5 Foods for a Healthier Gut

by Carla Henderson

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We all know that exercise and eating healthy are simple ways to achieve better health, but as it turns out, your gut health might have more to do with your overall health than just weight loss, gain, or maintenance. 

The association between gut microbiomes (the enormous communities of bacteria in your digestive tract) and improved well-being has been highlighted in numerous studies in recent years — for example, benevolent bacteria in our digestive systems have been singled out for improved brain performance , easier weight loss , lower cardiovascular disease risk , and more robust immune system function . Research even suggests that food allergies could be tied to the make-up of our microbiome. These tiny bacteria may play a role in how much active vitamin D is circulating in our bodies and how much muscle growth occurs after a bout of exercise.

Bacteria Buffet

When it comes to boosting your gut health, diet is obviously a major player. Case in point: According to a study published in the journal Nature Medicine , your gut microbiome can thrive or flounder based largely on what foods you include and exclude in your diet. 

For this study, the scientists analyzed the microbiomes of just over 1,000 people who had contributed several years’ worth of diet information to a major data-gathering effort called PREDICT 1, which aims to uncover the genetic and metabolic responses we have to the foods we eat. They found that diverse diets rich in certain foods — including vegetables, nuts, seafood, and eggs — are associated with the presence of beneficial gut microbes that have been linked to a lower risk of conditions including type 2 diabetes and heart disease.  Notable here is that it wasn’t just plant-based foods that improved participants’ microbiome makeups.

In contrast, the nefarious bacteria in our guts seem to prefer sweetened drinks like soda and highly refined grains like white bread. A separate study in the journal Gut determined that there’s a case to be made that a healthy diet consisting of fruits, vegetables, plant-based proteins, fish, nuts and low-fat fermented dairy could help the gut bacteria that provide anti-inflammatory effects thrive. Diets high in heavily processed foods and animal products had the opposite effect. 

Long story short, food not only nourishes your body, but also feeds the trillions of microbes that live inside your gut. It’s an ecosystem that you can support or diminish, depending on your diet. You have both good and bad actors in your gut, but noshing on these foods can help the superheroes of health win out. 

Avocado (Photo: GettyImages)

1. Avocado

Avocado has become one of the most well-known good fats around, and here’s even more proof that avocado is fatty in a good way. A recent study in the Journal of Nutrition that will surely please guacamole aficionados found that adults who added avocado to a single meal every day for 12 weeks had a higher count of gut microbes capable of breaking down dietary fiber and producing health-promoting compounds such as short-chain fatty acids, compared with those who did not include the creamy fruit in their diet. 

The avocado-eating group also had measurably lower levels of certain bile acids that tend to harm gut health. Daily avocado consumption was associated with greater microbial diversity, leaving the study authors to conclude that it can have a positive effect on our digestive physiology. Why this benefit to the microbiome occurs still needs to be nailed down, but it’s likely largely due to the combination of fiber, monounsaturated fat and bioactive compounds in the guac star.

Just remember that if you’re going to start tossing avocado on your salads and sandwiches, and maybe even blending it into your smoothies, you’ll need to scale back some calories elsewhere from your diet to maintain your current calorie intake. A single avocado can contain more than 300 calories. But, as this study demonstrates, not all calories are created equal for better gut health. 

2. Black Beans

You don’t need to be going plant-based full-stop to reap the benefits that these and other beans can have on your gut functioning. A cup of canned black beans delivers nearly 17 grams of dietary fiber, which helps keep the critters in your digestive tract well fed. 

Research shows that eating more fiber, including a certain type known as galacto-oligosaccharides that’s found in beans, can increase the amount of beneficial bacteria in our guts and increase their production of butyrate, which are short-chain fatty acids created when certain microorganisms feast on the fiber you eat. (Our digestive systems don’t do well at breaking down dietary fiber, but various gut microbes are very adept at the process.) 

