Sarcopenia is a disease associated with the aging process. Loss of muscle mass and strength, which in turn affects balance, gait and overall ability to perform tasks of daily living, are hallmark signs of this disease. Generally speaking, after the age of 50 we naturally lose about 1 % of our muscle mass per year. These small losses go mostly unnoticed, but over time they can accumulate, resulting in decreased strength and function which can lead to an increased risk of falling, physical disability, frailty and poor quality of life.
The prevalence of sarcopenia varies depending on the diagnostic criteria used but it is estimated to be 29 % of the elderly population. In one study, the prevalence of sarcopenia increased dramatically with age from 4 % of men and 3 % of women aged 70-75 to 16 % of men and 13 % of women aged 85 or older. In a recent study involving 1483 people over or at the age of 65 years in South Africa, 12.9% were diagnosed with sarcopenia and 10.3% with sarcopenic obesity.
Muscle weakness which can interfere with physical activity is a symptom of sarcopenia. However, clinical measures of the muscle mass and function are needed to detect sarcopenia, under the care of a clinical practitioner. Muscle mass can be measured by body composition assessment techniques such as DXAs (Dual X-ray absorptiometry), MRIs (Magnetic Resonance Imaging) and CTs (Computed Tomography); or bioelectrical impedance. Physical performance measures include knee extensions, walking speed, hand grip tests and time taken to stand from a seated position.
Maintaining our muscle health is essential to prevent sarcopenia. Exercise, combined with good quality protein, are key considerations for strong, healthy muscles. The best exercises to stimulate muscle growth are ‘resistance’ types, which are weight bearing or involve impact. Examples include brisk walking, running, lifting weights or step-aerobics. A balanced diet that includes sufficient protein is also needed. Animal based proteins, which include dairy, lean meat, poultry, fish and eggs are the richest sources, with legumes such as beans and lentils also providing some protein. Timing and quality are important when it comes to our consumption of protein and the optimal approach is that we spread our intake across the day, rather than concentrating a larger amount at one meal. This enables the body to be efficient in supplying the constant amounts needed by active muscles throughout the day.
Dairy foods such as milk, yogurt and cheese are good sources of calcium and rich in high quality protein. Calcium plays a role in normal muscle function, while protein contributes to muscle growth and maintenance. Proteins are made up of building blocks called amino acids, with an amino acid called leucine being one of the most effective at stimulating muscle growth. The dairy protein whey, which is rich in leucine, has been indicated as being particularly beneficial for muscle growth and repair. Dairy foods are also recognised as versatile and convenient foods that can be enjoyed across meal and snacking occasions, in cooking and baking. This makes it easy to include protein at regular intervals, which is recommended to supply the constant amounts needed by active muscles throughout the day.