Should we be getting our protein through animal based sources exclusively or are vegan sources optimal too?
Let’s get geeky...let's look at a study conducted in 2019 by Berrazaga et al. They looked at the anabolic (read-muscle building) properties of plant-based protein sources when compared with animal-based ones in supporting the maintenance of muscle mass in the elderly.
Older people develop what we call Sarcopenia which is essentially muscle mass reduction as we grow older. They develop a resistance to the stimulation of the process of muscle growth (also known as anabolic resistance) making them unable to compensate for protein losses, ultimately causing a reduction in muscle mass. This happens as we move beyond the age of 30, especially exascerbated when we, as women, start to experience menopause symptoms.
This highlights the importance of optimising both the quality and quantity of protein intake in the elderly – SHOUT IT OUT TO YOUR PARENTS, GRANNIES AND GRANDPAS, they gotta take note of this stuff!!
So far, the research has shown that protein quality in animal-based sources is higher than in its plant-based alternatives – this could perhaps be due to lower digestibility or a deficiency in certain amino acids (the building blocks of proteins) present in most plant-based proteins. Low essential amino acid content in our diets can limit muscle growth.
It has been proven in the study in question that soy (plant) proteins are digested more slowly than the whey (animal based – derived from milk) alternative so it doesn’t promote muscle growth at the same rate. Soy, and most other plant-based protein sources also have a lower leucine (one of the essential amino acids required for muscle growth) content and are deficient in certain other essential amino acids and so therefore, the rest of the amino acids present will not be used for muscle growth but rather oxidised and used as energy by the body.
Within the study it was found that muscle growth in older adults was 30-40% lower with a plant-based protein when compared with whey protein.
BUT...it is worth noting that in the research all findings were based on single protein sources taken ‘pure’, however, this is rarely applicable to daily life and more often than not proteins are consumed as part of a wider, more varied diet containing other proteins too. A holistic approach to our wellness, always, you know I'm all about that by now.
When considering ageing we can apply the results of this study to conclude that the differences in muscle growth/minimising effects of ageing and muscle loss between plant and animal-based proteins could be mitigated by ensuring adequate intake of either – however, it is important to note that ageing is also associated with lower levels of appetite so this may be easier said than done!
If plant-based protein sources are preferable we must ensure that we are mixing types of plant-based proteins to enable us to get a wide variety of those amino acids to ensure more are used in muscle growth as opposed to being ‘wasted’ in energy expenditure.
Think beans, pulses, whole grains with maybe a little bitta chicken and cheese thrown in there too!
Peace and love, A x
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