Walnuts are an excellent source of protein, fiber and alpha linoleic acid, which is a plant-based omega 3 fatty acid. It is also high in antioxidants and together with walnut oil, they have shown positive results in lowering cholesterol and increasing insulin sensitivity. However, in addition to these amazing properties, walnuts have also shown to reduce certain cancerous tumors. In an ongoing study conducted under the auspices of Paul Andrew Davis from the College of California Davis, walnut oil, walnut fats and whole walnuts were administered for 18 weeks to mice inflicted with prostrate cancer (an equivalent amount of 2.6 ounces for humans). The results indicated a decrease in COX-2 mRNA which curtailed the prostrate cancer growth in the mice, as well as an increase in MSMB mRNa, a known tumor suppressor. Although research is ongoing, feel free to incorporate this healthy food source into your diet, within moderation.