Delayed plasma amino acid response following ingestion of extruded pea protein compared with non-extruded pea proteins in healthy adults: a randomized crossover trial

Background Despite the growing availability of plant protein ingredients on the market, data on their digestibility and metabolic effects in humans are limited. Objective This study examined the effects of differently processed pea proteins on postprandial metabolism and compared them with those of whey protein. Methods In a randomized crossover trial, healthy men and women ( n =20, aged 24 ± 3 y, BMI 21.6 ±1.8 kg/m 2 ) consumed four test meals each containing 25 g protein from (i) pea protein concentrate (PC), (ii) pea protein isolate (PI), (iii) pea protein extrudate (PE) or (iv) whey protein (WP). Acetaminophen was administered with each test meal as a marker for gastric emptying. Venous blood samples were obtained in fasting state and at multiple time points postprandially (15-300 min). Samples were analyzed for the concentration of plasma amino acids (primary outcome), serum urea, plasma glucose, serum insulin, and uric acid. Satiety was assessed using visual analog scales. All data were analyzed using linear mixed models. Results Plasma essential amino acid (EAA) concentrations increased after ingestion of all test meals. Compared with WP, meals containing PC, PI, and PE resulted in lower plasma EAA concentrations (iAUC 0-300 , P< 0.001) without any significant difference between the three degrees of processing. The PE meal showed a delayed increase in EAA compared with PC, PI, and WP (iAUC 0-120 P =0.008, 0.016, <0.001 and Tmax P< 0.001). Following the WP meal uric acid decreased but increased after the PC, PI, and PE meals ( P< 0.001). No meal effect was observed for postprandial urea, glucose, insulin, and acetaminophen concentrations or in satiety ratings. Conclusion In healthy young adults, pea protein elicits a lower postprandial EAA response than WP, independent of processing degree. Comparisons across processing degrees indicate a delayed EAA response following PE consumption. Other metabolic parameters and satiety responses are comparable between pea and WP. This trial was registered at ClinicalTrials.gov ( https://clinicaltrials.gov/ ) as NCT06155656, date of registration: 30 November 2023.