outcomes Measurement Information System(PROMIS-Fatigue), body composition, and physical performance tests were assessed at baseline, Day 15, 29, and 43. Frequency and type of side effects were determined by NCI CTAE 4.0.(NCT03035409).

RESULTS

28/45 (62%) of patients dosed were evaluable at Day 43. The mean, SD for FACIT-F subscale improvement from baseline was 4.89 (± 13.07), P = .058, MFSI-SF (G) - 3.46 (± 6.86), P = 0.013, PROMIS-fatigue - 4.14 (± 7.88), P = 0.010, FAACT ACS 3.48 (± 8.13), P = 0.035. Godin Liesure-Time physical activity questionnaire 7.41 (± 16.50), P = 0.038. Weight (kg) 1.81 (± 2.63), P = 0.005, and Lean Body Mass 1.54 (± 1.85), P = 0.001, IGF-1 36.50 (± 48.76), P = 0.015. There was no significant improvement in physical performance outcomes. No adverse events > grade 3 related to the study drug were reported.

CONCLUSION

The use of the combination therapy was associated with improvement of CRF (FACIT-F fatigue, PROMIS-fatigue, MFSI-SF-general), activity (Godin-leisure time), anorexia (FAACT), body composition, and IGF-1 levels. Further studies using combination therapy for CRF are justified.

Sarcopenia in Patients Undergoing Lower Limb Bypass Surgery is Associated with Higher Mortality and Major Amputation Rates

BACKGROUND

Sarcopenia is adversely associated with survival in several diseases. Vasculopathy is often associated with multimorbidity and consequent deconditioning with poor long-term outcomes. This study examined the impact of sarcopenia on clinical outcome in patients with and without critical limb-threatening ischaemia who underwent infrainguinal bypass surgery.

METHODS

All patients undergoing infra-inguinal surgical revascularisation in 2016-2018 were retrospectively reviewed. Sarcopenia was defined as a skeletal muscle area at the L3 vertebral level (defined as L3 muscle area < 114cm² for men or <89.8cm² for women) on CT angiography. The primary outcome was overall survival by analysed by time to event analysis. Secondary outcomes included ipsilateral major lower-limb amputation, length of hospital stay, myocardial infarction and surgical-site infection.

RESULTS

A total of 116 patients with a mean age of 66.9 years were included, with a mean follow-up of 21 months. 14 (12%) of patients were sarcopenic; there were more patients with diabetes (40% vs 7%) in the sarcopenic group, p=0.018. Age, gender, Rutherford grade at presentation, other co-morbidities, other laboratory tests, conduit material and Rutherford grade at presentation were similar in those with and without sarcopenia and were statistically insignificant upon testing. Overall survival was worse for sarcopenic patients (Log Rank P=0.001) and Hazard Ratio for death 5.8; 95%CI 1.8-19.1; P=0.001. Major lower-limb amputation occurred more frequently in patients with sarcopenia (7/14 [50%] vs 23/102 [23%]; P=0.046). There was no difference in other secondary outcomes including rates of graft occlusion, myocardial infarction, surgical site infection and length of stay. Adding SMA measurement to a multivariate generalised linear model including age, sex, diabetes, and haemoglobin improved the AUROC from 0.75-0.85.

CONCLUSION

In this cohort of patients undergoing vascular surgery, sarcopenia defined using L3 muscle area was significantly associated with overall mortality and major lower-limb amputation.

β-Hydroxy-β-Methylbutyrate (HMB) Supplementation Prevents Bone Loss during Pregnancy-Novel Evidence from a Spiny Mouse (Acomys cahirinus) Model

The aim of this study was to determine the effects of ß-hydroxy-ß-methylbutyrate (HMB) supplementation during pregnancy on postpartum bone tissue quality by assessing changes in trabecular and compact bone as well as in hyaline and epiphyseal cartilage. The experiment was carried out on adult 6-month-old female spiny mice (Acomys cahirinus) divided into three groups: pregnant control (PregCont), pregnant HMB-treated (supplemented with 0.02 g/kg b.w of HMB during the second trimester of pregnancy, PregHMB), and non-pregnant females (NonPreg). Cross-sectional area and cortical index of the femoral mid-shaft, stiffness, and Young modulus were significantly greater in the PregHMB group. Whole-bone mineral density was similar in all groups, and HMB supplementation increased trabecular number. Growth plate cartilage was the thinnest, while the articular cartilage was the thickest in the PregHMB group. HMB supplementation increased the content of proteoglycans in the articular cartilage and the percentage of immature collagen content in metaphyseal trabeculae and compact bone. In summary, dietary HMB supplementation during the second trimester of pregnancy intensifies bone metabolic processes and prevents bone loss during pregnancy.

Nutritional Considerations and Strategies to Facilitate Injury Recovery and Rehabilitation

