Do you notice your grandparents shrinking as they age? If you pay close attention, you may see their bones sticking out at their shoulders or their clavicles. You may even start to feel the jut of their ribs when you give them a hug. Some of it could be fat loss, but there’s definitely loss of muscle mass, quality, and strength that occurs with age [1]. This is called sarcopenia, which shockingly, actually begins from the age of 30 [1]! While it happens with age, it can definitely be prevented with the right protein amount and distribution.
You need to eat enough protein to maintain muscle mass. Currently, it is recommended that all men and women above 19 years of age consume 0.8g of protein/kg/day [1]. However, studies have emerged suggesting that apart from the actual amount, protein amount and distribution across meals is crucial too. In this post, I will be discussing the optimal protein type, along with protein amount and distribution across the day to maximise muscle development.
1. Choose proteins of high biological value
All proteins are made up of amino acids—there are 20 types in total. Of these 20, nine are essential as our bodies cannot produce them. “Biological value” is a term used to describe a protein’s amino acid composition and digestibility—basically its “value” to the body. Foods are considered of high biological value when they contain all nine essential amino acids. Animal sources of protein like meat, fish, chicken, dairy products, and egg contain high biological value protein. Apart from soy protein, protein from plant sources like grains, beans, nuts, and seeds are of low biological value. This is because they do not contain all nine essential amino acids.
Therefore, choosing high biological value proteins is an easy way to optimise protein intake. This is especially important in the elderly, who may face difficulty with consuming even sufficient amounts of food. Similarly, vegetarians and vegans who are limited to only low biological value plant-based proteins should consume complementary proteins. This is a method of mixing and matching plant foods to get the complete range of all nine essential acids. Find out how in my post here!
2. Ensure the right protein amount and distribution throughout the day
It is important to spread protein intake out across the day the right way. Studies compared examined essential amino acid uptake in the elderly against the young. It was discovered that aging prevents skeletal muscle from responding to low doses (~7.5g) of essential amino acids as effectively as younger individuals [2]. However, at higher doses of 15g, the level of muscle protein synthesis stimulated in older individuals is similar to young adults [3]. That amount of amino acids translates to about 30 grams of high-quality protein at each meal [1]. A further review of the literature found that protein intake of 0.25-0.4g/kg maximises muscle protein synthesis in younger men, while older men may require up to 0.6g/kg at each meal [4]. Similarly, another study found that 20g of protein per meal is the maximum effective protein dose in young and healthy adults [5].
Therefore, it may be concluded that 20-30g of protein per meal is an ideal range to maximise muscle protein synthesis. Older individuals may require the higher end of the range, depending on body weight. So, if your total protein requirements is 60g/day, it makes more sense to have 20g at each of breakfast, lunch, and dinner, than 10g at lunch and 50g at dinner.
3. More protein is not better
A study investigated the effect of 113g of lean beef (30g protein) compared to 340g of lean beef (90g protein) on muscle protein synthesis. Larger portions of protein did not lead to greater muscle protein synthesis in both young and older adults. This supports the previous point that up to 30g of protein per meal is all that’s needed for maximal muscle protein synthesis [6].
Similarly, more is not always better in terms of whole day protein intake. Protein intake should follow nutritional guidelines. Adults above the age of 65 years should have at least 1-1.2g protein/kg body weight/day [7].
We know that different types of protein have varying biological value. However, recent evidence suggests that throughout the course of a day, protein amount and distribution is important too. Implementing this knowledge in the elderly is especially useful, as loss of muscle can impair strength, immune function, and quality of life. Every meal is an opportunity to optimise muscle protein synthesis. Therefore, remember to eat the right amount at each meal every day to maximise that! Know someone who may benefit from this article? Share it with them!
Individuals with medical conditions that may require protein restriction should consult a doctor or dietitian before adjusting protein intake.
References:
- Paddon-Jones D, Rasmussen BB. Dietary protein recommendations and the prevention of sarcopenia: Protein, amino acid metabolism and therapy. Curr Opin Clin Nutr Metab Care. 2009; 12 (1): 86-90. DOI: 10.1097/MCO.0b013e32831cef8b
- Katsanos CS, Kobayashi H, Sheffield-Moore M, Aarsland A, Wolfe RR. Aging is associated with diminished accretion of muscle proteins after the ingestion of a small bolus of essential amino acids. Am J Clin Nutr. 2005; 82 (5): 1065-73.
- Paddon-Jones D, Sheffield-Moore M, Zhang XJ, Volpi E, Wolf SE, Aarsland A et al. Amino acid ingestion improves muscle protein synthesis in the young and elderly. Am J Physiol Endocrinol Metab. 2004; 286 (3): E321-8.
- Schoenfeld BJ, Aragon AA. How much protein can the body use in a single meal for muscle-building? Implications for daily protein distribution. J Int Soc Sports Nutr. 2018; 15 (10). DOI: 1186/s12970-018-0215-1.
- Morton RW, McGlory C, Phillips SM. Nutritional interventions to augment resistance training-induced skeletal muscle hypertrophy. Front Physiol. 2015; 6: 245. DOI: 10.3389/fphys.2015.00245.
- Symons TB, Sheffield-Moore M, Wolfe RR, Paddon-Jones D. Moderating the portion size of a protein-rich meal improves anabolic efficiency in young and elderly. J Am Die Assoc. 2009; 109 (9): 1582-1586. DOI: 10.1016/j.jada.2009.06.369.
- Deutz NEP, Bauer JM, Barazzoni R, BIolo G, Boirie Y, Bosy-Westphal A et al. Protein intake and exercise for optimal muscle function with aging: Recommendations from the ESPEN Expert Group. Clin Nutr. 2014; 33: 929-936.
