As we age, our muscles undergo significant changes that lead to losing muscle mass, strength, and functional abilities. The good news is that a proper diet, especially one containing a lot of protein, can minimize these age-related damages.
In this article, we will understand why protein is essential for muscle maintenance and how we can use it to our advantage as we age.
The Role of Protein in Building Muscle
Proteins are considered macronutrients like fats and carbohydrates, as they provide energy. Proteins are also essential for muscle protein synthesis (MPS), the biological pathway by which the body builds new muscle proteins (1,2).
This process is essential for repairing and regenerating tissues after exercise or injury (1). Proteins are vital for:
- Muscle synthesis and repair: proteins are crucial for repairing muscle fibers after exercise, aiding in growth and strengthening.
- Anabolic Action: high-quality proteins, such as whey protein, activate the mTOR pathway, stimulating muscle growth (1, 3).
- Protein Balance: adequate protein intake helps maintain muscle synthesis and counteracts degradation, especially with aging.
After a workout, the muscles suffer microdamage that needs to be repaired. Protein helps regenerate these fibers and promote muscle growth. During post-exercise recovery, protein intake is essential to prevent muscle loss and repair damaged fibers efficiently.
What Happens to Muscles as We Age?
As we age, our body naturally undergoes a gradual and progressive loss of muscle mass. Several factors contribute to this landscape (1,2):
- The body’s response to exercise stimuli decreases,
- Muscle protein synthesis becomes less efficient,
- Muscle protein metabolism also slows down,
- Aging muscle is less sensitive to the positive effects of dietary protein on protein synthesis, a condition known as anabolic resistance (1).
Together, these factors contribute to the progressive loss of muscle mass, reduced strength, and physical endurance, a phenomenon known as sarcopenia (1). Sarcopenia affects people over 60, particularly sedentary adults, leading to a significant loss of strength and mobility. But don’t worry, maintaining muscle mass after 60 is possible, with the right care!
Sarcopenia: How to Prevent Muscle Loss in the Elderly
Sarcopenia affects an increasing number of older adults, with up to 30% of the population over 60 showing signs of the condition. The good news is that effective prevention and treatment are available (3). The secret is a combination of:
- regular exercise,
- especially resistance training,
- good nutrition, mainly adequate protein and energy intake (1).
Regular physical activity is essential for maintaining skeletal muscle strength and function in older adults. However, resistance exercise has been shown to significantly benefit aging muscles, promoting muscle mass, strength, and overall physical function (1).
Adequate protein intake after age 60 is crucial to maintaining muscle integrity. High-quality proteins, such as those found in whey, contain essential amino acids that stimulate muscle synthesis (1,3). Whey protein is particularly effective because it contains rapidly absorbed amino acids and a high concentration of leucine, which plays a crucial role in increasing muscle synthesis (1,3).
Several studies have reinforced the need to increase protein intake for older adults, helping to preserve muscle mass and prevent age-associated muscle loss. Some findings indicated that the optimal amount of protein to maximize MPS increases with age. In young adults (~20 years), around 20 g of protein is sufficient to maximize MPS (4). In contrast, in healthy adults over 70 years, a dose of 35 g provides a greater MPS stimulus than doses of 10 or 20 g (5). In healthy older adults over 70 years, a protein intake above 1.0 g/kg/day protects against weight loss (6).
How Much Protein to Prevent Muscle Loss?
Protein needs vary depending on age, sex, and physical activity level. People, especially those who are more active, may need more protein to support muscle building and prevent muscle loss (2). In general, the daily protein recommendation for healthy adults of all ages is 0.8 g per kg of body weight.
According to the European Society for Clinical Nutrition and Metabolism (ESPEN), this amount should be increased for people over 65 years of age. For healthy adults, the recommendation is to consume between 1.0 and 1.2 grams of protein per kg of body weight. For adults older than 65 years at risk of sarcopenia or who exercise regularly, this value can increase from 1.2 to 1.5 grams (1).
In addition, the ESPEN encourages regular physical activity among older adults to promote muscle health.
The Relationship Between Protein Intake and Muscle Function in Older Adults
As we age, our bodies require high amounts of protein, particularly due to anabolic resistance (1). Thus, the evidence provided by the ESPEN expert group suggests that adequate protein intake can improve muscle function in older adults (1).
Specifically, sufficient protein intake has been shown to (1,2,3):
