Walnuts have higher antioxidant activity than any other common nut. This activity comes from vitamin E, melatonin and plant compounds called polyphenols, which are particularly high in the papery skin of walnuts. Walnuts are significantly higher in omega-3 fat than any other nut, providing 2.5 grams per 1-ounce (28-gram).

The polyphenols in walnuts can help fight this oxidative stress and inflammation. ALA omega-3 fat, magnesium and the amino acid arginine in walnuts may also decrease inflammation. Walnuts are linked to a lower risk of type 2 diabetes is that they help control weight.