Walnuts are the only tree nut that is an excellent source of alpha-linolenic acid (ALA), the plant-based omega-3 essential fatty acid. As one of the best plant food sources of omega-3s, a one-ounce serving of walnuts provides 2.5 grams of ALA.

There are three main omega-3 fatty acids: alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Omega-3s cannot be made in the body (therefore called essential), so they must come from food. EPA and DHA are found in fatty fish, including salmon, mackerel, and trout. ALA is found in plant-based foods, such as walnuts, flaxseed, soybean oil, and canola oil.

For more information, read Dietitian Kristin Kirkpatrick’s article on The Science Behind Plant-Based Omega-3 ALA.