Scientists of Lithuanian Sports University (LSU) have been conducting research for many years to find out the importance of nutritional features for skeletal muscle mass and contractile strength. The data obtained were presented in the article “Effects of ten-week 30 % caloric restriction on metabolic health and skeletal muscles of adult and old C57BL/6 J mice“, published in journal “Mechanisms of Ageing and Development“ (impact factor – 4.304).
The research aimed at investigating the effects of caloric restriction on skeletal muscle in adults and the elderly. The experiments on humans are complicated by human genetic differences, the diversity of living conditions and eating habits, and the inaccuracies that result from estimating the caloric intake. Therefore, the scientists chose the C57BL / 6 J mice, often used to study the metabolic features of humans. Mice aged 6 and 24 months, corresponding to the human ages of 30 and 70, were selected for the research.
“The study revealed that with a 30 percent reduction in feed intake, adult and old mice lost 20 to 40 percent of their body mass and significantly improved their glucose metabolism. However, there was a decrease in skeletal muscle mass and contractile strength, which can have negative effects in old age, when muscle mass decreases,” says LSU scientist Prof. Aivaras Ratkevičius.
The study reveals a reduction in muscle mass, important for physical activity in mice, from 17 to 20 percent. The mass of other muscles, which are activated less frequently, changed even more – from 27 to 34 percent. Caloric restriction increased the amount of slow-twitch muscle fibers, which was reflected in slower muscle contractions.
The results of the research indicate that caloric restriction improves metabolic health but reduces skeletal muscle mass and strength. It is advisable to combine caloric restriction with exercise to reduce the negative effects on skeletal muscle. This is especially important in old age.
The research was conducted by LSU junior researcher Mindaugas Kvedaras, Dr. Petras Minderis, PhD student Raulas Krušnauskas and Prof. Aivaras Ratkevičius.