Evaluation of different protein supplements regarding their amino acid profile using the Digestible Indispensible Amino Acid Score (Diaas)

Protein products claim to help meeting the daily protein intake recommendations and sport specific requirements, however the bio availability and the respective amino acid profile need to be considered. An analyzation of 10 different protein products for sports was conducted to compare values for the digestible indispensable amino acid scores (DIAAS) and the leucine content according to the intake recommendations by the manufacturer. The amino acid profile of 10 commercially sold protein products (n=5 plant-based, n=5 dairy-based) were analyzed using the DIAAS. The DIAAS is the recommended method for dietary protein quality assessment on true ileal digestibility values of indispensable amino acids rather than a single faecal crude protein digestibility value. If the lowest DIAAS of an IAA in a product is > 100, it indicates a high quality protein regarding the indispensable amino acid profile and digestibility. DIAAS % = 100 x [(mg of digestible dietary indispensable amino acid in 1 g of the dietary protein) / (mg of the same dietary indispensable amino acid in 1g of the reference protein)] 10 (11%) of the indispensable amino acid data in all 10 products (90 IAA data = 10 products x 9 IAA) showed a DIAAS <100 and 2 (2%) had a DIAAS <75. 90% of an insufficient amount of IAA were found in vegan proteins. Considering the respective recommended intake of each product, the mean leucine content was 2,86g/ serving. The dairy-based protein products had an average leucine content of 3,10g/ serving (range: 2,80-3,57) and the vegan protein products had a mean leucine content of 2,62g/ serving (range:1,90-3,30). 60% of the products (n=3 vegan, n=3 dairy-based) did not meet the recommended 3g leucine/ serving when ingested according to the manufacturer’s recommendations. Vegan sport proteins, also multi compound products, show a lower quality in the amino acid composition than dairy-based products. When protein products are taken to replace meals or without combination with other foods a DIAAS > 100 for all IAA is recommended. Higher amounts of vegan protein have to be ingested to meet the FAO recommendations. Regarding optimal muscle protein synthesis a leucine content of 3g/ serving is recommended and not met by the majority of the vegan and dairy-based protein products.