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

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.

Sarcopenia in daily practice: assessment and management

BACKGROUND

Sarcopenia is increasingly recognized as a correlate of ageing and is associated with increased likelihood of adverse outcomes including falls, fractures, frailty and mortality. Several tools have been recommended to assess muscle mass, muscle strength and physical performance in clinical trials. Whilst these tools have proven to be accurate and reliable in investigational settings, many are not easily applied to daily practice.

METHODS

This paper is based on literature reviews performed by members of the European Society for Clinical and Economic Aspects of Osteoporosis and Osteoarthritis (ESCEO) working group on frailty and sarcopenia. Face-to-face meetings were afterwards organized for the whole group to make amendments and discuss further recommendations.

RESULTS

This paper proposes some user-friendly and inexpensive methods that can be used to assess sarcopenia in real-life settings. Healthcare providers, particularly in primary care, should consider an assessment of sarcopenia in individuals at increased risk; suggested tools for assessing risk include the Red Flag Method, the SARC-F questionnaire, the SMI method or different prediction equations. Management of sarcopenia should primarily be patient centered and involve the combination of both resistance and endurance based activity programmes with or without dietary interventions. Development of a number of pharmacological interventions is also in progress.

CONCLUSIONS

Assessment of sarcopenia in individuals with risk factors, symptoms and/or conditions exposing them to the risk of disability will become particularly important in the near future.

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.

Readmission and mortality in malnourished, older, hospitalized adults treated with a specialized oral nutritional supplement: A randomized clinical trial

BACKGROUND

Hospitalized, malnourished older adults have a high risk of readmission and mortality.

OBJECTIVE

Evaluation of a high-protein oral nutritional supplement (HP-HMB) containing beta-hydroxy-beta-methylbutyrate on postdischarge outcomes of nonelective readmission and mortality in malnourished, hospitalized older adults.

DESIGN

Multicenter, randomized, placebo-controlled, double-blind trial.

SETTING

Inpatient and posthospital discharge.

PATIENTS

Older (≥65 years), malnourished (Subjective Global Assessment [SGA] class B or C) adults hospitalized for congestive heart failure, acute myocardial infarction, pneumonia, or chronic obstructive pulmonary disease.

INTERVENTIONS

Standard-of-care plus HP-HMB (n = 328) or a placebo supplement (n = 324), 2 servings/day.

MEASUREMENTS

Primary composite endpoint was 90-day postdischarge incidence of death or nonelective readmission. Other endpoints included 30- and 60-day postdischarge incidence of death or readmission, length of stay (LOS), SGA class, body weight, and activities of daily living (ADL).

RESULTS

The primary composite endpoint was similar between HP-HMB (26.8%) and placebo (31.1%). No between-group differences were observed for 90-day readmission rate, but 90-day mortality was significantly lower with HP-HMB relative to placebo (4.8% vs. 9.7%; relative risk 0.49, 95% confidence interval [CI], 0.27 to 0.90; p = 0.018). The number-needed-to-treat to prevent 1 death was 20.3 (95% CI: 10.9, 121.4). Compared with placebo, HP-HMB resulted in improved odds of better nutritional status (SGA class, OR, 2.04, 95% CI: 1.28, 3.25, p = 0.009) at day 90, and an increase in body weight at day 30 (p = 0.035). LOS and ADL were similar between treatments.

LIMITATIONS

Limited generalizability; patients represent a selected hospitalized population.

CONCLUSIONS

Although no effects were observed for the primary composite endpoint, compared with placebo HP-HMB decreased mortality and improved indices of nutritional status during the 90-day observation period.

CLINICAL TRIAL REGISTRATION

www.ClinicalTrials.govNCT01626742.

β-Hydroxy-β-methylbutyrate, mitochondrial biogenesis, and skeletal muscle health

The metabolic roles of mitochondria go far beyond serving exclusively as the major producer of ATP in tissues and cells. Evidence has shown that mitochondria may function as a key regulator of skeletal muscle fiber types and overall well-being. Maintaining skeletal muscle mitochondrial content and function is important for sustaining health throughout the lifespan. Of great importance, β-hydroxy-β-methylbutyrate (HMB, a metabolite of L-leucine) has been proposed to enhance the protein deposition and efficiency of mitochondrial biogenesis in skeletal muscle, as well as muscle strength in both exercise and clinical settings. Specifically, dietary supplementation with HMB increases the gene expression of peroxisome proliferator-activated receptor gamma co-activator 1-alpha (PGC-1α), which represents an upstream inducer of genes of mitochondrial metabolism, coordinates the expression of both nuclear- and mitochondrion-encoded genes in mitochondrial biogenesis. Additionally, PGC-1α plays a key role in the transformation of skeletal muscle fiber type, leading to a shift toward type I muscle fibers that are rich in mitochondria and have a high capacity for oxidative metabolism. As a nitrogen-free metabolite, HMB holds great promise to improve skeletal muscle mass and function, as well as whole-body health and well-being of animals and humans.

