The #1 Nut for Gut Health, According to a Gastroenterologist

When we take care of our gut health, we are not only supporting digestion but also potentially bolstering our immune system, mood and energy levels. The gut is home to trillions of microorganisms that can support nutrient absorption, reduce inflammation and may help lower the risk of some chronic diseases.

When it comes to nurturing our gut health, the food choices we make can significantly impact our microbiome. Among the various options available, nuts stand out as a particularly beneficial choice. With their crunchy textures and delightful flavors, nuts are not just a tasty snack but also a powerhouse of nutrients that support our digestive system.

But while all nuts provide digestion-friendly fiber, you may wonder which nut tops our list as the best choice out there to help keep your gut health in tip-top shape. To dive deeper into this topic, we consulted a gastroenterologist to uncover which choice claims the title of the No. 1 best nut for gut health. The answer? Walnuts.

The Benefits of Walnuts for Gut Health

Provides Fiber

A 1-ounce serving of walnuts contains 2 grams of fiber. (This amount is equal to 14 walnut halves.) “Fiber is beneficial to our microbiome,” explains Will Bulsiewicz, M.D., a board-certified gastroenterologist and founder of the gut-health supplement company 38TERA. “Yet the vast majority of Americans are nowhere close to achieving even the minimum recommended amount of this nutrient,” he says.

Fiber plays a crucial role in supporting gut health by promoting regular bowel movements and preventing constipation. It aids in the maintenance of a balanced gut microbiome by providing nourishment for beneficial bacteria. This support helps to create a healthier digestive environment.

Research backs this up. Adults who ate 42 grams (about 1.5 ounces) of walnuts each day for three weeks experienced an increase in “good” gut bacteria and a decrease in secondary bile acids, compared to a control period. Both of these benefits may play a role in colon cancer, inflammation and gastrointestinal diseases, according to one small study.

Provides Omega-3 Fatty Acids

Walnuts are also an impressive source of omega-3 fatty acids, a heart-healthy fat that Bulsiewicz says is also good for gut health. These fatty acids may enhance the growth of beneficial gut bacteria, as well as help reduce gut inflammation, both crucial for maintaining the integrity of the gut lining. The gut lining is a barrier that allows nutrients and water through to the bloodstream while keeping out toxins and bacteria. However, a breakdown in this lining (also known as leaky gut) will allow these bad actors through, which can lead to inflammation and other health problems. 

Supports the Production of Butyric Acid

Butyric acid is a short-chain fatty acid that helps maintain the health of the colon. Research in Caucasian adults has found that consuming 1.5 ounces of walnuts daily promotes the proliferation of bacteria that produce probiotics and butyric acid.

An increased level of butyric acid is a plus for your microbiome because this fatty acid encourages the growth of beneficial bacteria while inhibiting harmful ones. It’s also associated with less inflammation in the gastrointestinal tract, supports intestinal function and promotes blood flow and gut motility to improve digestion.

Provides Antioxidants 

The antioxidants present in walnuts may play a role in maintaining gut health by protecting gut cells from oxidative stress, a condition that can lead to cellular damage and inflammation. Walnuts contain a plethora of antioxidant compounds, such as ellagitannins and flavonoids, that further protect the digestive tract and reduce inflammation. One review of 33 studies suggests that eating walnuts as part of a healthy diet may help reduce overall disease risk, including risk of colorectal cancer.

Other Strategies to Support Gut Health

While eating walnuts may bolster gut health in different ways, it’s certainly not the only thing you can do. Here are other dietitian-recommended practices that can help keep your microbiome happy:

• Chew slowly and thoroughly: Digestion begins in the mouth, and eating quickly can cause digestive distress, says Mascha Davis, M.P.H., RDN, founder of Nomadista Nutrition. “Eating slowly and chewing really well helps tremendously and also aids in preventing overeating,” she says.
• Incorporate probiotic-rich foods: Yogurt, kefir, fermented vegetables, sauerkraut, kimchi and miso are fermented foods that pack probiotics, live bacteria that can help restore and regulate gut bacteria, says Melissa Mitri, M.S., RD, owner of Melissa Mitri Nutrition. In addition, one study found that eating these types of foods every day for 10 weeks boosts the diversity of gut bacteria and reduces inflammation, adds Kaytee Hadley, M.S., RDN, founder of Holistic Health and Wellness in Richmond, Virginia. This was in comparison to a high-fiber diet, which had different effects like improving microbiome function.
• Limit alcohol consumption: “Excessive alcohol consumption can negatively affect gut health,” says Wan Na Chun, M.P.H., RD, owner of One Pot Wellness in Indianapolis. Alcohol is a gut irritant that causes inflammation and microbiome imbalance. “This imbalance can result in digestive issues, such as bloating and diarrhea and can contribute to more serious conditions like leaky gut syndrome, where the intestinal lining becomes more permeable,” she explains.
• Follow an active lifestyle: Get moving in some way, every day. (Micro workouts are one option!) “Emerging research suggests that exercise can positively influence the composition and diversity of the gut microbiome,” says Chun. “Regular physical activity may increase the abundance of beneficial bacteria, which can contribute to better digestion, enhanced immune function and reduced inflammation,” she explains.

The Bottom Line

One simple way to support gut health is to include more walnuts in your diet. Walnuts are rich in fiber, fatty acids and antioxidants that promote healthy gut bacteria and a diverse microbiome for better gut health. And they’re versatile, too. Along with making them a go-to snack-time nosh, try our Spinach Walnut Pesto, Walnut-Rosemary Crusted Salmon or any of our other healthy walnut recipes. Your gut health will thank you.