J Acad Nutr Diet. 2026 Aug 28:156835. doi: 10.1016/j.jand.2026.156835. Online ahead of print.
ABSTRACT
BACKGROUND: Walnuts may lower diet-related inflammation by providing anti-inflammatory compounds and displacing pro-inflammatory nutrients.
OBJECTIVE: To explore the association between daily walnut consumption or abstention for 2 years and the Dietary Inflammatory Index (DII®).
DESIGN: The Walnuts and Healthy Aging (WAHA) study is a dual-center (Loma Linda, California, USA and Barcelona, Spain), randomized trial, comparing a walnut-rich diet with a control diet over 2 years between May 2012 to May 2016, for age-related outcomes in healthy, free-living older adults aged 63-79 y. This ancillary study concerned only the Loma Linda cohort.
PARTICIPANTS/SETTING: A total of 319 older adults (mean age 69 y, 66% women) from Loma Linda, Ca were randomly assigned to walnut (n = 166) or control (n = 153) diets.
INTERVENTION: The walnut group consumed 1-2 oz walnuts/day (30-60 g/day, ∼15% of energy), while the control group abstained from walnuts and limited other nuts to <2 servings/week. Both groups followed their usual background diet.
MAIN OUTCOME MEASURES: DII scores were calculated from five 24-hour dietary recalls taken at random during the 2-year period.
STATISTICAL ANALYSES PERFORMED: Linear mixed models tested DII differences between the walnut and control groups, adjusting for sex, age, BMI, race, energy intake, smoking status, physical activity, and educational attainment.
RESULTS: The mean DII (SE) score was -0.025 (0.14) in the walnut group and 0.615 (0.14) in the control diet group (p<0.01). At the nutrient level, n-3 PUFAs (ß=-0.291; 95%CI: -0.450, -0.132; p<0.01), magnesium (ß=-0.014; 95%CI: -0.015, -0.013; p<0.01), carbohydrate (ß=-0.009; 95%CI: -0.014, -0.005; p<0.01), fiber (ß=-0.120; 95%CI: -0.133, -0.106; p=0.05), and protein (ß=-0.020; 95% CI: -0.031, -0.008; p<0.01), were associated with a more anti-inflammatory DII score, while intake of total and saturated fat were associated with a higher, more proinflammatory, DII score (ß=0.033; 95%CI: 0.020, 0.045; p<0.01 and ß=0.102; 95%CI: 0.080, 0.125; p<0.01 respectively).
CONCLUSION: Incorporating walnuts into the habitual diet was associated with more anti-inflammatory DII scores compared with a walnut-free control diet. These findings suggest that adding a single whole food may be a feasible complementary strategy for favorably improving the inflammatory potential of a diet.
PMID:42665183 | DOI:10.1016/j.jand.2026.156835