Background: Recently on the metabolic syndrome is considered as an inflammatory disease. So factors affecting inflammation are important in this condition.

Methods: This randomized cross-over clinical trial was undertaken on 42 postmenopausal women with metabolic syndrome. Participants were randomly assigned to consume a control diet (Dietary Approaches to Stop Hypertension= DASH), soy protein diet, or soy nut diet, each for eight weeks. Inflammatory markers were measured by ELISA.

 Results: The difference from the control diet for E-selectin (an inflammatory markers which shows the endothelial function) was -11.4% (P<0.01) on the soy nut consumption and -4.7% (p=0.19) on the soy protein diets. Soy nut consumption reduced interleukin-18 compared to the control diet (difference from the control diet: -9.2%, p<0.01). For C-reactive protein the difference from the control diet was -8.9% (P<0.01) on the soy nut diet and -1.6% (P<0.01) on the soy protein diet.

Conclusion: Short-term soy nut consumption reduced some markers of inflammation and increased plasma nitric oxide levels in postmenopausal women with the metabolic syndrome.