Emerging research suggests that bacteria-derived short-chain fatty acids can improve gut and other organ health by lowering inflammation and even potentially inhibiting cancer cell formation. And this recent study in the American Journal of Clinical Nutrition suggests that a compound called enterolactone, which is produced more abundantly by gut bacteria on a high-fiber diet, can help lower heart disease risk. Interestingly, the role that high-fiber diets play in lowering the risk for depression might come down to the way bacteria in our guts use fiber to reduce inflammation in the body. 

Only about five percent of Americans eat enough fiber on any given day, which is leaving important microorganisms famished. So sneaking more beans into your diet can help you get closer to meeting your daily fiber recommendation of at least 25 grams per day.

Salmon (Photo: GettyImages)

3. Salmon

We already know that the omega-3 fatty acids found abundantly in certain fish like salmon, sardines and mackerel are mega-healthy with wide-ranging benefits, including improved heart and brain functioning. Now we have a better idea of how they work to promote healthier aging, and it could come down to their prebiotic function in our guts. 

In an article in the aptly named Gut Microbes, researchers at King’s College in London discovered that 6 weeks of higher omega-3 intake resulted in participants having a higher population of desirable Coprococcus and Bacteroides strains of bacteria in their digestive tracts. They lead to an uptick in the production of the helpful short-chain fats iso-butyrate and isovalerate. Higher amounts of Coprococcus were associated with lower levels of the types of “bad” cholesterol that negatively impact heart health. 

Other research from the same institution found evidence that when microbes work on the omega-3 fatty acids, they produce compounds that could help fight the onset of depression, which plays further into the idea that there is a gut-brain axis. 

What remains to be determined is whether there are noticeable differences in how the microbiome responds to the longer-chain omega-3 fats you get from fatty fish compared to the shorter-chain omega-3s that are found in certain plant foods such as walnuts, canola oil and chia seeds. 

4. Kefir

Think of kefir as yogurt on steroids. Long popular in Eastern Europe, tangy kefir is a dairy product created when milk is fermented by lactic acid bacteria and yeasts encased in what are known as “kefir grains.” Most brands contain a greater overall population of probiotic microorganisms than regular yogurt. So by consuming kefir, you’re basically fertilizing your digestive tract with a bounty of good-for-you bacteria, including Lactobacillus and Bifidobacterium strains. 

Research shows that for some people, kefir can be easier to digest than milk. It’s a perk attributed to the robust population of bacteria in kefir feasting on and reducing levels of lactose – a natural sugar in dairy that can cause digestive woes. Kefir also contains a trifecta of items that can help you fortify your skeleton: protein, calcium and vitamin D.

Kefir is most often sold as a thick drink with a similar consistency to buttermilk. Flavored versions typically have a deluge of sugary calories that can negate some of the health benefits, so it’s best to go with plain. You can pour it into a glass and drink straight up, or use it in your post-gym protein shakes. It’s also a great replacement for milk when making overnight oats or buttermilk when preparing pancakes. You can even use it as a base for a gut-benefiting creamy salad dressing.

Dark Chocolate (Photo: GettyImages)

5. Dark Chocolate

In a study we all wish we were part of, investigators in South Korea randomly assigned adults to receive one ounce of extra dark chocolate (85 percent cocoa content), the same amount of not-so-dark chocolate (70 percent cocoa content) or no chocolate at all (bummer for them) for 3 weeks and then tested mood states and gut microbiota composition. The 85 percent cocoa content chocolate was the only trial to result in a noticeable improvement in mood as determined by a questionnaire designed to assess mental well-being. When compared with participants who missed out on chocolate consumption, those who ate dark chocolate were found to have a higher diversity of microbiota in their guts. 

Interestingly, there was a correlation between this greater diversity, which included higher levels of Blautia obeum bacteria, and mood state — another example of how the gut-brain axis plays a role in helping turn a frown upside down. 

Darker varieties of chocolate are rich in polyphenols, and emerging science has discovered that these antioxidants are metabolized by the bacteria that we host in our bodies and the resulting compounds may play a role in digestive, immune and mental health. This could be a major reason why eating more colorful antioxidant-rich fruits and vegetables is a recipe for good health. In the case of chocolate, you need to consume products with a high cocoa percentage so that you get more gut-friendly antioxidants and less added sugar.