‘Anabolic Resistance’ and Why You Might Need to up Your Protein Intake As You Age
How much protein do you need? It’s one of the biggest nutritional questions around, and the most contentious too. As a brand passionate about not just the macronutrient but nutrition and health in general, it’s a question we’ve looked at in depth before, coming to the conclusion that based on systematic reviews 1.2 to 2.0g of protein, per kg of body weight, per day should be enough.
However, a new paper threatens to complicate things further. Published in the highly respected journal Advances in Nutrition and written by three of the most respected names in the field, it points out that we’re still at a loss when it comes to our optimal intake of protein, especially when it comes to older adults (usually defined as aged 65 and over).
In terms of the research already out there, the essay highlights some sizeable holes. Firstly, most studies on protein intake lack older participants. Secondly, most recommendations are based on the needs of young, healthy adults; and finally, in the short duration of any studies on older adults (usually less than 6 months).
This all leads to the big headline from the paper: the belief that the recommended allowance of protein isn’t enough for older adults due to something called the “anabolic resistance” of muscle.
For some context, anabolic means to build up and is the opposite of catabolic, which is to break down. Anabolic resistance means that the signals to build up muscle through strength training or eating protein is muted in older adults. Luckily, This resistance can be overcome with an increased amount of strength training or a higher intake of protein.
The progressive loss of muscle as we age, known as sarcopenia, can seriously impact your life expectancy and quality of life. It starts at about 40 with around half of your muscle mass being shed between the ages of 20 and 90 due to sarcopenia and inactivity.
Periods of the latter among older adults, usually during an illness or injury, cause those signals from before to blunt. A practical way to overcome this is through a higher protein intake, especially protein-rich foods that contain a key amino acid, leucine.
Leucine is one of the 9 essential amino acids and has been found to play a critical role in protein synthesis. So kids, protein and leucine, it’s important when we’re young, but even more so when we’re older.
The paper’s conclusion is that older adults should consume at least 30 grams of protein per meal, with 2.5 grams of leucine or more to help overcome the anabolic resistance of ageing muscle. That could stretch to around 90 grams a day, which far outweighs previously recommended allowances. But if the result is a longer, more fulfilling life then it suddenly seems like a far easier step to take.