Nutritional interventions are not commonly a standard of care in rehabilitation interventions. A nutritional approach has the potential to be a low-cost, high-volume strategy that complements the existing standard of care. In this commentary, our aim is to provide an evidence-based, practical guide for athletes with injuries treated surgically or conservatively, along with healing and rehabilitation considerations. Injuries are a normal and expected part of exercise participation. Regardless of severity, an injury typically results in the athlete's short- or long-term removal from participation. Nutritional interventions may augment the recovery process and support optimal healing; therefore, incorporating nutritional strategies is important at each stage of the healing process. Preoperative nutrition and nutritional demands during rehabilitation are key factors to consider. The physiological response to wounds, immobilization, and traumatic brain injuries may be improved by optimizing macronutrient composition, caloric consumption, and nutrient timing and using select dietary supplements. Previous research supports practical nutrition recommendations to reduce surgical complications, minimize deficits after immobilization, and maximize the chance of safe return to play. These recommendations include identifying the individual's caloric requirements to ensure that energy needs are being met. A higher protein intake, with special attention to evenly distributed consumption throughout the day, will help to minimize loss of muscle and strength during immobilization. Dietary-supplement strategies may be useful when navigating the challenges of appropriate caloric intake and timing and a reduced appetite. The rehabilitation process also requires a strong nutritional plan to enhance recovery from injury. Athletic trainers, physical therapists, and other health care professionals should provide basic nutritional recommendations during rehabilitation, discuss the timing of meals with respect to therapy, and refer the patient to a registered dietitian if warranted. Because nutrition plays an essential role in injury recovery and rehabilitation, nutritional interventions should become a component of standard-of-care practice after injury. In this article, we address best practices for implementing nutritional strategies among patients with athletic injuries.

Impact of specialized oral nutritional supplement on clinical, nutritional, and functional outcomes: A randomized, placebo-controlled trial in community-dwelling older adults at risk of malnutrition

BACKGROUND & AIMS

The world's over-65 population is expanding rapidly, and the risk of malnutrition is prevalent in this population. Meeting nutritional needs is a recognized strategy to reduce and address multiple debilitating adverse health outcomes associated with malnutrition. The objective of this randomized, controlled trial was to determine the effects of oral nutritional supplement (ONS) containing beta-hydroxy-beta-methylbutyrate (HMB), along with dietary counseling, on health outcomes in community-dwelling older adults at risk of malnutrition.

METHODS

Strengthening Health In ELDerly through nutrition (SHIELD) studied adults aged ≥ 65 years in Singapore who were recruited between August 2017 and March 2019. Participants were community ambulant and classified as medium or high risk for malnutrition using Malnutrition Universal Screening Tool (MUST). Participants (n = 811) were randomly assigned to one of two study treatments for 180 days: (i) two servings/day of ONS containing HMB with dietary counseling (n = 405) or (ii) two servings/day of placebo supplement with dietary counseling (n = 406). The primary composite outcome was 'survival without hospital (re)admission and with at least 5% weight gain to day 180'. Dietary intakes, nutritional and functional outcomes were measured at baseline, 30, 90, and 180 days.

RESULTS

A higher proportion in intervention group met the 180-day primary composite outcome compared to placebo (33.4% vs. 8.7%, P < 0.001), largely driven by body weight component (36.2% vs. 9.4%, P < 0.001). Survival and hospital (re)admission rate were not significantly different between the groups. Weight, BMI, and mid upper arm circumference were significantly greater in the intervention group compared to placebo during the study (all P < 0.001), and at days 30, 90, and 180 (all P < 0.05). The odds of having better nutritional status during the study were also significantly higher in the intervention group compared to placebo, as measured using MUST risk (OR = 2.68, P < 0.001) and vitamin D status (OR = 4.23, P < 0.001). Intervention group had significantly higher energy, protein, fat, and carbohydrate intakes than the placebo group (all P ≤ 0.017). Leg strength at day 90 was significantly greater for the intervention group than for the placebo group (LSM ± SE: 12.85 ± 0.22 vs. 12.17 ± 0.22; P = 0.030). Handgrip strength for females was significantly higher at day 180 for the intervention group compared to placebo (LSM ± SE: 14.18 ± 0.17 vs. 13.70 ± 0.17; P = 0.048). Within the low appendicular skeletal muscle mass index (ASMI) subgroup, the intervention group had significantly greater calf circumference at days 90 and 180 compared to placebo (both P ≤ 0.0289).

CONCLUSIONS

For community-dwelling older adults at risk of malnutrition, daily consumption of specialized ONS containing HMB and vitamin D for six months, along with dietary counseling, significantly improved nutritional and functional outcomes compared to placebo supplement with dietary counseling.

CLINICAL TRIAL REGISTRATION

www.ClinicalTrials.govNCT03245047.

Metabolism and Functions of Amino Acids in the Skin

Amino acids are the building blocks of all proteins, including the most abundant fibrous proteins in the skin, as keratins, collagen and elastin. Sagging and wrinkled skin are features of chronic sun-damaged and aged uncared skin, and they are mainly associated with the deterioration of collagen and elastic fibers. The maintenance of skin structures by self-repair processes is essential to skin health. Thus, amino acids significantly impact the appearance of the skin. Amino acids are important nutrients required for (a) wound healing promotion and repair of the damaged skin; (b) acid-base balance and water retention in cellular layers, such as stratum corneum; (c) protection against sunlight damage; (d) maintenance of an appropriate skin microbiome. This review highlights the contribution of all proteinogenic amino acids and some related metabolites to the skin structures as constituents of the main cutaneous proteins or as signaling molecules for the regulation and determination of skin physiology.

Evaluation of Probiotics for Warfighter Health and Performance

The probiotic industry continues to grow in both usage and the diversity of products available. Scientific evidence supports clinical use of some probiotic strains for certain gastrointestinal indications. Although much less is known about the impact of probiotics in healthy populations, there is increasing consumer and scientific interest in using probiotics to promote physical and psychological health and performance. Military men and women are a unique healthy population that must maintain physical and psychological health in order to ensure mission success. In this narrative review, we examine the evidence regarding probiotics and candidate probiotics for physical and/or cognitive benefits in healthy adults within the context of potential applications for military personnel. The reviewed evidence suggests potential for certain strains to induce biophysiological changes that may offer physical and/or cognitive health and performance benefits in military populations. However, many knowledge gaps exist, effects on health and performance are generally not widespread among the strains examined, and beneficial findings are generally limited to single studies with small sample sizes. Multiple studies with the same strains and using similar endpoints are needed before definitive recommendations for use can be made. We conclude that, at present, there is not compelling scientific evidence to support the use of any particular probiotic(s) to promote physical or psychological performance in healthy military personnel. However, plausibility for physical and psychological health and performance benefits remains, and additional research is warranted. In particular, research in military cohorts would aid in assessing the value of probiotics for supporting physical and psychological health and performance under the unique demands required of these populations.

