Fresh Interest in a Forgotten Plant
Flax (Linum usitatissimum) is one of the world’s oldest cultivated plants. In times past, flax was grown for its oil-bearing seed and for its fiber. Linen cloth woven from flax has been found in ancient Egyptian tombs, while Jewish high priests of the Old Testament wore garments made from flax.
Records from early civilizations reveal that flax was also used internally as a mild laxative and for its soothing action on irritated mucous membranes. Flax was also applied to the skin as a poultice for the treatment of local inflammations and the relief of pain.
Flax is an annual plant that grows from 12 to 48 inches in height. Its sky-blue flowers bloom only during the morning hours. Flax is cultivated in both temperate and tropical regions throughout much of the world. Major commercial supplies of flax come from Argentina, Canada, North Africa, and Turkey.
Flaxseed, or linseed as it is called in some parts of the world, consists of the dried, ripe seeds of the fruit, a globular capsule about one quarter of an inch long. The flat, brown and glossy seeds contain up to 10 percent mucilage, as well as very high levels of linolenic acid (an omega-3 fat) and lignans, in addition to some protein.
Health Promoting Properties
Recently American consumers developed a real interest in the health-promoting properties of flaxseed and its oil. Flaxseed and the flour derived from flaxseed are increasingly being used in breads, cereals, and bakery products to provide a pleasant nutty flavor and to increase the nutritional and health benefits of the final product.
The present popularity of flax was spurred by the research findings that flax is a rich source of omega-3 fat. Clinical studies have shown that ground flax seed is useful for protection against cancer and for lowering the risk of heart disease in patients with elevated blood cholesterol levels. Flaxseed also has been reported to have glucose-reducing effects.
Blood Lipid Changes
Flaxseed has been shown to lower serum cholesterol levels in both subjects with normal blood lipid levels and in those with elevated lipid levels. Flaxseed lowers blood lipid levels because of its soluble fiber content and its very low saturated fat content. When 15 patients with elevated blood cholesterol levels were fed 15 grams ground flaxseed and three slices of flaxseed-containing bread daily for three months, the patients experienced about a 10 percent decrease in total cholesterol and LDL cholesterol levels as well as a substantial decrease in platelet clumping, while their HDL cholesterol and triglyceride levels did not significantly change.
Since defatted flaxseed can also produce a major drop in LDL cholesterol with a 70 percent reduction in athero-sclerosis in rabbits after only eight weeks, the cholesterol-lowering substance in flax is probably not the unsaturated fat. In another study 29 subjects with elevated blood cholesterol levels who consumed muffins made from partially defatted flaxseed experienced, on average, an 8 percent drop in their LDL cholesterol levels over three weeks, while their HDL cholesterol levels were unchanged. The regular use of flaxseed flour in one’s bakery products or morning cereal would appear to be useful in the control of high blood cholesterol levels.
Protection Against Breast Cancer
Animal studies have shown that flax added to the diet can significantly reduce the incidence of breast tumors and produce at least a 50 percent reduction in tumor size of chemically induced cancers. The number of tumors may be reduced by almost 40 percent in carcinogen-treated rats. The cancer-protective properties of flax are believed to result from their very high level of lignans.
Flaxseed is the richest known source of lignans, with 100 to 800 times the level of lignans found in other oil seeds, cereals, and legumes. Plant lignans are metabolized in the colon by bacterial fermen- tation. The lignan metabolites, which have a strong antioxidant activity, appear to be anticarcinogenic. They have structure similar to estrogens and can bind to estrogen receptors, thereby inhibiting the growth of breast cancer. Lignans may also produce positive effects in women with ovarian dysfunction.
Help for the Bowel
Today flaxseed is used as a mild laxative for chronic constipation and to relieve irritable bowel syndrome, diverticulitis, gastritis, and enteritis. Flaxseed is also used to correct bowel problems caused from the misuse and overuse of stimulant laxatives. The mucilaginous fiber in the seeds can absorb water in the colon, producing soft stools. Flaxseed fiber may also protect against colon cancer.
The use of flaxseed is considered safe. However, the use of large quantities of flax as a laxative with insufficient fluid intake can produce obstruction of the bowel. For gastritis and enteritis, the dose of coarsely ground meal is one tablespoon of whole seed with 150 milliliters of liquid, taken two to three times a day. A compress can be made from 30 to 50 grams (one to two ounces) of flax flour. German Commis-sion E suggests taking one to three tablespoons of whole or crushed flaxseed two to three times a day for chronic constipation. However, it is important that plenty of water be consumed with this remedy to avoid bowel obstruction.
Remember: Herbal products and dietary supplements can have pharmacological effects, may produce adverse reactions in some people, and could interact with over-the-counter and prescription medications you may take. Discuss with your physician your decision to use any herbal product. Anything mentioned in this article is not intended to diagnose, prescribe, or treat any ailment.
Winston J. Craig, Ph.D., R.D., is a professor of nutrition at Andrews University, Berrien Springs, Michigan.
