Walnuts may lower your risk of colon cancer and reduce overall inflammation in the body, according to a study recently published in the journal Cancer Prevention Research.
“The study shows that a simple and inexpensive dietary addition can provide health benefits to the colon without any downside risks,” study author Daniel Rosenberg told Fox News Digital.
Roseberg is the director of the colon cancer prevention program at the Carole and Ray Neag Comprehensive Cancer Center in Connecticut.
Researchers from the University of Connecticut School of Medicine said walnuts contain phytochemicals called ellagitannins, which are metabolized by the gut bacteria and converted into potent anti-inflammatory compounds known as urolithins.
High levels of urolithin A, formed by gut bacteria after walnut consumption, may positively affect immune cells in colon polyps and be linked with an overall reduction of inflammatory markers in urine, blood and fecal samples, according to the study.
“The effects are seen both in the colon, as well as in the blood,” Rosenberg said.
“The latter indicates the effects are systemic and not only limited to providing gut health.”
The study involved 39 participants between the ages of 40 and 60, considered to be at high risk for colon cancer. The participants avoided ellagitannin-containing foods and beverages for a week to get their bodies’ urolithin levels close to zero.
They were then closely monitored while following a diet that involved consuming walnuts, which are rich in ellagitannins, according to a UConn news release.
After the three-week study, the participants underwent a high-definition colonoscopy.
Researchers then looked at tissue from polyps removed during the procedure.
They found a direct association between patients with high levels of urolithin A formation — from gut biodome after consuming walnuts — with reduced levels of common proteins found in polyps.
This included the protein vimentin, which is associated with more advanced forms of colon cancer, according to the report.
Rosenberg told Fox News Digital that walnut ingestion “affects some of the inflammatory proteins that are surrounding a patient’s polyps, potentially adding additional health benefit.”
Reduced inflammatory markers were found in the urine and fecal samples of the participants who followed the walnut-consuming diet.
The study also found urolithin A-levels in participants’ urine correlated with a boost in serum levels of a protein associated with colorectal cancer inhibition known as peptide YY, according to the report.
Rosenberg said his team found walnut supplementation reduced the levels of several markers of inflammation in the participants’ blood, especially in individuals who had an elevated BMI in excess of 30.
“We believe that many of the effects we have observed with respect to inflammation are directly related to a patient’s ability to form urolithins,” Rosenberg told Fox News Digital.
“However, this ability is widely variable in human subjects. Some people can do this very well, whereas others lack this capacity.”
Rosenberg told Fox News Digital that his team’s long-term goal is to “figure out what microbes are responsible for this metabolic activity so that we can create probiotics that people can consume that will afford them the capacity to generate urolithins in their gut.”
To reap the health benefits, Rosenberg suggested eating about five to 10 walnuts per day.
Laura Feldman, a registered dietitian and assistant professor of nutrition at Long Island University in New York, was not affiliated with the study but told Fox News Digital that walnuts “are an excellent source of omega-3 fatty acids.”
These acids “are anti-inflammatory and, generally, Americans are not getting enough of them,” she said.
Feldman also noted that walnuts are rich in fiber, which is “another nutrient Americans are lacking.”
“Adequate fiber intake is associated with decreased risk of colorectal cancers.”
Although walnuts are a healthy snack, Feldman said they are considered a high-calorie food — so consumers should be mindful of portion sizes, “typically sticking to about a handful at a time throughout the day.”