Adding walnuts (a healthy plant source of omega-3 fatty acids) to a high-fat meal appears to benefit the arteries of people with high cholesterol. Researchers compared how arteries were affected by five teaspoons of olive oil versus eight walnuts when added to a fatty meal. While both walnuts and olive oil decreased inflammation, walnuts increased the elasticity and flexibility of the arteries (flow-mediated dilation, or FMD) in high cholesterol patients by 24%. In comparison, high-cholesterol patients who consumed olive oil showed a 36% decrease in FMD.
American Journal of Cardiology, 2006