Posted on 05/13/2025 4:37:24 AM PDT by Red Badger

Researchers have found that the source of protein in your diet may dramatically shape your gut microbiome, influencing key metabolic processes and even gut lining health. The results suggest certain proteins, like egg whites, could have surprising and possibly harmful effects on gut function.
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New research from NC State reveals that different protein sources in animal diets can dramatically alter the gut microbiome, both in composition and function.
A new study from researchers at North Carolina State University has found that the type of protein in an animal’s diet significantly influences both the composition and activity of the gut microbiome, the community of microorganisms living in the digestive tract.
These gut microbes play a crucial role in various aspects of health, and the study’s findings could contribute to improved strategies for preventing and treating gastrointestinal diseases that affect millions of people worldwide.
“There’s something wrong with what we’re eating today, and we are not close to knowing what that is,” said Alfredo Blakeley-Ruiz, an NC State postdoctoral researcher and co-corresponding author of a paper describing the study. “Our lab wanted to know how different diets impact what lives in the gut, and to learn something about what those microbes are doing, functionally, in response to that diet.”
In their experiment, the researchers examined the effects of specific dietary protein sources, such as those from milk, eggs, and plants like peas and soy, on the gut microbiomes of mice. The mice were each fed a diet consisting of a single protein source for one week. These sources included egg whites, brown rice, soy, and yeast, allowing the researchers to isolate the impact of each protein on the gut microbial ecosystem.
Shifts in Microbial Populations and Activity
Using an integrated metagenomics-metaproteomics approach requiring high resolution mass spectrometry, the researchers found that the mice gut microbiome changed a lot over the course of the study, with some protein sources showing extreme effects.
“The composition of the gut microbiome significantly changed every time we changed the protein source,” Blakeley-Ruiz said. “The protein sources with the biggest functional effects were brown rice, yeast, and egg whites.”
In examining the functional changes in the gut microbiome, the study showed that the two largest effects of dietary protein were on amino acid metabolism, which was expected by the researchers, and complex sugar degradation, which was not.

Brown rice and egg whites increase amino acid degradation in the mouse gut microbiome.
“Brown rice and egg white diets increased amino acid degradation in the mouse gut microbiome, meaning that the microbes were breaking down those proteins instead of making their own amino acids from scratch,” Blakeley-Ruiz said. “This makes intuitive sense because proteins are made of amino acids, but this is something we want to dig into more. Some amino acids can degrade into toxins, and others can impact the gut-brain axis, so there are potential health implications from these diets.”
The study also showed that long chains of sugars attached to the dietary proteins, called glycans, also play a role in changing gut microbiome function. Multiple dietary protein sources, including soy, rice, yeast, and egg white, caused microbes in the gut to change the production of enzymes that break down glycans, sometimes substantially.
“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.”
Potential Implications for Gut Health
Mucin is the substance that lines the inside of the gut, protecting the digestive system from things like acid and pathogens. So if bacteria are producing enzymes that, purposely or not, break down mucin, they could be damaging the intestinal lining and causing negative impacts on gut health.
“I’m excited to explore this potential connection between the expression of glycan degrading enzymes in the egg white diet and the breakdown of mucin by the gut microbiome in future studies,” says Blakeley-Ruiz.
Manuel Kleiner, an NC State associate professor of plant and microbial biology and co-corresponding author of the paper, said the study lays the groundwork for future investigation of the effects of protein sources on the gut microbiome.
“One of the limitations of our study is that, of course, the diets are very artificial and could lead to amplified results,” Kleiner said. “But we now show that egg white has extreme effects on the microbiome. For the future, we’re very interested in understanding what the mechanism of this effect is in a mixed protein diet in mice.
“Our study shows not only which bacterial species are in the gut microbiome and their abundance, but also what they are actually doing. Here, they are specifically digesting the glycans. The result is a very comprehensive picture of what really matters in the gut in terms of diet and function.”
Reference:
“Dietary protein source alters gut microbiota composition and function”
by J Alfredo Blakeley-Ruiz, Alexandria Bartlett, Arthur S McMillan, Ayesha Awan, Molly Vanhoy Walsh, Alissa K Meyerhoffer, Simina Vintila, Jessie L Maier, Tanner G Richie, Casey M Theriot and Manuel Kleiner, 21 March 2025, The ISME Journal.
DOI: 10.1093/ismejo/wraf048
The study was supported by the National Institutes of Health through awards R35GM138362, T32DK007737 and P30 DK034987, and by the USDA National Institute of Food and Agriculture, Hatch project 7002782.
Well, the study author was completely right about one thing he said, “There’s something wrong with what we’re eating today, and we are not close to knowing what that is.”
He is right there. They have no clue. Avoid sugar. Limit carbs unless you are activity level is extremely high. For the rest of us who just sit around all day, emphasize meat and vegetables. Eggs are a super food.
I wonder what happens when the protein is ONLY beef.
Dr. Jordan Peterson, and his daughter, live on it....all her auto-immune problems vanished.
Correct me if I am wrong, but life comes from an egg, right?
Like eating a spoonfull of wood screws.
I have a lot of doubt that this is even remotely true.
I now try to buy eggs from pasture raised chickens, though.
OK, so what do we eat to re-establish the right blend of buggies?
Lacking that, you are a pack of whinging idiots. This is like cherry picky some temperatures and then screaming for $$ to study the phenom until you retire.
Make some suggestions at the outset or shut the F@#$ up!
You do not understand what is going on unless you have a good idea on how to fix it.
You vill eat ze bugs!. Und you vill like zem!.............OR ELSE!..............
eat more bugs!
Based on all of these different studies I’m surprised the human race hasn’t gone extinct from whatever it has been eating. Somehow our ancestors managed to live and even thrive on foods cooked in lard, eating eggs and bacon and lots of red meat.
Olive and fried egg sandwiches, that was my Father’s specialty. He had been a cook in the Army and was probably the only person that actually enjoyed army food. Least we forget, he served chipped beef on toast and spam sandwiches often.
Hubby eats egg whites only. Gross.
Then the yolk’s on him!.................
A lot of data in the article but little information.
Then the yolk’s on him!
🙄😆
So, stay away from egg white omelets? Angelfood cake? Meringues? Soufflés?
Waffles and crepes as well!.................
“Eggs are unhealthy”.
“Eggs are healthy”.
“Eggs are unhealthy”.
Ad nauseum
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