Know-How: Protein for over 40

As we enter the third decade of life, a subtle but significant change in the body begins: age-related muscle loss. From the age of 30, a gradual decline in muscle mass and strength sets in, which can have far-reaching effects on physical performance.

To counteract this natural process, a targeted protein intake and a balanced diet are crucial. Proteins not only act as building blocks for the muscles, but also play a central role in the regeneration and maintenance of muscle mass in old age.

As they get older, many older athletes strive to maintain or even improve their performance from their younger years. However, this claim contrasts with the inevitable decline in performance that occurs as we age.

Peak endurance performance remains stable until around the age of 35, but this is followed by a gradual decline until the age of 50-60, followed by progressively steeper declines.

Physiological parameters such as Vo2max (maximum oxygen uptake), maximum heart rate and athletic performance are subject to a constant reduction with age. These changes contribute significantly to the loss of muscle mass and muscle strength, which in turn affects general physical performance.

In addition to these challenges, susceptibility to injury increases with age, accompanied by longer recovery times. This increased susceptibility to injury represents an additional hurdle for older individuals and requires careful consideration of training intensities and targeted rehabilitation measures.

Overall, this analysis illustrates the complex relationships between muscle loss, physiological changes and increased susceptibility to injury in old age. A holistic approach that includes nutrition, protein intake, adapted training and preventive measures is crucial to promote muscle health in old age and ensure an optimal quality of life.

Scientific source:

• Bean, Anita. The Complete Guide to Sports Nutrition: 8th edition (Complete Guides) (English Edition). Bloomsbury Publishing.
• Tanaka, H. & Seals, D.R. (2008). Endurance exercise performance in Masters athletes: age-associated changes and underlying physiologicalmechanisms. J Physiol. 586(1): pp 55-63.
• Janssen, I. et al. (2000), ‘Skeletal muscle mass and distribution in 468 men and women aged 18–88 yr’. J. Appl. Physiol., vol. 89(1), pp. 81–8.

As we age, the body's response to the anabolic effects of protein may be impaired, which may make older people less efficient at responding to protein intake than their younger counterparts. This lack of efficiency may mean that older people need a higher protein intake to prevent or at least slow down muscle loss.

Anabolic resistance, which characterizes a reduced effectiveness of anabolic stimuli, becomes more important with age. At an older age, the body is less receptive to the anabolic effects of protein. This underlines the need for increased protein intake, not only as a preventative measure against muscle loss, but also as a key strategy to counteract the negative effects of anabolic resistance.

The scientific sources of Rennie (2009) and Burd et al. (2013) provide insights into anabolic resistance and its effects on muscle health in old age. These studies emphasize the challenges associated with advancing age in terms of muscle health, particularly the impairment of protein utilization and anabolic responses.

Scientific source:

• Rennie, M. J. (2009), ‘Anabolic resistance: the effects of aging, sexual dimorphism, and immobilization on human muscle protein turnover’. Appl. Physiol. Nutr. Metab., vol. 34, pp. 377–81.
• Burd, N. A. et al. (2013), ‘Anabolic resistance of muscle protein synthesis with aging’. Exerc. Sport Sci. Rev., vol. 41, pp. 169–73.

The conventional guidelines for daily protein intake, in particular the recommended daily allowance (RDA) of 0.8g protein per kilogram of body weight, are being called into question by current research findings, particularly in relation to older people. The traditional RDA no longer seems to correspond to the latest findings, as current studies indicate that older people have an increased protein requirement of over 1.2g per kilogram of body weight in order to effectively prevent or at least reduce age-related muscle loss.

The latest research findings also emphasize the importance not only of the total amount of protein consumed but also of its distribution across meals. Due to anabolic resistance with age, it is recommended that each meal or portion should contain more than 25 grams of protein. This recommendation aims to maximize the anabolic response in the body and effectively minimize muscle breakdown.

This paradigm shift emphasizes the need for an individualized diet that meets the specific requirements of older people. The focus on the quantity and quality of protein intake is becoming a key element in the diet of older people. The findings from studies such as Bauer et al. (2013), Deutz et al. (2014), Lonnie et al. (2018), Wolfe (2012), Deer & Volpi (2015), Moore et al. (2015), Witard et al. (2016) underline the dynamic nature of the nutrition field and its constant adaptation to the latest scientific developments.

The overall picture of these findings highlights the importance of muscle health in old age and the central role that protein intake plays in this. It is recommended that existing guidelines be reviewed and an individualized approach be taken to meet the specific needs of older people and improve their quality of life.

Scientific source:

• Bauer, J. et al. (2013). Evidence-Based Recommendations for Optimal Dietary Protein Intake in Older People: A Position Paper From the PROT-AGE Study Group. JAMDA 14 (2013) 542-559.
• Deutza N.E.P. et al. (2014). Protein intake and exercise for optimal muscle function with aging: Recommendations from the ESPEN Expert Group. Clin Nutr. 33(6):929-936.
• Lonnie, M. et al. (2018). Protein for Life: Review of Optimal Protein Intake, Sustainable Dietary Sources and the Effect on Appetite in Ageing Adults. Nutrients. 10(360)
• Wolfe, R.R. (2012). The role of dietary protein in optimizing muscle mass, function and health outcomes in older individuals. British Journal of Nutrition (2012), 108, S88–S93.
• Deer, R. & Volpi, E. (2015). Protein Intake and Muscle Function in Older Adults. Curr Opin Clin Nutr Metab Care. 18(3): 248-253.
• Moore, D. R. et al. (2015), ‘Protein ingestion to stimulate myofibrillar protein synthesis requires greater relative protein intakes in healthy older versus younger men’. J. Gerontol. A. Biol. Sci. Med. Sci. vol. 70(1), pp. 57–62.
• Witard O.C, et al (2016), ‘Protein Considerations for Optimising Skeletal Muscle Mass in Healthy Young and Older Adults.’ Nutrients. Vol 8 (4), p.181.

