By Jan Hales, The Nutrition Bureau
One of the really interesting advanced sessions at FNCE 2018 was delivered by UK exercise science PhD student Ben Kirk and moderated by USA dietitian Katherine Dodd on Muscle, Protein, Exercise and Healthy Aging.
Whilst the session was about presenting current research, it clearly highlighted the untapped opportunities available for future innovation in the older adult space. The speaker summarised a number of simple evidence-based factors relating to older adults including the impact of nutrition on muscle, our ability to function as we age and how our bodies protect themselves against metabolic diseases (like diabetes and heart disease).
A key learning from the session, was that after the age of 40, the human body starts to lose around 1 – 3% of skeletal muscle each year, and once a human hits the age of 80, the rate of muscle loss is about 3 – 6 % annually. Whilst we might say 40 is the new 30, the evidence suggests that in the worst-case scenario, it is possible for a human to lose 50% of the muscle they had at the age of 40, by the time they reach 80 or 90! And, we’re not just talking the amount of muscle, but also its strength and function, which ultimately affects independence and quality of life. The good news however is that current evidence indicates regular exercise and adequately meeting dietary-protein needs (combined or independently), can work to offset the effects of age related muscle loss (or sarcopenia).
As dietitians and with respect to nutritional needs, the following three essential considerations were noted:
1. Protein – older people need about 50% more protein than younger adults or least 1.2g/kg each day versus 0.8g/kg each day.
2. Leucine – as we age, getting enough of the essential branched chain amino acid (BCAA), leucine is particularly important (think cheese, soybeans, beef, chicken, nuts and fish).
3. Protein and Leucine should be spread across the day – to maximise uptake of protein and leucine into the muscle, older adults should aim to eat approximately 0.4g protein/kg and at least 3g of leucine in each meal (based on 3 main meals per day).
Similarly, with the current and growing interest in plant-based proteins, it was interesting to consider the point that proteins from animal foods are typically more effective at minimising age-related muscle loss than plant-proteins, primarily due to the higher content of essential amino acids, especially leucine, in animal foods. The speaker followed this up by explaining it’s not that plant proteins are ineffective, but rather that one would need to eat a lot more of these foods to meet their nutritional targets for protein and leucine, and this may be challenging if appetite is limited or energy demands are relatively low.