Used interchangeably, linseed and flaxseed are both names for the seed of the flax plant. This seed is used in making linens, edible and non-edible oils, and as a dietary supplement. The scientific name for the flax plant is Linum usitatissimum.
Flax plants are 3–5 feet (0.9–1.2 m) tall, with slim stalks, topped with branched clusters of flowers. Flax itself consists of fibrous strands. Strands are about 12–30 (30–75 cm) inches long, and are usually white, gray, or buff colored. Flax fiber is used to make linen, a stronger, more durable fabric than cotton.
In ancient Greece and Rome, linseed and flaxseed were used as a source of food. Now, the seed has become less important in diets. Oils are one of the most popular uses of flaxseed now.
The seeds are 33–43 percent oil. If the oil is removed, the remaining seeds are often used in animal feeds. The oil itself is amber- or yellow-colored and thicker than most vegetable oils. A drying oil, linseed oil hardens if left in the air. It is often used to produce oil paints and inks, as well as in linoleum and varnish.
In addition to manufacturing purposes, the seeds of the flax plant are often sold for human consumption. Linseed and flaxseed can be found in seed form, as edible oils, or as dietary supplements. The seeds have antioxidant properties and also contain lignans. Lignans are basically plant estrogen, which evidence suggests help to fight cancer in humans.
Linseed and flaxseed also contain alpha-linolenic acid, an essential fatty acid. Essential acids are substances the human body must have to continue functioning but cannot produce on its own. Alpha-linolenic acid is an Omega-3 acid and can be found in other foods such as walnuts and canola oil.
As a type of unsaturated oil, linseed oil is very heart-healthy. Unsaturated oils are also preferred over the saturated varieties because they can lower bad cholesterol in a body. Linseed oil does not contain lignans, but many manufacturers will add them to their oils.
Although adding linseed to a diet can be helpful, many experts do not recommend using linseed and flaxseed dietary supplements. These supplements may claim to prevent cancer and heart disease, but these claims are an exaggeration. In fact, plant estrogens, like lignan, may have an adverse affect on the human body if consumed in high doses. People who wish to add flaxseed in any form in to their diets, should take care not to consume too much.