RESUMEN
BACKGROUND: The aging process has great impact on body composition, such as the increase of adipose tissue in abdominal region, and the decrease of lean body mass, due to skeletal muscle loss. A reduction in muscle mass is associated to high risk of fractures and falls, loss of mobility, and increased number of hospitalizations. Beta-hydroxy-beta-methylbutyrate (HMB) is a biological substance derived from leucine metabolism, with anabolic and anticatabolic properties. Some HMB effects are tissue repair stimulation and protein anabolism. AIMS: We aimed to evaluate the effects of HMB supplementation on body composition and muscle strength in elderly, as well as to identify the efficient dosages to reach these effects. METHODS: This review included studies that evaluated muscle mass and muscle strength, associated or not with physical exercise and diet in elderly people. Only studies published from 2008 to 2019 were selected for analysis. RESULTS: Six articles were included in the review. The used doses varied from 1.5 to 3 g. In 5 studies, HMB supplementation was associated with calcium; only 1 study did not use the oral administration route. Two studies used 4 g of maltodextrin as a vehicle; 1 used HMB with a hypercaloric and hyperproteic supplement; 1 associated HMB with lysine and arginine; and 1 with arginine and glutamine. Supplementation of 3 g of HMB has shown to be most beneficial in improving strength and body composition in people over 65 years, especially in bed rest and untrained conditions. CONCLUSION: Our findings suggest that HMB has a positive effect on body composition and strength, especially in bedridden or sedentary elderly, due to its anticatabolic properties.
Asunto(s)
Composición Corporal/efectos de los fármacos , Suplementos Dietéticos , Fuerza Muscular/efectos de los fármacos , Músculo Esquelético/efectos de los fármacos , Valeratos/administración & dosificación , Anciano , Anciano de 80 o más Años , Ensayos Clínicos como Asunto , Femenino , Humanos , Masculino , Sarcopenia/prevención & controlRESUMEN
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.