Can Extra Protein Help the Elderly Age Well?
With all the debates about fat, sugar and gluten, it is easy to forget about the other macronutrient: protein. Protein is necessary for all of us, but it is perhaps most important for older people. As people age, they tend to lose muscle mass from their bodies. Even if body weight stays the same, there is a strong tendency for muscle to turn into fat over a period of decades. This is due to a reduced ability for older people to synthesize new muscle tissue in response to stimuli like resistance exercise or insulin. Loss in muscle results in frailty and reduced ability to carry out normal, everyday activities. Helping people maintain muscle strength and function in old age is key to healthy aging.
Protein recommendations generally are based on bodyweight: for young adults to the elderly, the recommendation is 0.8 g protein per kg bodyweight per day, or around 56 g for someone who weighs 70 kg. But some researchers have called into question whether protein intakes should be the same for both young and old people. Amounts up to 1.5 kg per kg bodyweight per day have been proposed (Paddon-Jones). While older people are less active and on the surface may appear to need less protein, their reduced ability to build muscle may point to increased needs. Data also shows that older people tend to have a reduced appetite and their protein intakes are less likely to be adequate than younger people. The presentation discussed whether increasing protein intakes in the elderly are both feasible and beneficial for health.
Protein and muscle experts Paddon-Jones and Rasmussen published an influential article a few years ago about dietary protein recommendations for preventing sarcopenia that suggested that a more effective strategy for older people would be to increase protein intakes a little, and spread them out throughout the day. Their specific guide was to provide 25 g to 30 g of high-quality protein in the three main meals—normally, dinners contain plenty of protein, but breakfast and lunch are lacking. The 25-30 g guideline was based on data that shows that muscle synthesis in older people is diminished when total protein intake during a meal is less than 20 g. In addition, muscle building and increases in physical performance are only likely when people increase their levels of physical activity, including resistance exercise. The Pro-Muscle study was designed to test whether this protein intake regimen combined with exercise would be effective in increasing muscle and physical performance.
Tieland and co-workers report on the results. The study was performed using 65 frail, elderly subjects who were randomized to protein supplementation (15g at breakfast and lunch) or placebo, and all took part in a resistance exercise program (twice per week for 24 weeks). The extra protein was provided in dairy drinks. Surprisingly, and despite the exercise program, there was no significant change in skeletal muscle mass, nor did muscle fiber type change. What did change was muscle strength: it increased in both groups, and leg extension strength (which incorporates the largest muscle in the body) increased more than placebo. Physical performance increased in the group with protein supplementation but not in the placebo group. So despite no change in skeletal muscle mass, protein supplementation along with an exercise program improved physical performance in elderly people.
In light of a recent meta-analysis from ter Borg and colleagues that found that 10 to 12% of older adults do not meet the EAR for protein, the session continued to discuss how to incorporate more protein into older adults’ diets, either due to behavior change in the home setting, or when in medical care. Despite the importance of protein for healthy aging, it seems that there is a paucity of interventions and products to effectively and sustainably help seniors to raise their protein intakes, and a lack of knowledge on the part of health care providers and the wider community.
De Groot, L. 2015. Presentation: ‘High protein meals for the elderly: does it make sense?!’ at Healthy Ageing conference, 29th October 2015. Amsterdam, The Netherlands.
Tieland M, van de Rest O, Dirks ML, van der Zwaluw N, Mensink M, van Loon LJ, de Groot LC. Protein supplementation improves physical performance in frail elderly people: a randomized, double-blind, placebo-controlled trial. J Am Med Dir Assoc. 2012 Oct;13(8):720-6. doi: 10.1016/j.jamda.2012.07.005. Epub 2012 Aug 11. http://www.ncbi.nlm.nih.gov/pubmed/22889730
Paddon-Jones D, Campbell WW, Jacques PF, Kritchevsky SB, Moore LL, Rodriguez NR, van Loon LJ. Protein and healthy aging. Am J Clin Nutr. 2015 Apr 29. pii: ajcn084061. [Epub ahead of print]
Paddon-Jones D, Rasmussen BB. Dietary protein recommendations and the prevention of sarcopenia. Curr Opin Clin Nutr Metab Care. 2009 Jan;12(1):86-90. doi: 10.1097/MCO.0b013e32831cef8b. http://www.ncbi.nlm.nih.gov/pubmed/19057193
ter Borg S, Verlaan S, Mijnarends DM, Schols JM, de Groot LC, Luiking YC. Macronutrient Intake and Inadequacies of Community-Dwelling Older Adults, a Systematic Review. Ann Nutr Metab. 2015;66(4):242-55. doi: 10.1159/000435862. Epub 2015 Jul 16. http://www.ncbi.nlm.nih.gov/pubmed/26183836
Wolfe RR, Miller SL. The recommended dietary allowance of protein: a misunderstood concept. JAMA. 2008 Jun 25;299(24):2891-3. doi: 10.1001/jama.299.24.2891. http://www.ncbi.nlm.nih.gov/pubmed/18577734