Differential Responses of Blood Essential Amino Acid Levels Following Ingestion of High-Quality Plant-Based Protein Blends Compared to Whey Protein—A Double-Blind Randomized, Cross-Over, Clinical Trial

This study assessed the bio-equivalence of high-quality, plant-based protein blends versus Whey Protein Isolate (WPI) in healthy, resistance-trained men. The primary endpoint was incremental area under the curve (iAUC) of blood essential Amino Acids (eAAs) 4 hours after consumption of each product. Maximum concentration (C(max)) and time to maximum concentration (T(max)) of blood leucine were secondary outcomes. Subjects (n = 18) consumed three plant-based protein blends and WPI (control). An analysis of Variance model was used to assess for bio-equivalence of total sum of blood eAA concentrations. The total blood eAA iAUC ratios of the three blends were [90% CI]: #1: 0.66 [0.58–0.76]; #2: 0.71 [0.62–0.82]; #3: 0.60 [0.52–0.69], not completely within the pre-defined equivalence range [0.80–1.25], indicative of 30–40% lower iAUC versus WPI. Leucine C(max) of the three blends was not equivalent to WPI, #1: 0.70 [0.67–0.73]; #2: 0.72 [0.68–0.75]; #3: 0.65 [0.62–0.68], indicative of a 28–35% lower response. Leucine T(max) for two blends were similar to WPI (#1: 0.94 [0.73–1.18]; #2: 1.56 [1.28–1.92]; #3: 1.19 [0.95–1.48]). The plant-based protein blends were not bio-equivalent. However, blood leucine kinetic data across the blends approximately doubled from fasting concentrations, whereas blood T(max) data across two blends were similar to WPI. This suggests evidence of rapid hyperleucinemia, which correlates with a protein’s anabolic potential.