Delayed Plasma Amino Acid Response following Ingestion of Extruded Pea Protein Compared with Nonextruded 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.

OBJECTIVES

This study aimed to examine the effects of differently processed pea proteins on postprandial metabolism and compare them with those of whey protein (WP).

METHODS

In a randomized crossover trial, healthy males and females (n = 20, aged 24 ± 3 y, body mass index = 21.6 ± 1.8 kg/m2) consumed 4 test meals each containing 25 g protein from 1) pea protein concentrate (PC), 2) pea protein isolate (PI), 3) pea protein extrudate (PE), or 4) WP. Acetaminophen was administered with each test meal as a marker for gastric emptying. Venous blood samples were obtained in the 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 [incremental area under the curve (iAUC)0-300, P < 0.001] without any significant difference between the 3 degrees of processing. The PE meal showed a delayed increase in EAA compared with PC, PI, and WP (iAUC0-120P = 0.008, 0.016, <0.001, and time to reach the maximum plasma concentration P < 0.001). After 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 satiety ratings.

CONCLUSIONS

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 after PE consumption. Other metabolic parameters and satiety responses are comparable between pea and WP. This trial was registered at clinicaltrials.gov as NCT06155656.