Flaxseed oil is well known as one of the best sources of the essential fatty acids. It contains approximately 50-60% of the omega-3 essential fatty acid known as linolenic acid or alpha-linolenic acid and roughly 18-20% of the omega-6 essential fatty acid known as linoleic acid. Although flaxseed oil contains ample amounts of both essential fatty acids, its true importance is due to the fact that it is nature’s richest source of linolenic acid, which is frequently deficient in American diets. The essential fatty acids have several important functions. They are a necessary component of cell walls and cellular membranes throughout the body, they play an important role in energy production, and they regulate the metabolism of cholesterol and triglycerides. The essential fatty acids are also the precursors for the prostaglandins, which are hormone-like compounds that control a great deal of the biochemical activity within the body. Consequently, the essential fatty acids play a role in a wide range of health conditions.

Unfortunately, most Americans consume diets that contain too much of the omega-6 fatty acids along with a serious lack of omega-3 fatty acids. Since flaxseed oil is nature’s best source of the parent omega-3 fatty acid, linolenic acid, it has become a very important nutritional supplement.

Two forms of flaxseed oil are available. When natural components such as lignans and other soluble and insoluble fibers have been removed, the resulting oil has a golden yellow color. However, many people prefer flaxseed oil with lignans because lignans are known to provide additional anti-cancer activity. (1) Flaxseed oil that retains the lignans and other fiber components has a dark "muddy" appearance. Since these substances tend to settle out, this form of flaxseed oil should be shaken well before using.

Dosage Info

Dosage Range

From 1 to 2 tablespoonsful daily.

Most Common Dosage

1 tablespoonful daily.

Dosage Forms

Oil, gelcaps, and seeds.

Adult RDI

None established

Adult ODA

None established

Active Forms

Flaxseed oil (filtered) and flaxseed oil (unfiltered)


The fats in flaxseed oil are absorbed from the small intestine in humans.

Toxicities & Precautions


Flaxseed oil contains unsaturated fatty acids, which are highly susceptible to rancidification, otherwise know as oxidation. This process generates free radicals, which can be very destructive. When flaxseed oil becomes rancid, it develops a sharp/bitter taste, which signifies that it should be discarded.

Flaxseed oil should be protected from heat, light, and oxygen because these conditions promote its oxidation.

Flaxseed oil should never be used for cooking and should be kept refrigerated after opening the bottle.

Individuals taking flaxseed oil should be encouraged to take adequate antioxidant nutrients, especially vitamin E.

Functions in the Body


The essential fatty acids in flaxseed oil are vital components of the phospholipids that are a major part of the architectural structure of cellular membranes throughout the body. (2)


The essential fatty acids are precursors in the production of prostaglandins, which are hormone-like regulatory chemicals that control a tremendous amount of biochemical activity in all cells of the body. (3)

Cholesterol Metabolism

The essential fatty acids are important regulators of cholesterol metabolism in the body. (4)

Clinical Applications

Cardiovascular Disease

Omega-3 fatty acids lower plasma triglycerides, reduce platelet aggregation, relax blood vessels, and lower blood pressure. (5)

Skin Conditions

Abnormalities in fatty acid metabolism found in people with problems such as psoriasis and eczema and therapy with omega-3 fatty acids is frequently beneficial. (6)


Epidemiological studies from various countries and in the United States suggest that decreased consumption of omega-3 fatty acids correlates with increasing rates of depression. (7)

Elevated Cholesterol

Dietary alpha-linolenic acid is reported to lower cholesterol levels in the blood and in liver tissues. (8) , (9) , (10)


Flaxseed oil supplementation in healthy humans reduces the production of inflammatory cytokines, which results in increased calcium absorption and increased bone density. (11)


In the Edinburgh Artery Study, individuals with strokes had significantly lower levels of alpha-linolenic in their red blood cell phospholipids, which suggests that supplementation with flaxseed oil could play a role in preventing strokes. (12)


Studies report that vegetarians have lower platelet and plasma concentrations of n-3 polyunsaturated fatty acids and increased platelet stickiness compared to omnivores. Supplementation with flaxseed oil increased the omega-3 fatty acid concentrations in the platelet phospholipids and plasma lipids of male vegetarian volunteers. (13)


Supplemental omega-3 resulted in a decrease in asthma attacks and a reduction in the use of medications. (14)

Immune Enhancement

When additional dietary linolenic acid is administered to healthy men, several different measurements of immune function improved. (15)


Children with Attention Deficit Hyperactivity Disorder (ADHD) have significantly lower concentrations of EPA and DHA compared to controls. (16)


Low levels of omega-3 fatty acids are associated with increased incidence of breast cancer, (17) prostate cancer, (18) and colon cancer. (19)


Supplementation with the longer-chain omega-3 fatty acids provides a slight lowering of blood pressure. Reductions range between 3 and 10 mm Hg for both systolic and diastolic pressures. (20)

Rheumatoid Arthritis

Patients in a year-long double-blind study who took 2.6 gm of omega-3 daily experienced significant global improvements and pain reduction, which allowed a corresponding reduction in the use of pain medication. (21)

Symptoms and Causes of Deficiency

Since flaxseed oil is not produced in the body, no flaxseed oil deficiency condition exists. However, the diets of many people do not provide optimal amounts of the essential fatty acids, which is a problem that can cause or contribute to a wide variety of health problems. In general, many health problems are associated with a deficiency of omega-3 fatty acids and an excess of omega-6 fatty acids. With a ratio of approximately 60% omega-3 to 20% omega-6, flaxseed oil is one of the best options available to help reverse the imbalance between omege-3 and omega-6 that is so common in the United States.

Dietary Sources

Flaxseed oil is contained in flaxseeds. However, eating flaxseeds does not provide adequate amounts of flaxseed oil. Generally flaxseed oil is purchased as a commercial product after manufacturers have safely extracted and bottled the oil.


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