Leucine is the primary essential amino acid that drives muscle protein synthesis (MPS). The leucine content of most plant proteins is generally pretty low, but emerging research indicates that potato protein contains a decent amount of leucine, as well as other essential amino acids. A recent study aimed to determine the effects of potato protein on MPS, with and without resistance exercise, in healthy women.
24 recreationally active women were randomly assigned to consume a diet including 25g of potato protein (PP) twice daily, or a control diet (CON) with no protein supplementation. Prior to starting the intervention, participants consumed a baseline diet with 0.8 g/kg/day of protein for one week. Throughout the 2-week intervention, the PP group consumed a total of 1.6 g/kg/day of protein, and the CON group consumed 0.8 g/kg/day. Participants were prescribed a eucaloric diet and performed 3 resistance training sessions per week throughout the trial.
MPS was measured at baseline (before supplementation), at rest, and after exercise. Based purely on mean changes, it looks like potato protein increased resting MPS a little more than a protein-free placebo, but the increase in MPS from rest to exercise was virtually identical for both groups. There were no significant MPS differences between the groups at any single time point.
The bottom line: Due to the lack of differences between groups, it seems hard to recommend switching from an animal-derived protein (like whey) to potato protein based on these data. As long as you don’t follow a vegan diet or have digestion concerns, it seems that whey and other animal-based protein sources are probably the way to go. Several plant-based proteins can absolutely be used effectively, but may require higher doses to elicit the same anabolic effects as animal-based protein sources. For users of vegan protein supplements, more research is needed to determine how potato protein stacks up against other plant-based protein supplements, such as soy, bean, rice, and pea.