"Whether you’re looking at trending hashtags on TikTok or what the biggest health experts are focusing on, two buzzwords in particular have taken over the wellness world: protein and gut health. We already know that protein is essential for building muscle, healing hormones, and keeping a healthy metabolism, but it turns out that protein can greatly affect your gut health as well. And with more and more people prioritizing healing digestive symptoms and optimizing their gut, the fact that protein and gut health go hand-in-hand is great news. Studies suggest that dietary protein strongly impacts your gut microbiome and digestive function. However, when it comes to what type is optimal for gut health, not all protein is created equal. I asked experts to break down the connection between protein and gut health and which protein sources are considered best for a healthy gut.
How does protein impact gut health?
According to Alayna Hutchinson MS, LDN, RDN, a registered dietitian at microbiome biotech company Pendulum, protein is essential for the gut to function correctly, namely for digestion, nutrient absorption, immune function, and prevention of gut disorders like leaky gut. So, you know all those trendy gut health supplements? If you eat dietary protein, you’re already reaping a lot of the benefits. “Proteins are broken down into amino acids during digestion, and these amino acids are used by the body for various functions, including the synthesis of enzymes involved in digestion,” Hutchinson said. “Proper digestion is crucial for gut health, as it ensures the efficient absorption of nutrients and the elimination of waste products.”
Other than digesting and absorbing nutrients from the food and drinks we consume, our digestive system protects us from harmful invaders, with the small and large intestine housing nearly 80 percent of our immune system. And immune cells in the gut rely on proteins to carry out their functions, such as identifying and eliminating pathogens. “The cells lining the intestinal wall rely on proteins for structural support, helping to prevent the passage of pathogenic organisms and other toxins from the gut into the bloodstream,” Hutchinson explained.
To reap the most benefits protein has to offer, Hutchinson recommended eating about 0.8 grams of protein per kilogram of your body weight per day, depending on factors like age and activity level. If doing the math seems too complicated, you can shoot for around 1 gram of protein for every pound if you’re trying to gain muscle. If that’s not what you’re after or you engage in relatively low activity, the FDA suggests around 50 grams of protein daily for most U.S. adults.
Are all dietary proteins created equal when it comes to gut health?
The short answer is no—not all dietary proteins contribute to a healthy gut. Based on research published in the journal Nutrients, protein content, its source, processing methods, and interactions with other nutrients are factors that can impact gut microbiota composition and metabolism, potentially affecting physiological changes in the gut and overall health.
Animal versus plant proteins
The 2022 study found that the proteins from animal-based food sources, such as eggs, dairy, grass-fed meats, and wild-caught fish, may have better effects on gut microbiota compared to plant-based food sources, like beans, nuts, grains, and soy due to the higher digestibility of animal proteins. Additionally, the digestion of plant proteins may be limited by antinutrients, a group of substances that may not be properly absorbed. “Generally speaking, animal-based protein is more rapidly absorbed than plant-based protein, hence leading to fewer G.I. side effects, such as bloating and gas,” agreed Dr. Ibrahim Hanouneh, gastroenterologist and co-author of Regenerative Health. Animal proteins also have more balanced essential amino acids than plant proteins and are, therefore, considered higher-quality protein.
On the other hand, “Some plant-based proteins like nuts and seeds contain a substantial amount of fiber, which is beneficial for gut health, while some animal-based protein such as red meat may contain a significant amount of fat, which in excess may negatively impact the microbiome,” Dr. Hanouneh conveyed. More good news for plant-based consumers: Meat-free protein sources like lentils, beans, brown rice, peas, tofu/tempeh, quinoa, and chickpeas also support the gut’s well-being because they feed the healthy bacteria in the gut and produce short-chain fatty acids that support immunity, as Abby Grimm, MS, RDN and cofounder of FWDfuel Sports Nutrition, shared.
In summary, there are different gut benefits for both animal and plant-based protein, so getting a balance of the two is optimal for gut health. “Incorporating a variety of animal and plant-based proteins into the diet can support microbial diversity in the gut, which is associated with better gut health,” Hutchinson expressed. “Different protein sources provide varying amounts and types of essential nutrients, such as amino acids, fiber, vitamins, and minerals. Consuming a variety ensures that you obtain a wide range of nutrients necessary for overall health and optimal gut function.” If you opt for a diet without animal products, you can pair certain proteins together to get all nine essential amino acids. Think: quinoa and lentils, buckwheat and edamame, or peas and rice.
Processed versus whole proteins
Hutchinson cautioned reaching for the processed protein varieties, such as those found in processed meats like sausages and bacon, “fake meat” products, or certain protein powders, as they may include additives and preservatives that can disrupt gut health. “Processed meats and farm-raised animal protein have been shown to increase bad bacteria in the gut and should be rarely consumed if looking to optimize gut health,” Grimm elaborated. On the other hand, animal protein from pasture-raised chicken, grass-fed beef, wild-caught fish, and other organic sources contain high nutrients and do not contribute to the amount of inflammation we see in processed farm-raised meat, Grimm added. “These types of protein contain amino acids like glutamine, arginine, and tryptophan, which support the gut barrier and healthy blood flow in the gut.”
If you’re a plant-based eater, the same rules apply: “Fake meat” products made out of soy or whey and non-organic or unclean protein powders contain chemicals that majorly disrupt gut bacteria and can cause inflammation. In other words, the less processed your plant-based protein sources, the better. “These foods would also ideally be organic since plants can have high levels of pesticides and herbicides that may contribute to intestinal permeability,” Grimm described.
Which protein sources are best for gut health?
Hutchinson noted that determining the “best” protein sources for gut health can depend on individual preferences, dietary sensitivities, the starting microbiome you’re working with, and individual health goals. While protein sources are not one-size-fits-all, she said there are some deserving of the spotlight for their gut-friendly and diversifying qualities. Read on for a guide of proteins to choose from to include on your (diversified) plate, courtesy of Hutchinson.
Plant-based proteins
- Legumes (beans, lentils, chickpeas): rich in fiber, which promotes healthy digestion and
supports beneficial gut bacteria. - Nuts and seeds: provide essential fatty acids and fiber, supporting gut health and microbial
diversity. - Whole grains (quinoa, oats, brown rice): high in fiber and nutrients, contributing to a
healthy gut microbiome.
Fish and seafood
- Fatty fish (salmon, mackerel, sardines): rich in omega-3 fatty acids, which have
anti-inflammatory properties and may benefit gut health. - Shellfish (shrimp, crab, oysters): good sources of protein and certain nutrients that support
gut health.
Poultry and lean meats
- Skinless poultry (chicken, turkey): lean protein sources that provide essential amino acids and support muscle health.
- Lean cuts of beef and pork: good sources of protein, iron, and other nutrients when consumed in moderation.
Dairy products
- Yogurt: contains probiotics (beneficial bacteria) that support gut health and digestion.
- Kefir: another fermented dairy product rich in probiotics and protein.
- Cottage cheese: high in protein and low in fat, providing essential nutrients for gut health.