Whey protein isolate was associated with an increase in Bacteroidetes, while pea protein and mixed plant protein correlated with reduced fermentative bacteria, and rice protein predicted a higher representation of succinate-to-butyrate fermentation pathways. However, there was no significant change in the overall gut bacteria diversity.
“The data indicate complex interactions between supplement type, exposure duration, and microbiome response”, wrote researchers at the University of Warmia and Mazury in Olsztyn, Poland, in the journal Nutrients.
How protein affects athletes’ gut health
Athletes often follow high-protein diets to maximize muscle mass, strength, and endurance. Whey protein has traditionally been the most popular choice due to its complete amino acid profile, but plant proteins are gaining popularity as healthy, environmentally conscious alternatives.
Up to 10% of dietary protein reaches the colon undigested. Here, it is fermented by specific components of the microbiota, which can cause unbeneficial shifts in bacterial balance. For example, increased production of ammonia and phenolic compounds may compromise gut barrier function.
Impaired gut barrier integrity, or “leaky gut,” may result in a cascade of adverse events, including systemic inflammation, compromised immunity, and the development of chronic conditions.
In athletes, dysbiosis and compromised gut function can impair performance, energy levels, and recovery. Therefore, understanding the effects of different types of protein supplements and their metabolic potential can be key to supporting athletes and giving them an edge in performance.
Study details
The researchers randomly assigned 45 elite footballers to one of four supplement groups: Whey protein concentrate (WPC), pea protein isolate (PPI), rice protein isolate (RPI), or a plant-protein blend (MIX).
Participants consumed 30g (24 g protein) of their assigned supplement daily for eight weeks, recorded a food diary, and completed a standardized resistance training program. The researchers assessed microbiota using stool samples and DNA analysis.
The resulting data indicated none of the supplements led to significant alterations in the overall diversity of the gut microbiota. However, detailed analyses revealed “subtle but potentially relevant shifts in the predicted metabolic potential of the microbiome”, the researchers wrote.
“Whey protein concentrate (WPC) was associated with an increase in Bacteroidetes abundance and greater balance within the microbial community structure, whereas pea protein isolate (PPI) and the MIX correlated with reduced fermentative bacteria and elevated taxa potentially involved in cadaverine biosynthesis,” they wrote.
“Rice protein isolate (RPI) supplementation was associated with a higher predicted representation of taxa involved in succinate-to-butyrate fermentation pathways.”
The researchers concluded that the findings underscore a need for individualized dietary recommendations and supplementation strategies in professional football players to optimize gut health and training adaptations. Furthermore, they called for additional research to better understand the consequences of the microbiota alterations in response to different protein supplements.
Source: Nutrients, https://doi.org/10.3390/nu18050768, “Supplementation with Animal- and Plant-Derived Proteins Modulates the Structure and Predicted Metabolic Potential of the Gut Microbiota in Elite Football Players.” Authors: B. Kroplewski et al.
