Healthy Aging: How to combat Anabolic Resistance!
Aging in Society
Aging in our society is becoming increasingly more and more prevalent and something which is inevitable for all of us. There will be 1.1 billion people celebrating their 60th birthday between 2015 and 2030, with Europe's aged population being 23% greater in 2030! But do we know that with the right nutrition and the right exercise we can prevent the onslaught of the aging process and live active healthy lives into our 80s, 90s and beyond?
Anabolic Resistance: Fact or Fallacy?
With the cold weather officially having set in, many of our populations physical activity levels shoot way down over this winter period. This is one of the main causes of sarcopenia – physical inactivity. Even 1 - 2 weeks of a reduced daily step count can lead to reductions in muscle mass (1) and induce a condition known as anabolic resistance in our elderly populations. Anabolic resistance is a condition, predominantly seen in the elderly, where muscles are not as efficient at growing more muscle, compared to the muscle of a younger healthier person (2). This means that even though an elderly person may be eating the same foods and performing the same exercise as a younger person, their muscles are not going to maximize the growth of new muscle to the same degree.
Alongside this anabolic resistance, we have the obvious changes of an elderly persons’ physiology, such as their change in taste and smell, reductions in gut mobility, in addition to chewing and swallowing problems. These factors all contribute to an elderly individual not being as efficient at digesting and absorbing protein in comparison to their younger counterparts, or their grandkids for example! Not only are the gods against us by having anabolic resistance at play, they also make it difficult for elderly individuals to meet their daily protein needs. In fact, the standard diet of an elderly individual will typically revolve around only one large protein serving each day.
The Role of Protein
Protein - it’s all we hear about these days.. We’ve got protein bars, protein milks, protein powders and protein shakes. This nutrient is especially important for healthy aging. Since anabolic resistance prevents individuals from maximizing their gains of muscle mass after protein consumption, a method we can invoke to counteract this is by simply consuming more protein! Yes - the seemingly over-emphasized need for greater protein intake is also relevant to the elderly population - the age group that likely consume the least amount of protein. According to PROT-AGE and ESPEN, the guidelines set out are 1.2-1.5g per kg of body mass per day, with some older adults needing 2g per kg of body mass each day. This equates to , yes you guessed it! - more than their diet typically provides..
Timing of protein intake is important, not only because it is scientifically recommended but also because failing to space out your protein hits will make it very difficult to actually hit your daily target! So, with timing - it should be 3-4 big boluses of protein spaced 3-4 hours apart to keep stimulating that muscle protein growth. 30-40g is what has been scientifically identified to counteract anabolic resistance. That’s a lot of protein for one portion, so how can we achieve this? Dairy, yogurt, eggs, fish, beef, poultry and beans are all good protein sources, so incorporating them in as much as possible will help you achieve it.
The Whey To Go?
Not only is the amount of protein important, so is the quality of that protein. For example, animal protein is much more potent than plant protein at enhancing muscle protein growth. This is particularly evident in the soy vs whey protein argument. Whey is the way to go when choosing a muscle building protein source! With its high leucine content and its rapid digestibility, it is the optimal protein for maximizing muscle gains (3, 4). This branched chain amino acid (leucine) appears to be the key signpost for muscle protein growth, acting almost as a catalyst switching on the cellular mechanisms.
One of the other key drivers of muscle growth is physical activity, as previously mentioned. When we think of aging and the elderly, we may think of the frail old lady struggling to cross the road before the light goes green again. We rarely imagine people such as Edwina Brocklesby, who is the oldest British woman to complete an ironman triathlon at age 76 or indeed Robert Marchand, the centenarian cyclist at age 107. We cannot underestimate the power of exercise in relation to augmenting muscle protein growth. When these forces of nutrition and exercise are in combination they exert an even greater response of muscle growth. Combining a healthy dose of the both is the most optimal way to counteract anabolic resistance!
Take Home Message
So, what should be our take home message from this? Well take the most recent food pyramid for example. From this, we see the fruit and vegetable section at the bottom, followed by grains and pastas and finally the meats, fish and dairy sections third and fourth from bottom, of which 2-3 portions per day are recommended. As we age, we should be aiming to take in much more from this meat/dairy section - aiming for around 4-5 portions of a protein source each day. This seems like a lot but when you break it down it could look something like the example seen below. The key thing to remember is to always base your meals and snacks around a protein source and incorporate some resistance based training (as little as 15 minutes each day of simple stand-and-sit bodyweight exercises) in there to help counteract muscle wasting as we age!
1. Breen L, Stokes KA, Churchward-Venne TA, Moore DR, Baker SK, Smith K, et al. Two weeks of reduced activity decreases leg lean mass and induces "anabolic resistance" of myofibrillar protein synthesis in healthy elderly. J Clin Endocrinol Metab. 2013;98(6):2604-12.
2. Breen L, Phillips SM. Skeletal muscle protein metabolism in the elderly: Interventions to counteract the 'anabolic resistance' of ageing. Nutr Metab (Lond). 2011;8:68.
3. Tang JE, Moore DR, Kujbida GW, Tarnopolsky MA, Phillips SM. Ingestion of whey hydrolysate, casein, or soy protein isolate: effects on mixed muscle protein synthesis at rest and following resistance exercise in young men. J Appl Physiol (1985). 2009;107(3):987-92.
4. Murphy CH, Saddler NI, Devries MC, McGlory C, Baker SK, Phillips SM. 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(6):1594-606.