Putting Alternative Proteins to the Test: In vivo Digestibility for Alternative Proteins
As the InnoProtein project continues exploring more sustainable and nutritious protein sources, an important question remains: are these proteins safe, effective, and suitable for long-term consumption?
Not all proteins are nutritionally equal. Protein quality depends not only on how much protein a food contains, but also on its amino acid composition and how efficiently the body can digest and absorb it. Animal proteins typically score highly because they contain all nine essential amino acids and are generally well digested by the body[1]. But as the demand for sustainable and plant-based diets grows, so does the need for alternative proteins that can match this high nutritional standard set by animal sources.
Protein quality is not only about how much protein a food contains, but also how much the body can actually digest and use. One method, PDCAAS (Protein Digestibility-Corrected Amino Acid Score), estimates protein quality by comparing its amino acid profile to human requirements and adjusting for digestibility, but it has some limitations in accuracy [2]. A newer method, DIAAS (Digestible Indispensable Amino Acid Score), is more precise because it measures how well each essential amino acid is absorbed in the small intestine and does not cap high scores[3].
For alternative proteins to become viable solutions to global protein security and sustainability challenges, they must meet high nutritional and safety standards. Understanding how these proteins perform against such standards means rigorous biological testing.
Investigating Alternative Protein Safety
To better understand how these extracted proteins interact with the body, research partners at VRI designed a 12-week in vivo (within in a living being) feeding study, employing a mouse model commonly used to evaluate immune response, gut health, and metabolic function.
The study focuses on proteins derived from fungi, microalgae, and bacteria, all of which show promising amino acid profiles, including significant levels of lysine, an essential amino acid often limited in plant-based diets. Animals were divided into control and experimental groups, where conventional protein sources were either partially or fully replaced with one of the alternative proteins.
Throughout the study, researchers collected blood samples to monitor hematological and biochemical markers associated with overall health and metabolism. Faecal samples were also analyzed to assess potential changes in the gut microbiome. At the end of the trial, tissue samples from the intestine, liver, spleen, and kidneys were collected for further examination.
Monitoring Immune and Allergy Responses
An important component of the research is evaluating whether these proteins trigger immune responses associated with food allergies. Researchers are specifically examining IgE antibody levels, which are commonly associated with allergic sensitivity.
This type of assessment is essential when developing novel food ingredients. Understanding whether alternative proteins may invoke adverse immune reactions will help determine how they can be safely introduced into future food systems.
Building the Evidence Base for Novel Proteins
Together, these analyses aim to provide a more complete understanding of how the body responds to emerging protein sources over time.
While the research is still ongoing, the work reflects an important stage in the development of alternative proteins. The findings from studies like these will help determine not only whether alternative proteins can supplement existing food systems, but also how they can be responsibly integrated into everyday diets in the years ahead.
References
[1] FAO (2013). Dietary protein quality evaluation in human nutrition. FAO Food and Nutrition
Paper 92.
[2] Schaafsma, G. (2000). The protein digestibility-corrected amino acid score. Journal of Nutrition,
130(7), 1865S–1867S.
[3] FAO (2013). Dietary protein quality evaluation in human nutrition. FAO Food and Nutrition
Paper 92.
