Blessed proteins. The reserves of muscle function and for those over 60

Abstract: what does science say?

Proteins are macronutrients necessary for tissue building and maintenance, with a central role in muscle function, the immune system, and numerous metabolic processes. In older individuals, the ability to respond to anabolic stimuli from meals is attenuated ("anabolic resistance"): for this reason, specific recommendations suggest intakes that are, on average, higher than those provided by the current RDA for younger adults. Experimental and observational evidence indicates that protein intakes around 1.0–1.5 g/kg/day can support the maintenance of lean mass and recovery from illness in older subjects, while increasing protein intake is more effective when combined with resistance exercises. However, results vary by context (healthy vs. frail older adults, presence of acute or chronic illness, level of physical activity) and by the type and distribution of proteins throughout the day. Epidemiological observations suggest consistent associations, but the heterogeneity of randomized controlled trials necessitates a cautious interpretation: there is no universal rule valid for everyone, and nutritional choices must be personalized in relation to clinical status, appetite, and tolerance.

What it means in practice

For those involved in public health or for readers interested in preventing muscle mass loss, the practical message is concrete but not prescriptive. In the over-60 population, maintaining sufficient protein intake and regular physical activity—particularly resistance exercises—represents the strategy with the strongest evidence of benefit for strength, autonomy, and quality of life. Guidelines and consensus documents recommend a higher daily average compared to the classic RDA for young adults, with targets often indicated between 1.0 and 1.2 g/kg of body weight and up to 1.2–1.5 g/kg in cases of acute illness or rehabilitation; however, kidney function and the patient's general condition must be assessed. [1] The best-documented benefits emerge when protein intake is combined with resistance programs or multimodal interventions. [3][4]

How much, when, and what sources to choose

The literature indicates that distributing protein across multiple meals throughout the day and ensuring a sufficient amount of essential amino acids—particularly leucine—in each meal can improve the anabolic muscle response in older adults. [6] Sources with high biological value (meat, fish, eggs, dairy; or well-planned plant-based combinations) are more effective in providing the necessary amino acids. In contexts of reduced appetite, targeted supplementation can facilitate meeting requirements. [8]

Protein, satiety, and weight management

For the same calorie intake, increasing the energy percentage provided by protein tends to improve satiety and the preservation of lean mass during caloric restriction; this effect is mediated by multiple mechanisms, including hormonal changes and the higher energy expenditure for protein digestion. [5] However, individual effects vary and depend on meal composition and physical activity level.

Main scientific evidence and what it shows

Consensus guidelines and clinical studies provide important but not always consistent indications: the PROT-AGE group recommends, on average, higher intakes for those over 65 compared to the standard RDA. [1] Meta-analyses of protein supplementation interventions with exercise show more robust increases in lean mass and strength when supplementation is combined with resistance programs. [3][4] However, randomized clinical trials in specific populations have reported conflicting results: for example, a controlled study on older men with functional limitations did not document increases in lean mass when comparing 0.8 g/kg/d with 1.3 g/kg/d in the absence of changes in physical activity. [2] In frail populations and during rehabilitation, however, protein supplementation combined with nutritional and exercise interventions has shown improvements in physical performance. [8]

Key points to remember

• For those over 60, protein requirements tend to be higher than for young adults; typical consensus-recommended targets are 1.0–1.2 g/kg/day and up to 1.2–1.5 g/kg in particular clinical situations. [1]
• The most consistent effect on maintaining or gaining lean mass is achieved when protein intake is combined with resistance exercise. [3][4]
• Distributing protein across meals and prioritizing sources rich in essential amino acids, especially leucine, promotes muscle synthesis. [6]
• In weight loss contexts, higher protein intake can increase satiety and help preserve muscle. [5]
• Interventions must be individualized: kidney function, appetite, comorbidities, and dietary preferences are decisive factors.

Limitations of the evidence

It is important to distinguish between observational associations and causal evidence provided by randomized controlled trials. Much of the observational literature reports correlations between higher protein intake and better indicators of lean mass, but these associations do not prove causality. RCTs provide more robust evidence but are often limited by duration, sample size, and variability in the intervention (dose, type of protein, presence or absence of exercise). [2][4] Some controlled studies do not show clear benefits of increased protein alone in the absence of exercise, indicating that context is crucial. [2] Furthermore, biological measures (e.g., acute MPS) do not always translate into measurable chronic gains in muscle mass. [6] Finally, the studied population (healthy vs. frail older adults, presence of chronic disease, nutritional status) strongly influences the results; therefore, general recommendations must be adapted on a case-by-case basis.

Editorial conclusion

Proteins remain a central element in strategies aimed at protecting muscle function with advancing age. The literature supports the idea that, for many over 60, protein intakes higher than the classic RDA and adequate distribution throughout the day can contribute to maintaining lean mass, especially when combined with resistance exercises. However, there is no single solution: the choice of quantity, quality, and method of supplementation must be evaluated in light of clinical status, functional capacity, and individual preferences. For targeted interventions and for people with specific pathologies, consultation with qualified healthcare professionals remains essential.

Editorial note

This article revisits and updates previously published content, re-elaborating it according to scientific and divulgative criteria. It is for informational purposes only and does not replace personalized medical advice. For clinical decisions regarding diet, supplementation, or physical activity, consult a doctor or a qualified nutrition professional.

Scientific research

1. Evidence-based recommendations for optimal dietary protein intake in older people: a position paper from the PROT-AGE Study Group. J Am Med Dir Assoc. 2013. https://doi.org/10.1016/j.jamda.2013.05.021. [1]
2. Effect of Protein Intake on Lean Body Mass in Functionally Limited Older Men: A Randomized Clinical Trial. JAMA Intern Med. 2018. https://doi.org/10.1001/jamainternmed.2018.0008. [2]
3. A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training–induced gains in muscle mass and strength in healthy adults. Br J Sports Med. 2018. https://doi.org/10.1136/bjsports-2017-097608. [3]
4. Protein supplementation augments the adaptive response of skeletal muscle to resistance-type exercise training: a meta-analysis. Am J Clin Nutr. 2012. https://doi.org/10.3945/ajcn.112.037556. [4]
5. The role of protein in weight loss and maintenance. Am J Clin Nutr. 2015 (supplement). https://doi.org/10.3945/ajcn.114.084038. [5]
6. Evaluating the leucine trigger hypothesis to explain the post-prandial regulation of muscle protein synthesis in young and older adults: a systematic review. Front Nutr. 2021. https://doi.org/10.3389/fnut.2021.685165. [6]
7. The impact of whey protein supplementation on sarcopenia progression among the elderly: a systematic review and meta-analysis. Nutrients. 2023. https://doi.org/10.3390/nu15092039. [7]
8. Protein supplementation improves physical performance in frail elderly people: a randomized, double-blind, placebo-controlled trial. J Am Med Dir Assoc. 2012. https://doi.org/10.1016/j.jamda.2012.07.005. [8]