Aging and nutrition. Paving the way to better health

Sufficient caloric intake is important to maintain the balanced health status, especially during the period of aging, as aging and sickness share paths. Maintaining adequate nutritional balance is the best preventive measure to counteract the risk of malnutrition. There are several causes for malnutrition in elderly people, and some techniques such as anthropometric measurements, laboratory and clinical parameters could help to diagnose malnutrition in these patients. The use of a simple validated questionnaire called the 'Mini Nutritional Assessment' measures the nutritional status of elderly patients. In this review, we discuss about the malnutrition in elderly people with and without a known cause and we present some of nutritional intervention. There are promising strategies that help overcoming malnutrition.

Effect of administration of β-hydroxy-β-methyl butyrate-enriched formula after liver transplantation: A pilot randomized controlled trial

OBJECTIVE

Most patients undergoing liver transplantation (LT) have decreased skeletal muscle mass, malnutrition, and decreased physical activity levels. These comorbidities may prevent early recovery after surgery. The aim of this study was to examine the effects of oral nutritional formula-enriched β-hydroxy-β-methyl-butyrate (HMB), a leucine metabolite that promotes muscle synthesis and suppresses proteolysis, on postoperative sarcopenia and other outcomes after adult-to-adult living donor LT (LDLT).

METHODS

Thirty-three consecutive patients who underwent adult LDLT between March 2017 and October 2018 and who met inclusion criteria were randomly assigned in a 1:1 ratio to the HMB or control group. Patients in the HMB group received two packs of HMB-rich nutrients per day, which contained calcium-HMB (1500 mg), l-arginine (7000 mg), and l -glutamine (7000 mg) per pack orally or enterally from postoperative day 1 to 30 with postoperative rehabilitation. The primary endpoint was grip strength (GS) at 2 mo after LDLT. Secondary endpoints included GS at 1 mo after LDLT, skeletal muscle mass index (SMI) at 1 and 2 mo after LDLT, laboratory findings, incidence of postoperative bacteremia, and postoperative hospital length of stay (LOS).

RESULTS

Twelve patients in the HMB group and 11 in the control group were included in the final analysis. GS at 1 and 2 mo and SMI values at 2 mo were significantly higher in the HMB group than in the control group (GS: both P < 0.001, SMI: P = 0.04). In the HMB group, white blood cell count 3 wk after LDLT was significantly lower (P = 0.005), and postoperative hospital LOS was significantly shorter (P = 0.028) compared with the control group. The incidence of postoperative bacteremia was lower in the HMB group.

CONCLUSIONS

Postoperative administration of HMB-enriched formula with rehabilitation significantly increased GS at 1 and 2 mo and SMI at 2 mo and shortened postoperative hospital LOS after LDLT.

Effects of the Combination of β-Hydroxy-β-Methyl Butyrate and R(+) Lipoic Acid in a Cellular Model of Sarcopenia

: Sarcopenia is a clinical problem associated with several pathological and non-pathological conditions. The aim of the present research is the evaluation of the pharmacological profile of the leucine metabolite β-hydroxy-β-methyl butyrate (HMB) associated with the natural R(+) stereoisomer of lipoic acid (R(+)LA) in a cellular model of muscle wasting. The C2C12 cell line is used as myoblasts or is differentiated in myotubes, sarcopenia is induced by dexamethasone (DEX). A Bonferroni significant difference procedure is used for a post hoc comparison. DEX toxicity (0.01-300 µM concentration range) is evaluated in myoblasts to measure cell viability and caspase 3 activation after 24 h and 48 h; cell incubation with 1 µM DEX for 48 h is chosen as optimal treatment for decreasing cell viability and increasing caspase 3 activity. R(+)LA or HMB significantly prevents DEX-induced cell mortality; the efficacy is improved when 100 µM R(+)LA is combined with 1 mM HMB. Regarding myoblasts, this combination significantly reduces DEX-evoked O2- production and protein oxidative damage. During the early phase of myotube formation, the mixture preserves the number of myogenin-positive cells, whereas it completely prevents the DEX-dependent damage in a later phase of myotube differentiation (7 days), as evaluated by cell diameter and percentage of multinucleated cells. R(+)LA in association with HMB is suggested for sarcopenia therapy.

