Flaxseed oil is a cooking oil derived from the seeds of the flax plant, known for being an excellent source of the omega-3 fatty acid called alpha-linolenic acid (ALA). It is used as a dietary supplement for heart health, to reduce inflammation, and is available in both liquid and capsule forms. However, unlike the whole seed, flaxseed oil lacks dietary fiber, and the body must convert ALA into other beneficial fatty acids (EPA and DHA) which is often an inefficient process.