Protein and amino acid composition and digestibility
Protein quality isn’t just about the protein.
Current protein quality measures are based on amino acid composition and digestibility, and they have taken us a long way. They’ve been an important step forward and provide an important guide for how to choose protein sources based on their ability to support the maintenance of body protein and therefore muscle mass.
But the thing is . . . current scores focus on isolated protein sources and protein is never consumed in isolation.
Build diets around protein
When we build diets around protein, we also need to consider the intake of other nutrients that come with it, including minerals, vitamins, fatty acids, and, in some cases, fibre, and many of these have an influence on how well amino acids are absorbed, retained, and ultimately used by the body.
As our research questions shift from simple adequacy to function and optimisation, including muscle health, metabolic resilience, and ageing, it becomes clear that protein quality is shaped not only by the protein itself, but by how well that protein source contributes to the whole diet, and how the whole diet is constructed around it.
So the next step isn’t about replacing existing protein quality measures but extending them: we need to connect protein and amino acid composition to food matrices, accompanying nutrients, and dietary patterns.
Diet-level protein
The fundamental frameshift is this:
➡️Protein quality isn’t just a property of protein.
It’s a property of the diet. Because a high-quality diet is formulated around protein!
Carlene Starck, PhD Metabolic Nutrition Scientist | Translating Nutrition Science into Real-World Impact | Consultant to Health-Focused Brands | Founder, Starck Science
Carlene is from Rotoorangi, Waikato, New Zealand
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