Nutrition interventions to treat low muscle mass in cancer

Many patients with cancer experience poor nutritional status, which detrimentally impacts clinical outcomes. Poor nutritional status in cancer is primarily manifested by severe muscle mass (MM) depletion, which may occur at any stage (from curative to palliative) and often co-exists with obesity. The objective of this article was to discuss gaps and opportunities related to the role of nutrition in preventing and reversing low MM in cancer. It also provides a narrative review of relevant nutritional interventions for patients capable of oral intake. The impact of nutrition interventions to prevent/treat low MM in cancer is not well understood, potentially due to the limited number of studies and of clinically viable, accurate body composition assessment tools. Additionally, the type of study designs, inclusion criteria, length of intervention, and choice of nutritional strategies have not been optimal, likely underestimating the anabolic potential of nutrition interventions. Nutrition studies are also often of short duration, and interventions that adapt to the metabolic and behavioural changes during the clinical journey are needed. We discuss energy requirements (25-30 kcal/kg/day) and interventions of protein (1.0-1.5 g/kg/day), branched-chain amino acids (leucine: 2-4 g/day), β-hydroxy β-methylbutyrate (3 g/day), glutamine (0.3 g/kg/day), carnitine (4-6 g/day), creatine (5 g/day), fish oil/eicosapentanoic acid (2.0-2.2 g/day EPA and 1.5 g/day DHA), vitamin/minerals (e.g. vitamin D: 600-800 international units per day), and multimodal approaches (nutrition, exercise, and pharmaceutical) to countermeasure low MM in cancer. Although the evidence is variable by modality type, interventions were generally not specifically studied in the context of cancer. Understanding patients' nutritional requirements could lead to targeted prescriptions to prevent or attenuate low MM in cancer, with the overall aim of minimizing muscle loss during anti-cancer therapy and maximizing muscle anabolism during recovery. It is anticipated that this will, in turn, improve overall health and prognostication including tolerance to treatment and survival. However, oncology-specific interventions with more robust study designs are needed to facilitate these goals.

Net Absorption and Metabolism of β-Hydroxy- β-Methyl Butyrate during Late Gestation in a Pig Model

The leucine metabolite, β-hydroxy-β-methyl butyrate (HMB), is widely used in human nutrition and animal production as a nutritional supplement. Although the HMB usage during late gestation has been demonstrated to have a positive effect on fetal development, knowledge on net absorption and metabolism of HMB and impact of HMB on branched chain amino acids (BCAAs) metabolism is lacking. To address this, we conducted a study using pigs during the perinatal period as a model organism. Eight-second parity sows were fitted with indwelling catheters in the femoral artery and in the portal, hepatic, femoral, and mesenteric veins. Eight hourly sets of blood samples were taken starting 30 min before the morning meal on day –10 and day –3 relative to parturition. Four control (CON) sows were fed a standard lactation diet from day –15 and throughout the experiment, and 4 HMB sows were fed the control diet supplemented with 15 mg Ca(HMB)₂/kg body weight mixed in one third of the morning meal from day –10 until parturition. Blood gases, plasma metabolites, milk compositions, and apparent total tract digestibility of nutrients were measured. Arterial plasma concentrations of HMB (p < 0.001), Cys (p < 0.001), and Lys (p < 0.10) were increased in HMB supplemented sows, while arterial plasma triglycerides concentration was decreased (p < 0.05). The net portal recovery of Ala and Asp were increased in HMB sows (p < 0.05). Sows fed HMB had increased hepatic vein flow and net hepatic fluxes of Met, Asn, and Gln (p < 0.05). In contrast, the femoral extraction rates of Ala and Ser were decreased by dietary HMB supplementation (p < 0.05). Dietary HMB treatment and sampling time relative to feeding had an interaction on arterial concentrations, net portal fluxes, and femoral extraction rates of BCAAs. The net portal recovery of HMB was 88%, while 14% of supplemented HMB was excreted through urine and 4% through feces. Moreover, the gastrointestinal tract metabolized 8% while the liver metabolized 12%. Finally, 26% of the daily intake of HMB was secreted via colostrum at the day of farrowing. This study demonstrated that dietary HMB supplementation increased net uptake of amino acids and increased fatty acid oxidation through improving blood flow and insulin sensitivity during the late gestation. Most importantly, oral HMB administration could maintain a stable postprandial absorption and altered metabolism in BCAAs. Net portal flux of HMB at 5.5 to 6.5 h after feeding approached zero, indicating that HMB ideally should be administrated two or three times, daily.

Nutrition as a Health Determinant in Elderly Patients

BACKGROUND

An adequate caloric intake is a major determinant for the health status especially when degenerative conditions become a predominant risk for difficult-to-treat diseases as in aging.

METHODS

A structured search of literature on the major databases was performed using terms as nutrition, elderly and malnutrition.

RESULTS

According to most referenced articles, it appears to be unquestionable that both organic and social risk factors [economic hardship, loneliness, institutionalization] are important as determining causes of protein-caloric malnutrition. Some anthropometric, clinical and laboratory parameters can help to make diagnosis and quantify malnutrition. However, most of them are not cheap or are not simple to perform especially in the setting of General Practice. The application of a simple questionnaire [Mini Nutritional Assessment, MNA] allows to obtain in a fast, easy and non-invasive way a valid assessment of the nutritional status in geriatric patients. The maintenance of the nutritional status is the best measure to counteract the risk of proteincaloric malnutrition and its complications which often sneakily affects elderly population and in particular frail patients.

CONCLUSION

This review, based on updated concepts, examines all the above mentioned points together with some aspects associated with malnutrition as an indicator of disease severity and health costs in the elderly population. Finally, the impact of nutritional intervention and nutrients supplementation on general indices of malnutrition are discussed as a promising strategy.

Leucine Metabolites Do Not Enhance Training-induced Performance or Muscle Thickness

Leucine metabolites, α-hydroxyisocaproic acid (α-HICA) and β-hydroxy-β-methylbutyrate (calcium, HMB-Ca and free acid, HMB-FA), have been proposed to augment resistance training-induced changes in body composition and performance.

PURPOSE

We aimed to conduct a double-blind randomized controlled pragmatic trial to evaluate the effects of off-the-shelf leucine metabolite supplements of α-HICA, HMB-FA, and HMB-Ca on resistance training-induced changes in muscle thickness and performance.

