Sarcopenia is defined as a combination of low muscle mass with low muscle function. The term originated to describe the loss of muscle mass and performance associated with aging. Nowadays, recognized causes of sarcopenia besides aging also include chronic diseases, a physically inactive lifestyle, loss of mobility, and malnutrition (Tournadre, Vial, Capel, Soubrier, & Boirie, 2019). The decline in muscle function is an integral component of frailty, which is defined by a decrease in function of several physiological and psychological systems increasing vulnerability to stressors. In addition to reducing quality of life, there is also an increased risk of morbidity, hospitalization and mortality (Tessier & Chevalier, 2018).
The diagnosis of sarcopenia rests on muscle mass measurements and on functional tests that evaluate either muscle strength or physical performance. The adverse effects of sarcopenia are particularly great in patients with a high fat mass, a condition known as sarcopenic obesity. Typically, these patients are less easy to be recognized as malnourished since their weight/BMI is most often too high. Their fat reserves can account for the needed energy, but not for the protein, vitamin and mineral requirement.
The prevalence of sarcopenia ranges from 3% to 24% depending on the diagnostic criteria and increases with age. For example, in patients with rheumatoid arthritis 20-30% have sarcopenia (Tournadre, Vial, Capel, Soubrier, & Boirie, 2019).
Minimum levels of protein intake are essential for the preservation of muscle mass and function. Epidemiological studies suggest strong associations between protein intake and the different elements of sarcopenia (muscle mass, muscle strength) (Bonnefoy, et al., 2019). In a recently published meta-analysis looking specifically into geriatric rehabilitation patients, it was shown that there was a very high incidence of malnutrition (13%) and risk of malnutrition (47%). The nutritional status was linked to low protein intake and decreased functionality. The prevalence of sarcopenia in this population was very high 40%-76% (Wojzischke, et al., 2020).
In an effort to prevent sarcopenia and maintain physical function and long-term optimal health, large groups of experts issued a consensus statement to increase protein intake recommendations from 0.8 grams/kg body weight/day to 1.0-1.5 grams/ kg body weight/day, depending on the underlying condition of the patient (Deutz, et al., 2014). In addition, they recommend doing daily physical activity as long as activity is possible. Part of the activity should be resistance training. This type of training should be adapted to the age and physical fitness of the patient.
Numerous patients with or at risk of developing sarcopenia, already have difficulties meeting their daily nutritional requirements, resulting already in malnourishment. In Europe, up to 10% of community-dwelling older adults and 35% of those in institutional care do not eat enough to meet the 0.8 gr protein/kg body weight/day (Tieland, Borgonjen-van den Berg, Loon van, & Groot de, 2012). The increased need for protein might therefore be difficult to reach via a normal diet for many patients. A protein supplement can help to meet the daily requirement of patients that are not suffering from other deficiencies. In case of general disease-related malnutrition, an ONS high in protein (S-core) should be considered. This will also ensure supplementation of the most crucial vitamins (e.g. vitamin D and B vitamins) and minerals.