The role of protein in combatting age-related muscle weakness

As we get older, our muscle mass and strength naturally decrease¹. This can make it harder to do everyday activities and can increase the chances of falling or developing health conditions like diabetes, arthritis, osteoporosis, and heart disease^2-6. 

Strength training is one element that can prevent muscles from getting weaker as we age⁷. But another important factor is how much protein we eat every day. Protein might be the secret weapon for keeping muscles strong and healthy, and boosting overall health. So, are you getting enough protein in your diet? 

What is the right level of protein for you?   

It is recommended that healthy younger adults consume 1-1.2 grams of protein per kilogram of body weight each day to help maintain their muscle mass⁸. For adults of this age who are strength training, greater improvements in muscle mass have been linked with a higher level of protein intake of 1.2-1.6 grams per kilogram of body weight⁹.  

Regardless of whether they are strength training or not, the recommended protein intake for older adults is 1.2-1.5 grams per kilogram of body weight¹⁰. It's important to note that not getting enough protein in the diet for older adults can lead to a loss in muscle mass¹¹. Check out the table below for suggested protein amounts based on different body weights.  

Recommended protein intake per kilogram of body weight

How to maximise protein intake throughout the day   

While the body could potentially absorb an unlimited amount of protein, there is likely competition in how the body uses the different amino acids (the building blocks of protein). This idea may be why results from short-term studies contrast on what the maximal amount of protein can be consumed in one meal to improve muscle mass and strength^12,13. 

International position statements suggest that aiming for about 0.4 grams of protein per kilogram of body weight per meal across three to four meals is probably easier and best for reaching a daily intake of around 1.6 grams per kilogram of body weight to optimise muscle mass and strength, especially for those doing strength training^10,12,14. 

Interestingly, Australians tend to eat less protein at breakfast compared to lunch and dinner¹⁶.  Having protein for breakfast is a great way to evenly spread out your protein intake throughout the day¹⁵.  

What are the health benefits of a high protein diet?  

Higher protein diets have been linked to greater weight loss, preserving lean mass when losing weight, reductions in fasting glucose and blood pressure, and improvements in muscle and bone mass and strength, especially for older adults^2,3,17,18.  

Getting enough protein is an important component of a healthy lifestyle, especially as we get older. By getting an adequate protein intake throughout the day, we can get the most out of strength training to muscle mass, strength, and our overall health.   

References  

1. Nilwik R, Snijders T, Leenders M, Groen BBL, van Kranenburg J, Verdijk LB, et al. The decline in skeletal muscle mass with aging is mainly attributed to a reduction in type II muscle fiber size. Exp Gerontol 2013; 48:492–498. 

2. Trombetti A, Reid KF, Hars M, Herrmann FR, Pasha E, Phillips EM, et al. Age-associated declines in muscle mass, strength, power, and physical performance: impact on fear of falling and quality of life. Osteoporos Int 2016; 27:463–471.  

3. Chen Z, Franco OH, Lamballais S, Ikram MA, Schoufour JD, Muka T, et al. Associations of specific dietary protein with longitudinal insulin resistance, prediabetes and type 2 diabetes: The Rotterdam Study. Clin Nutr 2020; 39:242–249.  

4. Beasley JM, Lacroix AZ, Neuhouser ML, Huang Y, Tinker L, Woods N, et al. Protein intake and incident frailty in the women’s health initiative observational study. J Am Geriatr Soc 2010; 58:1063–1071.  

5. Veronese N, Soysal P, Stubbs B, Maggi S, Jackson SE, Demurtas J, et al. Dietary Protein Intake and Falls in Older People: Longitudinal Analyses From the Osteoarthritis Initiative. J Am Med Dir Assoc 2019; 20:1623–1627.  

6. Rizzoli R, Biver E, Brennan-Speranza TC. Nutritional intake and bone health. Lancet Diabetes Endocrinol 2021; 9:606–621.  

7. Fisher JP, Steele J, Gentil P, Giessing J, Westcott WL. A minimal dose approach to resistance training for the older adult; the prophylactic for aging. Exp Gerontol 2017; 99:80–86.  

8. Bauer J, Biolo G, Cederholm T, Cesari M, Cruz-Jentoft AJ, Morley JE, et al. 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; 14:542–559.  

9. Morton RW, Murphy KT, McKellar SR, Schoenfeld BJ, Henselmans M, Helms E, et al. 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; 52:376–384.  

10. Moore DR, Churchward-Venne TA, Witard O, Breen L, Burd NA, Tipton KD, et al. Protein ingestion to stimulate myofibrillar protein synthesis requires greater relative protein intakes in healthy older versus younger men. Journals Gerontol - Ser A Biol Sci Med Sci 2015; 70:57–62.  

11. Scott D, Blizzard L, Fell J, Giles G, Jones G. Associations between dietary nutrient intake and muscle mass and strength in community-dwelling older adults: The Tasmanian older adult cohort study. J Am Geriatr Soc 2010; 58:2129–2134.  

12. Morton RW, McGlory C, Phillips SM. Nutritional interventions to augment resistance training-induced skeletal muscle hypertrophy. Front Physiol 2015; 6:1–9.  

13. Areta JL, Burke LM, Ross ML, Camera DM, West DWD, Broad EM, et al. Timing and distribution of protein ingestion during prolonged recovery from resistance exercise alters myofibrillar protein synthesis. J Physiol 2013; 591:2319–2331.  

14. Jäger R, Kerksick CM, Campbell BI, Cribb PJ, Wells SD, Skwiat TM, et al. International Society of Sports Nutrition Position Stand: Protein and exercise. J Int Soc Sports Nutr 2017; 14. doi:10.1186/s12970-017-0177-8  

15. Mamerow MM, Mettler JA, English KL, Casperson SL, Arentson-Lantz E, Sheffield-Moore M, et al. Dietary protein distribution positively influences 24-h muscle protein synthesis in healthy adults. J Nutr 2014; 144:876–880.  

16. Noakes M. Protein Balance: New concepts for protein in weight management. CSIRO, Australia; 2018.   

17. Wycherley TP, Moran LJ, Clifton PM, Noakes M, Brinkworth GD. Effects of energy-restricted high-protein, low-fat compared with standard-protein, low-fat diets: A meta-analysis of randomized controlled trials. Am J Clin Nutr 2012; 96:1281–1298.  

18. Dong JY, Zhang ZL, Wang PY, Qin LQ. Effects of high-protein diets on body weight, glycaemic control, blood lipids and blood pressure in type 2 diabetes: Meta-analysis of randomised controlled trials. Br J Nutr 2013; 110:781–789.