METHODS

Forty men were randomly assigned to receive α-HICA (n = 10, fat-free mass [FFM] = 62.0 ± 7.1 kg), HMB-FA (n = 11, FFM = 62.7 ± 10.5 kg), HMB-Ca (n = 9, FFM = 65.6 ± 10.1 kg), or placebo (PLA; n = 10, FFM = 64.2 ± 5.7 kg). The training program consisted of whole body thrice weekly resistance training for 8 wk (seven exercises per session, three to four sets per session, at 70%-80% one repetition maximum). Skeletal muscle thickness by ultrasound, performance measures, and blood measures (creatine kinase, insulin-like growth factor 1, growth hormone, cortisol, and total testosterone) were evaluated at baseline and at the end of weeks 4 and 8.

RESULTS

Time-dependent changes were observed for muscle thickness (P < 0.001), one repetition maximum bench press and squat (P < 0.001), Wingate peak power (P = 0.02), countermovement jump height (P = 0.03), power (P = 0.006), creatine kinase, insulin-like growth factor-1, growth hormone, and cortisol (all P < 0.001). No significant between-group or time-group interactions were observed.

CONCLUSIONS

No leucine metabolite resulted in any ergogenic effects on any outcome variable. Supplementation with leucine metabolites-α-HICA, HMB-FA, or HMB-Ca-is not a supplementation strategy that improves muscle growth and strength development in young adult men.

[Functional recovery of the cardio-respiratory patient]

Introduction

Heart failure (HF), chronic obstructive pulmonary disease (COPD), and most chronic diseases are associated with mild to moderate chronic or recurrent inflammation. This inflammation contributes to malnutrition through different mechanisms: anorexia, decreased intake, alteration of metabolism with increased energy expenditure at rest and increased muscle catabolism. The decrease in lean mass has been included as a phenotypic criterion in the recently coined definition of malnutrition. In addition, a greater importance is given to the evaluation of the function, together with that of the morphological parameters. The grip strength, measured with a manual dynamometer and compared to reference populations, is a simple measure of muscle strength and correlates with the strength of the legs. On the other hand, the so-called "paradox of obesity" occurs in both patients with HF and COPD, since overweight and obese patients have lower overall mortality than patients with normal or low body mass index (BMI). The nutritional treatment, with an adequate contribution of macro and micronutrients and a contribution of proteins of fast absorption, with a higher content of leucine or its metabolite β-hydroxy-β-methylbutyrate, seems to offer a benefit in the preservation of muscle mass and its functionality in the patient with cardiorespiratory pathology. Nutritional treatment, associated with a pulmonary or cardiac rehabilitation regimen, is essential to obtain good morphological and functional results.

Sarcopenia Associated with Chronic Obstructive Pulmonary Disease

Sarcopenia is frequently associated with chronic diseases such as chronic obstructive pulmonary disease (COPD) and cancer. COPD, which is characterized by an irreversible airflow limitation, exacerbates respiratory distress as the disease progresses. The prevalence of sarcopenia in stable COPD was reported to be 15% to 25% in previous foreign studies and 25% in a Korean study. As the amount of activity decreases, muscle mass decreases and eventually oxygen cannot be used effectively, resulting in a vicious cycle of deterioration of exercise capacity. Deconditioning due to decreased activity is a major cause of limb muscle dysfunction in patients with COPD. In these patients, the factors that decrease muscle strength and endurance include chronic inflammation, oxidative stress, inactivity, hypoxemia, hormone abnormality, deficits of nutrients such as protein and vitamin D, and the use of systemic corticosteroid. Therefore, treatment and management should either inhibit this process or should be directed toward supplementing the deficiency, such as with exercise, nutritional support, and medications and supplements. The relationship between sarcopenia and COPD is increasingly being reported, with some overlap in clinical features and treatments. We are fascinated to be able to diagnose 2 diseases through similar physical performance tests and to improve both diseases using the same treatment such as exercise. Therefore, this review summarizes the clinical relevance and integrative management of the 2 diseases.

Transport Mechanisms for the Nutritional Supplement β-Hydroxy-β-Methylbutyrate (HMB) in Mammalian Cells

PURPOSE

β-Hydroxy-β-methylbutyrate (HMB), a nutritional supplement, elicits anabolic activity in muscle. Here we investigated the mechanism of HMB uptake in muscle cells.

METHODS

Murine muscle cells (C2C12) and human mammary epithelial cells (MCF7) were used for uptake. As HMB is a monocarboxylate, focus was on monocarboxylate transporters, monitoring interaction of HMB with H⁺-coupled lactate uptake, and influence of H⁺ directly on HMB uptake. Involvement of MCT1-4 was studied using selective inhibitors and gene silencing. Involvement of human Na⁺/monocarboxylate transporter SMCT1 was also assessed using Xenopus oocytes.

RESULTS

H⁺-coupled lactate uptake was inhibited by HMB in both mammalian cells. HMB uptake was H⁺-coupled and inhibited by lactate. C2C12 cells expressed MCT1 and MCT4; MCF7 cells expressed MCT1-4; undifferentiated C2C12 cells expressed SMCT1. SMCT1 mediated Na⁺-coupled HMB transport. Inhibitors of MCT1/4, siRNA-mediated gene silencing, and expression pattern showed that MCT1-4 were responsible only for a small portion of HMB uptake in these cells.

CONCLUSION

HMB uptake in C2C12 and MCF7 cells is primarily H⁺-coupled and inhibited by lactate, but MCT1-4 are only partly responsible for HMB uptake. SMCT1 also transports HMB, but in a Na⁺-coupled manner. Other, yet unidentified, transporters mediate the major portion of HMB uptake in C2C12 and MCF7 cells.

