Daily Walnut Consumption Linked to Lower-Inflammatory Diet Pattern

Researchers at Loma Linda University have found that a simple dietary addition—a daily handful of walnuts—appears to shift how inflammatory a person's overall diet becomes. The finding comes from a two-year clinical trial published in the Journal of the Academy of Nutrition and Dietetics, part of a larger investigation into how walnuts affect the health of aging adults.

The study tracked 319 older adults living in Loma Linda, California. Half of them were asked to eat between one and two ounces of walnuts each day—roughly a small handful. The other half, the control group, avoided walnuts and kept their consumption of other nuts to a minimum. Neither group received instructions to change anything else about their eating habits. Over the course of two years, participants checked in with researchers five times, each time reporting what they had eaten and drunk in the previous 24 hours.

To measure dietary inflammation, the researchers used a tool called the Dietary Inflammatory Index, or DII. This index doesn't measure inflammation in the body directly. Instead, it estimates whether someone's overall eating pattern—the combination of foods and nutrients they consume—tends toward characteristics associated with higher or lower inflammatory potential. At the end of the two-year period, the group eating walnuts daily showed statistically significantly lower DII scores than the control group. The difference was small but measurable and meaningful in research terms.

This latest finding builds on earlier results from the same Walnuts and Healthy Aging Study, which has now produced more than 20 published research papers. Previous work showed that people who ate walnuts daily had reductions in several circulating markers of inflammation—actual biological signals in the blood that indicate inflammatory activity. The new dietary pattern finding suggests the benefit works on two levels: the foods people choose to eat shift toward a less inflammatory overall diet, and at the same time, their bodies show reduced inflammatory markers.

Sujatha Rajaram, the study's senior investigator and a professor at Loma Linda's School of Public Health, emphasized the practical significance. The key insight, she explained, is that adding walnuts to what people already eat was linked with moving toward a less inflammatory dietary pattern. A relatively straightforward food choice, she noted, can meaningfully improve the overall quality of someone's diet. Lynnley Huey Stern, one of the study's primary coauthors, framed the finding within a broader public health shift toward prevention and sustainable approaches to healthier living. This research, she said, points to a simple and accessible step people can take as they work toward more inclusive and lasting improvements in how they eat.

The practical question of how to actually add walnuts to daily life matters. Jayme Brisco, the study's other primary coauthor, offered several approaches. Some people crush walnuts and mix them into salads. Others stir them into breakfast cereals. But the simplest method, Brisco suggested, might be the most powerful: eating a handful of walnuts as a daily snack, specifically in place of foods loaded with sugar and refined carbohydrates. That substitution—trading a processed snack for whole walnuts—appears to be enough to shift the inflammatory character of someone's diet.

The research was supported by a grant from the California Walnut Commission and conducted jointly by Loma Linda University School of Public Health and Hospital Clinic of Barcelona in Spain. Rajaram will present findings from the broader walnut research program at the Eighth International Congress on Vegetarian Nutrition, scheduled for March 14-16, 2027, in Loma Linda, with virtual attendance available. The symposium will focus on several research findings about how nuts influence diet quality and overall health.