Flax (Linum usitatissimum) is a plant native to the Mediterranean that has been used not only as a food, but also for its fibers, which can be woven into linen cloth for well over 5,000 years. In the 17th century, flax was first introduced and planted in Canada, the country that is currently a major producer of this extremely beneficial seed.

The major health benefits of flaxseeds centers around either their rich content of oil or fiber components known as lignans. Flaxseed oil contains nearly twice the level of omega-3 fatty acids as fish oils - although it is the smaller-chain alpha-linolenic acid rather than the longer-chain fats like EPA and DHA found in fish oils.

Flaxseeds are the most abundant sources of lignans. These components are fiber compounds that can bind to estrogen receptors and interfere with the cancer-promoting effects of estrogen on breast and prostate tissue. Lignans also increase the production of a compound known as sex hormone binding globulin, or SHBG. This protein regulates estrogen levels by helping to escort excess estrogen from the body.

Ground flaxseeds have also been shown to be helpful in improving blood lipid profiles.