Used by the ancient Egyptians, flax was originally grown in the Mediterranean and Western Europe for industrial, nutritional, and medicinal uses. It is now found as both a cultivated and semi-wild plant throughout temperate and tropical regions.

Flax is a rich source of dietary fiber that can lower cholesterol levels. The oil in flaxseed (linseed) is medicinally important for cardiovascular conditions and cancer prevention. Linseed oil contains both omega-3 fatty acids and omega-6 fatty acids as well as plant nutrients such as phytoestrogens. Linoleic and alpha-linolenic acid are essential fatty acids that the body requires for normal cellular function.

Alpha-linolenic acid (ALA) is an omega-3 oil while linoleic acid is an omega-6 oil. Flaxseed oil is nature's richest storehouse of omega-3 fatty acids. The content of omega-3 oils in flaxseed is more than double the quantity in fish oils. Experts think that the high amount of unsaturated fatty acids in flaxseed oil significantly reduces the risk for atherosclerosis.

Flax is an annual plant that grows up to five feet in height. It flourishes in deep moist soils rich in sand, silt, and clay. Ideally, flax should be quickly grown and harvested. Its gray-green leaves and delicate cordial blue (or sometimes white) flowers make it easily recognizable. The plant flowers only in the morning. The spherical, pea-size fruit contain flat, shiny, brown seeds filled with linseed oil. Mucilage is obtained from the husks of the seeds. Both the oil and mucilage of linseed are used for a variety of health conditions. The fruits are threshed to loosen the seeds, and the seeds do not actually ripen until after the plant has been harvested.

• Flowers (fresh flowering plant)
• Seeds (flaxseed oil)

Mucilages (3% to 10%); cyanogenic glycosides 0.05% to 0.1% (linustatin and neolinustin); fatty oil (30% to 45%), includes linolenic acid (40% to 70%), linoleic acid (10% to 25%), oleic acid (13% to 30%); mono- and triglycerides, free sterols, sterol esters, hydrocarbons: proteins (25%), ballast (25%), lignans, phenylpropane derivatives.

Flaxseed is available as whole, bruised, or milled seeds. Linseed oil can be purchased in liquid form (to use in preparing food) or as soft gels for dietary supplementation. For optimal benefits, flaxseed oil should be added to foods (such as salad dressings) but not cooked or heated.

Traditional Actions: whole seed, crushed seed, seed oil: bulking laxative, anti-inflammatory, demulcent, antitussive, emollient, vulnerary and expectorant. Was also historically used for gonorrhea, dysentary, and diarrhea, although herbalists no longer use it for these conditions.

Internal conditions: whole or cracked seed preparations for chronic constipation, colon problems due to laxative abuse, irritable colon, diverticulitis, mucilage for gastritis and enteritis. Decoction used for cough and bronchial irritation, bladder or urinary tract inflammation.

External conditions: poultice for burns and scalds, local skin irritation, drawing poultices for local infections, pimples, boils, etc.

Clinical applications: elevated cholesterol and triglycerides; preventative for cardiovascular disease and cancer

Epidemiological studies suggest that omega-3 oils significantly reduce the risk of heart disease. Omega-3 fatty acids lower LDL cholesterol and triglyceride levels. They also block platelet over-aggregation, reduce blood pressure in persons with hypertension, and lower fibrinogen levels. Consequently, omega-3 oils are clinically beneficial for hypercholesterolemia, angina, hypertension, psoriasis, eczema, cancer, and autoimmune disorders such as rheumatoid arthritis and multiple sclerosis.

ALA, the main fatty acid in linseed, improves arterial function by increasing the strength, flexibility, and permeability of cell membranes. ALA offers greater protection against heart attacks than oleic acid (found in canola and olive oil). But in one study, ALA was not responsible for the anti-arteriosclerosis effect in Type II flaxseed. ALA comprises only 2% to 3% of the total oil in Type II flaxseed.

Linolenic acid is a biologic precursor of prostaglandins. Prostaglandins are hormone-like substances that influence serum cholesterol levels, red blood cell aggregation, and smooth muscle function. Omega-3 oils help prevent cancer, stroke, and heart attacks by mediating the actions of prostaglandins. In other research, linseed oil had antibacterial action. Both linolenic acid and hydrolyzed linseed oil blocked the growth of methicillin-resistant strains of Staphylococcus aureus.

Flaxseed is a rich source of lignans. Lignans are platelet-activating factor-receptor antagonists that have recently sparked medical interest because of their role in improving cardiovascular health. The lignans in linseed oil have both estrogenic and anti-estrogenic effects. Phytoestrogens in linseed are thought to favorably reduce certain symptoms of menopause while other lignans act as weak estrogen antagonists.

There is new evidence that anti-estrogenic activity as well as other mechanisms inhibit carcinogenesis at various stages of tumor development. ALA and other compounds in linseed oil are known to have anti-cancer activity, particularly during the initiation and promotional stages of carcinogenesis. Lignans also suppress colon tumor growth, and it appears that flaxseed has both short-term and long-term protective effects against colon cancer.

In one investigation, the lignans enterolactone and enterodiol reduced the number of tumors observed in test animals genetically prone to developing mammary tumors. In another study, mice with experimentally-induced melanoma had flaxseed added to their diets. Flaxseed reduced metastasis and suppressed the development of metastatic secondary tumors in the animals. These findings strongly support the use of flaxseed as a complementary nutritional therapy for preventing metastasis in cancer patients. However, it should be noted that the correlations between dietary flaxseed supplements and cancer inhibition at various stages of carcinogenesis have been inconsistent.

Recommended dosage:

• Flaxseed: 1 tbsp. whole or bruised (but not ground) seed with 150 ml liquid bid to tid times a day for gastritis and enteritis; 2 to 3 tbsp. bulk seeds taken with 10 times the amount of water as a bulk laxative
• Poultice: 100 g soaked in boiling water for 10 to 15 minutes, strained, placed in cheesecloth and applied
• Decoction: 15 g of whole seed simmered in 1 cup water for 10 to 15 minutes
• Flaxseed oil: 1 tbsp. daily

There are no side effects if flaxseed and linseed oil are taken within recommended therapeutic doses. However, large quantities of flaxseed consumed without sufficient fluid can cause ileus (constriction of the small intestine).

Contraindications include esophageal stricture, ileus, GI stricture, and acute intestinal inflammation. No contraindications for pregnant or lactating women.

No clinically significant interactions between flaxseed and conventional medications are known to have been reported in the literature to date, including the German Commission E monograph (Blumenthal 1998). Although clinical relevance is unknown, flaxseed may interfere with the absorption of certain medications; therefore, ingestion of flaxseed several hours before or after other herbs or medications may be warranted. Please see monograph on ALA for additional information regarding that active ingredient.

The U.S. FDA classifies flaxseed as a dietary supplement.

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