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.

Maternal HMB treatment affects bone and hyaline cartilage development in their weaned piglets via the leptin/osteoprotegerin system

It has been demonstrated in animal studies that prenatal administration of β-hydroxy-β-methylbutyrate (HMB, metabolite of leucine) influences general growth and mechanical endurance of long bones in newborn offspring in sex-dependent manner. The present experiment was conducted to evaluate the effect of HMB treatment of pregnant sows on bone development in offspring at weaning. From 70th day until the 90th day of gestation, sows received either a basal diet (n = 12) or the same diet supplemented with HMB (n = 12) at the dose of 0.2 g/kg of body weight/day. Femora obtained from six males and females in each group weaned at the age of 35 days were examined. Maternal HMB treatment significantly enhanced body weight and changed bone morphology increasing femur mechanical strength in both sexes. Maternal HMB supplementation also elevated bone micro- and macroelement concentrations and enhanced content of proteoglycans in articular cartilage. Based on the obtained results, it can be concluded that maternal HMB supplementation in the mid-gestation period significantly accelerated bone development in both sexes by upregulation of a multifactorial system including leptin and osteoprotegerin. However, the sex (irrespective of the HMB treatment) was the factor which influenced the collagen structure in cartilages and trabecular bone, as demonstrated both by the Picrosirius red staining and performed analysis of thermal stability of collagenous tissues. The structural differences in collagen between males and females were presumably related to a different collagen maturity. No studies conducted so far provided a detailed morphological analysis of bone, articular cartilage, growth plate and the activities of the somatotropic and pituitary-gonadal axes, as well as leptin/osteoprotegerin system in weaned offspring prenatally treated with HMB. This study showed also the relationship between the maternal HMB treatment and bone osteometric and mechanical traits, hormones, and growth and bone turnover markers such as leptin, osteoprotegerin and insulin-like growth factor-1.

No effect of HMB or α-HICA supplementation on training-induced changes in body composition

β-hydroxy-β-methylbutyrate (calcium: HMB-Ca and free acid: HMB-FA) and α-hydroxyisocaproic acid (α-HICA) are leucine metabolites that have been proposed to improve body composition and strength when combined with resistance exercise training (RET). In this double-blind randomized controlled pragmatic trial, we evaluated the effects of off-the-shelf supplements: α-HICA, HMB-FA and HMB-Ca, on RET-induced changes in body composition and performance. Forty men were blocked randomized to receive α-HICA (n = 10, fat-free mass [FFM] = 62.0 ± 7.1 kg), HMB-FA (n = 11, FFM = 62.7 ± 10.5 kg), HMB-Ca (n = 9, FFM = 65.6 ± 10.1 kg) or placebo (PLA; n = 10, FFM = 64.2 ± 5.7 kg). The training protocol consisted of a whole-body resistance training routine, thrice weekly for 8 weeks. Body composition was assessed by dual-energy x-ray absorptiometry (DXA) and total body water (TBW) by whole-body bioimpedance spectroscopy (BIS), both at baseline and at the end of weeks 4 and 8. Time-dependent changes were observed for increase in trunk FFM (p < 0.05). No statistically significant between-group or group-by-time interactions were observed. Supplementation with HMB (FA and Ca) or α-HICA failed to enhance body composition to a greater extent than placebo. We do not recommend these leucine metabolites for improving body composition changes with RET in young adult resistance trained men.

Supplementation with beta-hydroxy-beta-methylbutyrate impacts glucose homeostasis and increases liver size in trained mice

β-hydroxy-β-methyl butyrate (HMB) is a bioactive metabolite derived from the amino acid leucine, usually applied for muscle mass increase during physical training, as well as for muscle mass maintenance in debilitating chronic diseases. The hypothesis of the present study is that HMB is a safe supplement for muscle mass gain by strength training. Based on this, the objective was to measure changes in body composition, glucose homeostasis and hepatic metabolism of HMB supplemented mice during strength training. Two of four groups of male mice (n = 6/group) underwent an 8-week training period session (climbing stairs) with or without HMB supplementation (190 mg/kgBW per day). We observed lower body mass gain (4.9 ± 0.43% versus 1.2 ± 0.43, p < 0.001) and increased liver mass (40.9 ± 0.9 mg/gBW versus 44.8 ± 1.3, p < 0.001) in the supplemented trained group compared with the non-supplemented groups. The supplemented trained group had an increase in relative adipose tissue mass (12.4 ± 0.63 mg/gBW versus 16.1 ± 0.88, P < 0.01) compared to the non-supplemented untrained group, and an increase in fasting blood glucose (111 ± 4.58 mg/dL versus 122 ± 3.70, P < 0.05) and insulin resistance (3.79 ± 0.19 % glucose decay/min versus 2.45 ± 0.28, P < 0.05) comparing with non-supplemented trained group. Adaptive heart hypertrophy was observed only in the non-supplemented trained group (4.82 ± 0.05 mg/gBW versus 5.12 ± 0.13, P < 0.05). There was a higher hepatic insulin-like growth factor-1 expression (P = 0.002) in supplemented untrained comparing with non-supplemented untrained group. Gene expression of gluconeogenesis regulatory factors was increased by training and reduced by HMB supplementation. These results confirm that HMB supplementation associated with intensive training protocol drives changes in glucose homeostasis and liver metabolism in mice.

