Studies show that walnuts can be beneficial for the cardiovascular system. The omega-3 fatty acids they contain can lower cholesterol levels, soften hardened arteries, and lower blood pressure caused by stress.
In one study, participants added 1.3 ounces of walnuts and one tablespoon of walnut oil to the standard American diet. They increased arterial function significantly when compared to a control diet without their addition, according to WebMD.
Ingesting walnuts after fasting for 12 hours during stressful times also decreased a person's blood pressure levels by two to three points. This improvement was in both the systolic and diastolic pressures.