Flax seeds AKA linseed are small oil seeds that originated in the Middle East thousands of years ago. It has gained popularity as a health food due to their high content of heart-healthy omega-3 fats fiber and other unique plant compounds. Flax seeds AKA linseed are small oil seeds that originated in the Middle East thousands of years ago. It has gained popularity as a health food due to their high content of heart-healthy omega-3 fats fiber and other unique plant compounds.