Probiotic administration increases amino acid absorption from plant protein – A placebo‐controlled, randomized, double‐blind, multicenter, crossover study
Authors: Zaragoza Javier Andres , Urbina Stacie , Purpura Martin , Jaeger Ralf , Tinsley Grant , Anzalone Anthony , Stone Jason , Askow Andrew T , Oliver Jonathan M , Fiore Walter , Biffi Andrea , Taylor Lem 
Published: April 2020

BACKGROUNDProtein supplementation is a well‐established nutritional strategy in weight management, and frequently used to improve post‐exercise recovery and enhance training adaptations. The type of protein can affect amino acid absorption, with animal proteins generally being more efficiently absorbed compared to plant proteins. In contrast to animal proteins, most plant proteins, such as pea protein, are incomplete proteins. Pea protein is low in methionine and contains lower amounts of branched‐chain amino acids (BCAAs), which play a crucial role in muscle health. The fate of dietary protein in the gut is determined by microbial and host digestion and utilization, and fermentation of proteins generate bioactive molecules that have wide ranging health effects on the host.HYPOTHESISWe hypothesized that probiotic supplementation results in favorable changes in the gut microbiota, aiding the absorption of amino acids from plant proteins by the host, potentially improving the naturally low amounts of methionine and BCAAs.METHODSFifteen healthy males (24.2±5.0 years, 178.0±7.6 cm, 85.3±12.9 kg, 16.7±5.8 %BF) co‐ingested 20 g of pea protein with either AminoAlta™, 10 billion CFU of a multi‐strain probiotic consisting of 2 strains belonging to Lactobacilli paracasei species, (SOFAR S.p.A., Italy) or a placebo for two weeks in a randomized, double‐blind, crossover design, separated by a 4‐week washout period. Blood samples were taken at baseline, and 30‐, 60‐, 120‐ and 180‐minutes post‐ingestion and analyzed for amino acid content. For statistical analysis, the area under the concentration vs. time curve (AUC) was calculated for each of the 22 amino acids, as well as BCAAs, essential amino acids (EAAs), and total amino acids, via the linear trapezoidal rule and using all available time points. Cmax was defined as the maximum observed concentration, and Tmax was the time at which Cmax was reached. AUC values were compared between conditions via paired‐samples t‐tests. A p‐value <0.05 was considered statistically significant.RESULTSProbiotic administration resulted in a statistically significant increase in AUC and Cmax for methionine (AUC: +20%, p = 0.007; Cmax: +16.3%, p = 0.008), histidine (+40.4%, p = 0.009; +49.2%, p = 0.048), valine (+21.5%, p = 0.013; +24.7%, p = 0.034), leucine (+23.3%, p = 0.006; +25.2%, p = 0.043), isoleucine (+26.0%, p = 0.017; +26.1%, p = 0.020), tyrosine (+16.0%, p = 0.009; +11.6, p = 0.014), total BCAA (+22.8%, p = 0.008; +26.8, p = 0.009), and total EAA (+16.0%, p = 0.005; +15.6, p = 0.022) without significantly changing the time to reach maximum concentrations.CONCLUSIONSAminoAlta™ supplementation can be an important nutritional strategy to improve protein utilization and to overcome compositional shortcomings of plant proteins.Support or Funding InformationSupport for this study was provided by SOFAR S.p.A., Italy.