The conventional leucine recommendation according to the Recommended Dietary Allowance (RDA) of 0.39 mg per kilogram of body weight is being called into question by current research findings, particularly in the context of the ageing process. Recent findings suggest that this previous leucine recommendation is not sufficient, especially for older people whose muscle health is the focus. It is now recommended that older people need double the previous amount of leucine, about 5 g of leucine per serving, to prevent muscle breakdown and actively promote muscle building.

Leucine, as an essential amino acid, moves(thereby) as a central stimulator for muscle building and maintenance. Its role in the stimulation of protein synthesis in muscle tissue (is of crucial importance and) gains relevance especially in old age.

As we get older, leucine becomes an essential building block for muscle building. This is particularly important as the body may respond less effectively to other anabolic signals. The targeted intake of leucine is therefore a key strategy for counteracting age-related muscle loss and maintaining muscle mass in old age.

The scientific sources, in particular studies such as Szwiega et al. (2021), Katsanos et al. (2005) und Murphy et al. (2016), support these findings. These studies emphasize the higher leucine requirement in older individuals to optimize protein synthesis and effectively combat muscle loss. Overall, these findings not only illustrate the increasing importance of leucine in the diet of older people but also the necessity to adjust existing recommendations according to the latest scientific knowledge. This paradigm shift emphasizes the dynamism of nutrition research and its continual adaptation to meet the individual needs of various stages of life.

Scientific source:

• Szwiega, S. et al. (2021). Dietary leucine requirement of older men and women is higher than current recommendations. Am J Clin Nutr 2021;113:410–419.
• Katsanos, C.S. et al. (2005). A high proportion of leucine is required for optimal stimulation of the rate of muscle protein synthesis by essential amino acids in the elderly. Am J Physiol Endocrinol Metab 291: E381–E387.
• Murphy, C.H. et al. (2016). Leucine supplementation enhances integrative myofibrillar protein synthesis in free-living older men consuming lower- and higher-protein diets: a parallel-group crossover study. Am J Clin Nutr 2016;104:1594–606.

The significance of leucine for muscle health extends not only to men aged 30 and above but also plays a crucial role in women in this age group. The findings from studies emphasize that leucine is not only crucial for men but also for women aged 30 and above. (siehe Devries et. al. 2018)

Leucine serves as an essential building block that can support not only muscle preservation but also muscle building in older women. It is becoming increasingly clear that leucine plays a key role in promoting muscle health, regardless of gender.

The targeted intake of sufficient leucine in conjunction with a balanced diet and regular physical activity can help older women to age healthily and maintain or even build their muscle mass. This underscores the importance of a holistic approach that combines nutrition, leucine intake, and physical activity to promote the muscle health of older women.

The research findings by Devries et al. from 2018 support these statements and emphasize that the leucine content in dietary supplements is a central determinant for the muscle anabolic responses of older women. This underscores the importance of targeted leucine intake as a strategic intervention point to effectively counteract age-related loss of muscle mass in women aged 30 and above.

Scientific source:

• Devries, M.C. et al. (2018). Leucine, Not Total Protein, Content of a Supplement Is the Primary Determinant of Muscle Protein Anabolic Responses in Healthy Older Women. The Hournal of Nutrition.
• Devries, M.C. et al. (2018). Protein leucine content is a determinant of shorter- and longer-term muscle protein synthetic responses at rest and following resistance exercise in healthy older women: a randomized, controlled trial. Am J Clin Nutr 2018;107:217–226.

The loss of muscle mass poses a significant challenge for individuals as early as 30 years old. It is associated with various negative effects such as sarcopenia, decline in athletic performance, and a general impairment of well-being. Here, leucine plays an outstanding role as a preventive measure. It holds a key position in the regulation of protein synthesis in muscle tissue.

The significance of leucine as a preventive strategy is supported by recent research findings outlined in the study by Kang et al. (2020). This randomized, double-blind, placebo-controlled trial demonstrates that targeted intake of leucine-enriched proteins in individuals aged 50 and above can help maintain muscle mass and counteract age-related muscle loss.

The study results illustrate that adequate leucine intake not only prevents muscle breakdown but also effectively maintains muscle mass. This, in turn, can have positive effects on overall health, athletic performance, and well-being.

The preventive role of leucine extends beyond just muscle health and has potential implications for various aspects of daily life. The insights from the study by Kang et al. underline the relevance of targeted leucine intake as a preventive measure to proactively address the challenges of muscle loss in aging.

Scientific source:

• Kang, Y. et al. (2020). Leucine-Enriched Protein Supplementation Increases Lean Body Mass in Healthy Korean Adults Aged 50 Years and Older: A Randomized, Double-Blind, Placebo-Controlled Trial. Nutrients 2020, 12, 1816