To optimize the environmental sustainability, a protein transition to more plant-based protein sources is required. However, the protein quality of plant-based sources is lower than that of the dairy proteins casein and whey, which contain high levels of essential amino acids. The amino acid absorption characteristics of many plant-based proteins are unknown.

The present study aims to estimate differences in postprandial plasma total essential amino acids (TEAA) profiles after protein consumption of different protein sources in blood of healthy participants. This explorative study has a randomized, cross-over, double-blind, controlled design.

Inclusion Criteria:

• Apparently healthy men and women;
• Age ≥18 and ≤40 years;
• Body mass index (BMI) ≥18.5 and ≤30 kg/m2 ;
• Having veins suitable for blood sampling via a catheter (judged by study nurse/ medical doctor).

Exclusion Criteria:

• Any self-reported metabolic, gastrointestinal, inflammatory or chronic disease (such as anemia, diabetes, hepatitis, cardiovascular disease);
• Having a history of medical or surgical events that may significantly affect the study outcome;
• Anaemia (Haemoglobin (Hb) values <7.5 mmol/L for women and <8.5 mmol/L for men), as assessed by finger prick blood during screening visit;
• Having a food or protein allergy
• Use of glucose lowering drugs, insulin;
• Use of medication that may impact gastric emptying (e.g. gastric acid inhibitors or laxatives);
• Use of antibiotic treatment less than 1 month before start of the study and during the study;
• Use of anti-depressives as a treatment for depression;
• Use of protein supplements (must be stopped 1 week before the first test day);
• Reported weight loss or weight gain of > 3 kg in the month prior to pre-study screening, or intention to lose weight during the study period;
• Reporting to follow or having planned a slimming or medically prescribed diet.
• Not willing to keep a stable lifestyle during the study period;
• Recent blood donation (<1 month prior to test day 1 of the study) or not willing to stop donation during and 1 month after the study;