Measuring Protein Digestibility in the Laboratory while Reducing Animal Testing

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How much of the proteins present in foods can the human body absorb and how high is the quality of these proteins? These are the key questions in discussions about a healthy and sustainable diet. Agroscope has developed a method that can reliably measure the protein digestibility of different foods in the laboratory. This opens up promising prospects in nutritional research and reduces the need for complex human and animal trials.

The need for a healthy and sustainable diet is increasingly being recognised, and proteins and their components - amino acids - play a crucial role in this context. Agroscope has succeeded in simulating the human digestive tract in the laboratory, enabling the protein digestibility of foods to be determined precisely. Results were recently published in the renowned journal Food Chemistry.

Research for a healthy and sustainable diet

Protein digestibility is a decisive factor for determining the quality of dietary proteins in foods. It tells us how much of the theoretically available amino acids in foods is actually available to be absorbed by the human body after the digestive process. Amino acids play a key role in metabolism and the muscular system. Protein digestibility therefore has a direct impact on a healthy and sustainable diet.

Reducing animal testing

In 2019, Agroscope succeeded in simulating the human digestive process in vitro in the laboratory -from saliva to stomach to the small intestine. Since then, researchers have further developed the method, measuring the protein digestibility of seven foods in humans, in pigs and in the test tube. Results for these three different environments were very similar, with deviations amounting to only around 0.2%. The method can thus help to avoid a large number of human and animal experiments in future.

How environmentally friendly are foods?

Agroscope is already using the new method in numerous projects to examine potential quality improvements in various foods, for example in experiments with soy products, yoghurts, plant-based dairy alternatives, or novel foods such as insects. Since protein digestibility affects the ecological footprint of foods, the results are also used in life-cycle assessments.

Determining the value of foods

The research findings should bring us one step closer to being able to determine the value of foods according to a global benchmark. To this end, the method is to be published as an ISO standard as soon as possible. Currently, the method is being tested for robustness in 32 different laboratories in 18 countries on four continents. The timing is ideal, as in future the Food and Agriculture Organization of the UN, the FAO, will require the protein digestibility of foods to be reported to provide consumers with information on food quality. The food industry, which cooperated in the research project, is also waiting for such an opportunity.

Further research fields

The new method will also be tested in the coming months on additional protein sources - for example, the researchers have yet to determine whether it is also suitable for analysing technologically processed foods. They also want to investigate which factors in food production influence protein digestibility. The eventual aim is to be able to simulate the varying digestion of humans of various age groups (e.g. infants and older people), or of those with medically impaired digestion. Agroscope will continue to research these topics as part of an international network and further expand its longstanding expertise in nutritional research.