Even casual partakers in the realm of wellness likely know that probiotics, prebiotics, and fermented foods are power players in the gut health game.

However, did you know that good old protein is also involved in how solid your microbiome and digestive health are? If not, you’ll want to keep reading. With help from Lucy Kerrison, RD, a UK–based dietitian and gut health specialist at The Gut Health Clinic, we’ll unpack the ins and outs of the interplay between the macro and your gut. Plus: pro tips to ensure your protein intake (as well as your greater diet) permits your friendly gut bacteria to thrive.

How are protein and gut health connected?

“The gut is a muscle and requires a certain level of protein to maintain correct functionality,” Kerrison begins. Per a 2019 review in the journal Current Protein & Peptide Science, gut microbes are involved in the digestion, absorption, metabolism, and transformation process of dietary protein in the GI tract. Protein’s components influence gut microbiota and microbial metabolites, which take part in diverse physiological functions involved in health.

“The gut is a muscle and requires a certain level of protein to maintain correct functionality.”
—Lucy Kerrison, RD, gut health specialist at The Gut Health Clinic

Are all protein sources good for your gut and digestion?

According to the review cited above, the primary factors that contribute to the composition, structure, and function of gut microbes include the protein’s source, concentration, and amino acid profile. Kerrison adds that specific types may be better than others, though it can vary based on the individual at hand and their goals. “For example, we know the amino acid L-glutamine is utilized by our gut cells and is important for cell regeneration, as well as maintaining tight junctions and barrier function,” she shares. Upping your intake of L-glutamine, she continues, can potentially improve conditions such as post-infectious IBS.

Some high-protein sources are also good sources of prebiotics, aka the food for probiotics, nabbing them some extra credit for gut-friendliness and diversifying capabilities. “Examples would be oily fish such as sardines, salmon, and mackerel,” Kerrison shares. Plant-based eaters aren’t left out, either, as chickpeas, butter beans, and lentils also fall under this bucket.

Next, Kerrison notes that protein is typically easy to digest—but additives in protein sources can complicate things. “For example, many protein powders have artificial sweeteners which are difficult to digest and can increase gut symptoms in a sensitive individual,” she explains. “Another example is the galacto-oligosaccharides, which are difficult to digest in certain vegan proteins such as pulses, legumes, cashews, and pistachios. Meat can also take a little longer to digest for some people,” especially when consumed in excess. (FWIW, some dietitians advise capping protein intake at about 30 grams per meal to offset adverse symptoms like digestive and kidney distress. Excessively high protein intake may also activate the immune response—which has the potential to heighten the risk of colitis, IBD, and Crohn’s—but more research in human participants is necessary to investigate this link further.)

“Examples would be oily fish such as sardines, salmon, and mackerel,” Kerrison shares. Plant-based eaters aren’t left out, either, as chickpeas, butter beans, and lentils also fall under this bucket.

The takeaway on protein and gut health

While you may not have realized that protein intake is closely linked to the state of digestion and greater gut health, it’s one part of a larger puzzle for a thriving microbiome (and ensuing wellness wins). It’s pretty easy to meet protein requirements per meal and per day.

Tip: follow this cheat sheet to get 30 grams of the macro at each of your main meals. Fortunately, most people in Kerrison’s native UK, as well as the U.S., aren’t lacking in this department. But just in case, a good rule of thumb is to enjoy a high-protein source—such as poultry, fish, tofu, tempeh, beans, or pulses—at each meal.

She also suggests getting at least 30 grams of fiber per day to bolster your gut even further. (Note: If your fiber intake is minimal, gradually build up intake and drink plenty of H2O to avoid digestive discomfort.) Finally, Kerrison advocates aiming for 30+ plant-based products per week, as it’s the magic number linked to gut diversity and microbiome improvements. “This includes whole grains, nuts/seeds, beans/pulses, fruits, and veggies,” she shares.

If you’ve covered all of these bases and still haven’t made progress on your gut health woes, it’s time to enlist help. “Anyone who is experiencing difficulty with digestion or gut symptoms should see a specialist gut-health dietitian or doctor to ensure there is no underlying medical condition,” Kerrison concludes.