Samenvatting

Background: Society ages, and the incidence of physical limitations and frailty is increasing. For frail older adults, these limitations will lead to more assistance in daily living activities. A significant cause of physical limitation and frailty is sarcopenia, age-related loss of skeletal muscle mass, strength and performance. Adequate dietary protein intake is essential to improve skeletal muscle mass, strength and performance during resistance training in older adults. Protein supplementation is a popular strategy among athletes (especially among bodybuilders) to increase muscle protein synthesis after exercise. The most common protein supplement is whey protein. Research has shown that 20-40 g of whey protein increases muscle protein synthesis in healthy young subjects. However, can protein supplementation increase muscle protein synthesis in elderly subjects? Method: A systematic review was conducted in order to answer the research question. PubMed database was searched (March first until April first) using pre-defined search terms. First, an independent researcher searched the studies and assessed them based on title and abstract. The rest of the studies were assessed on full text and selected based on eligibility. The study characteristics and outcomes were extracted and arranged in table 1. The Cochrane risk of bias tool and the AMSTAR 2 checklist was used to praise the quality of the included studies. Results: This systematic review identified a total of 165 studies. One study was a duplicate, and 164 studies were screened on title and abstract, from which seven were included in this systematic review. Seven primary studies involving 172 participants met the criteria and were analyzed. All studies used FSR to measure muscle protein synthesis and found that whey protein increased FSR significantly compared to other protein sources like milk or casein and maltodextrin. Conclusion: This review found that consuming whey protein stimulates muscle protein synthesis significantly higher when compared to other protein sources like milk or casein and increases daily protein intake, which plays an essential role in the prevention of sarcopenia and could aid those who do not consume enough daily and would therefore support healthy ageing.