Cognitive function is preserved in aged mice following long-term β-hydroxy β-methylbutyrate supplementation

β-hydroxy β-methylbutyrate (HMB) is a nutritional supplement purported to enhance skeletal muscle mass and strength, as well as cognitive function in older adults. The purpose of this study was to determine the potential for long-term HMB supplementation to preserve muscle function and cognition in aged mice, as well as provide evidence of a link between vessel-associated pericyte function and outcomes. Four- (Adult/Ad) and 17 month-old (Aged/Ag) C57BL/6J mice consumed chow containing 600 mg/kg BW/day of either Ca-HMB (Ad, n=16; Ag, n=17) or Ca-Lactate (Ad, n=16; Ag, n=17) for 6 months. HMB did not prevent age-related reductions in muscle mass, strength and coordination (Age main effect, P<0.05). The rate of muscle protein synthesis decreased within the mitochondrial fraction (age main effect, P<0.05), and this decline was not prevented with HMB. Despite no change in muscle mass or function, an age-dependent reduction in active avoidance learning was attenuated with HMB (Age and HMB main effects, P<0.05). Age detrimentally impacted muscle-resident pericyte gene expression with no recovery observed with HMB, whereas no changes in brain-resident pericyte quantity or function were observed with age or HMB. The findings from this study suggest that prolonged HMB supplementation starting in adulthood may preserve cognition with age.

Is β-hydroxy β-methylbutyrate an effective anabolic agent to improve outcome in older diseased populations?

PURPOSE OF REVIEW

β-Hydroxy β-methylbutyrate (HMB) has been used for many years in athletes for muscle buildup and strength, and endurance enhancement. In recent years, its interest quickly expanded in older (diseased) populations and during (exercise) rehabilitation and recovery from hospitalization and surgery. We will discuss recent literature about HMB metabolism, its pharmacokinetics compared with the frequently used metabolite leucine, effectiveness of HMB to improve outcome in older diseased adults, and novel approaches for HMB use.

RECENT FINDINGS

HMB supplementation resulted in positive outcomes on muscle mass and functionality, related to its anabolic and anticatabolic properties and prolonged half-life time in blood. Furthermore, it was able to increase the benefits of (exercise) rehabilitation programs to enhance recovery from illness or medical procedures. There is promising evidence that HMB might support bone density, improve cognitive function, and reduce abdominal obesity, which is of importance particularly in the older (diseased) population.

SUMMARY

The older diseased population might benefit from dietary HMB because of its established positive properties as well as its long lasting (pharmacological) effect. In addition to evaluating its efficacy and application in various clinical conditions, more research is needed into the mechanisms of action, the optimal dosage, and its potential additional beneficial effects on outcome.

Chromium supplementation does not improve weight loss or metabolic and hormonal variables in patients with polycystic ovary syndrome: A systematic review

Polycystic ovary syndrome (PCOS) is the most common endocrinopathy in women of reproductive age, and recently, chromium was discussed as an adjuvant way to manage it. Herein, a systematic review was conducted which centered on the effects of chromium on ovarian physiology with a focus on body mass index, as well as hormonal and metabolic dysfunctions in women suffering from PCOS. This review was performed using the guidelines from Preferred Reporting Items for Systematic Reviews. Clinical trials investigating chromium in women with PCOS with outcome measures related to metabolic and hormonal status were included. The search was conducted using PubMed, Scopus, and Google Scholar databases for clinical trials in the English language from the inception of the resources until May 2017 with the terms: chromium, chromium picolinate, CrP, polycystic ovary syndrome, PCOS, and sclerocystic ovary syndrome. The search resulted in 89 articles, and after inclusion and exclusion criteria were applied, 6 articles were selected for analysis. Two studies that evaluated the effect of chromium on body weight or body mass index reported no effect. Another study reported the beneficial effect of chromium on weight reduction. It seems that the effect of chromium in the reduction of blood glucose is insignificant, and results are inconsistent in relation to dyslipidemia. With regard to the effects of chromium on concentrations of sex hormones, a longer duration of treatment is needed to produce significant changes. The articles reviewed demonstrated that chromium supplementation has limited effects on weight reduction, glucose control, lipid profile, and hormonal disturbance of women with PCOS; however, more studies are needed due to the clinical changes observed in patients with PCOS after chromium supplementation.

Effects of Protein, Essential Amino Acids, B-Hydroxy B-Methylbutyrate, Creatine, Dehydroepiandrosterone and Fatty Acid Supplementation on Muscle Mass, Muscle Strength and Physical Performance in Older People Aged 60 Years and Over. A Systematic Review on the Literature

OBJECTIVES

The objective of this study was to perform a systematic review to investigate the effects protein, essential amino acids (EAA), β-hydroxy β-methylbutyrate (HMB), creatine, dehydroepiandrosterone (DHEA) and fatty acid supplementation on muscle mass, muscle strength and physical performance of elderly subjects.

METHODS

Using the electronic databases MEDLINE and EMBASE we identified RCTs published until February 2016 which assessed the effects of these nutrient supplementation on muscle strength, muscle mass or physical performance. Study selection and data extraction were performed by two independent reviewers.

RESULTS

Search strategy allowed us to identify 23 RCTs. Among them, four used proteins as nutritional supplement, seven EAAs, six creatine, four DHEA and finally, two HMB. From our systematic review, it seems that the effects of these supplementations on muscle health are rather limited. Only consistent effects of EAA supplementation on physical performance (3 out of the 4 RCTs using EAA supplementation found significant effect of this supplementation on physical performance) and HMB supplementation on muscle mass (all the 2 identified RCTs using HMB supplementation found significant effect of this supplementation on muscle mass) have been found across studies. No consistent effects were found for the other types of dietary supplementation. Because of the important limitations in study design, inconsistency and lack of directness, the overall quality of the evidence was judged to be low or very low using the GRADE system.

