Recent Research Sheds Light On The Impact Of Walnuts On Gut Health

As gut health becomes an increasingly important topic in overall wellness, many consumers are looking for simple ways to support their gut health and, by extension, their overall well-being. While there is still much to learn about the gut microbiota, one thing is clear: the foods we eat play a significant role in the health and diversity of the beneficial bacteria that reside in our guts.

Research has shown that walnuts may offer benefits for gut health. A study conducted by the USDA and the University of Illinois examined 18 healthy adults aged 35 to 68, who consumed 1.5 ounces of walnuts daily for three weeks. The results showed a decrease in secondary bile acids, which are linked to colon cancer, inflammation, and gastrointestinal disease. Additionally, walnut consumption increased beneficial gut bacteria, suggesting positive effects on gut health. While these findings are encouraging, more research is needed to better understand the cause-and-effect relationships. Walnuts are also packed with essential nutrients per 1-ounce (28-gram) serving, including 2.5 grams of omega-3 alpha-linolenic acid (ALA), 2 grams of fiber, 5.91 mg of tocopherols, and antioxidant polyphenols.

Recent evidence also suggests that walnuts may have prebiotic effects. Prebiotics are substances that promote the growth of beneficial gut bacteria. Two recent scientific papers published in Nutrients and Antioxidants explored the relationship between walnuts and a compound called urolithin A (UA). UA, produced by gut bacteria, may play a role in supporting gut microbiota health.

A study published in Nutrients in 2023 reviewed the effects of nut consumption on the gastrointestinal tract, with a particular focus on walnuts. The findings suggested that walnuts may contribute positively to the diversity of beneficial gut bacteria. While the results are promising, research on the specific health benefits related to gut bacteria, such as microbial alpha and beta diversity, remains inconsistent.

A second paper, published in Antioxidants in 2023, analyzed 33 studies on the benefits of walnuts, especially regarding inflammation and disease risk. The paper concluded that walnuts, as part of a balanced diet, may help reduce inflammation and support digestive function due to their unique nutrient composition and metabolites produced during digestion. Specifically, the paper highlighted ellagitannins (polyphenols in walnuts), which are metabolized by the gut microbiota into bioactive, anti-inflammatory urolithins.

“Evidence that microbial metabolism of ellagitannins from walnut consumption is highly patient-dependent led to our NIH-funded clinical study to examine ellagic acid metabolism in individuals at high risk for colorectal cancer. Our goal is to better understand how eating 2 ounces of walnuts daily, along with a regular diet, may impact an individual’s microbiome and identify the specific microbes responsible for these metabolic reactions needed to form urolithins."

In a study conducted in Armenia, the intestinal microbiota was referred to as the “second brain” due to the high number of bacteria and nerve cells it contains. Thought to develop in utero and influenced by environmental factors, the gut microbiota plays a crucial role in immune system function and metabolism regulation. Its imbalance has been linked to chronic diseases such as cancer, type 2 diabetes, and Alzheimer's. With some interventions, such as incorporating walnuts into your diet, it may be possible to prevent these diseases and improve overall gut health.

Walnuts offer a simple, affordable, and delicious way to support gut health and provide a range of potential health benefits. While research in this area continues to evolve, incorporating walnuts into your diet can be a great way to show your gut some love!

For easy ways to include walnuts in your meals, try these gut-friendly recipes like the fiber-rich Toasted Walnut, Black Bean, Corn, and Tomato Salad or the Steak Sandwich with Walnut Kimchi Salad.