The ergogenic supplement β-hydroxy-β-methylbutyrate (HMB) attenuates insulin resistance through suppressing GLUT-2 in rat liver

This study investigates the effect of the ergogenic supplement β-hydroxy-β-methylbutyrate (HMB) on insulin resistance induced by high-fructose diet (HFD) in rats. Male Sprague Dawley rats were fed 60% HFD for 12 weeks and HMB (320 mg·kg(-1)·day(-1), orally) for 4 weeks. HFD significantly increased fasting insulin, fasting glucose, glycosylated hemoglobin (HBA1C), liver glycogen content, and homeostasis model assessment of insulin resistance (HOMA-IR) index, while it decreased glucose and insulin tolerance. Furthermore, HFD significantly increased serum triglycerides (TG), low density lipoprotein cholesterol (LDL-C), and very low density lipoprotein cholesterol (VLDL-C) levels, while it significantly decreased high density lipoprotein cholesterol (HDL-C). Moreover, HFD significantly increased mRNA expression of glucose transporter type-2 (GLUT-2), the mammalian target of rapamycin (mTOR), and sterol regulatory element-binding protein-1c (SREBP-1c) but decreased peroxisome proliferator-activated receptor-alpha (PPAR-α) in liver. Aortic relaxation to acetylcholine (ACh) was impaired and histopathology showed severe hepatic steatosis. HMB significantly increased insulin tolerance and decreased fasting insulin, HOMA-IR, HBA1C, hepatic glycogen content, serum TG, LDL-C, and VLDL-C. Additionally, HMB enhanced ACh-induced relaxation, ameliorated hepatic steatosis, and decreased mRNA expression of GLUT-2. In conclusion, HMB may attenuate insulin resistance and hepatic steatosis through inhibiting GLUT-2 in liver.

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.

Evaluating the effect of 20-hydroxyecdysone (20HE) on mechanistic target of rapamycin complex 1 (mTORC1) signaling in the skeletal muscle and liver of rats

Phytoecdysteroids such as 20-hydroxyecdysone (20HE) are nutritional supplements marketed as enhancers of lean body mass. In this study the impact of 20HE ingestion on protein kinase B/Akt-mechanistic target of rapamycin complex 1 signaling in the skeletal muscle and liver of male rats was found to be limited. Bioavailability of 20HE, whether consumed alone or with leucine, also remained low at all doses ingested. Additional work is necessary to clarify 20HE mechanism of action in vivo.

Nutritional supplements in support of resistance exercise to counter age-related sarcopenia

Age-related sarcopenia, composed of myopenia (a decline in muscle mass) and dynapenia (a decline in muscle strength), can compromise physical function, increase risk of disability, and lower quality of life in older adults. There are no available pharmaceutical treatments for this condition, but evidence shows resistance training (RT) is a viable and relatively low-cost treatment with an exceptionally positive side effect profile. Further evidence suggests that RT-induced increases in muscle mass, strength, and function can be enhanced by certain foods, nutrients, or nutritional supplements. This brief review focuses on adjunctive nutritional strategies, which have a reasonable evidence base, to enhance RT-induced gains in outcomes relevant to sarcopenia and to reducing risk of functional declines.

Beta hydroxy beta methylbutyrate supplementation impairs peripheral insulin sensitivity in healthy sedentary Wistar rats

AIM

Investigate, in healthy sedentary rats, the potential mechanisms involved on the effects of beta hydroxy beta methylbutyrate (HMB) supplementation upon the glycaemic homeostasis, by evaluating the insulin sensitivity in liver, skeletal muscle, and white adipose tissue.

METHODS

Rats were supplemented with either beta hydroxy beta methylbutyrate (320 mg kg(-1)  BW) or saline by gavage for 4 weeks. After the experimental period, the animals were subjected to the glucose tolerance test (GTT) and plasma non-esterified fatty acids (NEFA) concentration measurements. The soleus skeletal muscle, liver and white adipose tissue were removed for molecular (western blotting and RT-PCR) and histological analysis.

RESULTS

The beta hydroxy beta methylbutyrate supplemented rats presented: (i) higher ratio between the area under the curve (AUC) of insulinaemia and glycaemia during glucose tolerance test; (ii) impairment of insulin sensitivity on liver and soleus skeletal muscle after insulin overload; (iii) reduction of glucose transporter 4 (GLUT 4) total and plasma membrane content on soleus; (iv) increased hormone-sensitive lipase (HSL) mRNA and protein expression on white adipose tissue and plasma NEFA levels and (v) reduction of fibre cross-sectional area of soleus muscle.

CONCLUSION

The data altogether indicate that beta hydroxy beta methylbutyrate supplementation impairs insulin sensitivity in healthy sedentary rats, which, in the long-term, could lead to an increased risk of developing type 2 diabetes.

An overview of amines as nutritional supplements to counteract cancer cachexia

Cancer cachexia is a complex multifactorial syndrome characterized by loss of skeletal muscle mass (with or without loss of fat mass) that cannot be fully reversed by conventional nutritional support and leads to progressive functional impairment. Recently, some amino acids and other amine dietary supplements have been highlighted in medical field due to positive effects upon diseases evolving skeletal muscle atrophy. Therefore, the aim of this brief review is to discuss the putative application of amines as dietary supplements to counteract skeletal muscle wasting on cancer cachexia. Specifically, we focus in two nutritional supplements: (1) branched-chain amino acids (BCAAs) and (2) creatine. Both BCAAs and creatine may attenuate proteolysis and enhance proteins synthesis in skeletal muscle. Although more experimental studies and clinical trials are still necessary to elucidate this therapeutic application, several evidences have demonstrated that amines supplementation is a promising coadjuvant treatment to cancer cachexia.