Effects of Cowpea Purée Supplementation and strength training on amino acid kinetics in young adults: A Pilot Study

Abstract

Introduction: Branched-chain amino acids (BCAAs) are essential for protein synthesis and muscle recovery and are therefore widely used in sports nutrition. Although rapidly digested animal proteins elicit strong anabolic responses, assessing plant-based alternatives such as cowpea (Vigna unguiculata) is essential for understanding their absorption kinetics. Problem Statement: Whether a dietary portion of a plant-based food matrix can raise post-exercise aminoacidemia remains unclear, given the typically lower digestibility and less complete amino acid profiles of plant proteins. Objective: This pilot study investigated changes in plasma BCAA concentrations after cowpea purée consumption in young adults following strength training, testing the competing hypotheses that supplementation would (H1) or would not (H0) significantly influence plasma BCAA concentrations. Material and Methods: Ten healthy young men participated in a repeated-measures pilot study under four conditions: control, exercise, supplementation, and combined supplementation and exercise. Participants ingested 150 g of cowpea purée (providing an estimated 5 to 6 g of protein) and performed a standardized strength training session. Blood amino acid kinetics were analyzed using HPLC-FLD, and data were treated with repeated-measures MANOVA (p < 0.05). Results: Supplementation did not significantly increase overall plasma BCAA concentrations. Leucine showed a decreasing trend over time in the supplementation plus exercise condition, isoleucine differed significantly between the control and combined conditions (p = 0.020), and valine showed no significant variation. Discussion: These findings are consistent with the slower digestion, lower leucine content and food-matrix effects of plant proteins, which may limit post-exercise anabolic signaling; the low protein dose provided by the purée (5 to 6 g) plausibly contributed to the absence of a robust aminoacidemic response. Conclusions: Cowpea purée supplementation under the tested conditions did not elicit a pronounced post-exercise increase in plasma BCAA kinetics, suggesting that dosage and food matrix optimization, together with controlled dietary standardization, are needed before plant-based recommendations can be established.