The secret to a healthy gut is simpler than you think

One of the secrets to better gut health is simpler than you might think: Eating a wide variety of plants helps a wide variety of beneficial bacteria flourish in your gut microbiome, according to a large study published in the journal Nature Microbiology. And it’s still good for you even if you occasionally enjoy meat, which is otherwise linked to more “bad” bacteria.

For the study, more than 21,000 people in the United States, United Kingdom, and Italy used an app to answer detailed questionnaires about what they ate on a regular basis. Their diets were grouped into three buckets: omnivore (including meat, dairy, and plants), vegetarian (no meat), or vegan (no animal products).

The researchers used DNA technology to analyze participants’ stool samples, which allowed them to identify the different types of bacteria proliferating in their microbiomes, says study author Nicola Segata, a professor and principal investigator at the CIBIO Department of the University of Trento in Italy. 

(Your gut health can affect the rest of your body. Here’s why.)

The study found that when people ate more whole plant foods—fruits, vegetables, and whole grains—their guts harbored more “good” bacteria, including microbes associated with healthy blood pressure and cholesterol, and less inflammation. Vegans in particular had gut microbiomes teeming with these beneficial bugs. 

Meanwhile, omnivores—particularly those who ate red meat—had more “bad” bacteria hanging out in their gut microbiomes, including those linked to a higher risk of developing inflammatory bowel disease and colorectal cancer.

The upside: Folks who ate lots of different plants and meat had plenty of good microbes in their guts, similar to vegans and vegetarians.

That means the healthy bacteria associated with eating more plants appear to balance out, potentially even restrain, some of the not-so-healthy bacteria linked with eating red or highly processed meats, says Ravinder Nagpal, assistant professor in the department of health, nutrition, and food sciences and director of The Gut Biome Lab at Florida State University, who was not involved in the study.

It’s too soon to say how big of a role this might play in preventing disease. While the existing research is promising, experts agree we need a stronger breadth of data to say that helpful bacteria stemming from plants simply offsets problematic bacteria linked to red meat. Plus, your unique microbiome is just one aspect of your wellbeing, so we also need more studies to better understand how this distribution of microscopic critters influences your health in general.      

One thing is clear, however: “Having a gut microbiome that’s in good shape is important,” Segata says—and loading up on plants is one of the most natural ways to transform it for the better.

How eating a variety of plants supports a healthy gut

Imagine your gut microbiome as a garden: It’s full of trillions of different microbes (flowers) that like different types of food (fertilizer). What you eat directly affects which microbes take hold in your body, just like certain fertilizers encourage certain flowers to bloom in abundance, Nagpal explains.

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Plant foods are full of fibers, some of which our bodies can’t digest well, explains Sean Spencer, a gastroenterologist and physician scientist at Stanford Medicine.

That’s where bacteria come in: They set up shop in your colon and feed on these undigested fibers, degrading and fermenting them. The chemical byproducts of this process, most notably short-chain fatty acids, can boost your health in distinctive ways, from supporting your immune system to regulating your mood.

(How much fiber do you really need to stay healthy?)

That’s why diversity is key: If you only use kale as a base for your daily lunch salad, you’re primarily feeding the bacteria that love kale, versus also feeding bacteria that prefer cabbage, brussels sprouts, or quinoa. Nourishing all these different microbes produces various short-chain fatty acids that can have different positive effects on your body. Plus, colorful plants are packed with phytonutrients, including a range of antioxidants that help protect your body against chronic diseases, in part by promoting bacteria that thwart inflammation. 

However, even plant-forward eaters can miss out on certain nutritional perks, Segata notes. For example, your microbiome won’t reap the same benefits if you’re mainly eating highly processed vegan foods (think: packaged items high in salt, sugar, and saturated fats) compared to whole fruits, vegetables, legumes, grains, nuts, and seeds. Plus, the study authors noted that vegans’ guts lacked the unique, health-promoting probiotics found in fermented dairy products like cheese and yogurt, so excluding healthy food groups can “leave its mark” on your microbiome too.

How to mix up your diet for better gut health

If you want to eat meat, Nagpal says being choosy with your animal proteins, as well as how often you eat them, is key.

He points to the widely studied Mediterranean-style diet. People who generally fall into this eating pattern may eat red meat, but not regularly. Seafood and lean poultry are more common protein sources (about two to three servings per week), and meals are centered around healthy fats like nuts and olive oil, low-fat dairy, whole grains, and fruits and vegetables.

Fiber should be on your radar (remember, this is the stuff your gut microbes feed on). Adults ideally need about 22 to 34 grams each day, and there are limitless ways to hit this mark. Consider the USDA’s recommendation for a balanced meal: Half your plate should be filled with fruits and vegetables, while the other half should be equal parts whole grains and protein.

(Want a better high-protein diet? You don’t have to eat more meat.)

Then do your best to switch it up daily—if oatmeal is your go-to breakfast, top it with strawberries on Monday and then sliced bananas on Tuesday, for example. If you always roast sweet potatoes, red onions, and broccoli for your weekly meal prep, swapping just one of those for a new veggie, like butternut squash or cauliflower, will introduce different fibers and nutrients to the mix. Or throw an apple or carrots into your work bag to snack on with your usual cheese and seedy crackers.

The most practical takeaway? Eating more plants is good for your gut, and you have a lot of wiggle room to experiment. So if you hate celery, no need to force it down. “There are so many plants out there, so many fiber-containing foods,” Spencer says. “You just need to find the ones you like.”