New research reveals that your choice of protein source — whether plant or animal-based — dramatically impacts your gut microbiome, potentially altering your long-term health outcomes and mortality risk.
At a Glance
- Different protein sources (plant, animal, yeast) significantly alter gut microbiota composition and function, with some causing dramatic shifts
- Animal protein consumption is linked to higher mortality rates, while plant-based proteins are associated with reduced mortality
- The egg white diet caused one bacterium to dominate and activate enzymes that break down mucin, potentially compromising gut barrier function
- Protein source has a greater impact on gut health than the amount of protein consumed
- High protein diets can lead to weight loss and reduced body fat, with significant changes observed in the gut microbiome
How Protein Sources Reshape Your Gut Microbiome
Recent studies have uncovered the profound influence that different protein sources have on the composition and function of our gut microbiome. Research using integrated metagenomics-metaproteomics approaches has demonstrated that proteins from varying sources—including animal, plant, and other alternatives—trigger specific shifts in gut microbial populations.
These changes subsequently affect metabolic and immune responses, which can have significant implications for overall health. The source of dietary protein appears to have a more substantial impact on gut microbiota than the actual amount consumed.
“The composition of the gut microbiome significantly changed every time we changed the protein source,” notes Blakeley-Ruiz from a study published in Technology Networks Immunology News. This research tested various protein sources including egg whites, brown rice, soy, and yeast, observing dramatic differences in how each affected the microbiome.
Plant vs. Animal Protein: Impact on Longevity
The relationship between protein sources and mortality has emerged as a significant finding from recent research. Studies suggest that dietary choices could potentially influence life expectancy through interactions with the gut microbiota. Animal protein consumption has been associated with higher mortality rates compared to plant-based protein sources. These findings align with broader nutritional research suggesting that a shift toward more plant-based proteins may offer health benefits, particularly for older adults concerned about long-term wellness.
Research shows that a diet rich in fruits, veggies, whole grains & lean proteins may reduce your risk of some diseases. Dr. Karley Mahalak at the ARS Dairy and Functional Foods Research Unit studies prebiotics & their role in gut health. https://t.co/Foye3eYywE #HealthyAgingMonth pic.twitter.com/C0kuQUqiil
— Agricultural Research Service (@USDA_ARS) September 26, 2024
When undigested protein reaches the colon, gut bacteria can process it into either beneficial compounds like short-chain fatty acids (SCFAs) or potentially harmful ones like ammonia and sulfides. The type of protein appears to determine which metabolic pathways dominate, which may explain some of the observed differences in health outcomes between those consuming primarily animal versus plant proteins. The gut microbiota’s ability to convert dietary proteins into various compounds is increasingly recognized as a factor in disease development.
Gut bacteria have also their own food preferences. Scientists have advanced in determining the nutrient preferences across bacteria through tracing into genus-specific bacterial protein sequences https://t.co/BUwzzepZmx pic.twitter.com/tXh7MdQSt2
— GutMicrobiota Health (@GMFHx) October 14, 2022
Specific Protein Sources and Their Unique Effects
Different protein sources trigger remarkably distinctive changes in the gut microbiome. In experimental studies, egg white protein caused particularly notable effects, with one bacterium dominating and activating glycan-degrading enzymes. This specific change raises concerns about potential impacts on gut barrier function, as these enzymes could break down the protective mucin layer lining the intestines. Brown rice and egg white diets also increased amino acid degradation in the gut microbiome, altering how microbes process proteins.
“This could be really meaningful, health wise,” Blakeley-Ruiz said. “In the egg white diet, in particular, one bacterium took over and activated a bunch of glycan-degrading enzymes. We then grew this bacterium in the lab and found that the glycan-degrading enzymes it produced in media containing egg white protein were similar to those produced in media containing mucin.”
In contrast, casein protein (found in milk) has shown promising effects in preventing obesity development in animal studies. Research indicates that “casein was the most efficient protein source preventing weight gain and accretion of adipose mass, whereas mice fed high protein diets based on ‘white meat’ (lean pork or chicken filets) had the highest increase in feed efficiency and adipose tissue mass,” according to researchers Lise Madsen, Lene S Myrmel, Even Fjære, Bjørn Liaset, and Karsten Kristiansen in their study published in the National Library of Medicine.
Protein Quality and Processing: Additional Considerations
Beyond simply choosing the source, protein quality and processing methods significantly influence how these foods affect gut health. Factors such as protein structure, glycation, oxidation, and processing techniques all impact digestibility and bioavailability, which in turn influence how gut microbiota interact with these proteins. The structure of proteins determines their susceptibility to digestive enzymes and consequently, the availability of substrates for gut microbiota to utilize.
“These findings provide a crucial foundation for understanding how protein diets influence the gut microbiome and open doors for further investigations into the role of diet in promoting a healthy gut and overall health,” explains Samson Adejumo from research published by the American Society for Microbiology.
Research also indicates that protein from seafood sources may be less likely to promote obesity than proteins from terrestrial animals. This growing body of evidence suggests that thoughtful selection of protein sources could be leveraged as a strategy to manipulate gut microbiota composition for improved health outcomes. The resilience of gut microbiota also means that dietary interventions may need to be consistent over time to maintain beneficial changes to the microbiome.