CONCLUSION

This systematic review showed a limited effect of nutritional supplementation on muscle mass, muscle power and physical function. Inconsistent positive effects were observed for some specific supplementations but the results only concerned one aspect of the muscle. Well designed and appropriately powered RCTs are needed to provide evidence for appropriate clinical recommendations.

Pharmacological targeting of exercise adaptations in skeletal muscle: Benefits and pitfalls

Exercise exerts significant effects on the prevention and treatment of many diseases. However, even though some of the key regulators of training adaptation in skeletal muscle have been identified, this biological program is still poorly understood. Accordingly, exercise-based pharmacological interventions for many muscle wasting diseases and also for pathologies that are triggered by a sedentary lifestyle remain scarce. The most efficacious compounds that induce muscle hypertrophy or endurance are hampered by severe side effects and are classified as doping. In contrast, dietary supplements with a higher safety margin exert milder outcomes. In recent years, the design of pharmacological agents that activate the training program, so-called "exercise mimetics", has been proposed, although the feasibility of such an approach is highly debated. In this review, the most recent insights into key regulatory factors and therapeutic approaches aimed at leveraging exercise adaptations are discussed.

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.

Novel targeted therapies for cancer cachexia

Anorexia and metabolic alterations are the main components of the cachectic syndrome. Glucose intolerance, fat depletion, muscle protein catabolism and other alterations are involved in the development of cancer cachexia, a multi-organ syndrome. Nutritional approach strategies are not satisfactory in reversing the cachectic syndrome. The aim of the present review is to deal with the recent therapeutic targeted approaches that have been designed to fight and counteract wasting in cancer patients. Indeed, some promising targeted therapeutic approaches include ghrelin agonists, selective androgen receptor agonists, β-blockers and antimyostatin peptides. However, a multi-targeted approach seems absolutely essential to treat patients affected by cancer cachexia. This approach should not only involve combinations of drugs but also nutrition and an adequate program of physical exercise, factors that may lead to a synergy, essential to overcome the syndrome. This may efficiently reverse the metabolic changes described above and, at the same time, ameliorate the anorexia. Defining this therapeutic combination of drugs/nutrients/exercise is an exciting project that will stimulate many scientific efforts. Other aspects that will, no doubt, be very important for successful treatment of cancer wasting will be an optimized design of future clinical trials, together with a protocol for staging cancer patients in relation to their degree of cachexia. This will permit that nutritional/metabolic/pharmacological support can be started early in the course of the disease, before severe weight loss occurs. Indeed, timing is crucial and has to be taken very seriously when applying the therapeutic approach.

A metabolite of leucine (β-hydroxy-β-methylbutyrate) given to sows during pregnancy alters bone development of their newborn offspring by hormonal modulation

The effects of dietary β-hydroxy-β-methylbutyrate (HMB) supplementation during gestation on bone, growth plate, and articular cartilage in newborns were determined. Thermal analysis of articular cartilage was performed to examine the structural changes in collagen. At day 70 of gestation, a total of 12 sows (Large White Polish breed, at the second parity) were randomly assigned to two groups, with each group receiving either a basal diet or the same diet supplemented with 0.2 g/day HMB until the 90^th day. Maternal HMB supplementation enhanced body weight, bone length, and diameter in males. It also improved geometric and mechanical properties contributing to increased bone morphology and endurance. In turn, alteration of the length was only observed in females. The positive effects were mediated by increased serum concentrations of insulin-like growth factor-1 and leptin. HMB-treatment enhanced the concentration of FSH, LH, estradiol, and testosterone. Serum TAP was enhanced by the HMB-treatment by 34% in females and 138% in males. Beneficial effects of the HMB-treatment on trabecular bone and content of proteoglycans in articular cartilage were shown. The HMB-treatment significantly changed the collagen structure in cartilages, especially in the females, which was demonstrated by the PSR analysis. Differences between the HMB-supplemented and the control females in the calorimetric peak temperatures were presumably related to different collagen fibril density in the articular cartilage structure. In summary, maternal HMB supplementation in the mid-gestation period significantly improved general growth and mechanical endurance of long bones by the influence on the somatotropic and pituitary-gonadal axes in the offspring.

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.

Cancer-induced muscle wasting: latest findings in prevention and treatment

Cancer cachexia is a severe and disabling clinical condition that frequently accompanies the development of many types of cancer. Muscle wasting is the hallmark of cancer cachexia and is associated with serious clinical consequences such as physical impairment, poor quality of life, reduced tolerance to treatments and shorter survival. Cancer cachexia may evolve through different stages of clinical relevance, namely pre-cachexia, cachexia and refractory cachexia. Given its detrimental clinical consequences, it appears mandatory to prevent and/or delay the progression of cancer cachexia to its refractory stage by implementing the early recognition and treatment of the nutritional and metabolic alterations occurring during cancer. Research on the molecular mechanisms underlying muscle wasting during cancer cachexia has expanded in the last few years, allowing the identification of several potential therapeutic targets and the development of many promising drugs. Several of these agents have already reached the clinical evaluation, but it is becoming increasingly evident that a single therapy may not be completely successful in the treatment of cancer-related muscle wasting, given its multifactorial and complex pathogenesis. This suggests that early and structured multimodal interventions (including targeted nutritional supplementation, physical exercise and pharmacological interventions) are necessary to prevent and/or treat the devastating consequences of this cancer comorbidity, and future research should focus on this approach.